Quality control of antimicrobial susceptibility testsAmr Eldakroury
This document discusses quality control for antimicrobial susceptibility testing. It describes different testing methods, including disk diffusion and microdilution, and how they provide qualitative or quantitative results. Key aspects of quality control are highlighted, such as using standardized reference strains, maintaining proper test conditions for media, antimicrobials, inoculum, incubation, and ensuring accurate interpretation. Close monitoring is important to identify potential errors at each step and ensure accurate patient results.
Phenotypic methods used in antimicrobial susceptibility testingILRI
This document provides instructions for performing antimicrobial susceptibility testing using phenotypic disk diffusion methods according to EUCAST guidelines. It describes the appropriate media, inoculum preparation, application of antimicrobial disks, incubation conditions, and reading of zone diameters. Mueller-Hinton agar is used for non-fastidious bacteria, while Mueller-Hinton with 5% blood and β-NAD is used for fastidious organisms. The inoculum is adjusted to a 0.5 McFarland standard and disks are applied and incubated according to organism-specific timeframes and conditions. Zones are read at the point of complete inhibition while accounting for any colonies within zones or fuzzy edges.
This document discusses quality assurance and quality control procedures for microlaboratories. It defines quality and quality management, and explains how quality is ensured in laboratories through controlling all factors that influence reliable test results. Quality assurance aims to ensure accurate and reliable data generation and use. Key quality control procedures discussed include regular equipment maintenance and calibration, sterilization validation methods, reagent and media quality control, and environmental monitoring. Adhering to these standardized quality control protocols is important for generating credible results and safeguarding patient health.
Staphylococcus epidermidis is an opportunistic pathogen that commonly forms biofilms on medical devices. These biofilms make infections very difficult to treat as bacteria in biofilms are up to 1000 times more resistant to antibiotics. The document discusses various strategies to control S. epidermidis biofilms, including using antibiotic combinations to prevent resistance development, targeting mechanisms of biofilm antibiotic resistance, and exploring natural compounds and their synergistic effects with antibiotics.
Antimicrobial susceptibility testing determines how effective antibiotic therapy is against bacterial infections. There are several methods for testing, including disk diffusion, dilution tests, and automated systems. Disk diffusion involves placing disks impregnated with antibiotics onto inoculated agar plates and measuring inhibition zones. Mueller-Hinton agar is commonly used as the growth medium. Dilution tests determine the minimum inhibitory concentration (MIC) of antibiotics using serial dilutions in broth or agar. Automated systems streamline the testing process. Proper technique and controls are important for accurate and reproducible results.
This document discusses automation in microbiology labs. It outlines several technologies currently used for semi-automation, including blood culture incubators, ID and susceptibility testing platforms, and automated stainers. Fully automated total lab automation (TLA) systems are also described, which use conveyor systems and digital imaging to automate specimen processing and plate reading. Advantages of TLA include continuous incubation, flexibility in plate reading times, efficient retrieval of plates as needed, and improved traceability. However, more research is still needed to assess the benefits of full microbiology automation.
The document discusses antimicrobial susceptibility testing (AST), which determines the susceptibility of bacteria to different antimicrobial agents through in-vitro laboratory procedures. It outlines various guidelines and standardization procedures for AST, including standardized bacterial inoculum, growth medium, incubation conditions, and antimicrobial concentrations. Common AST methods include dilution methods like broth microdilution and agar dilution, which determine minimum inhibitory concentrations (MICs), and diffusion methods like disc diffusion testing, which provide qualitative susceptibility results.
Quality control of antimicrobial susceptibility testsAmr Eldakroury
This document discusses quality control for antimicrobial susceptibility testing. It describes different testing methods, including disk diffusion and microdilution, and how they provide qualitative or quantitative results. Key aspects of quality control are highlighted, such as using standardized reference strains, maintaining proper test conditions for media, antimicrobials, inoculum, incubation, and ensuring accurate interpretation. Close monitoring is important to identify potential errors at each step and ensure accurate patient results.
Phenotypic methods used in antimicrobial susceptibility testingILRI
This document provides instructions for performing antimicrobial susceptibility testing using phenotypic disk diffusion methods according to EUCAST guidelines. It describes the appropriate media, inoculum preparation, application of antimicrobial disks, incubation conditions, and reading of zone diameters. Mueller-Hinton agar is used for non-fastidious bacteria, while Mueller-Hinton with 5% blood and β-NAD is used for fastidious organisms. The inoculum is adjusted to a 0.5 McFarland standard and disks are applied and incubated according to organism-specific timeframes and conditions. Zones are read at the point of complete inhibition while accounting for any colonies within zones or fuzzy edges.
This document discusses quality assurance and quality control procedures for microlaboratories. It defines quality and quality management, and explains how quality is ensured in laboratories through controlling all factors that influence reliable test results. Quality assurance aims to ensure accurate and reliable data generation and use. Key quality control procedures discussed include regular equipment maintenance and calibration, sterilization validation methods, reagent and media quality control, and environmental monitoring. Adhering to these standardized quality control protocols is important for generating credible results and safeguarding patient health.
Staphylococcus epidermidis is an opportunistic pathogen that commonly forms biofilms on medical devices. These biofilms make infections very difficult to treat as bacteria in biofilms are up to 1000 times more resistant to antibiotics. The document discusses various strategies to control S. epidermidis biofilms, including using antibiotic combinations to prevent resistance development, targeting mechanisms of biofilm antibiotic resistance, and exploring natural compounds and their synergistic effects with antibiotics.
Antimicrobial susceptibility testing determines how effective antibiotic therapy is against bacterial infections. There are several methods for testing, including disk diffusion, dilution tests, and automated systems. Disk diffusion involves placing disks impregnated with antibiotics onto inoculated agar plates and measuring inhibition zones. Mueller-Hinton agar is commonly used as the growth medium. Dilution tests determine the minimum inhibitory concentration (MIC) of antibiotics using serial dilutions in broth or agar. Automated systems streamline the testing process. Proper technique and controls are important for accurate and reproducible results.
This document discusses automation in microbiology labs. It outlines several technologies currently used for semi-automation, including blood culture incubators, ID and susceptibility testing platforms, and automated stainers. Fully automated total lab automation (TLA) systems are also described, which use conveyor systems and digital imaging to automate specimen processing and plate reading. Advantages of TLA include continuous incubation, flexibility in plate reading times, efficient retrieval of plates as needed, and improved traceability. However, more research is still needed to assess the benefits of full microbiology automation.
The document discusses antimicrobial susceptibility testing (AST), which determines the susceptibility of bacteria to different antimicrobial agents through in-vitro laboratory procedures. It outlines various guidelines and standardization procedures for AST, including standardized bacterial inoculum, growth medium, incubation conditions, and antimicrobial concentrations. Common AST methods include dilution methods like broth microdilution and agar dilution, which determine minimum inhibitory concentrations (MICs), and diffusion methods like disc diffusion testing, which provide qualitative susceptibility results.
This document discusses sensitivity testing, which determines the effectiveness of antimicrobial drugs against bacterial strains. Sensitivity testing helps select the most effective drug and identify pathogens. It is done using diffusion or dilution techniques to measure zones of inhibition or minimum inhibitory concentrations. However, sensitivity testing only measures drug effectiveness in laboratory conditions and does not account for patient factors. Antimicrobial resistance can develop through genetic mutations or exchange between bacteria, allowing resistance to spread to multiple drugs. Sensitivity testing guides optimal treatment while addressing the rise of antimicrobial resistance.
This document provides information on the genus Escherichia coli. It discusses the morphology, culture characteristics, biochemical reactions, antigenic structure, and virulence factors of E. coli. Key points include:
- E. coli is a gram-negative, facultative anaerobic rod that is a normal inhabitant of the gastrointestinal tract.
- It ferments glucose with acid and gas production and is capable of reducing nitrates to nitrites.
- E. coli has O, H, and K surface antigens that are used for serotyping. The O antigen lipopolysaccharide contributes to virulence.
- Virulence factors include surface antigens, fimbriae, and toxins
Automation provides benefits to clinical microbiology such as continuous monitoring of blood culture systems to detect pathogens faster. Automated identification and susceptibility testing systems like Vitek-2 can analyze test results every 15 minutes using optical detection of signals. Molecular diagnostic techniques allow for identification of pathogen nucleic acids.
The document discusses various aspects of reporting in diagnostic microbiology. It addresses the transition of microbiology from past practices to future advances. Various topics covered include what constitutes a laboratory report, how polymerase chain reaction changed biology, the changing role of microbiologists from clinics to laboratories, identifying infectious diseases, improving diagnostic methods, supporting laboratory results for different types of infections, key points about microbes and their diagnosis, defining terms, and challenges with automation and interpretation of results for clinicians. The document emphasizes clear communication between laboratories and clinicians.
This document discusses bacterial identification using API kits. It provides an overview of API, which contains identification databases for over 967 bacterial and yeast species. It then describes various API identification systems for gram negative bacteria, gram positive bacteria, anaerobes, and yeasts. The document focuses on using the API 20E kit, outlining the materials needed, inoculation procedure, incubation, result interpretation, and limitations. It emphasizes that API kits allow for rapid identification of known bacterial species contained within their databases.
Antimicrobial Susceptibility Testing involves procedures like diffusion and dilution methods to determine the susceptibility of microorganisms to antimicrobial agents. Key procedures discussed include Kirby-Bauer, agar and broth dilution tests. Interpretation of results defines organisms as susceptible, intermediate or resistant based on breakpoints. Quality control through reference strains is important to ensure accuracy and consistency of results. Automated methods now provide rapid and reproducible susceptibility testing through microdilution and detection of growth in broth cultures.
This document discusses ESBL (Extended Spectrum Beta Lactamases) which confer bacterial resistance to several classes of beta-lactam antibiotics. Early diagnosis of ESBL-producing pathogens is important to reduce mortality and morbidity. The document then describes several confirmatory tests for ESBL production, focusing on the double disk synergy test. This test involves placing disks containing beta-lactam antibiotics and amoxicillin-clavulanic acid on an inoculated agar plate. A positive result is indicated by a clear extension of the inhibition zone between the antibiotic and amoxicillin-clavulanic acid disks.
Biosafety & biosecurity overview naypyitawEhealthMoHS
This document provides an overview of biosafety and biosecurity. It defines biosafety as protecting people from pathogens through containment principles and practices, while biosecurity protects pathogens from people through security measures. The document discusses international biosafety authorities, societal expectations around biosafety, common laboratory accidents, and the goals of biosafety measures to ensure proper containment. It also summarizes the Joint External Evaluation conducted in Laos in 2017 and its recommendations to improve national biosafety and biosecurity standards, conduct pathogen inventories, and train biosafety officers.
This document provides an overview of quality assurance and quality control in microbiology. It discusses the importance of quality in microbiology laboratories given the consequences of unreliable test results. It defines key terms like quality assurance and quality control and describes various quality concepts. It also outlines factors that can influence quality like pre-analytical, analytical and post-analytical factors. The document discusses organization of microbiology laboratories, external and internal quality assessment, and quality control of different laboratory sections, equipment, and preservation of stock cultures.
Eschericia coli is a gram-negative, facultative anaerobic bacterium that is commonly found in the lower intestine of warm-blooded organisms. It can cause several types of infections including urinary tract infections, enteric infections like traveler's diarrhea, and other rare infections. Laboratory diagnosis involves microscopic examination of samples showing gram-negative bacilli, as well as culture-based identification using selective media and biochemical tests to confirm lactose fermentation and other properties. Treatment depends on the severity and type of infection, ranging from supportive care to antibiotics for serious complications.
This document discusses quality assurance in clinical microbiology. It emphasizes that test results must be clinically relevant, reliable, timely, and correctly interpreted. It defines quality and discusses factors that influence it, including pre-analytical, analytical, and post-analytical stages. Total quality management aims to control all variables that could affect test quality. Standard operating procedures, good laboratory practices, and quality control procedures are important to ensure accurate results.
This document provides guidance on proper specimen collection, transport, and aseptic technique in microbiology. It discusses the importance of collecting the right specimen from the right patient at the right time and transporting it properly to the laboratory. It provides details on proper collection and transport of various specimen types from different sites of infection, including respiratory, urinary, genital, and others. Proper labeling, containers, transport media, and aseptic technique are also covered to ensure sample quality and viability.
This document discusses quality control and quality assurance in microbiological laboratory investigations. It emphasizes the importance of standard operating procedures, internal quality assessment, and external quality assessment. Quality control occurs at multiple stages of analysis, including pre-analytical (specimen collection and transport), analytical (reagents, equipment, procedures), and post-analytical (reporting and interpretation of results). A quality control officer oversees quality control in the department through regular monitoring, assessment, communication, and analysis of quality control data.
The document discusses antibiotic sensitivity testing (AST), which measures the susceptibility of bacterial isolates to different antibiotics. AST aims to select the most appropriate antibiotic for patients and assess emerging resistance patterns. Common AST methods include disk diffusion, broth dilution, Etest, and automated systems. Disk diffusion is the most widely used method and involves placing antimicrobial disks on agar plated with the test organism and measuring inhibition zone sizes. Broth dilution determines the minimum inhibitory concentration (MIC) by visually inspecting bacterial growth in serial antibiotic dilutions.
This document discusses various direct and indirect methods used for the diagnosis of infectious diseases. Direct methods involve detecting the pathogen itself through microscopy, culture techniques, or molecular methods on a specimen. Indirect methods involve detecting the immune response to the pathogen through serology techniques like detecting IgM or rising titers of IgG antibodies. It then discusses various antigen-antibody reactions that can be used for serological diagnosis, including agglutination, precipitation, complement fixation, viral neutralization, immunofluorescence, ELISA, and radioimmunoassay.
The program file has been made with the vision for basic responsibilities of the Medical Microbiologists for optimal decisions in Diagnostic Microbiology, Every specimen reflects the scenario in the ongoing process of infection in the human body ( from vivo to vitro) , However it is important to know the predictive value of the tests we do in the laboratory or else the blind processing will certainly harmful if not useful Dr.T.V.Rao MD
doctortvrao@gmail.com
The viral neutralization test is a serological method that detects the presence of viral neutralizing antibodies. It involves mixing dilutions of antibodies with a standardized amount of virus, incubating them, and observing for cytopathic effects in cell cultures. If the antibodies neutralize the virus, no cytopathic effects will be observed as the cells remain intact. While the viral neutralization test is highly sensitive and specific, it is also slow, intensive, and requires skilled technicians. It remains the gold standard method for diagnosing viral infections in the laboratory by comparing other test methods to it.
The GeneDisc Rapid Microbiology System provides microbial test results in as little as two hours using quantitative PCR technology. The system consists of a DNA Extractor that prepares samples, GeneDisc plates that are loaded into a GeneDisc Cycler for analysis. It tests for key pathogens in biopharmaceuticals, foods, and water. The system offers simplicity, speed, security of results, and cost savings compared to traditional methods.
20160219 - M. Agostini - Nuove tecnologie per lo studio del DNA tumorale libe...Roberto Scarafia
Nano Inspired Biomedicine Laboratory
1 Department of Surgical, Oncological and Gastroenterological Sciences, University of Padua, Italy.
2 Istituto di Ricerca Pediatrica- Città della Speranza, Padova, Italy.
This document discusses sensitivity testing, which determines the effectiveness of antimicrobial drugs against bacterial strains. Sensitivity testing helps select the most effective drug and identify pathogens. It is done using diffusion or dilution techniques to measure zones of inhibition or minimum inhibitory concentrations. However, sensitivity testing only measures drug effectiveness in laboratory conditions and does not account for patient factors. Antimicrobial resistance can develop through genetic mutations or exchange between bacteria, allowing resistance to spread to multiple drugs. Sensitivity testing guides optimal treatment while addressing the rise of antimicrobial resistance.
This document provides information on the genus Escherichia coli. It discusses the morphology, culture characteristics, biochemical reactions, antigenic structure, and virulence factors of E. coli. Key points include:
- E. coli is a gram-negative, facultative anaerobic rod that is a normal inhabitant of the gastrointestinal tract.
- It ferments glucose with acid and gas production and is capable of reducing nitrates to nitrites.
- E. coli has O, H, and K surface antigens that are used for serotyping. The O antigen lipopolysaccharide contributes to virulence.
- Virulence factors include surface antigens, fimbriae, and toxins
Automation provides benefits to clinical microbiology such as continuous monitoring of blood culture systems to detect pathogens faster. Automated identification and susceptibility testing systems like Vitek-2 can analyze test results every 15 minutes using optical detection of signals. Molecular diagnostic techniques allow for identification of pathogen nucleic acids.
The document discusses various aspects of reporting in diagnostic microbiology. It addresses the transition of microbiology from past practices to future advances. Various topics covered include what constitutes a laboratory report, how polymerase chain reaction changed biology, the changing role of microbiologists from clinics to laboratories, identifying infectious diseases, improving diagnostic methods, supporting laboratory results for different types of infections, key points about microbes and their diagnosis, defining terms, and challenges with automation and interpretation of results for clinicians. The document emphasizes clear communication between laboratories and clinicians.
This document discusses bacterial identification using API kits. It provides an overview of API, which contains identification databases for over 967 bacterial and yeast species. It then describes various API identification systems for gram negative bacteria, gram positive bacteria, anaerobes, and yeasts. The document focuses on using the API 20E kit, outlining the materials needed, inoculation procedure, incubation, result interpretation, and limitations. It emphasizes that API kits allow for rapid identification of known bacterial species contained within their databases.
Antimicrobial Susceptibility Testing involves procedures like diffusion and dilution methods to determine the susceptibility of microorganisms to antimicrobial agents. Key procedures discussed include Kirby-Bauer, agar and broth dilution tests. Interpretation of results defines organisms as susceptible, intermediate or resistant based on breakpoints. Quality control through reference strains is important to ensure accuracy and consistency of results. Automated methods now provide rapid and reproducible susceptibility testing through microdilution and detection of growth in broth cultures.
This document discusses ESBL (Extended Spectrum Beta Lactamases) which confer bacterial resistance to several classes of beta-lactam antibiotics. Early diagnosis of ESBL-producing pathogens is important to reduce mortality and morbidity. The document then describes several confirmatory tests for ESBL production, focusing on the double disk synergy test. This test involves placing disks containing beta-lactam antibiotics and amoxicillin-clavulanic acid on an inoculated agar plate. A positive result is indicated by a clear extension of the inhibition zone between the antibiotic and amoxicillin-clavulanic acid disks.
Biosafety & biosecurity overview naypyitawEhealthMoHS
This document provides an overview of biosafety and biosecurity. It defines biosafety as protecting people from pathogens through containment principles and practices, while biosecurity protects pathogens from people through security measures. The document discusses international biosafety authorities, societal expectations around biosafety, common laboratory accidents, and the goals of biosafety measures to ensure proper containment. It also summarizes the Joint External Evaluation conducted in Laos in 2017 and its recommendations to improve national biosafety and biosecurity standards, conduct pathogen inventories, and train biosafety officers.
This document provides an overview of quality assurance and quality control in microbiology. It discusses the importance of quality in microbiology laboratories given the consequences of unreliable test results. It defines key terms like quality assurance and quality control and describes various quality concepts. It also outlines factors that can influence quality like pre-analytical, analytical and post-analytical factors. The document discusses organization of microbiology laboratories, external and internal quality assessment, and quality control of different laboratory sections, equipment, and preservation of stock cultures.
Eschericia coli is a gram-negative, facultative anaerobic bacterium that is commonly found in the lower intestine of warm-blooded organisms. It can cause several types of infections including urinary tract infections, enteric infections like traveler's diarrhea, and other rare infections. Laboratory diagnosis involves microscopic examination of samples showing gram-negative bacilli, as well as culture-based identification using selective media and biochemical tests to confirm lactose fermentation and other properties. Treatment depends on the severity and type of infection, ranging from supportive care to antibiotics for serious complications.
This document discusses quality assurance in clinical microbiology. It emphasizes that test results must be clinically relevant, reliable, timely, and correctly interpreted. It defines quality and discusses factors that influence it, including pre-analytical, analytical, and post-analytical stages. Total quality management aims to control all variables that could affect test quality. Standard operating procedures, good laboratory practices, and quality control procedures are important to ensure accurate results.
This document provides guidance on proper specimen collection, transport, and aseptic technique in microbiology. It discusses the importance of collecting the right specimen from the right patient at the right time and transporting it properly to the laboratory. It provides details on proper collection and transport of various specimen types from different sites of infection, including respiratory, urinary, genital, and others. Proper labeling, containers, transport media, and aseptic technique are also covered to ensure sample quality and viability.
This document discusses quality control and quality assurance in microbiological laboratory investigations. It emphasizes the importance of standard operating procedures, internal quality assessment, and external quality assessment. Quality control occurs at multiple stages of analysis, including pre-analytical (specimen collection and transport), analytical (reagents, equipment, procedures), and post-analytical (reporting and interpretation of results). A quality control officer oversees quality control in the department through regular monitoring, assessment, communication, and analysis of quality control data.
The document discusses antibiotic sensitivity testing (AST), which measures the susceptibility of bacterial isolates to different antibiotics. AST aims to select the most appropriate antibiotic for patients and assess emerging resistance patterns. Common AST methods include disk diffusion, broth dilution, Etest, and automated systems. Disk diffusion is the most widely used method and involves placing antimicrobial disks on agar plated with the test organism and measuring inhibition zone sizes. Broth dilution determines the minimum inhibitory concentration (MIC) by visually inspecting bacterial growth in serial antibiotic dilutions.
This document discusses various direct and indirect methods used for the diagnosis of infectious diseases. Direct methods involve detecting the pathogen itself through microscopy, culture techniques, or molecular methods on a specimen. Indirect methods involve detecting the immune response to the pathogen through serology techniques like detecting IgM or rising titers of IgG antibodies. It then discusses various antigen-antibody reactions that can be used for serological diagnosis, including agglutination, precipitation, complement fixation, viral neutralization, immunofluorescence, ELISA, and radioimmunoassay.
The program file has been made with the vision for basic responsibilities of the Medical Microbiologists for optimal decisions in Diagnostic Microbiology, Every specimen reflects the scenario in the ongoing process of infection in the human body ( from vivo to vitro) , However it is important to know the predictive value of the tests we do in the laboratory or else the blind processing will certainly harmful if not useful Dr.T.V.Rao MD
doctortvrao@gmail.com
The viral neutralization test is a serological method that detects the presence of viral neutralizing antibodies. It involves mixing dilutions of antibodies with a standardized amount of virus, incubating them, and observing for cytopathic effects in cell cultures. If the antibodies neutralize the virus, no cytopathic effects will be observed as the cells remain intact. While the viral neutralization test is highly sensitive and specific, it is also slow, intensive, and requires skilled technicians. It remains the gold standard method for diagnosing viral infections in the laboratory by comparing other test methods to it.
The GeneDisc Rapid Microbiology System provides microbial test results in as little as two hours using quantitative PCR technology. The system consists of a DNA Extractor that prepares samples, GeneDisc plates that are loaded into a GeneDisc Cycler for analysis. It tests for key pathogens in biopharmaceuticals, foods, and water. The system offers simplicity, speed, security of results, and cost savings compared to traditional methods.
20160219 - M. Agostini - Nuove tecnologie per lo studio del DNA tumorale libe...Roberto Scarafia
Nano Inspired Biomedicine Laboratory
1 Department of Surgical, Oncological and Gastroenterological Sciences, University of Padua, Italy.
2 Istituto di Ricerca Pediatrica- Città della Speranza, Padova, Italy.
This document discusses strategies for designing an extractables and leachables study for a packaging system. It provides background on identifying materials of construction, extraction conditions to mimic use conditions, qualitative analytical techniques, and identification of unknown extracts. The strategies include cut-and-cover extraction, full fill extraction, one-sided extraction, and large volume dynamic headspace analysis. Identification involves database searches, molecular formula generation, and MS/MS or CI fragmentation.
Antimicrobial susceptibility testing – disk diffusion methodsAnn Sam
This document provides information on antimicrobial susceptibility testing using disk diffusion methods. It discusses the importance of AST for treating infectious diseases and monitoring antimicrobial resistance. The Kirby-Bauer disk diffusion method is described in detail, including media preparation, inoculum standardization, disk and antibiotic solution preparation, quality control strains, incubation, reading zones of inhibition, and interpreting results according to CLSI guidelines. Special considerations are given to organisms like MRSA, VISA, and inducible clindamycin resistance in Staphylococci.
The document summarizes an analysis of residual solvents using an Agilent 8890 GC system according to a USP method. Key aspects include:
1) The Agilent 8890 GC was configured with dual FIDs, two columns, and an autosampler to analyze class 1-3 residual solvents.
2) Samples were prepared according to the USP method and run in triplicate to determine repeatability of retention times and peak areas.
3) Results for various class 1-3 solvents showed good repeatability with retention time RSDs below 1% and area RSDs below 5% on both columns.
Assay Standardisation - how this leads to improved patient resultsWalt Whitman
Clare Morris from NIBSC discusses the importance of assay standardization for improving patient results. Standardization leads to more accurate, robust and reproducible diagnostic assays by providing a common unit of measurement for comparison. This allows results from different laboratories and assays to be comparable. NIBSC establishes biological reference standards and reference materials to facilitate standardization. Examples are given showing how standardization has improved comparability for assays measuring PSA, HCV RNA, HIV RNA, and other markers. Challenges in standardizing assays across different sample matrices are also discussed.
The document describes the PSAwatch system, a point-of-care test for measuring prostate-specific antigen (PSA) levels. The key features are that it provides a quantitative PSA result in just 10 minutes using a small 35μl blood sample. The system includes PSAwatch cassettes containing the assay, a portable Bioscan reader to analyze the cassettes and provide results, and optional connectivity to printers or software. The PSAwatch test measures PSA from 0.5-25μg/l and has high specificity, precision, and standards equivalence, making it useful for prostate cancer screening and monitoring.
This document provides instructions for performing a complete blood count (CBC) with five-part differential on blood samples from NHANES 2001-2002. Key details include:
- The CBC is performed on a Beckman Coulter MAXM instrument using EDTA blood tubes collected from participants.
- The MAXM uses electrical impedance to count and measure the size of blood cells to determine various parameters like white blood cell count, hematocrit, and platelet count.
- Strict safety procedures must be followed when handling blood samples, which are potential biohazards. Quality control procedures like calibration and use of controls are specified.
Online Detection of Shutdown Periods in Chemical Plants: A Case StudyManuel Martín
In process industry, chemical processes are controlled and monitored by using readings from multiple physical sensors across the plants. Such physical sensors are also supplemented by soft sensors, i.e. adaptive predictive models, which are often used for computing hard-to-measure variables of the process. For soft sensors to work well and adapt to changing operating conditions they need to be provided with relevant data. As production plants are regularly stopped, data instances generated during shutdown periods have to be identified to avoid updating these predictive models with wrong data. We present a case study concerned with a large chemical plant operation over a 2 years period. The task is to robustly and accurately identify the shutdown periods even in case of multiple sensor failures. State-of-the-art methods were evaluated using the first half of the dataset for calibration purposes and the other half for measuring the performance. Results show that shutdowns (i.e. sudden changes) can be quickly detected in any case but the detection delay of startups (i.e. gradual changes) is directly related with the choice of a window size.
Dr. Jeff Baxter - Lab Testing StandardizationJohn Blue
This document summarizes a study on standardizing Trichomonas foetus DNA testing across multiple laboratories. The study aimed to minimize variables that could influence sample or testing quality. It evaluated pooling of positive samples, different sample preparation methods, and real-time PCR protocols across five feeder labs compared to a central study lab. The study found 95.6% agreement between labs and confirmed 175 of 176 positive samples as T. foetus by DNA sequencing. Pooling was found to potentially miss some positives, with 1:5 pooling missing 4% and 1:3 pooling missing 3.5% of positives. The study supports standardizing sample collection, handling, preparation and PCR analysis to increase testing accuracy and consistency.
Quality control in clinical biochemistryAshok Katta
This document discusses quality control in clinical biochemistry laboratories. It explains that laboratory tests play an important role in clinical diagnosis and treatment decisions. Therefore, test results must be reliable and accurate. Quality control involves measures to ensure test accuracy, including internal quality control procedures done daily in the lab and external quality assessment involving evaluation by an outside agency. Proper quality control is essential to producing test results that healthcare providers can trust in making decisions for patients.
This document discusses validation of membrane filtration processes. It begins by introducing membrane filtration and its uses in sterilization. The objectives of validation are to consistently produce the desired results when following standard operating procedures. Validation is necessary to ensure safety, quality, and consistency. The document outlines the various elements that must be validated including filter reproducibility, sterilization, integrity testing, operating conditions, shedding, and microbial challenge testing. It provides details on how to validate each of these elements. The validation report summarizes the findings and conclusions.
Presentation from the 3rd Joint Meeting of the Antimicrobial Resistance and Healthcare-Associated Infections (ARHAI) Networks, organised by the European Centre of Disease Prevention and Control - Stockholm, 11-13 February 2015
Continuous emissions monitoring systems (CEMS) consist of an automated measuring system (AMS) and an automated evaluation system (AES) to monitor pollutants like SO2, NOx, CO2, and other parameters required by regulations. Quality assurance for CEMS involves three levels (QAL1-3) to ensure suitability, proper installation, ongoing calibration and performance checks. Annual surveillance testing (AST) is also required to verify the uncertainty of measurements. Challenges include full uncertainty analyses, statistical approaches, and uncertainty due to location variations. Proper selection of in-situ vs. extractive systems also impacts the measurement uncertainty.
Key Learning Objectives:
• Identify emerging triple quadrupole Gas Chromatography-Mass Spectrometry/Mass Spectrometry (GC-MS/MS) technology designed to address increasing regulatory demands and requirements
• Explore potential time savings in sample prep, method development/transition, and data analysis
• Demonstrate how to optimize the GC-MS/MS workflow from sample prep to sample analysis to automated data analysis
Overview:
Regulatory lab requirements continue to drive detection limits lower with an ever increasing list of compounds to analyze. These requirements also demand greater precision at these lower limits. Triple quadrupole GC-MS/MS is a viable option for enhanced analysis and increased productivity with an emphasis on simplicity. We discuss emerging trends and technologies designed to ensure that laboratories are well-equipped to address these increased demands with minimal investment in training and method development. Find out how you can adopt triple quadrupole GC-MS/MS technology in your laboratory using existing methods and source parameters in most instances while requiring less sample prep and enjoying the benefits of automated data analysis for increased simplicity and productivity.
For more information: www.thermoscientific.com/tsq8000
lect 7 quality control quant tests slides.pdfmariammansour18
This document discusses quality control procedures for quantitative medical tests. It defines key terms like accuracy, precision, controls, calibration, and outlines steps to establish quality control limits and monitor test performance using control charts. Control materials are run to validate test reliability and ensure results are accurate. Statistical analysis of control values over time allows detection of random and systematic errors. The Westgard rules provide criteria for determining when test results may be unreliable and corrective action is needed.
lect 7 quality control quant tests slides.pdfmariammansour18
This document discusses quantitative quality control for laboratory tests. It defines key terms like accuracy, precision, controls, calibration, and outlines the steps to implement a quality control program. This includes selecting and storing control materials, running controls to establish reference ranges, and using Levey-Jennings charts to monitor performance over time. Control values that exceed thresholds could indicate errors that require investigation and corrective action to ensure patient results are reliable.
This document provides a standard operating procedure for using the Enterolert test method to detect and quantify enterococcus levels in water samples. It describes the applicable matrix, detection limits, safety considerations, equipment needed, reagents, sample handling procedures, quality control checks, step-by-step test procedures, data analysis and reporting, method performance estimates, and waste disposal requirements. The Enterolert test can detect one enterococcus per 100 mL of water within 24 hours of incubation at 41°C.
The BenchMark Special Stains Product Guide includes product specific information about BenchMark Special Stains kit components and reagents, a visual demonstration of the protocol options for each assay, and information about optimizing staining performance for the BenchMark Special Stains automated staining platform.
The AQT90 FLEX analyzer allows for quick and easy blood testing at the point of care. It can test for various parameters like troponin, CRP, and pregnancy markers from a single blood sample without any preparation. Test results are available within 30 seconds and the analyzer can run up to 30 tests per hour. It has a simple touchscreen interface and ensures accuracy equivalent to laboratory methods.
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The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help boost feelings of calmness, happiness and focus.
Preventing preventable diseases: a 12-slide primer on foodborne diseaseILRI
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms for those who already suffer from conditions like anxiety and depression.
Preventing a post-antibiotic era: a 12-slide primer on antimicrobial resistanceILRI
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise boosts blood flow, releases endorphins, and promotes changes in the brain which help enhance one's emotional well-being and mental clarity.
Food safety research in low- and middle-income countriesILRI
Presentation by Hung Nguyen-Viet at the first technical meeting to launch the Food Safety Working Group under the One Health Partnership framework, Hanoi, Vietnam, 28 September 2023
The Food Safety Working Group (FSWG) in Vietnam was created in 2015 at the request of the Deputy Prime Minister to address food safety issues in the country. It brings together government agencies, ministries, and development partners to facilitate joint policy dialogue and improve food safety. Over eight years of operations led by different organizations, the FSWG has contributed to various initiatives. However, it faces challenges of diminished government participation over time and dependence on active members. Going forward, it will strengthen its operations by integrating under Vietnam's One Health Partnership framework to better engage stakeholders and achieve policy impacts.
Reservoirs of pathogenic Leptospira species in UgandaILRI
Presentation by Lordrick Alinaitwe, Martin Wainaina, Salome Dürr, Clovice Kankya, Velma Kivali, James Bugeza, Martin Richter, Kristina Roesel, Annie Cook and Anne Mayer-Scholl at the University of Bern Graduate School for Cellular and Biomedical Sciences Symposium, Bern, Switzerland, 29 June 2023.
Assessing meat microbiological safety and associated handling practices in bu...ILRI
Presentation by Patricia Koech, Winnie Ogutu, Linnet Ochieng, Delia Grace, George Gitao, Lily Bebora, Max Korir, Florence Mutua and Arshnee Moodley at the 8th All Africa Conference on Animal Agriculture, Gaborone, Botswana, 26–29 September 2023.
Ecological factors associated with abundance and distribution of mosquito vec...ILRI
Poster by Max Korir, Joel Lutomiah and Bernard Bett presented the 8th All Africa Conference on Animal Agriculture, Gaborone, Botswana, 26–29 September 2023.
Practices and drivers of antibiotic use in Kenyan smallholder dairy farmsILRI
Poster by Lydiah Kisoo, Dishon M. Muloi, Walter Oguta, Daisy Ronoh, Lynn Kirwa, James Akoko, Eric Fèvre, Arshnee Moodley and Lillian Wambua presented at Tropentag 2023, Berlin, Germany, 20–22 September 2023.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Mending Clothing to Support Sustainable Fashion_CIMaR 2024.pdfSelcen Ozturkcan
Ozturkcan, S., Berndt, A., & Angelakis, A. (2024). Mending clothing to support sustainable fashion. Presented at the 31st Annual Conference by the Consortium for International Marketing Research (CIMaR), 10-13 Jun 2024, University of Gävle, Sweden.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
The cost of acquiring information by natural selectionCarl Bergstrom
This is a short talk that I gave at the Banff International Research Station workshop on Modeling and Theory in Population Biology. The idea is to try to understand how the burden of natural selection relates to the amount of information that selection puts into the genome.
It's based on the first part of this research paper:
The cost of information acquisition by natural selection
Ryan Seamus McGee, Olivia Kosterlitz, Artem Kaznatcheev, Benjamin Kerr, Carl T. Bergstrom
bioRxiv 2022.07.02.498577; doi: https://doi.org/10.1101/2022.07.02.498577
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Juaristi, Jon. - El canon espanol. El legado de la cultura española a la civi...
Quality control of susceptibility testing (Part 2)
1. Quality control of
susceptibility testing
Erika Matuschek, Ph D
EUCAST Development Laboratory (EDL)
Växjö, Sweden
ICARS - ILRI webinar series
6 April 2022
2. Routine quality control (QC)
• Monitors day-to-day reliability and reproducibility
• Control of materials and equipment
– Medium
– Antibiotic disks/concentrations in panels
– Incubators
– Etc.
• Control of the procedures
– Inoculum and inoculation
– Incubation time
– Reading of results
– Etc.
3. Target1
Range2
Target1
Range3
Amikacin 1-2 0.5-4 30 22-23 19-26
Amoxicillin 4 2-8 - - -
Amoxicillin-clavulanic acid4,5
4 2-8 20-10 21 18-246
Ampicillin 4 2-8 10 18-19 15-226
Ampicillin-sulbactam5,7
2 1-4 10-10 21-22 19-246
Aztreonam 0.125 0.06-0.25 30 32 28-36
Cefadroxil - - 30 17 14-20
Cefalexin 8 4-16 30 18 15-21
Cefepime 0.03-0.06 0.016-0.125 30 34 31-37
Cefixime 0.5 0.25-1 5 23 20-26
Cefotaxime 0.06 0.03-0.125 5 28 25-31
Escherichia coli ATCC 25922
Antimicrobial agent
MIC
(mg/L)
Disk content
(µg)
Inhibition zone diameter
(mm)
(NCTC 12241, CIP 76.24, DSM 1103, CCUG 17620, CECT 434)
See EUCAST Breakpoint Tables for short descriptions of MIC and disk diffusion methodology.
QC ranges and targets
Range
Used to allow for
random variation
Target
Mean values from repeated measurements should
optimally be on target ± 1 mm (mode MIC on target)
4. Using a complete system
• Disk diffusion methodology
– Media, inoculum, incubation time, disk potencies, reading
instructions
• QC criteria
• Breakpoints
– Zone diameter breakpoints are calibrated to clinical MIC
breakpoints using the recommended methodology
• Never mix systems/guidelines!
– EUCAST breakpoints are only valid if EUCAST
methodology is used!
6. Routine quality control
Recommended control strains
Organism Number Characteristics
E. coli ATCC 25922 Susceptible, wild type
P. aeruginosa ATCC 27853 Susceptible, wild type
S. aureus ATCC 29213 Weak β-lactamase producer
E. faecalis ATCC 29212 Susceptible, wild type
S. pneumoniae ATCC 49619 Reduced susceptibility to
benzylpenicillin
H. influenzae ATCC 49766 Susceptible, wild type
Campylobacter jejuni ATCC 33560 Susceptible, wild type
Organism Number Characteristics
E. coli ATCC 35218 TEM-1 β-lactamase
K. pneumoniae ATCC 700603 SHV-18 ESBL
K. pneumoniae ATCC BAA-2814 KPC-3 carbapenemase
S. aureus ATCC 29213 β-lactamase
7. Quality control strains
• Available from culture collections or commercial sources.
• Store by a method that minimises the risk of mutations,
for example at -70°C on beads in glycerol broth.
• Store two vials of each control strain:
1. In-use supply
2. Archive
• Always pick several colonies when subculturing a QC
strain, to avoid selecting a mutant.
• If mutation or contamination is suspected, subculture
from the archive or buy a new QC strain.
10. EUCAST QC recommendations
• Control tests should be set up and checked daily, or at least four
times per week, for antibiotics which are part of routine panels.
• Control tests should always be read and evaluated before reporting
results for clinical isolates.
• Each day that tests are set up, examine the results of the last 20
consecutive tests.
• Examine results for trends and for zones falling consistently above
or below the target.
• If two or more of 20 tests are out of range investigation is required.
EUCAST Disk Diffusion Manual, Section 9
11. Response to QC results out of range
• If two non-consecutive control zone diameters of 20 tests are
outside the acceptable range – then report susceptibility test results
and investigate.
• If two consecutive control zone diameters of 20 tests are outside the
acceptable range – then investigate before reporting susceptibility
test results. The tests may have to be repeated.
• If multiple disks (>2) are out of range on one day – then investigate
before reporting susceptibility test results. The tests may have to be
repeated.
• If resistance in a resistant control strain is not recognised – then
suppress susceptibility test results, investigate and retest.
EUCAST Disk Diffusion Manual, Section 9
12. Monitoring Laboratory QC results
Target
Upper limit
Lower limit
Single results
out of range
All results within
range but on one
side of the target
Consecutive results
out of range on same
side of the target
15. Example of registration of disk diffusion QC data
Project
Strain CTX5 CAZ10 MER10 TZP36 SXT25 CIP5 LEV5 PEF5
E. coli ATCC 25922 28 27 32 25 27 35 34 30
E. coli ATCC 25922 27 26 31 23 26 33 31 30
E. coli ATCC 25922 27 27 32 25 27 33 31 29
E. coli ATCC 25922 27 26 33 24 28 31 29 28
E. coli ATCC 25922 27 26 33 24 26 33 31 29
E. coli ATCC 25922 26 25 31 22 27 32 30 29
E. coli ATCC 25922 27 27 32 25 27 34 33 31
E. coli ATCC 25922 28 26 33 23 27 34 32 29
E. coli ATCC 25922 29 28 33 25 28 35 34 30
E. coli ATCC 25922 27 27 33 24 29 33 33 30
Mean 27 27 32 24 27 33 32 30
Target 28 26 31-32 24 26 33 33 29
Range 25-31 23-29 28-35 21-27 23-29 29-37 29-37 26-32
Strain CTX5 CAZ10 MER10 TZP36 SXT25 CIP5 LEV5 PEF5
E. coli ATCC 35218 31 29 35 27 25 34 32 31
E. coli ATCC 35218 29 28 35 23 25 31 29 28
E. coli ATCC 35218 31 30 35 27 22 33 31 30
E. coli ATCC 35218 28 28 35 25 25 32 30 28
E. coli ATCC 35218 30 29 34 26 21 31 29 28
E. coli ATCC 35218 29 28 34 23 24 31 30 28
E. coli ATCC 35218 31 30 35 27 21 32 31 30
E. coli ATCC 35218 29 29 34 23 26 32 31 27
E. coli ATCC 35218 29 29 34 25 21 32 31 27
E. coli ATCC 35218 29 28 33 23 24 31 30 27
Mean 30 29 34 25 23 32 30 28
Target - - - 24 - - - -
Range - - - 21-27 - - - -
On target ± 1 mm
Upper limit
Lower limit
Out of range
16. QC testing scheme
• Routine testing
– Daily, or at least 4 times a week (EUCAST
recommendation)
– Each agent should be tested against at least one relevant
strain
– Strains can be divided between departments (e.g. S.
aureus at wound dept, and E. coli at urine dept)
• Projects
– At each test occasion or every second day (EDL routines)
– Include relevant QC strains to cover the species of the
clinical isolates and relevant strains to control all agents
used
18. EUCAST disk QC studies
• Study layout (EUCAST SOP 9.2)
– Initial two-site study: 2 labs x 3-4 media (15
replicates)
– Validation study: ≥4 sites x local media (10
replicates)
– Disks from 2-3 disk manufacturers
• Reasonable variation between materials from
different manufacturers, test sites and readers
are built into the system
18
19. 1: Initial two-site study
0
10
20
30
40
50
60
70
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
No
of
readings
Inhibition zone diameter (mm)
Agent X vs. test site
S. pneumoniae ATCC 49619
SSI
EUCAST
0
10
20
30
40
50
60
70
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
No
of
readings
Inhibition zone diameter (mm)
Agent X vs. disk manufacturer
S. pneumoniae ATCC 49619
Mast
Liofilchem
0
10
20
30
40
50
60
70
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
No
of
readings
Inhibition zone diameter (mm)
Agent X vs. MH-F manufacturer
S. pneumoniae ATCC 49619
Oxoid IH
Oxoid C
Bio-Rad C
BBL IH
Lefamulin 5 µg
S. pneumoniae
ATCC 49619
Mean (mm) 17.9
Median (mm) 18
Range (mm) 14-24
Mean (mm) 17.9
Median (mm) 18
Range (mm) 15-22
15-21 (18)
98.2
Initial two-site QC study
(n=240)
QC validation study
(n=100)
Suggested range (target)
Readings within range (%)
Agent X
19
20. 0
5
10
15
20
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
No
of
readings
Inhibition zone diameter (mm)
Agent X (Liofilchem disks)
S.pneumoniae ATCC 49619
Verona
Växjö
Madrid
Kalmar
Istanbul
0
5
10
15
20
6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
No
of
readings
Inhibition zone diameter (mm)
Agent X (Mast disks)
S.pneumoniae ATCC 49619
Verona
Växjö
Madrid
Kalmar
Istanbul
2: Validation study
Lefamulin 5 µg
S. pneumoniae
ATCC 49619
Mean (mm) 17.9
Median (mm) 18
Range (mm) 14-24
Mean (mm) 17.9
Median (mm) 18
Range (mm) 15-22
15-21 (18)
98.2
Initial two-site QC study
(n=240)
QC validation study
(n=100)
Suggested range (target)
Readings within range (%)
Laboratory Medium
Istanbul bioMérieux commercial
Kalmar Oxoid in-house
Madrid Oxoid commercial
Växjö Bio-Rad in-house
Verona Oxoid in-house
Agent X
20
22. Example 1
• Problem: Amoxicillin-clavulanic acid zone
diameters above QC range for H. influenzae
ATCC 49766.
– Correct disk potency?
• No, 20-10 µg-disk used!
• Solution: Change to
correct disk potency
23. Example 2
• Problem: Amoxicillin-clavulanic acid zone
diameters above QC range for H. influenzae
ATCC 49766.
– Correct disk potency?
• Yes, 2-1 µg-disk used.
– Other agents within range?
• Yes, but some are in the upper part of the QC ranges.
– Amoxicillin-clavulanic acid zones for
S. pneumoniae ATCC 49619 within range?
• Yes, but in the upper part of the QC range.
24. Example 2
• Problem: Amoxicillin-clavulanic acid zone diameters
above QC range for H. influenzae ATCC 49766.
– Correct agar depth?
• Agar depth 3.0 mm
• Solution: Adjust volume of agar to achieve
agar depth of 4.0 mm.
Correct agar depth Agar depth too thin
= larger zones
25. Measuring agar depth
• Check the agar depth for all new lots of plates,
both commercial and in-house produced.
Correct agar depth: 4.0 mm, with occasional
variation between 3.5 and 4.5 mm!
26. Example 3
• Problem: Meropenem zone diameters below QC range
for H. influenzae ATCC 49766.
– Disks lost potency?
• Disks within the expiry date?
– Yes!
• Active desiccant?
– Yes!
• Correct storage?
– Yes!
– Meropenem zones for E. coli ATCC 25922, P. aeruginosa
ATCC 27853 and S. pneumoniae ATCC 49619 within
range?
• Yes, but in the lower part of the QC range for S. pneumoniae.
27. Example 3
• Problem: Meropenem zone diameters below
QC range for H. influenzae ATCC 49766.
– MH-F plates within the expiry date?
• Yes!
– MH-F plates sufficiently dry?
• No, condensation inside the lid!
• Solution: Check storage conditions and/or dry
plates prior to inoculation.
28. Drying and storage of MH-F
In-house produced
plate stored in
ventilated rack
- Clear zone edge
Commercial plate
stored in plastic bag
- Fuzzy zone edge
- Regrowth close to
disk
29. Drying and storage of MH-F
• No drops of water should be visible on the surface of the agar or
inside the lid.
• Store plates unpacked in the fridge
• Dry plates before inoculation
• 20-25°C overnight, or at 35°C, with the lid removed, for 15 min.
30. Example 4
• Problem: Tobramycin zones in the lower part of the range,
and sometimes out of range for E. coli ATCC 25922.
– Methodology adhered to?
• Yes!
– Disks and media stored and handled according to
instructions?
• Yes!
– Reproducible between batches of disks?
• Yes!
– Reproducible between batches of media?
• Yes!
31. Example 4
• Problem: Tobramycin zones in the lower part
of the range, and sometimes out of range for
E. coli ATCC 25922.
– Are results related to the MH media used?
• Yes, zones are larger when tested using the same
strain and disk on agar from another manufacturer.
32. E. coli and tobramycin
• Problem: Tobramycin zones in the lower part of the
range, and sometimes out of range for E. coli ATCC
25922.
– Do results for clinical isolates comply with reference data in the
EUCAST database?
• Yes!
– Solution: Monitor data over time
Reference
database
0
5
10
15
20
25
30
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
No
of
observations
Inhibition zone diameter (mm)
E. coli with tobramycin 10 µg
33. E. coli and tobramycin
• Problem: Tobramycin zones in the lower part of the
range, and sometimes out of range for E. coli ATCC
25922.
– Do results for clinical isolates comply with reference data in the
EUCAST database?
• No!
– Solution: Contact manufacturer and consider changing
to another manufacturer
Reference
database
0
5
10
15
20
25
30
35
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
No
of
observations
Inhibition zone diameter (mm)
E. coli with tobramycin 10 µg
34. Example 5
• Problem: Ciprofloxacin zone diameters below QC range
for E. coli ATCC 25922.
– Disks lost potency?
• Disks within the expiry date?
– Yes!
• Correct storage of disks?
– Yes!
– Media within the expiry date?
• Yes!
– Ciprofloxacin zones within ranges for other QC strains?
• Yes!
35. Example 4
• Problem: Ciprofloxacin zone diameters below QC range
for E. coli ATCC 25922.
– Agar plates correctly inoculated?
• Yes!
– Ciprofloxacin zones edges?
• Fuzzy zone edges!
• Solution: Follow reading instructions and perform
reading exercises to educate staff.
36. Reading zones
• Read MH plates from the back
against a dark background
illuminated with reflected light.
• Read MH-F plates from the
front with the lid removed
illuminated with reflected light.
37. Fuzzy zone edges
Enterobacteriaceae
• Hold the plate against a dark background about 30 cm
from the naked eye and estimate where the zone edge is.
Do not hold the plate up to light (transmitted light) or use
a magnifying glass.
Reading of zones with fuzzy zone edges for Enterobacteriaceae.
38. Example 6
• Problem: Zone diameters for multiple agents below
QC ranges for P. aeruginosa ATCC 27853 and E.
coli ATCC 25922.
– Correct agar depth?
• Yes!
– Agar plates correctly inoculated?
• No, growth too heavy due to over-inoculation!
• Solution: Make sure that plates are correctly
inoculated.
39. Inoculation of agar plates
• Spread the inoculum evenly over the entire agar surface.
• Gram-negative bacteria: remove excess fluid by pressing and
turning the swab against the inside of the tube to avoid over-
inoculation.
• Gram-positive bacteria: do not press or turn the swab against the
inside of the tube. Take particular care to ensure that there are no
gaps between streaks.
40. Example 7
• Problem: Piperacillin-tazobactam zone
diameters above QC range for K. pneumoniae
ATCC 700603.
– Pip-tazo zones within range for E. coli ATCC 25922?
• Yes, piperacillin content ok!
– Pip-tazo zones within range for E. coli ATCC 35218?
• Yes, tazobactam component ok!
– ATCC 700603 lost resistance!
• Solution: Prepare a new subculture of the QC
strain from frozen stock.
42. Example 8
• Problem: Clinical isolate of S. pneumoniae with
oxacillin zone 18 mm and PCG gradient test MIC
0.032 mg/L.
– QC data for S. pneumoniae ATCC 49619 ok?
• Oxacillin disk diffusion: Yes, the mean value is on target
±1 mm.
• PCG gradient test: Within range, but in the lower part.
• Solution: Perform BMD (or send to reference
laboratory)!
45. EUCAST/CCUG reference panel
• A panel of 10 S. pneumoniae with varying beta-
lactam susceptibility is available from CCUG for
validation of MIC determination of
benzylpenicillin in S. pneumoniae. Reference
MICs are available on the EUCAST website,
https://www.eucast.org/ast_of_bacteria/strains_
with_defined_susceptibility/.
46. Potential sources of error (1)
Medium
Storage of plates
Not prepared according to instructions
Batch to batch variation or change of supplier of agar
Supplements (batch to batch variations, incorrect amount
or expired)
pH
Agar depth/Agar volume
Expiry date
Test
conditions
“15-15-15”-rule not adhered to (suspension used within 15
min, disks applied within15 min, incubation within 15 min)
Incubation (temperature, atmosphere and time)
Incorrect inoculation (too light, too heavy or uneven)
Reading conditions (background, light)
Reading zone edges
47. Potential sources of error (2)
Disks
Incorrect disk (wrong agent or wrong disk strength)
Disk potency (incorrect storage, labile agent, expiry date)
Disks not at room temperature when containers opened
Too many disks on plate (interference between agents)
Control
organisms
Incorrect QC strain
Mutation
Contamination
Age of culture