Performance Evaluation of Newly Developed Korean Antimicrobial Susceptibility Testing Panels for MicroScan System Using Clinical Isolates from Teaching Hospitals in Korea

Abstract

Background: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea. Methods: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods. Results: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were ＞90% in all the antimicrobials tested in this study. The rates of major error (ME) were also ＜3%, and only three very major error (VME) were identified; each of ampicillin, tetracycline, and quinupristin-dalfopristin in enterococcal isolates. By KSCM-2 panel for Enterobacteriaceae, the rates of CA were also above 90%, and those of ME and VME were less than 3% and 1.5%, respectively. KSCM-3 panels for glucose- non-fermenting Gram-negative bacilli, also showed good agreement rates, i.e., CA rates ＞90%, ME rates ＜3%, and VME rates ＜1.5%. Conclusion: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories.