An update on carbapenem-resistant Enterobacterales: A prospective study from Western India

Abstract

Introduction: Antimicrobial resistance is a global health threat. Carbapenem-resistant Enterobacterales (CRE) are increasingly becoming an important cause of concern. We aimed to present a comprehensive update on CRE, including their prevalence, antimicrobial susceptibility profile, phenotypic and genotypic characterization. The study also evaluated the activity of ceftazidime-avibactam (CZA) against CRE.

Materials and methods: This was a prospective observational study conducted in a multispecialty tertiary care teaching hospital in Jaipur, western India. All consecutive non-duplicate CRE strains isolated from various clinical samples received in the laboratory during the study period were included in the study. Detection of carbapenemase enzyme production and phenotypic characterization was done using modified carbapenem inactivation method (mCIM) and EDTA-modified carbapenem inactivation method (eCIM), respectively, and genotypic detection was performed by multiplex PCR.

Results: CRE prevalence was 43%, and 91% were found to be carbapenemase producers. In addition, 94%, 91%, 21%, and 20% susceptibility was observed for tigecycline, colistin, amikacin, and trimethoprim/sulfamethoxazole, respectively. Thirty-three percent of CRE were susceptible to CZA alone, and 93% were found to exhibit synergy between CZA and aztreonam. The most prevalent carbapenemase gene detected in the current study was bla OXA-48 , which was found in 61.4% of the isolates tested. More than one carbapenemase gene was detected in 35% of the isolates.

Conclusions: This study highlights the escalating threat of CRE and emphasizes the pressing need for their continuous surveillance for appropriate management.

Keywords: Carbapenem-resistant Enterobacterales; carbapenemase production; ceftazidime–avibactam; multiplex PCR; synergy testing.

Figure 1

Result of mCIM and eCIM tests, and summary of the workflow and results of the study. CRE = carbapenem-resistant Enterobacterales, CZA = ceftazidime–avibactam

Figure 2

Representative gel image showing amplification of CRGs (bla_OXA, bla_NDM, and bla_KPC) among isolates

Figure 3

Distribution of carbapenemase genes (bla_OXA, bla_NDM, bla_KPC, bla_IMP, and bla_VIM) among the isolates. The pink highlighted region shows the presence of CRG, and the pale white region shows the absence of CRG