Endemicity of OXA-48 and NDM-1 Carbapenemase Producing Klebsiella pneumoniae and Escherichia coli from a Tertiary Hospital in Varanasi, India

Background: Increase in global dissemination of NDM-1 and OXA-48 particularly among Klebsiella pneumoniae and Escherichia coli pose serious threat to antimicrobial therapy.

Aim: This study investigated the prevalence of OXA-48 like and NDM-1 among clinical isolates of K. pneumoniae and E. coli. E. coli and K. pneumoniae were isolated from clinical samples collected from patients’ referred to microbiology laboratory for diagnosis.

Study Design: Investigative.

Method: Minimum inhibitory concentration break point for carbapenem and third generation cephalosporin on multidrug resistant isolates of K. pneumoniae and E. coli were determined by agar dilution method and carbapenem resistant isolates identified. DNA templates from the carbapenem resistant isolates were extracted by boiling and centrifugation method, and the extracted DNA template were later subjected to a multiplex PCR-based detection of the blaNDM-1 and blaOXA-48 genes. Amplicon positive for NDM-1 and OXA-48 were sequenced and a blast search was performed on the sequenced data on NCBI data base. A total of 293 E. coli and 236 K. pneumoniae were isolated, and 391 of these isolates were multidrug resistant. 159 isolates; comprising of 64 E. coli and 75 K. pneumoniae, of the multidrug resistant isolates were identified as carbapenem resistant enterobacteriaceae. Fifty; 50/159(31.4%) isolates were positive for NDM-1 and 44/159(27.7%) for OXA-48, while 17/159(10.7%) co-harboured NDM-1 and OXA-48 like genes. Sequence data for NDM-1 and OXA-48 revealed 99% sequence identity to sequences containing NDM-1 and OXA-181 respectively.

Conclusion: OXA-48-like carbapenemases are the most difficult to identify in routine diagnosis hence the need to formulate a robust routine diagnostic and infection control policy to curb the spread of pathogens habouring these carbapenem resistance genes.