Understanding and Addressing CLSI Breakpoint Revisions: a Primer for Clinical Laboratories

Abstract

The Clinical and Laboratory Standards Institute (CLSI) has revised several breakpoints since 2010 for bacteria that grow aerobically. In 2019, these revisions include changes to the ciprofloxacin and levofloxacin breakpoints for the Enterobacteriaceae and Pseudomonas aeruginosa, daptomycin breakpoints for Enterococcus spp., and ceftaroline breakpoints for Staphylococcus aureus. Implementation of the revisions is a challenge for all laboratories, as not all systems have FDA clearance for the revised (current) breakpoints, compounded by the need for laboratories to perform validation studies and to make updates to laboratory information system/electronic medical record builds in the setting of limited information technology infrastructure. This minireview describes the breakpoint revisions in the M100 supplement since 2010 and strategies for the laboratory on how to best adopt these in clinical testing.

The Clinical and Laboratory Standards Institute Subcommittee on Antimicrobial Susceptibility Testing: Background, Organization, Functions, and Processes

“…This has resulted in most, but not all, of the CLSI breakpoints in M100 being listed in the STIC table. A discussion of the reasons why certain CLSI breakpoints are not in the FDA STIC table can be found elsewhere (7).…”

Prevalence, serotypes, and antimicrobial resistance of Salmonella isolates from patients with diarrhea in Shenzhen, China

“…The MacFarland 0.5 inoculums were prepared and swabbed on the entire surface of Mueller-Hinton agar (Huankai, China) and left to dry for 3-5 min. Antimicrobial susceptibility test discs (Oxoid, UK) were placed on the inoculated agar plate with a disc dispenser (Oxoid, UK) and incubated at 37°C for 24 h. After incubation, the diameter of inhibition zone was measured and the results were interpreted as susceptible, intermediate, and resistant according to the Clinical and Laboratory Standards Institute guideline (CLSI, 2019) [38]. Escherichia coli strain ATCC 25922 and Pseudomonas aeruginosa strain ATCC 27853 was used as quality control for disk diffusion and Vitek-2 compact system, respectively.…”

Antimicrobial Susceptibility Testing of Antimicrobial Peptides to Better Predict Efficacy

“…Most AST, and its interpretation, is conducted using internationally recognised standards developed by bodies including the International Organization for Standardization (ISO), Clinical and Laboratory Standards Institute (CLSI), the European Committee on Antimicrobial Susceptibility Testing (EUCAST), The United States Committee on Antimicrobial Susceptibility Testing (USCAST) and the US Food and Drug Administration (FDA) Center for Drug Evaluation and Research (CDER) ( Table 1 ) (Magiorakos et al, 2012 ; Kahlmeter, 2015 ; Humphries et al, 2019 ). Susceptibility Test Interpretive Criteria (STIC), also known as “breakpoints,” are used to determine the optimal dose of antimicrobials for treating infection and are based on those published by the CLSI, EUCAST, USCAST and the FDA.…”

“…Antimicrobial susceptibility testing (AST) determines the concentration of an antimicrobial that inhibits microbial growth, for both microbicidal and microbiostatic agents (Brown et al, 2016 ; Sanguinetti and Posteraro, 2018 ; Humphries et al, 2019 ; van Belkum et al, 2019 ). The importance of accurate AST in at least guiding antibiotic use in the clinic cannot be underestimated (Doern et al, 1994 ; Kumar et al, 2009 ; Weiss et al, 2012 ; Holmes et al, 2016 ).…”