Integron Carriage among Carbapenem Resistant Enterobacteriaceae Isolated from a Tertiary Hospital in North India

Background: Carbapenem resistant enterobacteriaceae (CRE) constitute major public health threat. They account for significant morbidity and mortality and also present patients with difficult to treat infection. This study examines the integron carriage rate and gene content among CRE.

Methods: Samples were collected from patients and enterobacteriaceae identified in accordance with standard practice. Antimicrobial susceptibility testing was performed in line with CLSI guidelines, and referenced criteria were used to screen for multidrug resistant enterobacteriaceae (MDRE) and carbapenem non susceptible isolates (CNSI). Further susceptibility test of the CNSI to carbapenems and third generation cephalosporin by agar dilution method as per CLSI guide lines was performed to screen for CRE, and Int1and Int2 specific primers were used to amplify class 1 and 2 integron respectively. IntCS primer was used to amplify integrons variable region and a blast search on the amplicons’ sequenced data was performed on NCBI site to identify the gene content. Results: Of the 512 MDRE, 62.1% were CNSI and 56.0% of the CNSI were CRE. While K. pneumoniae and E. coli were the predominant isolates, 87.1% and 9.0% of the CRE isolates were positive for integron class 1 and 2 respectively. The amplified variable region did not reveal the presence of carbapenemase coding gene.

Conclusion: Although the variable region did not show presence of carbapenemase coding gene, high class 1 integron carriage rate underscore high potentials for dissemination of resistance determinants among isolates, thus the need to step up infection control measures in order to reduce spread of these pathogens.