Head of EUCAST Bacterial Development Laboratory
Antimicrobial susceptibility testing (AST) is pivotal in both individualized and empirical treatments. Notably, standards set for interpreting AST results enable clinicians to choose suitable medications and optimal treatment plans, acting as a significant tool in controlling antimicrobial resistance. The most influential bodies in this space are the Clinical and Laboratory Standards Institute (CLSI) of the United States and the European Committee on Antimicrobial Susceptibility Testing (EUCAST). These entities aim to standardize AST procedures and reduce experimental errors.
The Problem at Hand:
Despite their aligned goals, the recommended antimicrobial content by both CLSI and EUCAST sometimes differs, creating potential issues in the field. In 2018, to address these discrepancies, both bodies established a joint working group. The latest progress of this initiative was presented by Dr. Erika Matuschek, head of EUCAST’s Bacterial Development Laboratory, at the 33rd European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2023).
Methods:
The united approach by CLSI and EUCAST targets the optimization of the paper disk diffusion test, a globally recognized standard method. After in-depth reviews of past research on content selection for antimicrobial paper disks, a standard selection procedure was proposed.
Results:
– Phase one involved testing ten different concentrations of antimicrobial disks on at least four isolates of each relevant target bacteria.
– The second phase utilized the best 2-4 antimicrobial concentrations from phase one. This stage involved more strains, including wild-type isolates and those with higher minimum inhibitory concentrations (MICs).
– Data from each bacterial group was presented graphically, and adherence to the selection criteria was verified.
The standard criteria for single antimicrobial paper disk selection were detailed, emphasizing repeatability, applicability across various bacterial strains, and robust differentiation capabilities.
Expert Insight:
In an interview with Infectious Disease Frontline (IDF), Dr. Matuschek highlighted her role at the EUCAST Development Laboratory in Sweden. The team, she noted, is dedicated to the continual development and maintenance of EUCAST’s methods. Their efforts span from developing criteria for new antimicrobial agents to enhancing quality control across laboratories.
Dr. Matuschek also emphasized the pivotal role of AST in determining the treatment course for severe infections like bloodstream infections. Rapid results can facilitate prompt and more effective treatment, curbing the development of antibiotic resistance.
Summary:
The joint effort by CLSI and EUCAST has led to a unified procedure for AST, which is now available online. This alignment between the entities offers advantages to pharmaceutical companies, antimicrobial disk manufacturers, and testing laboratories, aiming to standardize approaches and improve patient care outcomes.
