Molecular detection of CTX-M ESBL-encoding genes in Escherichia coli isolated from quail cloacal swabs in Surabaya markets.

Abstract

Background: Escherichia coli (E. coli)is a common commensal bacterium in poultry and a key indicator of antimicrobial resistance (AMR). The emergence of extended-spectrum β-lactamase (ESBL)-producing strains, particularly those carrying cefotaximase (CTX-M) genes, poses a significant One Health concern. However, data on CTX-M-producing E. coli in quails from traditional markets in Surabaya are limited.

Aim: This study aimed to detect the CTX-M gene in E. coli isolates obtained from quail cloacal swabs from traditional markets in Surabaya and to assess their antimicrobial resistance profiles.

Methods: A total of 100 cloacal swab samples were collected from quails in five traditional markets from November to December 2024. Escherichia coli isolation and identification were performed using Eosin Methylene Blue Agar, Gram staining, and biochemical tests. The Kirby-Bauer disk diffusion method was also used to assess antibiotic sensitivity in accordance with the Clinical and Laboratory Standards Institute guidelines. The CTX-M gene was then detected in aztreonam (ATM)-resistant isolates using polymerase chain reaction (PCR).

Results: Of the 100 samples, 98% were confirmed to be E. coli. High resistance to ciprofloxacin (50%), tetracycline (33.67%), and ATM (20.4%) was observed. Four isolates (4.08%) demonstrated multidrug resistance. Among 20 ATM-resistant isolates, eight tested positive for CTX-M genes by PCR. Resistance patterns differed among markets due to differences in antimicrobial usage or exposure.

Conclusion: The high prevalence of E. coli and the detection of CTX-M-positive isolates indicate that traditional markets may act as reservoirs of ESBL-producing bacteria in quails. These findings underscore the need for strengthened AMR surveillance, improved hygiene practices, and One Health-oriented interventions along the quail production and distribution chain.