scholarly journals CIM City: the Game Continues for a Better Carbapenemase Test

2019 ◽  
Vol 57 (7) ◽  
Author(s):  
Romney M. Humphries
Keyword(s):  
Antimicrobial Susceptibility ◽  
Clinical Microbiology ◽  
Susceptibility Testing ◽  
Clinical Care ◽  
Antimicrobial Susceptibility Testing ◽  
European Committee ◽  
Link Type ◽  
Clinical Laboratories ◽  
The Right

ABSTRACT The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing agree that carbapenemase testing is not necessary for clinical care, provided that the laboratory is up to date with current breakpoints. Nonetheless, publication on the development and modification of carbapenemase tests continues, as is the case in this issue of the Journal of Clinical Microbiology (R. W. Beresford and M. Maley, J Clin Microbiol 57:e01852-18, 2019, https://doi.org/10.1128/JCM.01852-18). This commentary explores modifications to the carbapenem inactivation method—but is this the right focus for clinical laboratories?

scholarly journals Point-Counterpoint: Differences between the European Committee on Antimicrobial Susceptibility Testing and Clinical and Laboratory Standards Institute Recommendations for Reporting Antimicrobial Susceptibility Results

2019 ◽  
Vol 57 (9) ◽  
Author(s):  
Gunnar Kahlmeter ◽  
Christian G. Giske ◽  
Thomas J. Kirn ◽  
Susan E. Sharp
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Test Results ◽  
Diffusion Test ◽  
Disk Diffusion Test ◽  
Technical Variability ◽  
European Committee ◽  
Clinical Laboratories ◽  
Antibiotic Susceptibility Test

INTRODUCTION Antibiotic susceptibility test results are among the most important results issued by clinical microbiology laboratories because they routinely guide critical treatment decisions. Interpretations of MIC or disk diffusion test results, such as “susceptible” or “resistant,” are easily understood. Clinical laboratories also need to determine whether and how their reports will reflect more complex situations. Such situations include, first, whether there is need to administer higher or more frequent doses of antibiotic than usual for clinical efficacy; second, whether an antimicrobial is likely to be effective at a body site where it concentrates; and third, whether there is some uncertainty in the test results due to technical variability that cannot be eliminated. Two leading organizations that set standards for antimicrobial susceptibility testing, the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI), have taken different strategies to deal with these challenges. In this Point-Counterpoint, Gunnar Kahlmeter and Christian Giske discuss how EUCAST is addressing these issues, and Thomas Kirn and Susan Sharp discuss the CLSI approach.

scholarly journals Public Health Efforts Can Impact Adoption of Current Susceptibility Breakpoints, but Closer Attention from Regulatory Bodies Is Needed

2018 ◽  
Vol 57 (3) ◽  
Author(s):  
James A. McKinnell ◽  
S. Bhaurla ◽  
P. Marquez-Sung ◽  
A. Pucci ◽  
M. Baron ◽  
...  
Keyword(s):  
Public Health ◽  
Patient Safety ◽  
Los Angeles ◽  
Antimicrobial Susceptibility ◽  
Los Angeles County ◽  
Susceptibility Testing ◽  
Clinical Care ◽  
Public Health Intervention ◽  
Antimicrobial Susceptibility Testing ◽  
Outreach Program

ABSTRACT Microbiological testing, including interpretation of antimicrobial susceptibility testing results using current breakpoints, is crucial for clinical care and infection control. Continued use of obsolete Enterobacteriaceae carbapenem breakpoints is common in clinical laboratories. The purposes of this study were (i) to determine why laboratories failed to update breakpoints and (ii) to provide support for breakpoint updates. The Los Angeles County Department of Public Health conducted a 1-year outreach program for 41 hospitals in Los Angeles County that had reported, in a prior survey of California laboratories, using obsolete Enterobacteriaceae carbapenem breakpoints. In-person interviews with hospital stakeholders and customized expert guidance and resources were provided to aid laboratories in updating breakpoints, including support from technical representatives from antimicrobial susceptibility testing device manufacturers. Forty-one hospitals were targeted, 7 of which had updated breakpoints since the prior survey. Of the 34 remaining hospitals, 27 (79%) assumed that their instruments applied current breakpoints, 17 (50%) were uncertain how to change breakpoints, and 10 (29%) lacked resources to perform a validation study for off-label use of the breakpoints on their systems. Only 7 hospitals (21%) were familiar with the FDA/CDC Antibiotic Resistance Isolate Bank. All hospitals launched a breakpoint update process; 16 (47%) successfully updated breakpoints, 12 (35%) received isolates from the CDC in order to validate breakpoints on their systems, and 6 (18%) were planning to update within 1 year. The public health intervention was moderately successful in identifying and overcoming barriers to updating Enterobacteriaceae carbapenem breakpoints in Los Angeles hospitals. However, the majority of targeted hospitals continued to use obsolete breakpoints despite 1 year of effort. These findings have important implications for the quality of patient care and patient safety. Other public health jurisdictions may want to utilize similar resources to bridge the patient safety gap, while manufacturers, the FDA, and others determine how best to address this growing public health issue.

scholarly journals Data Mining Validation of Fluconazole Breakpoints Established by the European Committee on Antimicrobial Susceptibility Testing

2009 ◽  
Vol 53 (7) ◽  
pp. 2949-2954 ◽  
Author(s):  
Isabel Cuesta ◽  
Concha Bielza ◽  
Pedro Larrañaga ◽  
Manuel Cuenca-Estrella ◽  
Fernando Laguna ◽  
...  
Keyword(s):  
Machine Learning ◽  
Antimicrobial Susceptibility ◽  
Roc Curve ◽  
False Positive ◽  
Statistical Power ◽  
Susceptibility Testing ◽  
False Positive Rate ◽  
Antimicrobial Susceptibility Testing ◽  
European Committee ◽  
Positive Rate

ABSTRACT European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints classify Candida strains with a fluconazole MIC ≤ 2 mg/liter as susceptible, those with a fluconazole MIC of 4 mg/liter as representing intermediate susceptibility, and those with a fluconazole MIC > 4 mg/liter as resistant. Machine learning models are supported by complex statistical analyses assessing whether the results have statistical relevance. The aim of this work was to use supervised classification algorithms to analyze the clinical data used to produce EUCAST fluconazole breakpoints. Five supervised classifiers (J48, Correlation and Regression Trees [CART], OneR, Naïve Bayes, and Simple Logistic) were used to analyze two cohorts of patients with oropharyngeal candidosis and candidemia. The target variable was the outcome of the infections, and the predictor variables consisted of values for the MIC or the proportion between the dose administered and the MIC of the isolate (dose/MIC). Statistical power was assessed by determining values for sensitivity and specificity, the false-positive rate, the area under the receiver operating characteristic (ROC) curve, and the Matthews correlation coefficient (MCC). CART obtained the best statistical power for a MIC > 4 mg/liter for detecting failures (sensitivity, 87%; false-positive rate, 8%; area under the ROC curve, 0.89; MCC index, 0.80). For dose/MIC determinations, the target was >75, with a sensitivity of 91%, a false-positive rate of 10%, an area under the ROC curve of 0.90, and an MCC index of 0.80. Other classifiers gave similar breakpoints with lower statistical power. EUCAST fluconazole breakpoints have been validated by means of machine learning methods. These computer tools must be incorporated in the process for developing breakpoints to avoid researcher bias, thus enhancing the statistical power of the model.

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