Isolation of Escherichia coli from faecal matter of wild captive animal species of Rajasthan

Abstract

Background:  Transmission of Zoonotic diseases of antimicrobial-resistant bacteria from wildlife to humans is a matter of serious global concern. Among these, Escherichia coli (E. coli) serves as an effective indicator of faecal contamination and antimicrobial resistance in all the major species including both human and animal populations.

Objectives: This study aimed to isolate and characterize E. coli from the faecal samples of wild captive animals in two zoological parks in Rajasthan, India—Bikaner Zoo and Machia Biological Park, Jodhpur—and assess their antimicrobial resistance profiles.

Methods: A total of 66 faecal samples were collected aseptically from various captive wild species residing in two biological parks of Rajasthan. Isolation was performed as per protocol  using standard culture techniques on MacConkey and EMB agar. Identification was done by Gram staining and Confirmation using biochemical profiling through the VITEK 2 system and genotypic confirmation via 16S rRNA gene PCR amplification. Antimicrobial susceptibility was examined using the disc diffusion method against 15 commonly used antibiotics, and resistance was interpreted following CLSI guidelines.

Results: Out of 66 samples, 59 isolates were confirmed as Escherichia coli, yielding an overall recovery rate of 89.39%. Bikaner Zoo showed a higher prevalence (92.38%) compared to Machia Biological Park (84%). Antibiogram results indicated high sensitivity to ciprofloxacin and gentamicin, while significant resistance was observed against polymyxin B, cefaclor, and cefepime. VITEK 2 accurately identified 100% of the isolates, and 16S rRNA PCR confirmed their genetic identity.