Prevalence of Metallo-β-Lactamase IMP and VIM Producing Gram Negative Bacteria in Different Hospitals of Lahore, Pakistan

Gram negative rod (GNR) infections cause a substantial amount of morbidity and mortality among hospitalized patients across the globe. Currently, beta-lactam ring containing antibiotics predominantly carbapenems, are considered as last treatment option against multi-drug resistance GNR infections. However, the emergence of carbapenemases particularly metallo beta-lactamases (MBLs) in bacteria have severely mitigated the efficiency of carbapenems. MBLs producing gram-negative bacteria have been reported from various hospital settings, worldwide. However, data is lacking in Pakistan regarding their frequency particularly among GNRs. Therefore, the present study aimed at determining the frequency of carbapenemase and beta-lactamase producing GNRs recovered from different tertiary care hospitals of Lahore during January-December 2015. Additionally, existence of bla(IMP) and bla(VIM) carbapenems resistance determinant genes in carbapenems resistant isolates was also evaluated. The carbapenemase and beta-lactamases production were evaluated by Modified Hodge test (MHT) and combined disks diffusion (CDD) method, respectively. The MBL producing clinical isolates were further subjected to PCR for the existence of bla(IMP) and bla(VIM) genes. The carbapenem resistant A. baumannii (n=32), P. aeruginosa (n=26), K. pneumoniae (n=19), E. coli (n=16), C. ferundi (n=04), P. vulgaris (n=02) and E. cloacae (n=01), were isolated from clinical samples of hospitalized patients. Out of these 100 carbapenem resistant isolates, 93 and 89 isolates were positive for cabapenemase and beta-lactamase production, respectively. Notably, 3 (3.3%) of MBL producing strains harbor bla(IMP) gene while 29 (32.5%) of MBL producing clinical strains were positive for bla(VIM) gene. In a nutshell, several species of MBL-positive gram-negative rods are distributed broadly in different hospitals of Lahore region of Pakistan. The findings of the present study should be considered for planning strategies to treat and prevent the further spread of MBL-producing gram-negative rods infections.