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Expert Consensus on Polymyxin Antimicrobial Susceptibility Testing and Clinical Interpretation
Qi Wen Yang1, Xiao Ling Ma2, Fu Pin Hu3
1Department of Clinical Laboratory, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
Abstract:
The polymyxins are important antimicrobial agents against antibiotic-resistant gram-negative bacilli. In 2020, the Clinical and Laboratory Standards Institute modified the clinical breakpoints for polymyxin susceptibility test by eliminating the "susceptible" interpretive category, only reporting intermediate (≤2 mg/L) and resistant (≥4 mg/L). However, the European Committee on Antimicrobial Susceptibility Testing recommended the use of clinical breakpoints of ≤2 mg/L as susceptible and >2 mg/L as resistant. The first-line laboratorians and clinicians in China have been perplexed by the inconsistence of international polymyxin clinical breakpoints and discouraged by the difficulty of conducting polymyxin susceptibility testing. Therefore, it is urgently needed to make it clear for the laboratorians in China to know how to accurately carry out polymyxin susceptibility testing and standardize the interpretation of susceptibility testing results. To this end, the experts from relevant fields were convened to formulate this consensus statement on the testing and clinical interpretation of polymyxin susceptibility. Relevant recommendations are proposed accordingly for laboratorians and clinicians to streamline their daily work.
Insights
Polymyxin breakpoints differ internationally, confusing Chinese labs. This consensus provides clear guidance on polymyxin susceptibility testing and results interpretation for accurate clinical use.
Area of Science:
- Microbiology
- Clinical Pharmacy
Background:
- Polymyxins are crucial for treating infections caused by antibiotic-resistant gram-negative bacteria.
- Conflicting international guidelines on polymyxin susceptibility testing create challenges for Chinese laboratorians and clinicians.
Purpose of the Study:
- To clarify polymyxin susceptibility testing methods and interpretation standards for Chinese laboratories.
- To address the inconsistencies in clinical breakpoints set by international bodies.
Main Methods:
- Convening experts from relevant fields to develop a consensus statement.
- Reviewing and analyzing existing international guidelines from CLSI and EUCAST.
- Formulating practical recommendations for daily laboratory work.
Main Results:
- Identified discrepancies between the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoint recommendations.
- Highlighted the difficulties faced by Chinese laboratorians in performing and interpreting polymyxin susceptibility tests.
Conclusions:
- A standardized approach to polymyxin susceptibility testing and interpretation is urgently needed in China.
- The consensus statement provides clear recommendations to streamline daily practices for laboratorians and clinicians.
- Accurate testing and interpretation will improve the clinical management of infections caused by resistant gram-negative bacilli.
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