Plasmid-mediated quinolone resistance in Escherichia coli isolates from commercial broiler chickens in Semnan, Iran

Behrouz Javadi; Khatereh Kafshdouzan; Seyed Hesamoddin  Emadi Chashmi; Omid Pazhand

doi:10.18502/ijm.v16i2.15352

Behrouz Javadi Department of Pathobiology, School of Veterinary Medicine, Semnan University, Semnan, Iran
Khatereh Kafshdouzan Department of Pathobiology, School of Veterinary Medicine, Semnan University, Semnan, Iran
Seyed Hesamoddin Emadi Chashmi Department of Clinical Sciences, School of Veterinary Medicine, Semnan University, Semnan, Iran
Omid Pazhand Department of Microbiology, Semnan University of Medical Sciences, Semnan, Iran

DOI: https://doi.org/10.18502/ijm.v16i2.15352

Keywords: Anti-bacterial agents; Drug resistance; Escherichia coli; Poultry diseases; Quinolones

Abstract

Background and Objectives: Antibiotic resistance within the poultry sector presents a considerable health concern due to treatment inefficacy and resistance transmission to humans and the environment. The investigation of plasmid-mediated quinolone resistance (PMQR) in Escherichia coli, acknowledged for its role in advancing resistance, remains inadequately studied in Iranian poultry. This study aimed to evaluate PMQR gene prevalence as well as to determine correlation between resistance phenotype and genotype in E. coli obtained from poultry colibacillosis.

Materials and Methods: A collection of 100 E. coli isolates from the viscera of broilers suspected to colibacillosis was assessed. Using the Kirby-Bauer disk diffusion method, antimicrobial susceptibility tests were conducted for ofloxacin, nalidixic acid, levofloxacin, ciprofloxacin, and ampicillin. Additionally, PCR was employed to screen for qnrS, qnrB, and aac(6)Ib-cr genes.

Results: Among the analyzed E. coli isolates, 51% demonstrated resistance to at least one of the tested antibiotics, with 17% exhibiting resistance to four different antibiotics. Nalidixic acid displayed the highest resistance rate at 48%, while ampicillin had the lowest at 16%. PMQR genes were detected in 28% of the E. coli isolates, with aac(6′)-Ib-cr being the most prevalent at 14%, followed by qnrB in 13%, and qnrS in 7%.

Conclusion: The study underscores the vital need for careful antibiotic usage in poultry to curb the emergence of antibi- otic-resistant bacteria. The results illuminate the prevalence of PMQR genes and their association with resistance trends in Iranian poultry, forming a pivotal basis for forthcoming approaches to combat antibiotic resistance within the poultry sector.