Antimicrobial resistance profile of bacterial isolates from fecal and cloacalswab samples collected from broiler chickens in Chennai, Southern India

Abstract

This study was aimed to analyze the antimicrobial resistance profile of bacterial isolates from fecal and cloacalswab samples collected from healthy broiler chickens in Chennai. Fresh fecal droppings were collected in sterile containers and cloacal swabs were collected using nylon swabs and brought to the laboratory with cold chains. Bacterial strains were isolated from the collected samples using standard bacterial culture methods. Antimicrobial susceptibility of the isolates was screened using Kirby-Bauer disk diffusion method. Extended spectrum β-lactamase (ESBL), metallo-β-lactamase (MBL), and AmpC β-lactamaseproducers were identified using Combination Disk Method. A total of 58 bacterial strains were isolated from fresh fecal droppings and 84 from cloacal swabs collected from broiler chickens. Escherichia coli (117) was the predominantly isolated bacteria followed byKlebsiellapneumoniae(17). Bacterial isolates showed 100% resistance to ampicillin, followed by piperacillin (97.8%), polymixin-B (87.3%), piperacillin-tazobactam (85.2%), tetracycline (77.4%), andnalidixic acid (65.4%). These isolates showed highest susceptibility to fosfomycin (96.4%). ESBL production was found among 59.1% of the isolates and AmpC β-lactamase production was noted among 43.6% of the isolates. None of the bacterial isolates were tested positive for MBL production. This study finding revealed that fecal waste of broiler chickens contains β-lactamase producing multidrug-resistant bacterial strains.