Molecular and genetic characterization of carbapenemase-producing bacteria in Venezuela

Carbapenem-resistant Gram-negative bacteria isolated in Venezuela have been poorly characterized. The present study characterized a total of 34 isolates obtained from 27 patients; five of these patients were multi-infected. The bacterial species identified were Klebsiella pneumoniae (17), Pseudomonas aeruginosa (9), and Acinetobacter baumannii (8). From these isolates, 85% were identified as carbapenemase-producing bacteria, and the identified carbapenemase genes were blaKPC-2 (10/29 [34.4%]), blaVIM-type (7/29 [24.1%]), blaOXA-23 (7/29 [24.1%]), blaNDM-1 (8/29 [27.5%]), and the coexistence of blaOXA-23/blaNDM-1 (2/29 [6.8%]). Patient 1 was multi-infected by K. pneumoniae ST11 and ST2413 isolates harbouring the blaNDM-1 and blaKPC-2 genes, respectively. The other patients were multi-infected by two or three different bacterial species such as ESBL-producing K. pneumoniae isolates, P. aeruginosa harbouring the blaVIM-type gene, K. pneumoniae ST147 harbouring the blaKPC-2 gene and by A. baumannii harbouring the blaOXA-23 gene. The blaNDM-1 gene in A. baumannii is flanked by an uncommon genetic structure, whereas blaNDM-1 gene in K. pneumoniae revealed a common structure described in different plasmids from Enterobacteriaceae isolates. This study provides new information about the epidemiology of carbapenemase-producing bacteria in clinical setting in Venezuela.