Prevalence and clonal relatedness of NDM and OXA-48-producing in a tertiary care hospital in South India.

Background: Carbapenems are used for the treatment of serious infections caused by multidrug-resistant . Resistance to carbapenems in is mainly due to metallo-beta-lactamases (NDM, IMP, and VIM) and class D oxacillinase (OXA-48-like).

Aim And Objective: This study was undertaken to detect the genes encoding for carbapenemase in and to determine the clonal relatedness of selected isolates of producing NDM and OXA-48 by pulsed-field gel electrophoresis method (PFGE).

Materials And Methods: The isolates were collected over a period of 1 year. A total of 370 clinically significant, nonduplicate isolates of were included in this study. Phenotypic tests for the detection of carbapenemases were performed for all the isolates. Polymerase chain reaction (PCR) was carried out for the detection of carbapenemase genes such as , , , , and . PFGE was performed, and the PFGE profiles were analyzed and compared using BioNumerics version 7.6.

Results: Of the 370 isolates of , carbapenemase genes were detected in 13.78% (51/370). was the prevalent gene detected followed by and . Thirty strains of selected by PFGE analysis were divided into five clusters (A, B, C, D, and E). Cluster C was the major type detected carrying and genes.

Conclusion: was the most prevalent gene detected in this study. PCR is useful in detecting carbapenemase genes, especially , which may show false susceptibility to carbapenems. There was no direct correlation detected between PFGE profiles and antibiotic susceptibility pattern. PFGE has revealed the genomic diversity among isolates, thereby suggesting heterogeneity in strain circulation within intensive care unit and wards of the hospital. Monitoring and molecular typing is essential to curtail the spread of multidrug-resistant strains and control the outbreaks of infection.