This document describes a new method for detecting Staphylococcus bacteria using a specific volatile organic compound (VOC) produced by Staphylococcus called 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid (ATMAP). A simple colorimetric assay using methyl red as a pH indicator can specifically detect Staphylococcus by changing color from yellow to orange due to ATMAP production. The assay was tested on liquid cultures and plate cultures to detect various Staphylococcus and other bacterial strains, demonstrating 100% specificity and sensitivity. This new detection method could provide a low-cost and easy-to-use
Microbiological tests detect microorganisms or the host immune response to infection. They can identify infectious agents, provide information to guide antimicrobial therapy, and assess drug susceptibility. Test results must be interpreted carefully based on factors like specimen type, test characteristics, clinical findings, and communication between clinician and microbiologist. A variety of methods are used, including microscopy, culture, antigen and antibody detection, and nucleic acid amplification tests.
This document describes the development of a fluorescence-based assay called "ProteAl" to detect the volatile biomarker 2-methylbutanal produced by Proteus bacteria. Gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy were used to identify 2-methylbutanal in the headspace of Proteus cultures. A fluorescent dye, 5-dimethylaminonaphthalene-1-sulfonylhydrazine, was found to react specifically with 2-methylbutanal, producing a distinct green fluorescence. Testing of 95 bacterial strains showed the ProteAl assay can identify Proteus with 100% specificity and sensitivity, providing a simple method for rapid surveillance of this pathogen.
International Journal of Pharmaceutical Science Invention (IJPSI)inventionjournals
The document summarizes a study conducted over six months to identify common bacterial contaminants in a microbiology laboratory. Samples were collected from surfaces, air, hands, and clothing of laboratory personnel using culture methods and identified using biochemical and molecular tests. The most common contaminants isolated were Micrococcus (52.94% of cultures) and Bacillus subtilis (23.52% of cultures), primarily from surfaces and air, respectively. The study concludes that proper disinfection, sterilization, and personal hygiene are needed to reduce laboratory contaminants and prevent false positive culture reports and laboratory-acquired infections.
This document discusses accelerating rapid diagnostics using new detection methods. Traditional diagnostic workflows can take 2+ days but detecting pathogens faster could improve patient outcomes and reduce costs. LumiByte is developing new methods like MuScan for single-cell detection and Colony Tracker for monitoring microbial growth that can provide results in hours rather than days. Faster diagnostics are needed to combat antimicrobial resistance by improving treatment and reducing inappropriate antibiotic use.
Infectious diseases are clinically evident diseases that can be transmitted between individuals or species. They are caused by pathogenic microorganisms like bacteria, viruses, fungi, protozoa, or parasites. Laboratory diagnosis of infectious diseases involves direct or indirect methods. The direct method detects microorganisms or their components in patient specimens through microscopic examination, culture techniques, or non-culture methods. The indirect method detects antibodies against microorganisms in the patient's serum. Microscopic examination is often the first step and involves making stained or unstained smears to look for microorganisms. Culture techniques aim to isolate and identify microbes using various media, tests, and molecular methods. Non-culture techniques more rapidly detect specific antigens or gene sequences
The document discusses advances in diagnostic microbiology, including newer molecular techniques that are transforming the field. It notes that techniques like functional genomics, gene delivery, and transgenic animal models are helping address questions in infectious diseases. The text highlights how microbiology labs are evolving, with automation and standardized testing replacing older labor-intensive methods. Rapid identification of pathogens through techniques like MALDI-TOF mass spectrometry is emphasized as critical for improving patient outcomes in sepsis.
This document summarizes rapid detection methods for foodborne pathogen bacteria. It discusses how foodborne illnesses are a major public health problem and rapid detection of pathogens is needed. Several detection methods are outlined, including traditional culturing as well as newer techniques like PCR, real-time PCR, LAMP, and immunoassays. LAMP is highlighted as a new method that can rapidly detect pathogens under isothermal conditions. The document concludes that LAMP is a promising technique for pathogen detection due to its speed, simplicity and accuracy.
Microbiological tests detect microorganisms or the host immune response to infection. They can identify infectious agents, provide information to guide antimicrobial therapy, and assess drug susceptibility. Test results must be interpreted carefully based on factors like specimen type, test characteristics, clinical findings, and communication between clinician and microbiologist. A variety of methods are used, including microscopy, culture, antigen and antibody detection, and nucleic acid amplification tests.
This document describes the development of a fluorescence-based assay called "ProteAl" to detect the volatile biomarker 2-methylbutanal produced by Proteus bacteria. Gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy were used to identify 2-methylbutanal in the headspace of Proteus cultures. A fluorescent dye, 5-dimethylaminonaphthalene-1-sulfonylhydrazine, was found to react specifically with 2-methylbutanal, producing a distinct green fluorescence. Testing of 95 bacterial strains showed the ProteAl assay can identify Proteus with 100% specificity and sensitivity, providing a simple method for rapid surveillance of this pathogen.
International Journal of Pharmaceutical Science Invention (IJPSI)inventionjournals
The document summarizes a study conducted over six months to identify common bacterial contaminants in a microbiology laboratory. Samples were collected from surfaces, air, hands, and clothing of laboratory personnel using culture methods and identified using biochemical and molecular tests. The most common contaminants isolated were Micrococcus (52.94% of cultures) and Bacillus subtilis (23.52% of cultures), primarily from surfaces and air, respectively. The study concludes that proper disinfection, sterilization, and personal hygiene are needed to reduce laboratory contaminants and prevent false positive culture reports and laboratory-acquired infections.
This document discusses accelerating rapid diagnostics using new detection methods. Traditional diagnostic workflows can take 2+ days but detecting pathogens faster could improve patient outcomes and reduce costs. LumiByte is developing new methods like MuScan for single-cell detection and Colony Tracker for monitoring microbial growth that can provide results in hours rather than days. Faster diagnostics are needed to combat antimicrobial resistance by improving treatment and reducing inappropriate antibiotic use.
Infectious diseases are clinically evident diseases that can be transmitted between individuals or species. They are caused by pathogenic microorganisms like bacteria, viruses, fungi, protozoa, or parasites. Laboratory diagnosis of infectious diseases involves direct or indirect methods. The direct method detects microorganisms or their components in patient specimens through microscopic examination, culture techniques, or non-culture methods. The indirect method detects antibodies against microorganisms in the patient's serum. Microscopic examination is often the first step and involves making stained or unstained smears to look for microorganisms. Culture techniques aim to isolate and identify microbes using various media, tests, and molecular methods. Non-culture techniques more rapidly detect specific antigens or gene sequences
The document discusses advances in diagnostic microbiology, including newer molecular techniques that are transforming the field. It notes that techniques like functional genomics, gene delivery, and transgenic animal models are helping address questions in infectious diseases. The text highlights how microbiology labs are evolving, with automation and standardized testing replacing older labor-intensive methods. Rapid identification of pathogens through techniques like MALDI-TOF mass spectrometry is emphasized as critical for improving patient outcomes in sepsis.
This document summarizes rapid detection methods for foodborne pathogen bacteria. It discusses how foodborne illnesses are a major public health problem and rapid detection of pathogens is needed. Several detection methods are outlined, including traditional culturing as well as newer techniques like PCR, real-time PCR, LAMP, and immunoassays. LAMP is highlighted as a new method that can rapidly detect pathogens under isothermal conditions. The document concludes that LAMP is a promising technique for pathogen detection due to its speed, simplicity and accuracy.
Importance of real time pcr in diagnosis of infectious diseasesCentral Govt, India
1) Real time PCR provides a rapid, sensitive and specific method for diagnosis of infectious diseases compared to conventional methods. It can detect pathogens within 1 hour compared to days or months for cultures.
2) The document discusses various infectious diseases and the recommended tests for their diagnosis. Real time PCR is highlighted as the most effective method for diagnosis of diseases like tuberculosis, hepatitis B, hepatitis C and human papillomavirus.
3) Point-of-care testing using technologies like TrueNat provide portable, easy-to-use and low-cost real time PCR diagnostics that can be used even in remote locations.
The document discusses diagnostic microbiology and the role of the clinical microbiology laboratory. The key responsibilities of the laboratory include testing specimens to identify microorganisms causing illness, providing antimicrobial susceptibility results, and advising physicians. Important techniques used in diagnosis include microscopy, culture, antigen detection methods like ELISA, and molecular methods like PCR. Proper specimen collection, transport, and processing are essential for accurate diagnostic testing.
Isolation, Characterization, and Antibiotics Resistance Profile of Staphyloco...AdeyemiKayode2
This document summarizes a student's presentation on a project isolating, characterizing, and analyzing antibiotic resistance of Staphylococci bacteria from indoor air samples collected from student halls of residence at Obafemi Awolowo University, Nigeria. A total of 26 Staphylococci isolates were recovered from the air samples. Biochemical testing showed that 46% were DNase positive and 54% were DNase negative. Antibiotic susceptibility testing found resistance rates of 0%, 15.4%, and 38.5% to Ciprofloxacin, Gentamicin, and Tetracycline respectively. The presentation concludes that air contamination poses a health risk and calls for improved hygiene and ventilation to reduce
The document describes a proposed research study to isolate and characterize bacteriophages that infect Klebsiella pneumoniae. Samples will be collected from Regent's Canal in London and screened against 6 strains of K. pneumoniae to identify lytic bacteriophages. Isolated bacteriophages will undergo restriction enzyme profiling, genome sequencing, and tests to determine burst size and growth behavior. The goal is to find bacteriophages that could potentially be used to treat K. pneumoniae infections.
detect and identify common human bacterial pathogens in high purity water.Saad Farooqi
A rapid culture independent methodology toquantitatively detect and identify common human bacterial pathogens associated with contaminated high purity water
This document provides an overview of the history and methods of microbial identification. It discusses how identification methods have evolved from using tubed and plated media in the 1960s to now using miniaturized biochemical reactions and system-dependent approaches comparing reaction patterns to databases. Modern rapid identification approaches include varying conventional testing, unique substrates that detect activity without growth, antigen-antibody reactions, and molecular detection methods. Specific techniques like colorimetry, fluorescence, and turbidity are used to detect metabolic activity. Rapid tests for identifying common bacteria like Staphylococcus aureus and Streptococcus pyogenes using agglutination, chromogenic media, DNA probes, PCR, and immunochromatographic assays are also overviewed.
1. Proper specimen collection is essential for accurate laboratory diagnosis of bacterial infections, as the wrong sample, delay in transport, or contamination can limit test usefulness.
2. Common examination methods for diagnosing bacterial infections include morphological analysis, isolation and culture of pathogens, biochemical reactions, antibiotic susceptibility testing, and detection of antigens or nucleic acids.
3. Antibiotic susceptibility testing determines the sensitivity of isolated bacteria to different antibiotics, which helps clinicians select the proper treatment. Methods include minimum inhibitory concentration and disk diffusion tests.
This document provides details of a study on screening, characterization, and antibiotic resistance testing of pathogens from various clinical specimens. Over 6,000 samples, including urine, blood, pus, sputum, and others, were collected and analyzed using microbiological techniques. Isolates were identified based on morphological and biochemical characteristics. Antibiotic susceptibility testing was performed using disk diffusion methods. Multiple drug-resistant organisms were detected. The study aimed to determine the prevalence and antibiotic resistance patterns of pathogens from different specimens to help guide treatment of infectious diseases.
The document discusses conventional microbiological techniques used in diagnostic microbiology laboratories. It describes how Robert Koch and Ronald Ross helped develop culturing pathogens and the discovery that specific microbes cause diseases. It also discusses how conventional techniques like growing bacteria in broth or on solid media, staining, and microscopy are still important today, but that molecular biology techniques may revolutionize disease diagnosis in the future. Gram staining remains one of the most rapid diagnostic methods for identifying bacteria in clinical specimens.
Microbiological tests of periodontal significanceMehul Shinde
This document discusses diagnostic microbiology techniques for periodontal infections. It covers specimen collection, transport, and various laboratory analysis methods including bacterial culturing, microscopic analysis, and molecular biology techniques. Specifically, it provides details on collecting a subgingival plaque sample for periodontal infections, transporting it anaerobically with minimal time, and analyzing it using methods like culturing, Gram stain, and molecular analysis to identify putative periodontal pathogens.
The document discusses clinical microbiology and the diagnosis of infectious diseases. It covers the following key points in 3 sentences:
Clinical specimens must be properly collected, transported, and processed to accurately diagnose infectious diseases. A variety of specimen types can be used to identify different types of bacterial, fungal, parasitic and viral infections. The clinical microbiology laboratory works to isolate, identify, and test pathogens from specimens to assist clinicians in diagnosing and treating infectious diseases.
This document describes a multicenter collaborative trial that validated two real-time PCR assays (GeneDisc arrays GD1 and GD2) for detecting Clostridium botulinum types C, D, C-D and D-C. The trial involved eight European laboratories testing the GeneDisc arrays on DNA from 33 C. botulinum isolates and 48 clinical samples. Results showed 99.4-100% concordance between laboratories. The assays demonstrated high reproducibility with low variability (1.1-7.1%). Given the high level of agreement, the GeneDisc PCR arrays were determined to be robust and suitable tools for rapid detection of C. botulinum types C, D and their mosaic variants. This was the first
The reliability of using vitek 2 compact system to detectAlexander Decker
The study aimed to determine the reliability of the Vitek 2 system for detecting extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates in Accra, Ghana. 400 E. coli and K. pneumoniae isolates were tested for ESBL phenotypes using the Vitek 2 system and combined disk synergy method. The Vitek 2 system detected 202 ESBL producers with a sensitivity of 98.5%, specificity of 98.9%, positive predictive value of 99% and negative predictive value of 98.5% compared to the reference combined disk synergy method. Therefore, the Vitek 2 system is a reliable method for the rapid and accurate
Doctors Data Inc A Revolution in the Evaluation of Gastrointestinal MicrofloraBonnieReynolds4
Recent research regarding the gastrointestinal microbiome has irrefutably confirmed the fact that the
microbial inhabitants of the gastrointestinal tract, and their astonishing scope of metabolic activities,
are at the very core of health and numerous disease processes. It is also clear that clinical microbiology
testing should be optimized to address the relative abundance of all bacterial species present in a stool
specimen.
Diagnostic Medical Microbiology - Traditional and Modern approachChhaya Sawant
Updated version of Diagnostic Microbiology - Traditional and Modern approach. The presentation is an overview of conventional techniques still used in many laboratories and new technologies such as Molecular- and Protein-based testing
A study of antibiotic resistance of Extended-Spectrum Beta-Lactamases produci...Premier Publishers
This study investigated antibiotic resistance of Extended-Spectrum Beta-Lactamases (ESBLs) producing Enterobacteriaceae isolated at the University Hospital of Befelatanana in Madagascar. The study found 73 ESBL producing isolates over 6 months, representing 6.3% of total bacteria cultured. The most common ESBL species were Klebsiella spp (34.2%), E. coli (32.9%), and Enterobacter spp (30.1%). All isolates were resistant to amoxicillin, amoxicillin-clavulanic acid, and 3rd generation cephalosporins. Resistance to other antibiotics ranged from 0% to over 75%. Patients under
Identification of bacteria and fungi in the solid waste generated in hospita...Dr. Gawad Alwabr
This study identified bacteria and fungi present in solid hospital waste in Sana'a, Yemen. Samples were collected from hospital wards, departments, and storage areas over 8 months. Testing identified the following microorganisms: Klebsiella spp., E. coli, Citrobacter spp., Candida spp., Proteus spp., Cladosporium werneckii spp., Bacillus spp., Aspergillus spp., Trichothecium spp., Mucor spp., and Acinetobacter spp. The types and amounts of microorganisms varied by season and location. This study confirms the presence of pathogenic bacteria and fungi in hospital solid waste that could spread infection
Methicillin-resistant Staphylococcus aureus (MRSA) infections have been recognized for decades as hospital acquired MRSA (HA-MRSA). Nowadays, MRSA is also recognized as a worldwide emerging community-associated pathogen. Community associated- MRSA (CA-MRSA) has been shown to be more virulent with a high degree of severity of disease when compared to HA-MRSA.
This document contains the curriculum vitae of Panagiotis Alexandros Paralis. It details his education in biomedical sciences from Oxford Brookes University in 2006. It then outlines his relevant work experience, including roles at Oxford University Hospitals from 2008-2013 where he gained experience in various laboratory roles and techniques. Most recently, he has worked as a biomedical scientist in diagnostic centres in Thessaloniki, Greece since 2015.
ABSTRACT- This study was an attempt to estimate the prevalence of Antimicrobial resistance in patients attending the OPD and IPD of IIMS&R, hospital, Lucknow. Total 453 urine samples were included in this study. Urinary isolates from symptomatic UTI cases were identified by conventional methods. Of the 453 processed samples 166 samples showed significant colony count of pathogens among which the most prevalent were E. coli (49.39%) followed by Klebsiella species (7.83%). The majority of the isolates were from female (68.67%) while the remaining was from male (31.32%). Dysuria was the most common clinical presentation followed by fever and abdominal pain. Diabetes and urogenital instrumentation were the major risk factors for UTI. Among the 166 urine samples which showed significant colony count, 152 (91.56%) of specimen showed pus cells in wet film examination. Among the gram-negative enteric bacilli high prevalence of resistance was observed against Ampicillin, Cefotaxime, Ciprofloxacin, Nalidixic acid and co-trimoxazole. 44% of isolates were detected to produce ESBL among the gram negative bacteria. Carbapenemase production was seen in 13 (11.71%) isolates. Among the 32 Enterococcus isolates 14 (43.75%) were resistant to High level Gentamicin, 2 (6.25%) were resistant to High level Streptomycin while 12 (37.50%) of isolates were resistant to both of the antimicrobial drugs. Among the 16 Staphylococcus species, 8 (50%) were MRSA.
KEYWORDS- MRSA, Antimicrobial resistance, UTI, ESBL, Gram-negative bacteria
Importance of real time pcr in diagnosis of infectious diseasesCentral Govt, India
1) Real time PCR provides a rapid, sensitive and specific method for diagnosis of infectious diseases compared to conventional methods. It can detect pathogens within 1 hour compared to days or months for cultures.
2) The document discusses various infectious diseases and the recommended tests for their diagnosis. Real time PCR is highlighted as the most effective method for diagnosis of diseases like tuberculosis, hepatitis B, hepatitis C and human papillomavirus.
3) Point-of-care testing using technologies like TrueNat provide portable, easy-to-use and low-cost real time PCR diagnostics that can be used even in remote locations.
The document discusses diagnostic microbiology and the role of the clinical microbiology laboratory. The key responsibilities of the laboratory include testing specimens to identify microorganisms causing illness, providing antimicrobial susceptibility results, and advising physicians. Important techniques used in diagnosis include microscopy, culture, antigen detection methods like ELISA, and molecular methods like PCR. Proper specimen collection, transport, and processing are essential for accurate diagnostic testing.
Isolation, Characterization, and Antibiotics Resistance Profile of Staphyloco...AdeyemiKayode2
This document summarizes a student's presentation on a project isolating, characterizing, and analyzing antibiotic resistance of Staphylococci bacteria from indoor air samples collected from student halls of residence at Obafemi Awolowo University, Nigeria. A total of 26 Staphylococci isolates were recovered from the air samples. Biochemical testing showed that 46% were DNase positive and 54% were DNase negative. Antibiotic susceptibility testing found resistance rates of 0%, 15.4%, and 38.5% to Ciprofloxacin, Gentamicin, and Tetracycline respectively. The presentation concludes that air contamination poses a health risk and calls for improved hygiene and ventilation to reduce
The document describes a proposed research study to isolate and characterize bacteriophages that infect Klebsiella pneumoniae. Samples will be collected from Regent's Canal in London and screened against 6 strains of K. pneumoniae to identify lytic bacteriophages. Isolated bacteriophages will undergo restriction enzyme profiling, genome sequencing, and tests to determine burst size and growth behavior. The goal is to find bacteriophages that could potentially be used to treat K. pneumoniae infections.
detect and identify common human bacterial pathogens in high purity water.Saad Farooqi
A rapid culture independent methodology toquantitatively detect and identify common human bacterial pathogens associated with contaminated high purity water
This document provides an overview of the history and methods of microbial identification. It discusses how identification methods have evolved from using tubed and plated media in the 1960s to now using miniaturized biochemical reactions and system-dependent approaches comparing reaction patterns to databases. Modern rapid identification approaches include varying conventional testing, unique substrates that detect activity without growth, antigen-antibody reactions, and molecular detection methods. Specific techniques like colorimetry, fluorescence, and turbidity are used to detect metabolic activity. Rapid tests for identifying common bacteria like Staphylococcus aureus and Streptococcus pyogenes using agglutination, chromogenic media, DNA probes, PCR, and immunochromatographic assays are also overviewed.
1. Proper specimen collection is essential for accurate laboratory diagnosis of bacterial infections, as the wrong sample, delay in transport, or contamination can limit test usefulness.
2. Common examination methods for diagnosing bacterial infections include morphological analysis, isolation and culture of pathogens, biochemical reactions, antibiotic susceptibility testing, and detection of antigens or nucleic acids.
3. Antibiotic susceptibility testing determines the sensitivity of isolated bacteria to different antibiotics, which helps clinicians select the proper treatment. Methods include minimum inhibitory concentration and disk diffusion tests.
This document provides details of a study on screening, characterization, and antibiotic resistance testing of pathogens from various clinical specimens. Over 6,000 samples, including urine, blood, pus, sputum, and others, were collected and analyzed using microbiological techniques. Isolates were identified based on morphological and biochemical characteristics. Antibiotic susceptibility testing was performed using disk diffusion methods. Multiple drug-resistant organisms were detected. The study aimed to determine the prevalence and antibiotic resistance patterns of pathogens from different specimens to help guide treatment of infectious diseases.
The document discusses conventional microbiological techniques used in diagnostic microbiology laboratories. It describes how Robert Koch and Ronald Ross helped develop culturing pathogens and the discovery that specific microbes cause diseases. It also discusses how conventional techniques like growing bacteria in broth or on solid media, staining, and microscopy are still important today, but that molecular biology techniques may revolutionize disease diagnosis in the future. Gram staining remains one of the most rapid diagnostic methods for identifying bacteria in clinical specimens.
Microbiological tests of periodontal significanceMehul Shinde
This document discusses diagnostic microbiology techniques for periodontal infections. It covers specimen collection, transport, and various laboratory analysis methods including bacterial culturing, microscopic analysis, and molecular biology techniques. Specifically, it provides details on collecting a subgingival plaque sample for periodontal infections, transporting it anaerobically with minimal time, and analyzing it using methods like culturing, Gram stain, and molecular analysis to identify putative periodontal pathogens.
The document discusses clinical microbiology and the diagnosis of infectious diseases. It covers the following key points in 3 sentences:
Clinical specimens must be properly collected, transported, and processed to accurately diagnose infectious diseases. A variety of specimen types can be used to identify different types of bacterial, fungal, parasitic and viral infections. The clinical microbiology laboratory works to isolate, identify, and test pathogens from specimens to assist clinicians in diagnosing and treating infectious diseases.
This document describes a multicenter collaborative trial that validated two real-time PCR assays (GeneDisc arrays GD1 and GD2) for detecting Clostridium botulinum types C, D, C-D and D-C. The trial involved eight European laboratories testing the GeneDisc arrays on DNA from 33 C. botulinum isolates and 48 clinical samples. Results showed 99.4-100% concordance between laboratories. The assays demonstrated high reproducibility with low variability (1.1-7.1%). Given the high level of agreement, the GeneDisc PCR arrays were determined to be robust and suitable tools for rapid detection of C. botulinum types C, D and their mosaic variants. This was the first
The reliability of using vitek 2 compact system to detectAlexander Decker
The study aimed to determine the reliability of the Vitek 2 system for detecting extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae isolates in Accra, Ghana. 400 E. coli and K. pneumoniae isolates were tested for ESBL phenotypes using the Vitek 2 system and combined disk synergy method. The Vitek 2 system detected 202 ESBL producers with a sensitivity of 98.5%, specificity of 98.9%, positive predictive value of 99% and negative predictive value of 98.5% compared to the reference combined disk synergy method. Therefore, the Vitek 2 system is a reliable method for the rapid and accurate
Doctors Data Inc A Revolution in the Evaluation of Gastrointestinal MicrofloraBonnieReynolds4
Recent research regarding the gastrointestinal microbiome has irrefutably confirmed the fact that the
microbial inhabitants of the gastrointestinal tract, and their astonishing scope of metabolic activities,
are at the very core of health and numerous disease processes. It is also clear that clinical microbiology
testing should be optimized to address the relative abundance of all bacterial species present in a stool
specimen.
Diagnostic Medical Microbiology - Traditional and Modern approachChhaya Sawant
Updated version of Diagnostic Microbiology - Traditional and Modern approach. The presentation is an overview of conventional techniques still used in many laboratories and new technologies such as Molecular- and Protein-based testing
A study of antibiotic resistance of Extended-Spectrum Beta-Lactamases produci...Premier Publishers
This study investigated antibiotic resistance of Extended-Spectrum Beta-Lactamases (ESBLs) producing Enterobacteriaceae isolated at the University Hospital of Befelatanana in Madagascar. The study found 73 ESBL producing isolates over 6 months, representing 6.3% of total bacteria cultured. The most common ESBL species were Klebsiella spp (34.2%), E. coli (32.9%), and Enterobacter spp (30.1%). All isolates were resistant to amoxicillin, amoxicillin-clavulanic acid, and 3rd generation cephalosporins. Resistance to other antibiotics ranged from 0% to over 75%. Patients under
Identification of bacteria and fungi in the solid waste generated in hospita...Dr. Gawad Alwabr
This study identified bacteria and fungi present in solid hospital waste in Sana'a, Yemen. Samples were collected from hospital wards, departments, and storage areas over 8 months. Testing identified the following microorganisms: Klebsiella spp., E. coli, Citrobacter spp., Candida spp., Proteus spp., Cladosporium werneckii spp., Bacillus spp., Aspergillus spp., Trichothecium spp., Mucor spp., and Acinetobacter spp. The types and amounts of microorganisms varied by season and location. This study confirms the presence of pathogenic bacteria and fungi in hospital solid waste that could spread infection
Methicillin-resistant Staphylococcus aureus (MRSA) infections have been recognized for decades as hospital acquired MRSA (HA-MRSA). Nowadays, MRSA is also recognized as a worldwide emerging community-associated pathogen. Community associated- MRSA (CA-MRSA) has been shown to be more virulent with a high degree of severity of disease when compared to HA-MRSA.
This document contains the curriculum vitae of Panagiotis Alexandros Paralis. It details his education in biomedical sciences from Oxford Brookes University in 2006. It then outlines his relevant work experience, including roles at Oxford University Hospitals from 2008-2013 where he gained experience in various laboratory roles and techniques. Most recently, he has worked as a biomedical scientist in diagnostic centres in Thessaloniki, Greece since 2015.
ABSTRACT- This study was an attempt to estimate the prevalence of Antimicrobial resistance in patients attending the OPD and IPD of IIMS&R, hospital, Lucknow. Total 453 urine samples were included in this study. Urinary isolates from symptomatic UTI cases were identified by conventional methods. Of the 453 processed samples 166 samples showed significant colony count of pathogens among which the most prevalent were E. coli (49.39%) followed by Klebsiella species (7.83%). The majority of the isolates were from female (68.67%) while the remaining was from male (31.32%). Dysuria was the most common clinical presentation followed by fever and abdominal pain. Diabetes and urogenital instrumentation were the major risk factors for UTI. Among the 166 urine samples which showed significant colony count, 152 (91.56%) of specimen showed pus cells in wet film examination. Among the gram-negative enteric bacilli high prevalence of resistance was observed against Ampicillin, Cefotaxime, Ciprofloxacin, Nalidixic acid and co-trimoxazole. 44% of isolates were detected to produce ESBL among the gram negative bacteria. Carbapenemase production was seen in 13 (11.71%) isolates. Among the 32 Enterococcus isolates 14 (43.75%) were resistant to High level Gentamicin, 2 (6.25%) were resistant to High level Streptomycin while 12 (37.50%) of isolates were resistant to both of the antimicrobial drugs. Among the 16 Staphylococcus species, 8 (50%) were MRSA.
KEYWORDS- MRSA, Antimicrobial resistance, UTI, ESBL, Gram-negative bacteria
The document introduces Hai Kang Life Corporation and its novel EFADchip technology for rapid point-of-care disease diagnosis. Some key points:
- Hai Kang Life is developing an electric field-assisted diagnostic chip (EFADchip) using nanotechnology for quick, affordable detection of infectious diseases and biomarkers.
- The EFADchip aims to revolutionize point-of-care applications by providing multiplex testing on a single low-cost, reusable cartridge without the need for fluorescence or sample tagging.
- Potential applications include screening for health threats like influenza, HIV, cancer markers; environmental monitoring of bacteria; and food/veterinary testing.
- Hai Kang Life's goal is
Staphylococcus aureusis a major hospital and community pathogen that is attributed to a wide variety of infections in humans and bio film production is one of the most important virulence factors of S. aureus that contributes to its multiple drug resistance. Therefore, searching for a valuable alternative to the used antibiotics is considered an important goal for study. For this reason one hundred and fifty different clinical samples were collected from various clinical sources and healthcare workers in Al-Imame in Al-Kadhimae in Medical City,Al-Numan Teaching Hospital, Medical City/Teaching laboratories and Central Child Teaching Hospital during the period from1/10/2020to 1/2/2021 in Baghdad City. Isolates were identified by conventional methods (cultural, microscopic and biochemical tests) in addition to the identification by the VITEK® 2Compact, and fifty isolates were recorded as Staphylococcus aureus.
DIAGNOSTICS - Diagnosis of TB - A Nanodiagnostic Approach.pdfsudeepbhattacharyya
The document discusses diagnosis of tuberculosis and highlights opportunities for nanotechnology-based diagnostic approaches. It summarizes several existing methods for TB diagnosis including microscopy, culture-based techniques, immunological methods, and molecular tests. However, current diagnostics have limitations such as low sensitivity, long turnaround time, and requirements for specialized equipment and facilities. The document proposes that nanodiagnostics utilizing nanoparticles, antigens, and antibodies may enable the development of improved point-of-care tests for more rapid, affordable and accurate TB detection.
The annual Research Poster Session at the conference features cutting-edge food safety research related to fresh and fresh-cut produce from researchers around the world. Posters will be on display during the conference and researchers will be available at their posters on June 21 from 2-4pm to discuss their research. The document then provides summaries of 4 research posters that will be presented on topics including the antimicrobial effects of haskap berry extracts on foodborne pathogens, using whole genome sequencing and genetic analysis to map contamination sources in produce packing facilities, developing alternative seed disinfection methods for sprouted vegetables, and developing methods to encapsulate ethylene to control fruit ripening.
This research article examines the ability of 5 nitric oxide donor compounds to disperse biofilms formed by Salmonella enterica and Escherichia coli O157:H7 on surfaces. The study found that all 5 nitric oxide donors were able to significantly disperse both pathogen biofilms, ranging from 35-80% dispersal. However, the degree of dispersal and optimal conditions varied between compounds and bacterial strains. In particular, molsidomine was effective at dispersing up to 50% of pre-formed Salmonella biofilm even at 4°C, suggesting potential use under refrigerated conditions. The study also identified a Salmonella genomic region that appears to be involved in the bacteria's response to nitric oxide signaling.
Microbiology is the study of
living organisms of microscopic
size which includes bacteria ,
Fungi , Algae , Protozoa and Viruses. It is concerned with the forms, structure , reproduction , physiology , metabolism and classification.
Principle Of Microbiology
Medical microbiology deals with the causative agent of the infectious disease of the human , the ways in which they produce disease in the body and essential information for diagnosis and treatment.
Microbiology presentation MEDICAL COLLEGEdmfrmicro
The document provides an overview of a laboratory presentation on medical microbiology. It discusses several key areas:
1. The introduction defines a laboratory and lists its main departments including clinical chemistry, hematology, microbiology, and blood bank.
2. Microbiology is defined as the study of microorganisms like bacteria, fungi, algae, protozoa and viruses. Medical microbiology deals with infectious disease causative agents.
3. The various fields of medical microbiology covered include bacteriology, virology, parasitology, mycology, and immunology. Common laboratory procedures in each field like microscopy, staining, culture and biochemical testing are summarized.
Antibiotic susceptibility pattern of bacteria isolated fromAlexander Decker
This document summarizes a study on the antibiotic susceptibility patterns of bacteria isolated from surgical wounds of patients at two hospitals in Owerri, Nigeria. A total of 146 bacterial isolates were obtained from 100 wound specimens collected. Staphylococcus species were the most predominant bacteria isolated, while Proteus vulgaris was the least occurring. The antibiotic susceptibility testing revealed that Pseudomonas aeruginosa was more sensitive to nitrofurantoin but most resistant to amoxicillin. P. vulgaris was most sensitive to amoxicillin and nalidixic acid. The study provides information on the antibiotic resistance patterns of bacteria isolated from surgical wounds that can help inform empiric antibiotic therapy.
A total number of 74 coagulase negative Staphylococci were isolated from orthopaedic patients in Ahmadu Bello University Teaching Hospital, Zaria, Nigeria. They were further characterized into various Staphylococci species using API STAPH identification kit: Staph xylosus (31.1%), Staph lentus (10.8%), Staph hominis (10.8%), Staph cohnii cohnii (5.4%), Staph epidermidis (4.1%) others were Staph cohnii ureal., Staph hyicus, Staph lugdunensis (2.7% each) Staph caprae , Staph capitis, Staph haemolyticus, Staph scuiri, Staph chromogenes and Staph warneri (1.4% each). Microcossus spp was 8.2% while 13.5% isolates were undetermined. Kirby Baurer disk method was used for the antibiotics susceptibility test, the result showed gentamicin and ciprofloxacin to be most active (96.6%), followed by vancomycin (93.1) and pefloxacin (87.9). The isolates were resistant to ampicillin (96.6), amoxicillin clavulanic acid (65.5%), clindamycin 41.4%). The aim of this study is to classify the coagulase negative Staphylococci isolates into species and to determine their antibiotic susceptibility
Nuhu et al_Poster NAPA2016 correction and observationNuhu Tanko
The study determined the prevalence and genetic profiles of ESBL-producing uropathogens among members of the Enterobacteriaceae family at Specialist Hospital Sokoto, Nigeria. A total of 64 Gram-negative uropathogens were isolated from 365 urine samples, with E. coli and Salmonella arizonae being most prevalent. The isolates showed high resistance to cotrimoxazole, nalidixic acid, ciprofloxacin and norfloxacin. 64.1% of isolates were multidrug resistant. ESBL production was detected in 23.4% of isolates. PCR analysis showed 73.3% of ESBL producers contained the blaCTX-M gene and 26.7
This document summarizes a study that analyzed 267 fecal samples from cattle, goats, and poultry in Botswana for the presence of Cryptococcus neoformans. A total of 72 samples (26.9%) tested positive for C. neoformans, mostly from cattle. The isolates were further analyzed to determine their mating type (MATα, MATa, or hybrids). Mating type analysis revealed the presence of all three types in the isolates from cattle, poultry, and goats, with MATα being most common. The results suggest that veterinary animals can act as reservoirs for C. neoformans and highlight the need to prevent transmission to at-risk human populations.
Antibiogram of Bacterial Isolates at Hail General Hospital, KSA June 1 – Dece...iosrjce
This research study focused on the antibiogram of bacterial isolates at Hail General Hospital,
Kingdom of Saudi Arabia. It sought to answer the following questions: (1) What is the percentage distribution of
the isolates on the specimens when classified according to the following bacteria? Enterobacter aerogenes,
Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus spp., Pseudomonas aeruginosa,
Raoultella (K.) ornithinolytica. (2) What is the antibiogram result of the bacterial isolates? Descriptive research
using content analysis was employed wherein the Automated Sensitivity Testing Machine data obtained from the
Microbiology section of Hail General Hospital. The statistical tools were frequency and percentage. The results
revealed that based on the percentage distribution of the specimens, the highest number of isolates for
Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae and Proteus spp. was from throat swab,
urine for Escherichia coli and Psedomonas aeruginosa, ward swab and high vaginal swab for Raoultella (K.)
ornithinolytica. On antibiogram result, the most sensitive antibiotics for Enterobacter aerogenes was
Meropenem; Cirpofloxacin and Levofloxacin for Enterobacter cloacae; Imipenem for Escherichia coli;
Amikacin for Klebsiella pneumoniae; Ertapenem, Imipenem and Pip/Tazo for Proteus spp.; Pip/Tazo for
Pseudomonas aeruginosa, and Imipenem for Raoultella (K.) ornithinolytica. The most resistant antibiotics for
Enterobacter aerogenes, Escherichia coli, Klebsiella pneumonaie and Raoultella (K.) ornithinolytica was
Ampicillin; Amox/K Clav, Cefazolin and Cefoxitin for Enterobacter cloacae; Cefotaxime for Pseudomonas
aeruginosa and for Proteus spp. was Cefazolin. The researchers recommend for the conduct of an annual
antibiogram study by institution, disseminate the information through seminars/fora especially to clinicians,
conduct another study to include other hospitals and other types of bacteria.
This document describes the production of Short Chain Variable Fragments (ScFv) that specifically bind to E. coli for use in detecting E. coli in water samples. Chickens were immunized with bacterial glycoconjugates to produce antibodies. RNA from the chickens was used to generate a ScFv gene library displayed on phages. ScFvs that bound strongly to E. coli were isolated through biopanning. The purified phage was used to produce soluble ScFv in E. coli for assessment of binding specificity to E. coli and Enterobacter cloacae via dot blot analysis. The ScFv showed strong binding to E. coli samples and negligible binding to E. cloacae, indicating potential for use
This study analyzed faecal specimens from 2,495 diarrhoea cases in Kolkata, India between 2007-2009 to determine the seasonal distribution and characteristics of norovirus (NoV) infections. NoV was detected in 78 cases, mostly children under 2 years old, sometimes as the sole pathogen but often along with other enteric pathogens. Sequencing of the NVGII strains showed clustering with GII.4, GII.13 and GII.6 NoV types. NoV infections occurred year-round and were associated with mild dehydration in children and adults in Kolkata.
This document summarizes a study on multidrug resistant organisms and their antibiotic resistance patterns among intensive care unit patients in Surat City, India. The study found that Pseudomonas aeruginosa and Klebsiella species were the most common causes of healthcare-associated infections. It also found high resistance of these organisms to cephalosporins but that amikacin and imipenem were the most effective antibiotics. Regular monitoring of resistance patterns was deemed important for guiding empirical treatment of infections in ICU patients.
PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF ESBL IN SOKOTO PDFNuhu Tanko
This study examined the prevalence and antimicrobial susceptibility of extended-spectrum beta-lactamase (ESBL)-producing gram-negative uropathogens in Sokoto, Nigeria. 365 urine samples were collected and analyzed between November 2014 and February 2015. Gram-negative uropathogens made up 60.9% of positive cultures. The most common isolates were E. coli (29.7%) and Salmonella arizonae (23.4%). 15 isolates (23.3%) were confirmed as ESBL producers, with E. coli and Enterobacter gergoviae being the most common. The isolates showed high resistance to cotrimoxazole but high susceptibility to nitrofurantoin. This study demonstrates
PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY OF ESBL IN SOKOTO PDF
saranya ppr
1. 1 23
Applied Microbiology and
Biotechnology
ISSN 0175-7598
Volume 99
Number 10
Appl Microbiol Biotechnol (2015)
99:4423-4433
DOI 10.1007/s00253-015-6573-6
Simple and specific colorimetric detection
of Staphylococcus using its volatile 2-[3-
acetoxy-4,4,14-trimethylandrost-8-en-17-
yl] propanoic acid in the liquid phase and
head space of cultures
Raju Saranya, Raju Aarthi & Krishnan
Sankaran
2. 1 23
Your article is protected by copyright and
all rights are held exclusively by Springer-
Verlag Berlin Heidelberg. This e-offprint is
for personal use only and shall not be self-
archived in electronic repositories. If you wish
to self-archive your article, please use the
accepted manuscript version for posting on
your own website. You may further deposit
the accepted manuscript version in any
repository, provided it is only made publicly
available 12 months after official publication
or later and provided acknowledgement is
given to the original source of publication
and a link is inserted to the published article
on Springer's website. The link must be
accompanied by the following text: "The final
publication is available at link.springer.com”.
3. METHODS AND PROTOCOLS
Simple and specific colorimetric detection of Staphylococcus
using its volatile 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl]
propanoic acid in the liquid phase and head space of cultures
Raju Saranya1
& Raju Aarthi1
& Krishnan Sankaran1
Received: 15 November 2014 /Revised: 13 March 2015 /Accepted: 24 March 2015 /Published online: 22 April 2015
# Springer-Verlag Berlin Heidelberg 2015
Abstract Spread of drug-resistant Staphylococcus spp. into
communities pose danger demanding effective non-invasive
and non-destructive tools for its early detection and surveil-
lance. Characteristic volatile organic compounds (VOCs) pro-
duced by bacteria offer new diagnostic targets and novel ap-
proaches not exploited so far in infectious disease diagnostics.
Our search for such characteristic VOC for Staphylococcus
spp. led to the depiction of 2-[3-acetoxy-4,4,14-
trimethylandrost-8-en-17-yl] propanoic acid (ATMAP), a
moderately volatile compound detected both in the culture
and headspace when the organism was grown in tryptone soya
broth (TSB) medium. A simple and inexpensive colorimetric
method (colour change from yellow to orange) using methyl
red as the pH indicator provided an absolutely specific way for
identifying Staphylococcus spp., The assay performed in liq-
uid cultures (7-h growth in TSB) as well as in the headspace of
plate cultures (grown for 10 h on TSA) was optimised in a 96-
well plate and 12-well plate formats, respectively, employing
a set of positive and negative strains. Only Staphylococcus
spp. showed the distinct colour change from yellow to orange
due to the production of the above VOC while in the case of
other organisms, the reagent remained yellow. The method
validated using known clinical and environmental strains (56
including Staphylococcus, Proteus, Pseudomonas, Klebsiella,
Bacillus, Shigella and Escherichia coli) was found to be
highly efficient showing 100 % specificity and sensitivity.
Such simple methods of bacterial pathogen identification are
expected to form the next generation tools for the control of
infectious diseases through early detection and surveillance of
causative agents.
Keywords Staphylococcus . Colorimetric . Methyl red .
Surveillance . Nosocomial infection
Introduction
Infectious diseases and their severity due to drug-resistant
pathogens are emerging threats to health care and economy
(Anne 2006). Emerging infectious diseases cause severe epi-
demics or pandemics with their wide spectrum of infections.
Hence, surveillance becomes essential as a measure to control
pathogens and prevent emergence of their resistance to potent
drugs. This is especially applicable for highly populated coun-
tries like India (Vincent Ki et al. 2008). The existing protocols
and instruments for field detection and identification of such
pathogens are low throughput, time-consuming and demand
technical skill to serve as effective surveillance tools
(Guernion et al. 2001).
Despite major advances in the medical arena,
Staphylococcus spp. (Kloos and Schleifer 1986) are a chal-
lenge for modern day medicine due to the complexity of dis-
ease process, presence and expression patterns of their respec-
tive virulence factors. Staphylococcal infections can range
from a minor boil or skin abscess to life-threatening infections
such as septicaemia or endocarditis. This bacterium is respon-
sible for invasive infections including bacteremia related to
intravenous catheters, pneumonia and ventriculitis or menin-
gitis in the neonate. Problematically, methicillin-resistant
Staphylococcus aureus (MRSA) has become a major cause
Electronic supplementary material The online version of this article
(doi:10.1007/s00253-015-6573-6) contains supplementary material,
which is available to authorized users.
* Krishnan Sankaran
ksankran@yahoo.com
1
Centre for Biotechnology, Anna University, Sardar Patel road,
Guindy, Chennai 600 025, India
Appl Microbiol Biotechnol (2015) 99:4423–4433
DOI 10.1007/s00253-015-6573-6
Author's personal copy
4. of hospital-acquired infections (Gomez et al. 2007). It is being
recognised with increasing frequency in community-acquired
infections, which is a dangerous trend. Therefore, develop-
ment of rapid and sensitive technique for early detection
(Marlowe and Bankowski 2011), screening, and preventive
surveillance of Staphylococcus spp. is very important for ef-
fective treatment.
Conventional methods of bacteriological testing
employing time-consuming microbiological culturing
and bacterial isolation are the reasons why alternative
detection and identification technologies are needed
(Velusamy et al. 2010). Modern and sophisticated
methods are not found favourable for clinical diagnosis
due to either high cost, or being laborious or requiring
special skills (Kohne et al. 1984). Recent developments
in biosensors (sensitivity panels, arrays, electronic nose)
provide rapid detection but these sensors are not devel-
oped for pathogen detection (Prakash and Saxena 2013).
These limitations and the necessity for constant surveil-
lance prompted us to develop an appropriate methodol-
ogy to detect Staphylococcus spp. (Kelechi et al. 2011).
Volatile organic compounds (VOCs) released by bac-
teria are either unique or characteristic under certain
experimental growth conditions (Senecal et al. 2002).
In recent years, VOCs raise a growing interest since
they are measurable through non-invasive and non-
destructive methods that can be used for early diagnos-
tics and continuous surveillance. Though bacterial
VOCs include carbonyl compounds, carboxylic acids,
amines, amides and sulphur compounds, only specific
subset is released by particular bacteria under specified
growth conditions. In other words, VOC signature or
biomarkers VOC are distinct possibilities remaining un-
exploited (Carey et al. 2011). Specific release of VOC
in appropriate growth conditions is the novel approach
taken in this study. However, we have used this novel
approach to develop rapid detection of Staphylococcus.
Identification of the VOCs released from in vitro bac-
terial cultures is performed in the laboratories using gas
chromatography (GC) (Boots et al. 2014), GC coupled
with mass spectrometry (Tait et al. 2013), proton-transfer
reaction mass spectrometry (Bunge et al. 2008), and se-
lected ion flow tube coupled with mass spectrometry
(Allardyce et al. 2006). These methods fail and are not
suitable for clinical practice or environmental testing for
obvious reasons, thus failing in effective surveillance.
Adapting simpler colorimetric methods employing re-
agents like acid-base indicators provides a cost-effective and
high-throughput detection method and inexpensive diagnostic
tool for effective surveillance. Therefore, after designing con-
ditions for specific release of a carboxylic compound, we have
developed a rapid and inexpensive colorimetric assay for de-
tecting Staphylococcus species.
Our laboratory investigations of waste dump sites (includ-
ing hospital wastes) clearly showed the predominance of
Staphylococcus. Therefore, we chose to study this organism
for VOC-based detection, in line with what was developed for
Proteus (Aarthi et al. 2014), but focusing on colorimetric for
better field deployment.
Materials and methods
Collection and identification of strains
Standard strains Strains of Salmonella paratyphi (MTCC
3220); Salmonella enterica sub spp. (MTCC 3231);
Salmonella typhimurium (MTCC 3224); Escherichia coli
(MTCC 568, MTCC 901, MTCC 723, MTCC 443);
Staphylococcus aureus (MTCC 3160, MTCC 6908);
Staphylococcus epidermidis (MTCC 435); Staphylococcus
chromogenes (MTCC 6153); Klebsiella pneumoniae
(MTCC 2653, MTCC 661); Proteus mirabilis (MTCC 1429,
MTCC 425); Proteus vulgaris (MTCC 1771); Staphylococcus
haemolyticus (MTCC 8924); Klebsiella oxytoca (MTCC
2275); Pseudomonas aerunginosa (MTCC 424, MTCC
1934); Shigella flexneri (MTCC 1457, MTCC 9543);
Streptococcus pneumoniae (MTCC 655); Streptococcus
thermorphilus (MTCC 1938); Listeria monocytogenes
(MTCC 839, MTCC 1143); Enterobacter aerogenes
(MTCC 111); Lactobacillus fermentum (MTCC 903);
Lactobacillus acidophilus (MTCC 447); Bacillus subtilis
(MTCC 1790) and Streptococcus pyogenes (MTCC 1927)
were obtained from Microbial Type Culture Collection
(MTCC), Chandigarh, India. Escherichia coli (ATCC
25922), Bacillus cereus (ATCC 21769), Staphylococcus
aureus (ATCC 25923), Shigella flexneri (ATCC 29508),
Proteus mirabilis (ATCC 29906),Proteus vulgaris (ATCC
6380), Klebsiella pneumoniae (ATCC 13883) and
Pseudomonas aerunginosa (MTCC-27853) were obtained
from Sri Ramachandra University, Chennai, Tamil Nadu,
India.
Clinical isolates Clinical diarrheagenic Escherichia coli
(EPEC) strains were isolated from stool samples of
children, who were hospitalised with acute or persistent
diarrhoea at the Institute of Child Health (IHC) and
Hospital for Children (HC), Chennai, Tamil Nadu,
India. Salmonella typhimurium strain was obtained
from Sri Ramachandra University, Chennai, and
uropathogens such as uropathogenic Escherichia coli
(UPEC), Klebsiella, Proteus, Pseudomonas aeruginosa,
Citrobacter and Staphylococcus aureus were obtained
from M/s Trivitron Healthcare Ltd., Chennai, Tamil
Nadu, India.
4424 Appl Microbiol Biotechnol (2015) 99:4423–4433
Author's personal copy
5. Environmental samples Escherichia coli, Pseudomonas
aerunginosa, Staphylococcus aureus, Proteus and Bacillus
were isolated from soil in different places including hospital
wastes. Environmental strains were collected from three dif-
ferent areas including Madipakkam (hospital waste),
Pallikaranai (domestic waste) and Taramani (laboratory
waste) located within 15 km from our laboratory. Around
10 g of soil samples were collected from each location by
digging the ground approximately 6 in.. From this, 1 g of
the soil was suspended in 10 ml of sterile distilled water and
was serially diluted and plated onto Luria-Bertani (LB) agar
plates. Colonies with different morphology (size, colour, tex-
ture etc.) visually were picked and identified by standard mi-
crobiological (colony morphology, gram staining and growth
on differential medium), and biochemical (methyl red/Voges-
Proskauer (MR/VP) test, urease, catalase, triple sugar iron,
phenylalanine deaminase test) tests.
Preparation of nutrient broth
Nutrient broth (NB) was prepared by dissolving 5 g of peptic
digest of animal tissue (HiMedia, India), 1.5 g of beef extract
(HiMedia, India), 1.5 g of yeast extract (HiMedia, India) and
5 g of NaCl (Merck, India) in 1 L of distilled water, after the
pH was adjusted to 7.3 with 1 M sodium hydroxide, the broth
was autoclaved at 15 lbs pressure for 20 min.
Preparation of Luria-Bertani broth
Luria-Bertani (LB) broth was prepared by dissolving 10 g of
tryptone (HiMedia, India), 5 g of yeast extract (HiMedia,
India), and 10 g of NaCl (Merck, India) in 1 L of distilled
water, and the pH was adjusted to 7.2 with 1 M sodium hy-
droxide (HiMedia, India) and autoclaved at 121 °C and 15 lbs
pressure for 20 min.
Preparation of soya bean casein digest medium Soya bean
casein digest medium or tryptone soya broth (TSB) (HiMedia,
India) was prepared by dissolving 30 g of the powder in 1 L of
distilled water and the pH was adjusted to 7.25 with 1 M
sodium hydroxide (HiMedia, India) and autoclaved at
121 °C and 15 lbs pressure for 20 min.
Preparation of modified soya bean casein digest
agar Tryptone soya broth agar (TSA) was prepared by dis-
solving 30 g of soya bean casein digest medium or tryptone
soya broth (TSB) (HiMedia, India) with 2 % NaCl and 2 %
agar (HiMedia, India) in 1 L of distilled water and the pH was
adjusted to 7.25 with 1 M sodium hydroxide (HiMedia, India)
and autoclaved at 121 °C and 15 lbs pressure for 20 min.
Dye reagent specific for Staphylococcus The colorimetric
dye, methyl red (M/s Merck), was chosen for the study. The
dye was prepared by dissolving 0.01 g of 2-(N,N-Dimethyl-4-
aminophenyl)azobenzenecarboxylic acid (also called C.I.
Acid Red 2, commonly known as methyl red) in 100 ml of
distilled water. When the dye was directly added to the culture,
the distinct colour change from yellow to orange could be
visualised instantly. For testing, 50 μL of the dye was mixed
with 200 μL of sample in 96-well microtitre plate.
Standardisation of colorimetric assay To standardise, the
assay was performed after 7 h of growth of bacterial strains.
Absorbance was read at 462 nm using multiscan reader (mod-
el: Enspire, PerkinElmer, USA) and the same plate was im-
aged using a camera (Canon SX160 IS) for visualisation.
Extraction of volatile organic compounds (VOCs) from
culture To 1 ml of sterile TSB medium contained in 2-mL
centrifuge tube, 20 μL (105
cells) of each organism were in-
oculated separately. After incubation in a rotary shaker set at
37 °C and 120 rpm for 7 h, 1 mL of chloroform or dichloro-
methane (DCM) or ethyl acetate, was added and vortexed for
1 min to extract the VOCs. The solvent phase was collected
and analysed using GC-MS and FT-IR.
Comparison of Staphylococcus cultures in NB, LB
and TSB
The methyl red assay for detecting Staphylococcus spe-
cies was performed in NB, LB and TSB. Each well was
filled with 180 μL of medium and 20 μL of 105
cells
of the test strains were inoculated. The plate was incu-
bated at 37 °C and 100 rpm for 7 h in an orbital
shaker. The optical densities (600 nm) of bacterial cul-
tures were measured after 7 h using Multiscan reader
(Thermo, Finland) and then the methyl red assay was
performed by adding 50 μL of the 0.01 % dye solution.
The absorbance was measured at 462 nm immediately
using the plate reader and the plates were also imaged.
Similarly as mentioned above, DCM extract of
Staphylococcus cultures in NB, LB and TSB were pre-
pared. The solvent phase was collected and analysed
using gas chromatography (GC).
Purification of VOC from Staphylococcus
Dichloromethane fraction was purified by column chromatog-
raphy using chloroform/methanol (60:40) as eluent. It was
checked on thin layer chromatography (TLC) and showed a
single spot and also confirmed the compound of interest by
methyl red staining. Chromatographic developments were
carried out in a glass beaker. The percentage composition of
the solvent system was acetone/dichloromethane/ethanol
(6:60:10); 0.5 μL of TSB medium (negative control) and pu-
rified and crude samples of Staphylococcus extract culture
Appl Microbiol Biotechnol (2015) 99:4423–4433 4425
Author's personal copy
6. components reacted with methyl red (0.01 %) were spotted on
chromatogram and dried. The development of the chromato-
gram was allowed to proceed until the solvent had travelled 6–
7 cm beyond the starting line. The chromatogram of purified
and crude produced single spot.. The plates were removed
from the chamber and allowed to dry in air. Then, it was
subjected to gas chromatography-mass spectrometry (GC-
MS) analysis.
Gas chromatography-mass spectroscopy (GC-MS)
analysis An Agilent 6890 N GC system with Jeol
(Turbovac) mass selective detector was used for analysis of
all the extracts. GC separation was achieved using HP-5 ms
capillary columns (30 m×0.25 mm i.d., film thickness
0.25 μm) using Helium as a carrier gas. The GC system was
programmed in the following temperature mode: initial tem-
perature 60 °C, hold 1 min, linear ramp 10 °C per minute to
180 °C and then ramped at 4 °C per minute to 300 °C and held
for 15 min. The MS detection was carried out in full scan
mode, and used the mass-to-charge ratio (m/z) of 50–650 with
a cycle time of 2.28 scans s−1
and EI ionisation of 70 eV. The
ion source temperature was 230 °C with the interface temper-
ature of 180 °C. The event time and solvent cut time were
14.66 s and 1.5 min, respectively. Identification was based
on comparing the mass spectra of the chromatographic peaks
with those reported in the mass spectral library.
Fourier transform-infrared (FT-IR) analysis
The FT-IR vibrational spectra of the solvent extracts were read
using a Thermo Nicolet IR-100 spectrometer (make:
ThermoNicole Corporation, Madison). IR spectrum was re-
corded by introducing the sample into the IR path. The spec-
trum was taken from 450 to 4000 cm−1
with a resolution of
1 cm−1
.
Colorimetric assay for detection of Staphylococcus
species The methyl red assay for detecting the acidic com-
pound released by Staphylococcus species was performed in
a 96-well plate. Each well was filled with 180 μL of TSB
medium and 20 μL of 105
cells of the test strains were inoc-
ulated. The plate was incubated at 37 °C and 100 rpm for 7 h
in an orbital shaker. The optical densities (600 nm) of bacterial
cultures were measured after 7 h using Multiscan reader
(Thermo, Finland). The liquid culture had approximately 109
cells after 7 h growth and then the Methyl red assay was
performed by adding 50 μL of the 0.01 % dye solution. The
absorbance was measured at 462 nm immediately using the
plate reader and the plates were also imaged. To profile VOC
release with respect to time, the assay was performed every 1 h
of bacterial growth. A quantitative estimation of the VOC in
the culture at different time point (from the fourth hour) was
obtained using the standard graph.
Testing the volatility of the volatile metabolite
from culture
To check whether the target of the assay is a volatile acid released
by the bacteria, the assay plate was incubated open at room
temperature (≈27 °C), on ice, and 60 °C, assay was performed
every 15 min up to 2 h.
Laboratory validation
After optimising and testing the assay conditions, a set of 95
strains including 39 standard and 56 known clinical and envi-
ronmental strains representing frequently encountered patho-
gens (Table 1) were validated. The experiment was repeated
twice, and the absorbance is given in Table 1.
Headspace analysis of volatile organic compound
Bacteria were plated during log phase growth on tryptic soy agar.
Bacterial suspensions were prepared by inoculating 5 mL of
TSB with a single colony and allowing it to grow overnight.
From this, 10 μL of 105
cells of the culture was spread onto a
60-mm TSA Petri dish. The plate culture was a lawn after 10-h
incubation of 105
cells spread on the plate. A control (10 μL of
TSB without the bacterial inoculum) was included in parallel for
each experiment. Silica-coated discs (TLC, Merck) was inserted
into the lid of the Petri dish. The Petri dish was closed and
housed in an incubator at 37 °C for 10 h and after incubation,
5 μL of methyl red dye was added in silica-coated discs and the
change in colour was observed. The same was adapted in 12-
well plate with 1 ml of TSA for better field deployment.
Sensitivity and specificity calculation and the confidence
level
Sensitivity and specificity of the assay was calculated using
the formula, sensitivity=[a/(a+c)]×100 and specificity=[d/
(b+d)]×100, where a is true positive, b is false positive, c is
false negative and d is true negative (Abdul and Anthony
2008). When the growth (OD) of the strains was similar, the
99 % confidence for the positive (Staphylococcus) and nega-
tives were calculated using the formula.
X Æ 2:58 δ=
ffiffiffi
n
pÀ Á
where X is sample mean, δ is population standard deviation
and n is sample size (Jose 2009).
Results
Developing a colorimetric method based on VOC was our
aim. Staphylococcus spp. was our interest as it is a common
4426 Appl Microbiol Biotechnol (2015) 99:4423–4433
Author's personal copy
8. nosocomial as well as community pathogen. The results of the
study are given below.
Characterisation of the VOCs extracted
from Staphylococcus using GC-MS and FT-IR analysis
When the volatile compounds extracted from cell-free culture
supernatant in DCM were subjected to GC-MS analysis, among
the presence of various compounds, 2-[3-acetoxy-4,4,14-
trimethylandrost-8-en-17-yl] propanoic acid (ATMAP) was
found to be specific for Staphylococcus in comparison with the
other common pathogens like Pseudomonas, Proteus, Shigella,
Salmonella, and Escherichia coli employed in this study. The
mass spectra showing the gas chromatogram of Staphylococcus
having peaks at 14.3, 16.12, 17.72, 19.17 and 21.83 min is given
in Fig. 1a. Furthermore, when the mass spectrum at each Rt was
analysed, the fraction at 19.17 min showed a compound with an
ion mass of 355 (shown in Fig. 1b). Matching retention indices
and fragmentation pattern with the spectral library and from lit-
erature (Venkatachalam et al. 2013) indicated that the compound
could be ATMAP. Reconfirmation of the compound was done
after purification by GC-MS analysis shown in Fig. 2a. Its low
abundance, however, was well above the detection limit of the
colorimetric assay developed.
FT-IR analysis of the DCM-extracted sample
for functional group identification
The FT-IR spectra of extracts of Staphylococcus spp. grown in
TSB after eliminating DCM peaks are shown in Fig. 2b. In the
spectra the peak at 1646 cm−1
was characteristic of aryl–
COOH representing the presence of carboxylic acid group.
Another characteristic peak was also shown at 1373 cm−1
that
represents C–O stretching of acids. The two peaks at 1285 and
1048 cm−1
are attributed to the medium intensity –C–0
stretching indicating the presence of carbonyl functional
group. The absorption peak at 975 cm−1
represents a O–H
bending corresponding to an acid. The intense peak at
3407 cm−1
(O–H stretching) showed that there was an inter-
molecular hydrogen bonding of carboxylic acids at low
frequencies.
Comparison of Staphylococcus cultures in NB, LB
and TSB
The gas chromatogram of Staphylococcus extracts in NB, LB
and TSB is shown in Fig. 3. The comparative analysis of
chromatograms revealed the absence of 19 min peak in LB
and NB compared to TSB medium which confirms the release
of the characteristic compound under the desired conditions.
Detection of Staphylococcus by colorimetric method
Once the release of ATMAP by Staphylococcus spp. was
characterised, a simple colorimetric method for the detection of
the bacteria in cultures using methyl red was devised. The meth-
yl red changed its yellow colour at neutral pH to orange in
Staphylococcus spp. cultures presumably due to acidity caused
by the release of acidic compounds. The concomitant absorption
with peak at 462 nm was seen only for Staphylococcus and not
Fig. 1 GC analysis of DCM
extract from Staphylococcus
culture and the mass spectrum of
the material at retention time
19.17 min. a Gas chromatograms
of VOCs released by
Staphylococcus spp. in the DCM
extracts. b Mass spectrum of the
unique compound for
Staphylococcus spp. at 19.17 min.
The fragment peak at 73m/z is the
base peak showing 100 %
abundance and corresponding to
ATMAP
4428 Appl Microbiol Biotechnol (2015) 99:4423–4433
Author's personal copy
9. for 25 other pathogens tested. Figure 4a shows the spectral re-
sults of Staphylococcus and a few other common pathogens. For
the routine assay, optical measurement was set at 462 nm.
The volatile component released by Staphylococcus being
responsible for the acidity and detection in colorimetric
assay
The fact that the acidity of the medium as revealed by pH
measurement using pH metre, was predominantly due to the
presence of volatile molecule was evident from the distinct
colour change with methyl red. This could be seen after 1 or
2 h in samples maintained on ice but not in those at room
temperature and left at 60 °C, presumably due to evaporation,
as shown in Fig. 4c.
Screening of bacterial strains using colorimetric assay
The assay performed at various time points during 24 h of
growth after the inoculation of 105
cells, as shown in
Fig. 4b, revealed that colour change of methyl red was visu-
ally observed by 4 h and measured by 3 h. Under the assay
conditions, the colour intensity increased linearly up to 10 h
and plateaued after that. In case of lower inocula size, the time
of detection increased progressively. For inoculum containing
102
cells, corresponding to low abundance or early stage of
infection, visible and instrumental detection was possible after
7 and 6 h, respectively.
Since surveillance requires high-throughput method, the
assay was adapted to the standard 96-well microtitre plate
format and read using a colorimetric plate reader or im-
aged with a camera. The assay was found to be 100 %
sensitive and specific to Staphylococcus in laboratory val-
idation with known clinical and environmental bacterial
isolates. Figure 5 shows the laboratory validation results
of 39 standard strains and 56 samples of clinical and
environmental bacterial isolates consisting of common
pathogens like Escherichia coli, Proteus spp.,
Pseudomonas aeruginosa, Klebsiella spp., Enterobacter,
Citrobacter, Staphylococcus spp. and Salmonella spp. As
can be seen, the assay showed absolute specificity and
sensitivity for the genus Staphylococcus; only the 13
Staphylococcus strains were identified unequivocally
among 96 bacteria; 99 % confidence interval for sensitiv-
ity and specificity of all positives and negative samples
were between 0.941 and 1.039.
Headspace analysis for the volatile compound
for the detection of Staphylococcus
Since our main interest is to develop a remote assay
without getting into physical contact with the culture
Fig. 2 a Gas chromatogram of
Staphylococcus culture extract
after purification The inset figure
shows the chromatogram with a
single spot produced by purified
and crude samples. b FT-IR
spectra of Staphylococcus spp.
solvent extract
Appl Microbiol Biotechnol (2015) 99:4423–4433 4429
Author's personal copy
10. or the bacterium, we tested the applicability of the
method in the head space. The silica-coated discs when
placed in the inside of the lid and exposed to the head-
space of bacterial plate cultures, the silica adsorbed the
VOC including the propionic acid derivative. After 10-h
exposure, spotting of methyl red produced red coloured
spot only in the case of Staphylococcus and remained
yellow for other strains, thus indicating that headspace
detection for Staphylococcus is possible using this meth-
od. Since this is of great value in diagnostics, we have
adapted it to a 12-well format and the results for 12
different strains, including Staphylococcus are shown
in Fig. 6.
Discussion
Preventive control of infectious diseases is becoming a
necessity because of the increasing virulence and persis-
tence of the causative organisms like bacteria. The
daunting challenge of multi drug resistance, especially
when the prospect of developing new antibiotics is
bleak, makes the development of tools to prevent the
diseases imperative. In this regard, Staphylococcus in-
fections due to both community and hospital-acquired
strains are prime targets because of their high preva-
lence, quick spread, morbidity (Hospital statistics
2012), and mortality (Elixhauser and Steiner 2007).
Apart from their early identification, surveillance for
their presence and spread require techniques that are
quite simple, easy and inexpensive, non-destructive and
automated using instrumentation. The study described
here has addressed this lacuna by developing a simple
colorimetric method on the basis of a detailed molecular
study for the presence of extracellular VOC in the cul-
ture liquid and the headspace. Though the test involves
simply the addition of the pH indicator, methyl red, to
the culture or as a spot on the silica plate exposed to
the headspace, the absolute specificity and sensitivity
among 96 different strains belonging to 25 commonly
encountered pathogenic bacteria is remarkable.
Moreover, the results are unambiguous. The specificity
of VOC release with respect to the medium used for
culturing is an important factor in this test.
VOC secreted by bacteria under specific conditions
appear to be its finger print, which could be exploited
as promising targets for preventive diagnosis. In case of
Staphylococcus, we found ATMAP to be one such char-
acteristic volatile compound released as secondary me-
tabolite in response to growth in TSB medium but not
in LB or NB, as revealed by the GC analysis of DCM
extract. This is evident from the TLC and GC results
shown in Figs. 2 and 3, respectively. Among the com-
pounds in the DCM extract from Staphylococcus
Fig. 3 Comparison of gas chromatogram of Staphylococcus cultures
extract in NB (a), LB (b) and TSB (c) showing the absence of 19-min
peak on the GC traces. d Colorimetric assay on Staphylococcus cultures
in TSB, minimal NB and LB. The figure shows the distinct colour change
of Staphylococcus from yellow to orange in TSB unlike others
4430 Appl Microbiol Biotechnol (2015) 99:4423–4433
Author's personal copy
11. cultures, only one acid-positive spot corresponding to
the purified preparation of ATMAP could be seen in
TLC. Its release in millimolar concentration appears to
be the cause for reduction in pH (from 7.4 to 5.2), as
indicated by the pH measurement of the culture medium
(supplemental Table S1) and the neutral pH of the
DCM-extracted culture medium. Taking these evidences
collectively, the characterised volatile compound appears
to be responsible for the pH reduction.
The reason for this specificity is not clear now. It is mod-
erately volatile at 37 °C and hence, the test has to be carried
out immediately after growth or after immediate chilling for
the best and accurate results.
Though reports suggest a variety of dyes like 4-
pyrene methanol (Cubero-Herrera et al. 2006), dansyl
cadaverine (Lee et al. 1989), 1-pyrenyl diazomethane
(Nimura and Kinoshita 1988), and 4-bromomethyl-7-
methoxycoumarin (Dunges 1977) reagents specific for
carboxylic acids, bronsted acid-base dye and methyl
red, was found to be best suited for the method. This
is because the above reagents generally require aprotic
solvents, higher temperatures and prolonged heating for
derivatization, conditions not suitable for field-level
tests. Moreover, they are either expensive, require strin-
gent storage conditions, hazardous or require costlier
instrumentation and working skill.
The characterisation of ATMAP as the volatile organ-
ic molecule responsible for the acidity (we found that
the pH of the culture changed from 7.3±0.2 to 5.2±0.2
in grown culture at the time of detection) was interest-
ing from the point of view of the metabolism of the
organism. Though this secondary metabolite is produced
in sufficient quantities to change the pH of the medium
(weakly buffered) by about 2 units, there is not much
information on the anabolic biochemical pathway or the
importance of the metabolite.
Fig. 4 a Determination of absorption maximum for bacterial cultures of
Staphylococcus, Proteus and Salmonella after reaction with methyl red
dye. b Graph of the absorbance response for bacterial cultures using
methyl red assay performed every hour up to 24 h. c Absorbance
intensity of methyl red reaction with volatile acids in the
Staphylococcus cultures kept at room temperature (27 °C), 60 °C and
on ice (0 °C) reduces drastically as a function of temperature as well as
duration of storage indicating volatile nature
Appl Microbiol Biotechnol (2015) 99:4423–4433 4431
Author's personal copy
12. The test has been developed in a high-throughput mode
by performing in 96-well microtitre plate format for
liquid-based detection and moderately throughput for using
headspace. Though the results can be obtained visually,
for instrumentation including automation, the results of
the liquid assay can be readily obtained using microplate
reader, which are common in laboratories, or through im-
aging using a camera and image analysis software. In the
case of headspace assay, apart from visual judgement, it is
possible to use available optoelectronic devices like strip
Fig. 5 Validation of assay using
standard and clinical strains. The
performance of methyl red assay
using standard strains, clinical
isolates and environmental
samples as given in Table 1. The
Staphylococcus spp. were
distinguished among other
species by the characteristic
change in colour (orange) from
the medium blank and negatives,
all showing yellow colour
Fig. 6 Colour difference for
different bacterial strains resulting
from colorimetric assay exposure
to 12-well plate growing cultures
after 10 h
4432 Appl Microbiol Biotechnol (2015) 99:4423–4433
Author's personal copy
13. readers or even electronic noses that are being developed
to detect characteristic VOCs.
Acknowledgments We are grateful to Mr. Suresh Lingham, M/s
Trivitron Pvt Ltd. for clinical samples and Dr. Sridhar, Dept. of Microbi-
ology, Sri Ramachandra University, for providing standard bacterial cul-
tures. Our sincere thanks to P. Dineshkumar and S. Akshay for their
contribution to our study. We acknowledge the financial support from
Centre with Potential for Excellence in Environmental Science
(CPEES) of University Grants Commission. One of the authors, R Aarthi,
acknowledges CSIR for providing CSIR-SRF. We also express our
deepest gratitude to our family and friends.
Conflict of interest There is no conflict of interests among the authors
for submitting this article. This work was supported by the Centre with
Potential for Excellence in Environmental Science (CPEES) of
University Grants Commission, India. They have no involvements in
the study design; in the collection, analysis and interpretation of data; in
the writing of the article and in the decision to submit the article for
publication.
References
Aarthi R, Saranya R, Sankaran K (2014) 2-methylbutanal, a volatile bio-
marker, for non-invasive surveillance of Proteus. Appl Microbiol
Biotechnol 98(1):445–454
Abdul GL, Anthony M (2008) Clinical tests: sensitivity and specificity.
Contin Educ Anaesth Crit Care Pain 8:221–223
Allardyce RA, Hill AL, Murdoch DR (2006) The rapid evaluation of
bacterial growth and antibiotic susceptibility in blood cultures by
selected ion flow tube mass spectrometry. Diagn Microbiol Infect
Dis 55:255–261
Anne VG (2006) Patterns of antimicrobial susceptibility among bacterial
pathogens in South Africa. Monitoring susceptibility. CME 22(4):
189–192
Boots AW, Smolinska A, van Berkel JJBN, Fijten RRR, Stobberingh EE,
Boumans MLL, Moonen EJ, Wouters EFM, Dallinga JW, Van
Schooten FJ (2014) Identification of microorganisms based on head-
space analysis of volatile organic compounds by gas chromatogra-
phy–mass spectrometry, IOP Publishing Ltd. doi:10.1088/1752-
7155/8/2/027106
Bunge M, Araghipour N, Mikoviny T, Dunkl J, Schnitzhofer R, Hansel
A, Schinner F, Wisthaler A, Margesin R, Märk TD (2008) On-line
monitoring of microbial volatile metabolites by proton transfer
reaction-mass spectrometry. Appl Environ Microbiol 74:2179–2186
Carey JR, Suslick KS, Hulkower KI, Imlay JA, Imlay KRC (2011) Rapid
identification of bacteria with a disposable colorimetric sensing ar-
ray. J Am Chem Soc 133(19):7571–7576
Cubero-Herrera L, Guy RD, Ramaley L (2006) 1-Pyrenemethanol, a
useful fluorometric reagent for the detection and determination of
carboxylic acids in atmospheric samples. Instrum Sci Technol 34:
239–255
Dunges W (1977) 4-Bromomethyl-7-methoxycoumarin as a new fluores-
cence label for fatty acids. Anal Chem 49:442–445
Elixhauser A, Steiner C (2007) Infections with methicillin-resistant
Staphylococcus Aureus (MRSA) in U.S. Hospitals, 1993–2005,
Agency for Healthcare Research and Quality, Published on July
Eseonu KC, Middleton SD, Eseonu CC (2011) A retrospective study of
risk factors for poor outcomes in methicillin-resistant
Staphylococcus aureus (MRSA) infection in surgical patients. J
Orthop Surg Res 6(1):25
Gomez JE, Garcia-Vazquez R, Barios M, Canteras J, Ruiz V,
Barios JA, Valdes HM (2007) Predictors of mortality in pa-
tients with methicillin-resistant Staphylococcu aureus
(MRSA) bacteraemia: the role of empiric antibiotic therapy.
Eur J Clin Microbiol Infect Dis 26:239–245. doi:10.1007/
s10096-007-0272-x
Guernion N, Ratcliffe NM, Spencer-Phillips PT, Howe RA (2001)
Identifying bacteria in human urine: current practice and the poten-
tial for rapid, near-patient diagnosis by sensing volatile organic com-
pounds. Clin Chem Lab Med 39(10):893–906
Hospital statistics 2012–13 (2013) Staphylococcus aureus bacteraemia in
Australian public hospitals, Australian Institute of Health and
Welfare, ISBN 978-1-74249-525-5
Jose GR (2009) Statistical intervals: confidence, prediction, enclosure.
SAS Institute Inc., USA
Kloos WE, KH Schleifer (1986) Staphylococcus, Bergey’s manual of
systematic bacteriology 2:1013–1019
Kohne DE, Steigerwalt AG, Brenner DJ (1984) Nucleic acid probe spe-
cific for members of the genus Legionella, Legionella: Proceedings
of the 2nd
international symposium. Am Soc Microbiol: 107–108
Lee Y-M, Nakamura H, Nakajima T (1989) Fluorometric determination
of carboxylic acids by high performance liquid chromatography
after derivatization with monodansyl cadaverine. Anal Sci 5:681–
685
Marlowe EM, Bankowski MJ (2011) Conventional and molecular
methods for the detection of methicillin-resistant Staphylococcus
aureus. J Clin Microbiol 49(9):S53–S56. doi:10.1128/JCM.
00791-11
Nimura N, Kinoshita T (1988) 1-pyrenyldiazomethane as a fluorescent
labeling reagent for liquid chromatographic determination of car-
boxylic acids. Anal Chem 60:2067–2070
Prakash D, Saxena RS (2013) Distribution and antimicrobial susceptibil-
ity pattern of bacterial pathogens causing urinary tract infection in
urban community of Meerut City, India, ISRN Microbiol
Senecal AG, Magnone J, Yeomans W, Powers EM (2002) Rapid detec-
tion of pathogenic bacteria by volatile organic compound (VOC)
analysis, U.S. Army Soldier and Biological Chemical Command
(USA), Proc. SPIE 4575, Chemical and Biological Early Warning
Monitoring for Water, Food, and Ground 121: doi:10.1117/12.
456915.
Tait E, Perry JD, Stanforth SP, Dean JR (2013) Identification of volatile
organic compounds produced by bacteria using HS-SPME-GC –
MS, J Chromatogr Sci: 1–11. doi:10.1093/chromsci/bmt042
Velusamy V, Arshak K, Korostynska O, Oliwa K, Adley C, Catherine A
(2010) An overview of foodborne pathogen detection: In the per-
spective of biosensors. Biotechnol Adv 28(2):232–254. doi:10.
1016/j.biotechadv.2009.12.004
Venkatachalam M, Singaravelu G, Govindaraju K, Ahn JS (2013)
PTP 1B inhibitory action of a phytochemical propanoic acid,
2-(3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl). Curr Sci
105:828–831
Vincent Ki MD, Coleman Rotstein MD, FRCPC (2008) Bacterial skin
and soft tissue infections in adults: a review of their epidemiology,
pathogenesis, diagnosis, treatment and site of care. Can J Infect Dis
Med Microbiol 19(2):173–184
Appl Microbiol Biotechnol (2015) 99:4423–4433 4433
Author's personal copy