One of the most important functions of the clinical microbiology laboratory is the detection and characterization of organisms causing bloodstream infections
The laboratory detection of bacteremia and fungemia using blood cultures is one of the most
simple and commonly used investigations to establish the etiology of bloodstream infections.
Rapid, accurate identification of the bacteria or fungi causing bloodstream infections provides vital clinical information required to diagnose and treat sepsis.
The presentation summarises important methods and protocols of Clinical Microbiology. It may be useful to learners of Clinical microbiology at the undergraduate label. The presentation describes the procedures for collecting clinical samples, transport, and testing. It also describes the different methods of antimicrobial susceptibility testing and standards.
This document discusses methods for detecting Methicillin-Resistant Staphylococcus aureus (MRSA). MRSA is any strain of S. aureus that is resistant to beta-lactam antibiotics due to the mecA gene. Rapid detection of MRSA is important for optimal treatment and reducing costs. The document describes several screening methods, focusing on the oxacillin salt agar screening test which involves growing bacterial samples on agar containing oxacillin and 4% NaCl. Growth of more than one colony indicates oxacillin resistance and identifies the strain as MRSA.
MRSA is a type of staph bacteria that is resistant to certain antibiotics such as methicillin and penicillin. It can cause infections of the skin or other parts of the body. MRSA was first identified in the 1960s and has since emerged in both healthcare and community settings. Risk factors for MRSA infection include prior MRSA infection or colonization, exposure to healthcare settings, and underlying medical conditions. Laboratories test for MRSA resistance using methods such as cefoxitin disk screening and PCR detection of the mecA gene. Proper hand hygiene and infection control practices can help reduce the spread of MRSA.
Blood culturing is the most important test for detecting pathogens in the bloodstream. It involves collecting blood in specialized bottles that contain growth media for aerobic and anaerobic organisms. It is critical that the collection procedure is done aseptically. Newer automated systems can continuously monitor blood cultures and detect microbial growth within 24-48 hours, providing faster results than conventional methods. Rapid identification of pathogens in positive blood cultures is important for guiding appropriate treatment.
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.
The presentation summarises important methods and protocols of Clinical Microbiology. It may be useful to learners of Clinical microbiology at the undergraduate label. The presentation describes the procedures for collecting clinical samples, transport, and testing. It also describes the different methods of antimicrobial susceptibility testing and standards.
This document discusses methods for detecting Methicillin-Resistant Staphylococcus aureus (MRSA). MRSA is any strain of S. aureus that is resistant to beta-lactam antibiotics due to the mecA gene. Rapid detection of MRSA is important for optimal treatment and reducing costs. The document describes several screening methods, focusing on the oxacillin salt agar screening test which involves growing bacterial samples on agar containing oxacillin and 4% NaCl. Growth of more than one colony indicates oxacillin resistance and identifies the strain as MRSA.
MRSA is a type of staph bacteria that is resistant to certain antibiotics such as methicillin and penicillin. It can cause infections of the skin or other parts of the body. MRSA was first identified in the 1960s and has since emerged in both healthcare and community settings. Risk factors for MRSA infection include prior MRSA infection or colonization, exposure to healthcare settings, and underlying medical conditions. Laboratories test for MRSA resistance using methods such as cefoxitin disk screening and PCR detection of the mecA gene. Proper hand hygiene and infection control practices can help reduce the spread of MRSA.
Blood culturing is the most important test for detecting pathogens in the bloodstream. It involves collecting blood in specialized bottles that contain growth media for aerobic and anaerobic organisms. It is critical that the collection procedure is done aseptically. Newer automated systems can continuously monitor blood cultures and detect microbial growth within 24-48 hours, providing faster results than conventional methods. Rapid identification of pathogens in positive blood cultures is important for guiding appropriate treatment.
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.
Automated blood culture systems like BacT/ALERT and BACTEC provide continuous monitoring of blood culture specimens to more quickly detect pathogens. They work by monitoring changes in carbon dioxide or fluorescence levels that occur as pathogens metabolize nutrients in the culture bottles. This allows for earlier detection compared to conventional manual methods. Popular systems include BacT/ALERT, BACTEC, Vital, and VersaTREK systems. They have increased pathogen detection rates while reducing the hands-on time needed compared to older techniques.
This document discusses several major blood group systems including Lewis, I, P, MNSs, Kell, Kidd, Duffy, Lutheran, Bg, Sda, and Xg. It provides information on the antigens and genes involved in each system, the clinical significance of associated antibodies, and inheritance patterns. Some key points covered include that Lewis, I, and P antigens produce cold-reacting antibodies while Kell, Kidd, and Duffy produce warm-reacting antibodies. The MNSs, Kell, and Kidd systems can produce clinically significant antibodies implicated in hemolytic transfusion reactions and hemolytic disease of the newborn.
This example shows mixed field agglutination in the forward grouping. The causes could be a recent blood transfusion of group O cells or a bone marrow transplant. To resolve it, the tests should be repeated on a new sample or the cells washed and retested.
This document discusses the processing and examination of cerebrospinal fluid (CSF) samples in a medical laboratory to diagnose bacterial or fungal meningitis. It describes the procedures for receiving, labeling, logging, and rejecting CSF specimens. The document outlines microscopic examination and culture techniques for the first day of processing to look for pathogens, including making Gram stains of purulent CSF and culturing all CSF samples. It also provides information on possible bacterial, fungal, parasitic and viral causes of meningitis.
Epidemiological marker (serotyping and bacteriocin typing)Santosh Kumar Yadav
This document discusses various epidemiological marker typing methods used to differentiate bacterial strains, including serotyping, bacteriocin typing, and colicin typing. Serotyping is based on antigenic differences expressed on bacterial cell surfaces and has good reproducibility but poor discriminatory power. Bacteriocin typing examines bacteriocin production and susceptibility patterns to distinguish strains. It has fair reproducibility and discriminatory power but some strains are non-typeable. Colicin typing specifically examines colicin production in E. coli strains using a spot culture method with indicator strains. These typing methods can help epidemiological studies and hospital infection control.
Forward and reverse grouping by Negash AlaminNegash Alamin
This document describes the forward and reverse blood grouping method used to determine a patient's blood type. The method involves separating a patient's blood into plasma and red blood cell components, mixing them in test tubes with known antibodies and blood cells, and observing for agglutination to identify reactions. If agglutination occurs, the corresponding antibody has detected the patient's blood type antigen. This method allows determining a patient's ABO blood group but not other minor blood types. It is routinely used in medical labs to identify a patient's blood type for transfusion compatibility testing.
This document discusses various techniques for diagnosing malaria, including microscopy, immunological techniques, and molecular techniques. Microscopy techniques include thick and thin blood smears, which are the gold standard, and the quantative buffy coat test. Immunological techniques include indirect fluorescent antibody testing, enzyme-linked immunosorbent assay, and rapid diagnostic tests targeting antigens like HRP-2, plasmodium aldolase, and lactate dehydrogonase. Molecular techniques include polymerase chain reaction and other nucleic acid amplification techniques, which can detect malaria parasites with greater sensitivity than microscopy.
Collection, transport & storage of clinical specimensDolatsinh Zala
The document provides guidelines for safely collecting, transporting, and storing clinical specimens. It recommends using personal protective equipment like gloves and lab coats during collection. Specimens should be placed in leakproof containers and transported quickly in dedicated transport bags or autoclaved before disposal. For transport over long distances, specimens must be packaged in a triple container system with absorbent material to contain any leaks. Proper storage conditions are also outlined depending on the specific test or specimen type.
This document discusses the importance of blood cultures for diagnosing bloodborne pathogens and the need for optimal blood collection and culture methods. It outlines the current process for blood culture collection and identifies areas for improvement, including faster detection times and greater automation. New technologies like the BacT/AlerT 3D culture system aim to continuously monitor blood cultures and detect pathogens more quickly through non-invasive means.
41. laboratory diagnosis of common fungal diseasessulochan_lohani
The document discusses laboratory diagnosis of common fungal diseases. It provides data on clinical specimens submitted for fungal isolation from 2004-2006, with the most common being respiratory and body fluids. The most frequent fungal isolates were Candida albicans, C. tropicalis and C. parapsilosis. Methods for diagnosing mycoses include direct microscopic examination, culture techniques, biochemical tests and special tests. Common superficial cutaneous fungal infections affecting the skin, hair and nails are also described, along with their characteristic lesions, causative organisms and laboratory identification.
The document discusses evaluating the efficacy of the OraQuick rapid HIV test kit using oral fluid for HIV antibody detection in patients attending dental hospitals in India. The study found the OraQuick test to have a sensitivity and specificity of 100% compared to standard blood tests. It was found to be an effective and accurate screening tool for HIV detection using oral fluid. However, it could not distinguish between HIV-1 and HIV-2 antibodies. Further larger studies were recommended to introduce it as a routine screening procedure.
Nocardia are aerobic, gram-positive bacteria that are ubiquitous environmental saprophytes found in soil. They cause opportunistic infections in both immunocompromised and immunocompetent individuals. Nocardia infections can manifest as cutaneous disease, pulmonary disease, disseminated disease, or central nervous system infections such as brain abscesses. Diagnosis involves microscopic examination of samples showing branching filaments, culture growth on selective media, and molecular techniques such as PCR and 16S rRNA sequencing. Treatment involves prolonged courses of antibiotics such as trimethoprim-sulfamethoxazole or amikacin depending on the species.
The Widal test detects antibodies in patient serum that agglutinate Salmonella antigens, indicating a current or previous typhoid or paratyphoid infection. It involves mixing patient serum with Salmonella typhi O and H antigens and S. paratyphi A and B antigens. Agglutination within 1 minute is a positive result. A quantitative test determines the antibody titer. While useful, the Widal test has limitations as it can be negative early in infection or late after 4 weeks, and results need to be interpreted in light of local antibody levels, as false positives can occur due to prior vaccination or cross-reacting infections.
This document discusses gel card technology used in blood banking tests. It provides details on the history and development of gel cards, how they work, the types of tests they can be used for (including ABO typing, cross-matching, antibody screening), and their advantages over traditional tube-based methods such as improved sensitivity and reproducibility. Gel cards contain a gel matrix in microtubes that allows red blood cells to be separated based on agglutination during centrifugation, providing clear and standardized test results.
Cross-matching is a procedure performed prior to blood transfusion to check compatibility between donor blood and recipient blood. It involves testing donor red blood cells with recipient serum in a major cross-match, and testing recipient red blood cells with donor serum in a minor cross-match. The purposes of cross-matching are to detect any antibodies in the recipient that could react with antigens on donor red blood cells, as well as to check for errors in blood typing or sample collection. A positive result showing hemolysis or agglutination during the cross-match test would indicate blood incompatibility.
The document provides an overview of the department of histopathology and its various benches. It describes histopathology as the microscopic examination of tissue to study disease manifestations. The key benches mentioned are processing, gross sectioning, tissue processing, embedding, cutting, staining including H&E, immunohistochemistry, special stains, cytology, cytogenetics, and semen analysis. The roles of each bench are briefly outlined.
2021 laboratory diagnosis of infectious diseases dr.ihsan alsaimarydr.Ihsan alsaimary
2021 laboratory diagnosis of infectious diseases
dr. ihsan alsaimary
university of basrah - college of medicine- DEPARTMENT OF MICROBIOLOGY
POBOX 696 ASHAR
BASRAH 42001
IRAQ
The document provides guidelines for collecting and transporting various medical specimens for microbiological laboratory testing. It discusses appropriate collection, labeling, and transport methods for common specimens including blood, urine, sputum, swabs, stool, pus, and cerebrospinal fluid. Proper collection and rapid transport of adequate and correctly labeled samples are essential for successful laboratory investigations and accurate patient diagnosis and treatment.
An antibiogram is a summary of antimicrobial susceptibility testing results for a specific microorganism against a range of antimicrobial drugs. It provides the percentages of organisms tested that were susceptible to each drug. Antibiograms help clinicians select appropriate empirical antimicrobial treatment and allow healthcare facilities to monitor antimicrobial resistance trends over time. They have limitations as they do not show subtle resistance trends below thresholds or account for synergistic drug combinations.
Laboratory diagnosis of_infectious_diseasesShilpa k
This document summarizes the diagnostic cycle for infectious diseases and provides guidelines for collecting and transporting various specimen types, including blood, respiratory samples, urine, wounds, and stool. It describes the pre-analytical, analytical, and post-analytical phases of diagnosis and outlines optimal practices for collecting, transporting, and processing samples to accurately identify pathogens and inform treatment. Key steps include using appropriate collection methods and containers, maintaining sample integrity during transport, and rejecting samples that do not meet criteria.
The document discusses various microbiological methods used to examine clinical samples and diagnose microbial diseases. It covers bacterioscopic, bacteriological, serological, and express diagnosis techniques used to identify bacteria like Neisseria meningitidis, Streptococcus pneumoniae, and Mycobacterium tuberculosis from samples like blood, urine, and cerebrospinal fluid. It provides details on proper sample collection and the media and methods used to isolate, culture, and identify microbes from clinical specimens.
Introduction: Bloodstream infections (BSIs) are associated with a high mortality rate of 20%-50%. Blood culture is paramount to identify causative agents of BSIs to choose an appropriate antimicrobial therapy. Objectives: The present study was undertaken to analyze the various microorganisms causing BSIs and study their antimicrobial resistance patterns in a tertiary care hospital, Eastern India. Materials and Methods: A total of 239 blood specimens from clinically suspected cases of BSIs were studied for 6 months from July 2015 to December 2015. Blood specimens were incubated in BacT/ALERT ® 3D system (bioMerieux, Durham, NC, USA) a fully automated blood culture system for detection of aerobic growth. Identification and antimicrobial susceptibility testing were conducted on VITEK ® 2 (bioMerieux, Durham, NC, USA) as per Clinical Laboratory Standards Institute guidelines. Results: Out of 239 specimens, 41 (17.2%) yielded growth of different microorganisms. From these isolates, 20 (48.8%) were Gram-negative bacilli, 18 (43.9%) were Gram-positive cocci and rest 3 (7.3%) were yeasts. Among Gram-negative bacilli, Klebsiella pneumoniae sub spp. pneumoniae (70%) was most commonly isolated. Coagulase-negative staphylococci (88.9%) were the most common isolate among Gram-positive cocci. All three Candida spp. isolated were nonalbicans Candida (two Candida tropicalis and one Candida krusei). Gram-negative isolates were least resistant to tigecycline and colistin. All Gram-positive cocci were sensitive to linezolid. Conclusion: Monitoring of data regarding the prevalence of microorganisms and its resistance patterns would help in currently prescribing antimicrobial regimens and improving the infection control practices by formulating policies for empirical antimicrobial therapy.
Automated blood culture systems like BacT/ALERT and BACTEC provide continuous monitoring of blood culture specimens to more quickly detect pathogens. They work by monitoring changes in carbon dioxide or fluorescence levels that occur as pathogens metabolize nutrients in the culture bottles. This allows for earlier detection compared to conventional manual methods. Popular systems include BacT/ALERT, BACTEC, Vital, and VersaTREK systems. They have increased pathogen detection rates while reducing the hands-on time needed compared to older techniques.
This document discusses several major blood group systems including Lewis, I, P, MNSs, Kell, Kidd, Duffy, Lutheran, Bg, Sda, and Xg. It provides information on the antigens and genes involved in each system, the clinical significance of associated antibodies, and inheritance patterns. Some key points covered include that Lewis, I, and P antigens produce cold-reacting antibodies while Kell, Kidd, and Duffy produce warm-reacting antibodies. The MNSs, Kell, and Kidd systems can produce clinically significant antibodies implicated in hemolytic transfusion reactions and hemolytic disease of the newborn.
This example shows mixed field agglutination in the forward grouping. The causes could be a recent blood transfusion of group O cells or a bone marrow transplant. To resolve it, the tests should be repeated on a new sample or the cells washed and retested.
This document discusses the processing and examination of cerebrospinal fluid (CSF) samples in a medical laboratory to diagnose bacterial or fungal meningitis. It describes the procedures for receiving, labeling, logging, and rejecting CSF specimens. The document outlines microscopic examination and culture techniques for the first day of processing to look for pathogens, including making Gram stains of purulent CSF and culturing all CSF samples. It also provides information on possible bacterial, fungal, parasitic and viral causes of meningitis.
Epidemiological marker (serotyping and bacteriocin typing)Santosh Kumar Yadav
This document discusses various epidemiological marker typing methods used to differentiate bacterial strains, including serotyping, bacteriocin typing, and colicin typing. Serotyping is based on antigenic differences expressed on bacterial cell surfaces and has good reproducibility but poor discriminatory power. Bacteriocin typing examines bacteriocin production and susceptibility patterns to distinguish strains. It has fair reproducibility and discriminatory power but some strains are non-typeable. Colicin typing specifically examines colicin production in E. coli strains using a spot culture method with indicator strains. These typing methods can help epidemiological studies and hospital infection control.
Forward and reverse grouping by Negash AlaminNegash Alamin
This document describes the forward and reverse blood grouping method used to determine a patient's blood type. The method involves separating a patient's blood into plasma and red blood cell components, mixing them in test tubes with known antibodies and blood cells, and observing for agglutination to identify reactions. If agglutination occurs, the corresponding antibody has detected the patient's blood type antigen. This method allows determining a patient's ABO blood group but not other minor blood types. It is routinely used in medical labs to identify a patient's blood type for transfusion compatibility testing.
This document discusses various techniques for diagnosing malaria, including microscopy, immunological techniques, and molecular techniques. Microscopy techniques include thick and thin blood smears, which are the gold standard, and the quantative buffy coat test. Immunological techniques include indirect fluorescent antibody testing, enzyme-linked immunosorbent assay, and rapid diagnostic tests targeting antigens like HRP-2, plasmodium aldolase, and lactate dehydrogonase. Molecular techniques include polymerase chain reaction and other nucleic acid amplification techniques, which can detect malaria parasites with greater sensitivity than microscopy.
Collection, transport & storage of clinical specimensDolatsinh Zala
The document provides guidelines for safely collecting, transporting, and storing clinical specimens. It recommends using personal protective equipment like gloves and lab coats during collection. Specimens should be placed in leakproof containers and transported quickly in dedicated transport bags or autoclaved before disposal. For transport over long distances, specimens must be packaged in a triple container system with absorbent material to contain any leaks. Proper storage conditions are also outlined depending on the specific test or specimen type.
This document discusses the importance of blood cultures for diagnosing bloodborne pathogens and the need for optimal blood collection and culture methods. It outlines the current process for blood culture collection and identifies areas for improvement, including faster detection times and greater automation. New technologies like the BacT/AlerT 3D culture system aim to continuously monitor blood cultures and detect pathogens more quickly through non-invasive means.
41. laboratory diagnosis of common fungal diseasessulochan_lohani
The document discusses laboratory diagnosis of common fungal diseases. It provides data on clinical specimens submitted for fungal isolation from 2004-2006, with the most common being respiratory and body fluids. The most frequent fungal isolates were Candida albicans, C. tropicalis and C. parapsilosis. Methods for diagnosing mycoses include direct microscopic examination, culture techniques, biochemical tests and special tests. Common superficial cutaneous fungal infections affecting the skin, hair and nails are also described, along with their characteristic lesions, causative organisms and laboratory identification.
The document discusses evaluating the efficacy of the OraQuick rapid HIV test kit using oral fluid for HIV antibody detection in patients attending dental hospitals in India. The study found the OraQuick test to have a sensitivity and specificity of 100% compared to standard blood tests. It was found to be an effective and accurate screening tool for HIV detection using oral fluid. However, it could not distinguish between HIV-1 and HIV-2 antibodies. Further larger studies were recommended to introduce it as a routine screening procedure.
Nocardia are aerobic, gram-positive bacteria that are ubiquitous environmental saprophytes found in soil. They cause opportunistic infections in both immunocompromised and immunocompetent individuals. Nocardia infections can manifest as cutaneous disease, pulmonary disease, disseminated disease, or central nervous system infections such as brain abscesses. Diagnosis involves microscopic examination of samples showing branching filaments, culture growth on selective media, and molecular techniques such as PCR and 16S rRNA sequencing. Treatment involves prolonged courses of antibiotics such as trimethoprim-sulfamethoxazole or amikacin depending on the species.
The Widal test detects antibodies in patient serum that agglutinate Salmonella antigens, indicating a current or previous typhoid or paratyphoid infection. It involves mixing patient serum with Salmonella typhi O and H antigens and S. paratyphi A and B antigens. Agglutination within 1 minute is a positive result. A quantitative test determines the antibody titer. While useful, the Widal test has limitations as it can be negative early in infection or late after 4 weeks, and results need to be interpreted in light of local antibody levels, as false positives can occur due to prior vaccination or cross-reacting infections.
This document discusses gel card technology used in blood banking tests. It provides details on the history and development of gel cards, how they work, the types of tests they can be used for (including ABO typing, cross-matching, antibody screening), and their advantages over traditional tube-based methods such as improved sensitivity and reproducibility. Gel cards contain a gel matrix in microtubes that allows red blood cells to be separated based on agglutination during centrifugation, providing clear and standardized test results.
Cross-matching is a procedure performed prior to blood transfusion to check compatibility between donor blood and recipient blood. It involves testing donor red blood cells with recipient serum in a major cross-match, and testing recipient red blood cells with donor serum in a minor cross-match. The purposes of cross-matching are to detect any antibodies in the recipient that could react with antigens on donor red blood cells, as well as to check for errors in blood typing or sample collection. A positive result showing hemolysis or agglutination during the cross-match test would indicate blood incompatibility.
The document provides an overview of the department of histopathology and its various benches. It describes histopathology as the microscopic examination of tissue to study disease manifestations. The key benches mentioned are processing, gross sectioning, tissue processing, embedding, cutting, staining including H&E, immunohistochemistry, special stains, cytology, cytogenetics, and semen analysis. The roles of each bench are briefly outlined.
2021 laboratory diagnosis of infectious diseases dr.ihsan alsaimarydr.Ihsan alsaimary
2021 laboratory diagnosis of infectious diseases
dr. ihsan alsaimary
university of basrah - college of medicine- DEPARTMENT OF MICROBIOLOGY
POBOX 696 ASHAR
BASRAH 42001
IRAQ
The document provides guidelines for collecting and transporting various medical specimens for microbiological laboratory testing. It discusses appropriate collection, labeling, and transport methods for common specimens including blood, urine, sputum, swabs, stool, pus, and cerebrospinal fluid. Proper collection and rapid transport of adequate and correctly labeled samples are essential for successful laboratory investigations and accurate patient diagnosis and treatment.
An antibiogram is a summary of antimicrobial susceptibility testing results for a specific microorganism against a range of antimicrobial drugs. It provides the percentages of organisms tested that were susceptible to each drug. Antibiograms help clinicians select appropriate empirical antimicrobial treatment and allow healthcare facilities to monitor antimicrobial resistance trends over time. They have limitations as they do not show subtle resistance trends below thresholds or account for synergistic drug combinations.
Laboratory diagnosis of_infectious_diseasesShilpa k
This document summarizes the diagnostic cycle for infectious diseases and provides guidelines for collecting and transporting various specimen types, including blood, respiratory samples, urine, wounds, and stool. It describes the pre-analytical, analytical, and post-analytical phases of diagnosis and outlines optimal practices for collecting, transporting, and processing samples to accurately identify pathogens and inform treatment. Key steps include using appropriate collection methods and containers, maintaining sample integrity during transport, and rejecting samples that do not meet criteria.
The document discusses various microbiological methods used to examine clinical samples and diagnose microbial diseases. It covers bacterioscopic, bacteriological, serological, and express diagnosis techniques used to identify bacteria like Neisseria meningitidis, Streptococcus pneumoniae, and Mycobacterium tuberculosis from samples like blood, urine, and cerebrospinal fluid. It provides details on proper sample collection and the media and methods used to isolate, culture, and identify microbes from clinical specimens.
Introduction: Bloodstream infections (BSIs) are associated with a high mortality rate of 20%-50%. Blood culture is paramount to identify causative agents of BSIs to choose an appropriate antimicrobial therapy. Objectives: The present study was undertaken to analyze the various microorganisms causing BSIs and study their antimicrobial resistance patterns in a tertiary care hospital, Eastern India. Materials and Methods: A total of 239 blood specimens from clinically suspected cases of BSIs were studied for 6 months from July 2015 to December 2015. Blood specimens were incubated in BacT/ALERT ® 3D system (bioMerieux, Durham, NC, USA) a fully automated blood culture system for detection of aerobic growth. Identification and antimicrobial susceptibility testing were conducted on VITEK ® 2 (bioMerieux, Durham, NC, USA) as per Clinical Laboratory Standards Institute guidelines. Results: Out of 239 specimens, 41 (17.2%) yielded growth of different microorganisms. From these isolates, 20 (48.8%) were Gram-negative bacilli, 18 (43.9%) were Gram-positive cocci and rest 3 (7.3%) were yeasts. Among Gram-negative bacilli, Klebsiella pneumoniae sub spp. pneumoniae (70%) was most commonly isolated. Coagulase-negative staphylococci (88.9%) were the most common isolate among Gram-positive cocci. All three Candida spp. isolated were nonalbicans Candida (two Candida tropicalis and one Candida krusei). Gram-negative isolates were least resistant to tigecycline and colistin. All Gram-positive cocci were sensitive to linezolid. Conclusion: Monitoring of data regarding the prevalence of microorganisms and its resistance patterns would help in currently prescribing antimicrobial regimens and improving the infection control practices by formulating policies for empirical antimicrobial therapy.
The document discusses bloodstream infections, including the etiological agents, types, clinical manifestations, laboratory diagnosis, and fever of unknown origin. It defines various types of bloodstream infections such as bacteremia, septicemia, and fungemia. The document also outlines the diagnostic process for bloodstream infections including specimen collection, culture methods, identification, and antimicrobial susceptibility testing.
Outcome-of-Screening-Test-Performed-on-Volunteer-Blood-Donors-in-Chittagong-CityMorshedul Alam Sazzad
This study aimed to screen 1500 volunteer blood donors in Chittagong, Bangladesh for infectious diseases like hepatitis B, hepatitis C, HIV, malaria, and syphilis. Testing was conducted from January to September 2011 using standard methods. The results found 21 cases positive for hepatitis B (1.40%), 2 cases positive for HIV (0.13%), 2 cases positive for hepatitis C (0.13%), 7 cases positive for syphilis (0.46%), and 1 case positive for malaria (0.06%). The study demonstrates that screening of both voluntary and professional blood donors is important to ensure a safe blood supply and prevent transfusion-transmitted infections.
This document discusses blood cultures and bacteremia/septicemia. It describes how blood cultures can help diagnose pyrexia of unknown origin and reveal pathogens to guide antibiotic therapy. Positive blood cultures indicate bacteria or toxins in the bloodstream (bacteremia or septicemia, respectively). The document provides guidelines for collecting blood culture samples, including volume based on patient age, timing of collections, and techniques to avoid contamination. It also discusses culture methods, common pathogens, and interpreting positive and negative results.
Candidemia in HIV-positive patients in Dschang District Hospital (West Region...Claude Nangwat
Candidemia has been identified as a public health problem in HIV-infected patients. The evaluation of CD4 count, transaminases and blood glucose, are being used as a means to monitor the health of HIV-infected patients, without excluding the diagnosis of candidemia and other opportunistic infections. In order to contribute in improving the care of HIV-infected patients attending Dschang District Hospital and later on, in other hospitals in Cameroon, we conducted from June to September 2014 a cross-sectional study, with general objective; to determine the association between candidemia and selected biochemical and haematological parameter changes in HIV-infected patients, as a possible indicator in monitoring HIV disease progression.
To do this, blood samples were collected from HIV-infected patients assigned to the UPEC of Dschang District Hospital for follow up, and haemogram report, CD4 counts, ALAT level, ASAT level, and glucose level in blood were evaluated by cytometric and spectrophotometric assays. Candida species were isolated from some blood samples, and then identified using CHROMagar Candida culture medium. The broth microdilution method was afterwards used to test the susceptibility of the fungal isolates vis-a-vis three conventional antifungal agents.
Mycological analysis of blood samples showed that eight (08) patients had candidemia, a prevalence of 6.11%. Eight (08) isolates were obtained from these eight (08) candidemic HIV-infected patients; this consisted of 4(50%) Candida albicans, 3(37.5%) Candida parapsilosis and 1(12.5%) Candida glabrata. All these isolates were resistant (MICs ranged from 2 to >256 µg/mL) to the antifungals used, that is, ketoconazole, amphotericin B and nystatin.
A significant correlation was found between candidemia and white blood cell count, with a correlation coefficient of r = 0.240 (p < 0.05). Based on the results obtained, the systematic diagnosis of candidemia should be performed in patients infected with HIV in Cameroon in order to improve on their care.
Key words: Candidemia, HIV, biochemical parameters, hematological parameters, Antifungals activities.
BacCapSeq is a bacterial capture sequencing platform that uses probes targeting over 307 pathogenic bacterial species, antimicrobial resistance genes, and virulence factors to increase sensitivity of detection and characterization of bacteria from clinical samples. Compared to unbiased high-throughput sequencing, BacCapSeq yielded higher bacterial read counts, improved genome coverage, and was able to detect bacteria at lower concentrations in whole blood samples spiked with bacterial DNA or cells. When applied to positive blood cultures and samples from sepsis patients, BacCapSeq identified causative agents and antimicrobial resistance genes consistent with standard clinical tests.
This document outlines the diagnostic approach and laboratory tests for evaluating a patient presenting with pyrexia of unknown origin (PUO). It describes collecting relevant clinical history and performing a physical exam. Specimens including blood, urine, sputum, CSF and tissues may be obtained for bacterial, viral, parasitic and fungal cultures and stains. Tests like blood cultures, urine cultures, sputum smears and cultures, and CSF analysis can help identify potential infectious causes. Serology, skin tests, hematology, immunology and biopsy may also provide diagnostic clues. Empiric antibiotic therapy is guided by risk factors and test results.
Study of Some Serological Markers (Hbs Ag, Anti-Hbs and AntHbc Igm) for Detec...IOSRJPBS
The present study was conducted in Diyala province for the period from15/ 1 / 2016 to 15 / 12/ 2016, In the Central Blood Bank in the public Health Laboratory in Diyala. The aim of the study was to detection the rate of Occult Hepatitis B virus infection among blood donors using ELISA test to screening different serological markers (HBs Ag, anti- HBs and anti- HBc IgM). The study included; 200 apparently healthy blood donors were attended central blood bank in Diyala. 183of blood donors were males and 17 were females. The age range was 18 years to 58 years. The results showed that the rate of HBs Ag among blood donors (4.5%), and the rate of anti-HBs was (10%), while the rate of anti-HBc IgM was (4%). The present results revealed that the rate of anti-HBs was (9.4%) among HBs Ag negative blood donors, and the anti-HBc IgM (4.1%).While the rate of positive serological markers was 13.6%. The present study showed that there was relationship between the HBs Ag positivity rate and anti-HBs against anti-HBc IgM do not have
A novel coronavirus from patients with pneumonia in china, 2019Juan Rubio
- In late December 2019, a cluster of patients with pneumonia of unknown cause was linked to a seafood market in Wuhan, China. Through testing samples from these patients, a novel coronavirus was discovered and named 2019-nCoV.
- Using samples from the pneumonia patients, researchers were able to isolate and culture the novel coronavirus (2019-nCoV) using human airway epithelial cells. Electron microscopy of the cultured cells showed coronavirus particles.
- Genomic sequencing of samples from the patients identified the virus as a new strain of coronavirus within the subgenus sarbecovirus, most closely related to SARS-CoV and MERS-CoV but distinct from them.
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
Infective endocarditis is a life-threatening disease caused by bacterial infection of the endothelium and cardiac valves, either native or prosthetic. In the present work the role of the new microbiological techniques (techniques of detection and amplification of the subunit 16 ribosomal sRNA by means of the chain reaction of the polymerase in blood or tissue, fluorescent in situ hybridization, and matrix-assisted laser is reviewed desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) in the diagnosis of infective endocarditis.
Blood stream infections- clinical microbiologySijo A
Blood stream infections (BSI) refers to the presence of organisms in blood which are threat to every organ in the body.
It causes shock, multiple organ failure and DIC (Disseminated Intravascular Coagulation).
The presence of bacteria in blood is called Bacteremia.
The bacteria circulate and actively multiply in the blood stream is called Septicemia.
The presence of virus in blood is called Viremia.
The presence of parasite in blood is called Parasitemia.
The presence of fungi in blood is called Fungemia.
Sepsis is a life-threatening condition that arises from the body's response to infection. It can cause tissue damage and organ failure. Signs of sepsis include fever, rapid breathing and heart rate, low blood pressure, and confusion. Sepsis is diagnosed based on signs of infection along with indicators of organ dysfunction. Common causes are bacterial and fungal infections. Treatment involves timely administration of antibiotics, IV fluids, and organ support such as ventilation or dialysis. Antibiotic therapy, source control, fluid therapy, and hemodynamic management are key to treatment. Early recognition and treatment improve outcomes for sepsis patients.
This document provides an overview of sepsis, including its definitions, epidemiology, pathophysiology, clinical manifestations, complications, diagnosis, and management. It notes that sepsis is a systemic inflammatory response to infection that can lead to life-threatening organ dysfunction. An estimated 750,000 cases of severe sepsis and septic shock occur annually in the US, with over 200,000 deaths. The pathophysiology involves a complex interplay between the host's immune response and invading pathogens. Diagnosis is challenging as there is no single diagnostic test, but suspected cases should be promptly investigated and treated.
Blood culture role in sepsis and it's managementDr Nisha Singh
This document discusses blood culture as the gold standard for sepsis diagnosis. It begins with definitions of sepsis, sepsis diagnosis, and sepsis burden. It then discusses sources of sepsis and outlines the sepsis six protocol. The document emphasizes that blood culture identifies the organism and enables antibiotic sensitivity testing to guide therapy. It also discusses newer rapid diagnostic methods but notes blood culture remains the gold standard.
Bacteremia is the presence of bacteria in the blood, and can cause symptoms ranging from no symptoms to septic shock depending on factors like host immunity and bacterial toxin production. It is classified based on origin site, causative agent, location of acquisition, and duration. Bacteremia has several risk factors and can be associated with various clinical syndromes. Blood cultures are the main diagnostic test and involve collecting multiple blood samples using proper techniques to maximize detection of bacteria. Contamination must be distinguished from true bacteremia based on identification and replication of results. Prevention involves immunization and minimizing healthcare-associated infections.
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BLOOD CULTURE AS AN IMPORTANT DIAGNOSTIC TOOL IN MEDICAL MICROBIOLOGY
1. BLOOD CULTURE
AS AN IMPORTANT DIAGNOSTIC
TOOL IN MEDICAL MICROBIOLOGY
BY
OSAYANDE CHELSEA IMUETINYANOSA
A SEMINAR PRESENTATION IN PARTIAL FULFILMENT FOR INTERNSHIP
IN MEDICAL MICROBIOLOGY, NATIONAL HOSPITAL ABUJA.
SEMINAR SUPERVISOR: SCT. NDIKE U.P. (PMLS)
CO-ORDINATOR: SCT. AKHIGBE ALEX (CMLS)
13TH JANUARY, 2023
3. INTRODUCTION
One of the most important functions of the clinical microbiology laboratory is the
detection and characterization of organisms causing bloodstream infections
(Gonzalez et al., 2020).
The laboratory detection of bacteremia and fungemia using blood cultures is one of
the most
simple and commonly used investigations to establish the etiology of bloodstream
infections.
Rapid, accurate identification of the bacteria or fungi causing bloodstream infections
provides vital clinical information required to diagnose and treat sepsis (CLSI
document M47-A, 2007). `
4. DEFINITION OF TERMS
Bacteremia
• The presence of bacteria in the blood. It may be transient,
intermittent or continuous. he presence of bacteria in the
blood. It may be transient, intermittent or continuous
Fungemia:
• The presence of fungi in the blood
Septicemia:
• Clinical syndrome characterized by fever, chills, malaise,
tachycardia, etc. when circulating bacteria multiply at a rate
that exceeds removal by phagocytosis
(Singer et al., 2016).
5. WHAT IS A BLOOD CULTURE?
A blood culture is a laboratory test in which blood, taken from the patient, is inoculated
into bottles containing culture media to determine whether infection-causing
microorganisms (bacteria or fungi) are present in the patient’s bloodstream (Singer et
al., 2016).
Blood cultures are intended to:
Confirm the presence of microorganisms in the bloodstream
Identify the microbial etiology of the bloodstream infection
Help determine the source of infection (e.g., endocarditis)
Provide an organism for susceptibility testing and optimization of antimicrobial therapy
(Singer et al., 2016).
6. HISTORY
Manualithic
(pre-1970)
• Dr. Jean Antoine
Villemin déveloped
biological blood
culture
• recognition of
“Liquoid” as a
potent anticoagulant
Bactecene
(1970 to 1990
• Automated blood
culture systems first
became available in
the 1970s
• 1984 a new
generation of
BACTEC
instruments was
released that
used spectrophoto
metry to detect
CO2.[
Continuous
Monitorassic
(1990 to 2000)
• BacT/Alert
colorimetric
microbial detection
system in 1990
• Bactec 9000 series
• ESP
Ampliaissance
(post-2000) ages
• Molecular based
assays or high-
resolution
spectrometry
• Increase speed of
detection
(Ombelet et al., 2019)
7. WHEN SHOULD A BLOOD CULTURE BE PERFORMED?
Blood cultures should always be requested when a bloodstream infection or sepsis is
suspected.
Clinical symptoms in a patient which may lead to a suspicion of a bloodstream
infection are:
undetermined fever (≥38°C) or hypothermia (≤36°C)
shock, chills, rigors
severe local infections (meningitis, endocarditis, pneumonia, pyelonephritis, intra-
abdominal suppuration).
abnormally raised heart rate
low or raised blood pressure
raised respiratory rate
Baron (et al., 2005).
10. MEDIA FORMULATIONS
Base :
soybean casein digest (trypticase soy broth)
supplemented peptone broth
brain heart infusion broth
Anticoagulant :
sodium polyanethol sulfonate (SPS)
Headspace Atmoshere:
CO2 and N2 for anaerobic bottles and ambient
air supplemented with CO2 for aerobic bottles
Additives
Reducing agent
Polymeric resin beads
Yeast extract
(Gross et al., 2018).
11. PREVENTING CONTAMINATION OF BLOOD CULTURES
Disinfect Skin sites for collection with an
alcohol containing disinfectant.
blood should not be collected from an
intravascular device
use of commercial diversion devices
(Doern et al., 2019).
Figure: steripath gen2 initial specimen
diversion device
12. ORDER OF DRAW
If using a winged blood collection set, then the
aerobic bottle should be filled first to prevent transfer
of air in the device into the anaerobic bottle.
If using a needle and syringe, inoculate the
anaerobic bottle first to avoid entry of air.
If the amount of blood drawn is less than the
recommended volume*, then approximately 10 ml of
blood should be inoculated into the aerobic bottle
first, since most cases of bacteremia are caused by
aerobic and facultative bacteria (Ombelet et al.,
2019).
13. WHAT VOLUME OF BLOOD SHOULD BE COLLECTED?
The American Society for Microbiology (ASM) and the Infectious Diseases Society of
America (IDSA) jointly recommend 2 to 4 collections per septic episode.
Blood culture bottles are designed to accommodate the recommended blood- to-
broth ratio (1:5 to 1:10) with optimal blood volume.
ADULTS
for adults, 40 to 60 ml of blood collected from the patient for the 4 to 6 bottles, with 10
ml per bottle.
PEDIATRIC
The optimal volume of blood to be obtained from infants and children is less well
prescribed. The recommended volume of blood to collect should be based on the
weight of the patient (Mosta et al., 2017).
14. Weight of
patient
Patient’s total
blood volume
(ml)
Recommended
volume of blood
for culture (ml)
Total volume
for culture (ml
)
% of patient’s
total blood
volume
kg Ib Culture
no.1
Culture
no.2
≤1 ≤2.2 50-99 2 2 4
1.1-2 2.2-4.4 100-200 2 2 4 4
2.1-12.
7
4.5-27 >200 4 2 6 3
12.8-3
6.3
28-80 >800 10 10 20 2.5
>36.3 >80 >2,200 20-30 20-30 40-60 1.8-2.7
Table 1: Blood volumes suggested for cultures from infants and children
(Kellog el al., 2000).
15. LABORATORY ANALYSIS
BLOOD CULTURE SYSTEMS
INCUBATION
PROCESSING POSITIVE BLOOD CULTURE
INSTRUMENTATION
CONTAMINANT OR TRUE PATHOGEN
QUALITY CONTROL
16. BLOOD CULTURE SYSTEMS
MANUAL SYSTEMS
The bottles are visually examined for indicators of microbial growth, which might
include cloudiness, the production of gas, the presence of visible microbial
colonies, or a change in colour from the digestion of blood, which is
called hemolysis.
Conventional broth based system
Biphasic systems such as hemoline and septi-check system
Displacement (signal) system
lysis centrifugation (isolator) system to culture blood for molds and mycobacteria.
(Mosta et al., 2017).
17. Figure: Signs of growth in blood culture bottles. (A) pellicle formation on surface; (B) gas
production; (C) turbidity (left bottle: no growth; right bottle: turbidity); (D) puff balls (Ombelet
et al., 2019).
18. BLOOD CULTURE SYSTEMS contd
CONTINUOUS-MONITORING BLOOD CULTURE SYSTEM (CMBCS).
BacT/ALERT
Colorimetric change (at the bottom of the bottle) caused by drop in pH from
increased CO2 levels
BACTEC
Change in fluorescence caused by a drop in pH from increased CO2 levels
VersaTREK
Measures pressure changes caused by gas consumption or production (Doern et
al., 2019).
20. Figure : Clinically significant isolates per day demonstrating recommended days of incubati
on (Bourbeau and Foltzer , 2005).
21. PROCESSING POSITIVE BLOOD CULTURES
STAINING METHODS
• Gram stain
• Acridien orange
IDENTIFICATION
• subculture
• Molecular testing
• Mass spectrometry
MALDI-TOF MS),
DIRECT
IDENTIFICATION
• Accelerate phenotest
BC kit
• BD phoenix and
biome ́rieux VITEK2
systems
• Rapid AST (RAST)
method based on
direct disk diffusion
(ddd) testing
• Enzyme-based
targeted AST
(Singer et al., 2016).
22. CLINICAL EVIDENCE OF BACTERIAL INFECTION IS PRESENT
features of SSTI, urosepsis, pneumonia, SIRS criteria).
Detection of the same pathogen in blood culture sets from different venipuncture
sites
Pathogens that rarely indicate contamination:
oS. aureus
oS. pneumoniae
oS. pyogenes
oEnterobacteriaceae spp. including E. coli
oH. influenzae
oP. aeruginosa
oCandida spp
oListeria monocytogenes
oNeisseria meningitidis
oAnaerobic Gram-negative rods
(Doern et al., 2019).
24. CONTAMINANT OR A TRUE PATHOGEN?
A false positive is defined as growth of bacteria in the blood culture bottle that were
not present in the patient’s bloodstream, and were most likely introduced during
sample collection.
Contamination can come from a number of sources:
The patient’s skin,
The equipment used to take the sample,
The hands of the person taking the blood sample, or
The environment.
Certain microorganisms such as coagulase-negative staphylococci, viridans- group
streptococci, Bacillus spp, Propionibacterium spp., diphtheroids, Micrococcus spp.
rarely cause severe bacterial infections or bloodstream infections. These are common
skin contaminants (Hall and Lyman, 2006).
25. NEGATIVE BLOOD CULTURE
Before ruling out bacteremia, consider the following steps:
Determine whether it is likely the result could be a false-negative
Consider if:
Collection performed during current antibiotic treatment
Insufficient inoculation
volume of each blood culture
Prolonged transportation time
Assess whether the pathogen identified is a plausible cause of the presenting
infection.If necessary, arrange for new blood culture sampling and analysis (Doern et
al., 2019).
26. CONCLUSION
Blood cultures allow the identification of pathogens, such as bacteria and fungi, in
blood and their specific resistance testing. Knowing the pathogen enables effective,
individualized antibiotic treatment, which reduces mortality, improves prognosis,
minimizes the length of hospital stays, and reduces the growing number of antibiotic-
resistant pathogens
27. REFERENCES
Baron EJ, Weinstein MP, Dunne Jr. WM, Yagupsky P, Welch DF, Wilson DM. Cumitech 1C,
Blood Cultures IV. Coordinating ed., E.J. Baron. ASM Press, Washington D.C. 2005.
Bourbeau PP, Foltzer M. Routine incubation of BACT/ALERT* FA and FN blood culture bottles
for more than 3 days may not be necessary. J Clin Microbiol. 2005;43:2506-250
Doern GV, Carroll KC, Diekema DJ, et al. A comprehensive update on the problem of blood
culture contamination and a discussion of methods for addressing the problem. Clin Microbiol
Rev 2019;33(1). e00009-19
Doern GV, Carroll KC, Diekema DJ, et al. Practical Guidance for Clinical Microbiology
Laboratories: A Comprehensive Update on the Problem of Blood Culture Contamination and a
Discussion of Methods for Addressing the Problem. Clin Microbiol Rev. 2019; 33
(1). doi: 10.1128/cmr.00009-19
Gonzalez, M. D., Chao, T., & Pettengill, M. A. (2020). Modern Blood Culture. Clinics in
Laboratory Medicine. doi:10.1016/j.cll.2020.07.001
Hall KK, Lyman JA. Updated Review of Blood Culture Contamination. Clin Microbiol Rev.
2006,19(4):788.
28. REFERENCES
https://www.slideshare.net/MostafaMahmoud76/manual-blood-culture-techniques
Kellog JA, Manzella JP, Bankert DA. Frequency of low-level bacteremia in children from birth
to fifteen years of age.J Clin Microbiol. 2000;38:2181-2185.
Ombelet S, Barbé B, Affolabi D, Ronat J-B, Lompo P, Lunguya O, Jacobs J and Hardy L
(2019) Best Practices of Blood Cultures in Lowand Middle-Income Countries. Front. Med.
6:131. doi: 10.3389/fmed.2019.00131
Principles and procedures for Blood Cultures; Approved Guideline, CLSI document M47-A.
Clinical and Laboratory Standards Institute (CLSI); Wayne, P.A. 2007
Singer M, Deutschmann CS, Seymour CW, et al. The Third International Consensus
Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810.
Singer M, Deutschmann CS, Seymour CW, et al. The Third International Consensus
Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810.
A blood culture medium must be:
sensitive enough to recover:
-a broad range of clinically relevant microorganisms, even the most fastidious (Neisseria, Haemophilus.)
-microorganisms releasing small amounts of CO2 (Brucella, Acinetobacter)
versatile: able to provide a result for all types of sample collection
(adults, infants, patients receiving antibiotic therapy, sterile body fluids...)
Most modern media formulations are similar, a base of soybean casein digest (trypticase soy broth) with sodium polyanethol sulfonate (SPS) as an anticoagulant.
The headspace of the bottles consists of CO2 and N2 for anaerobic bottles and ambient air
supplemented with CO2 for aerobic bottles. Anaerobic bottles also include reducing
agents.
Resins can neutralize select antibacterial
agents (including common empirically utilized antibiotics such as piperacillintazobactam, vancomycin, and some cephalosporins), but have lower to no ability to
neutralize other agents (eg, carbapenems and fluoroquinolones).
Contamination of blood cultures has a big impact on patient care and hospital resources. Several key factors that can reduce contamination rates have been clearly
demonstrated.
Skin sites for collection should be disinfected with an alcoholcontaining disinfectant, and blood should not be collected from an intravascular device unless specifically requested out of concern it is the source of bacteremia
the use of commercial diversion devices reduced contamination rates,
which in models is projected to lead to considerable cost savings and reductions in
patient length of stay
Because of the cost of diversion devices We can do this by diverting a small
amount of blood using vacutainer tubes by changing the test draw order, which could
also be accomplished for blood cultures alone by simply discarding the diverted
portion.
For an adult, the recommended volume of blood to be obtained per culture is 20 to 30 ml. 16
Note: This volume is recommended to optimize pathogen recovery when the bacterial/fungal burden is less than 1 Colony Forming Unit (CFU) per ml of blood, which is a common finding
Three US Food and Drug Administration (FDA)-cleared CMBCS are avail- able, including BACTEC (Becton-Dickinson, Sparks, MD, USA), BacT/Alert (bio- Me ́ rieux, Inc., Durham, North Carolina) and VersaTREK (Thermo Scientific, Waltham, Massachusetts).
Three US Food and Drug Administration (FDA)-cleared CMBCS are avail- able, including BACTEC (Becton-Dickinson, Sparks, MD, USA), BacT/Alert (bio- Me ́ rieux, Inc., Durham, North Carolina) and VersaTREK (Thermo Scientific, Waltham, Massachusetts).
Note: However, published data suggest that three days may be adequate to recover over 97% of clinically significant microorganisms.
Note:
Blood cultures are routinely incubated for 4 to 7 days with CMBCS. Studies indicate that 98% to 99% of true pathogens are detected within 5 days of incubation relative to longer incubation times
However, published data suggest that three days may be adequate to recover over 97% of clinically significant microorganisms.
Some microorganisms stain poorly
or not all with Gram reagents, and for positive blood cultures with negative Gram stains there are alternative stains, such as acridine orange, which can be employed in
addition to repeating Gram stains.
Note: However, published data suggest that three days may be adequate to recover over 97% of clinically significant microorganisms.
Note: However, published data suggest that three days may be adequate to recover over 97% of clinically significant microorganisms.
It is unlikely that the detected pathogen
is the cause of the presenting infection (e.g., presence of skin microbiota
such as Corynebacteria
and Propionibacteria).
Pathogens that likely indicate contamination:
Corynebacterium
spp.
Bacillus spp. (except B. anthracis
)
Others: Micrococcus spp., Cutibacterium acnes
Most coagulase-negative staphylococci
Pathogens that may indicate contamination:
Enterococci
S. viridans
Clostridium
spp.
Blood culture sets were collected from an indwelling catheter.
Detection of the same pathogen
in the blood culture set in the peripheral vein and in the catheter
Marked differential time to positivity
Bacterial detection was only successful in one blood culture bottle.
It is unlikely that the detected pathogen
is the cause of the presenting infection (e.g., presence of skin microbiota
such as Corynebacteria
and Propionibacteria).
Pathogens that likely indicate contamination:
Corynebacterium
spp.
Bacillus spp. (except B. anthracis
)
Others: Micrococcus spp., Cutibacterium acnes
Most coagulase-negative staphylococci
Pathogens that may indicate contamination:
Enterococci
S. viridans
Clostridium
spp.
Blood culture sets were collected from an indwelling catheter.
Detection of the same pathogen
in the blood culture set in the peripheral vein and in the catheter
Marked differential time to positivity
Bacterial detection was only successful in one blood culture bottle.