Study of biofilm formation and antibiotic resistance pattern of gram-negative Bacilli among the clinical isolates at BPKIHS, Dharan

Gram-negative bacilli are the common causative agents for community-acquired, nosocomial and opportunistic infections. The recent upsurge of biofilm, as well as beta-lactamases producing strains, have synergistically led to the extensive dissemination of multi-drug resistant gram-negative bacilli. This study was carried out with an intention to detect the biofilm formation by gram-negative bacilli and determine their antibiogram along with the detection of extended-spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) production. Among 314 isolates, Escherichia coli (38%) were the predominant isolates followed by Acinetobacter spp. (20%), Klebsiella spp. (16%), and Pseudomonas spp. (12%). Overall, 197 (62.73%) of isolates were biofilm positive. 84 (26.75%) and 51 (16.24%) were confirmed as ESBL and MBL producers respectively. The association between MBL production and biofilm formation was statistically significant ( χ 2 = 10.20, P value= 0.002) whereas it was insignificant between ESBL and biofilm production (χ 2 = 0.006, P -value= 0.937). Most of the biofilm and MBL producing strains were multi-drug resistant.