Vet World   Vol.11   December-2018  Article-12

Prevalence and molecular detection of fluoroquinolone-resistant genes (qnrA and qnrS) in Escherichia coli isolated from healthy broiler chickens

Background and Aim: The present study was carried out to determine the prevalence and molecular detection of fluoroquinolone-resistant Escherichia coli carrying qnrA and qnrS genes in healthy broiler chickens in Mymensingh, Bangladesh, and also to identify the genes responsible for such resistance.

Materials and Methods: A total of 65 cloacal swabs were collected from apparently healthy chickens of 0-14 days (n=23) and 15-35 days (n=42) old. The samples were cultured onto Eosin Methylene Blue Agar, and the isolation and identification of the E. coli were performed based on morphology, cultural, staining, and biochemical properties followed by polymerase chain reaction (PCR) targeting E. coli 16S rRNA genes. The isolates were subjected to antimicrobial susceptibility test against five commonly used antibiotics under fluoroquinolone (quinolone) group, namely gatifloxacin, levofloxacin, moxifloxacin, ofloxacin, and pefloxacin by disk diffusion method. Detection of qnrA and qnrS genes was performed by PCR.

Results: Among the 65 cloacal samples, 54 (83.08%) were found to be positive for E. coli. Antibiotic sensitivity test revealed that, of these 54 isolates, 18 (33.33%) were found to be resistant to at least one fluoroquinolone antibiotic. The highest resistance was observed against pefloxacin (61.11%). By PCR, of 18 E. coli resistant to fluoroquinolone, 13 (72.22%) were found to be positive for the presence of qnrS. None of the isolates were found positive for qnrA.

Conclusion: Fluoroquinolone-resistant E. coli harboring qnrS genes is highly prevalent in apparently healthy broiler chickens and possesses a potential threat to human health. Keywords: Escherichia coli, healthy broiler chickens, polymerase chain reaction, qnrA, qnrS, quinolone resistance.

Keywords: Escherichia coli, healthy broiler chickens, polymerase chain reaction, qnrA, qnrS, quinolone resistance.

How to cite this article: Mahmud S, Nazir KHMNH, Rahman MT (2018) Prevalence and molecular detection of fluoroquinolone-resistant genes (qnrA and qnrS) in Escherichia coli isolated from healthy broiler chickens, Veterinary World, 11(12): 1720-1724.

Received: 16-08-2018  Accepted: 09-11-2018     Published online: 24-12-2018

Corresponding author: Md. Tanvir Rahman   E-mail: tanvirahman@bau.edu.bd

DOI: 10.14202/vetworld.2018.1720-1724

Copyright: Mahmud, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.