Adaptation of bla_NDMthrough IncP plasmid within broad host range

It was also known that the IncP-1 plasmids are ubiquitous in environmental bacteria and those reside in soil, sewage, marine sediments and in manure. The bla_NDMis associated with resistance determinants along with various mobile elements such as plasmid, insertion sequences and transposons, which facilitates its horizontal dissemination. These plasmids, if tracked, can be a starting point for the control of infection due to multidrug-resistant pathogens. The aim of the study was to investigate that IncP-type plasmids carrying bla_NDMis adapted in different hosts.

Thirteen of the isolates were harbouring IncP-type plasmid and they all were Escherichia coli isolated from hospitalised patients of Silchar Medical College and Hospital, India. The isolates were checked for susceptibility test, and the stability was assessed by a serial passage. These isolates were further subjected to transcriptional analysis of NDM gene as well as plasmid copy number alteration.

The study isolates were highly stable, and the resistance gene (bla_NDM) was retained within isolates till 55^th subsequent serial passages. Plasmid copy number alteration was random in isolates when exposed to carbapenem antibiotics, whereas increasing trend in transcriptional expression was observed with the increase in imipenem concentration.

This study was able to underscore the presence of IncP plasmid that was harbouring bla_NDMand was maintained within diverse host. The finding also highlights the adaptation of the broad-host-range plasmid that responds in terms of transcriptional expression under antibiotic exposure.