Development and Evaluation of Multiplex PCR for the Detection of Carbapenemase-Producing Enterobacteriaceae

Background: The isolation of carbapenemase-produc-ing Enterobacteriaceae (CPE) has become increas-ingly common. Continuous surveillance for these or-ganisms is essential because their infections are closely related to outbreaks of illness and are asso-ciated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously. Methods: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbape-nem-susceptible clinical strains. Results: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis , Escherichia coli , Klebsiella pneumoniae , Acinetobacter baumannii , and Pseudomonas aeruginosa , showed negative results. Conclusion: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories. (Ann Clin Microbiol 2019;22:9-13)