Comparison of sCIM and mCIM for Detection of Carbapenemase-producing Carbapenem-Resistant Enterobacterales in Saraburi Hospital

Abstract

This study aimed to compare the efficacy of phenotypic detection of CPE (carbapenemase-producing Enterobacterales)  between simplified carbapenem inactivation method (sCIM)  and modified carbapenem inactivation method (mCIM) comparable with genotypic method (multiplex PCR; polymerase chain reaction). The sCIM is based on the mCIM with the improvement of experimental procedures. Instead of 4-hours incubating the meropenem disk in trypticase soy broth medium, the organism was smeared directly onto the imipenem disk in the sCIM. The results revealed that the prevalence of CRE (carbapenem-resistant Enterobacterales)  was 1.38%, classified as Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli (64.42, 19.23, and 16.35%, respectively). Comparing the results of CPE detection, both methods and multiplex PCR showed 100% concordance with positive results for all 103 strains and negative results for 1 strain.  (Cohen’s kappa = 1.0, 95%CI =1.0-1.0). Thus, the sCIM is easy to perform, reducing the step to make it more convenient, cost-effective, and does not require special tools, however, the amount of bacterial load has been carefully considered. Therefore, the sCIM may be suitable for routine use in clinical microbiology laboratories.