Characterization of antimicrobial resistance genes in Haemophilus parasuis isolated from pigs in China

College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
Qingdao Yebio Biological Engineering Co., Ltd, Qingdao, Shandong, China
DOI
10.7287/peerj.preprints.3386v1
Subject Areas
Microbiology, Molecular Biology, Epidemiology, Statistics
Keywords
Antimicrobial resistance genes, QRDR, Haemophilus parasuis, PFGE
Copyright
© 2017 Zhao et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Zhao Y, Guo L, Li J, Huang X, Fang B. 2017. Characterization of antimicrobial resistance genes in Haemophilus parasuis isolated from pigs in China. PeerJ Preprints 5:e3386v1

Abstract

Background: Haemophilus parasuis is a common porcine respiratory disease that causes high rates of morbidity and mortality in farmed swine. We performed a molecular characterization of antimicrobial resistance genes harbored by H. parasuis from pig farms in China.

Methods: We screened 143 H. parasuis isolates for the presence of 64 antimicrobial resistance genes by PCR amplification and DNA sequence analysis. We determined quinolone resistance determining region mutations of DNA gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE). The genetic relatedness among the strains was analyzed by pulsed-field gel electrophoresis.

Results: We found 14 antimicrobial resistance genes were present in these isolates, including TEM-1, ROB-1.ermB,ermA ,flor, catl,tetB,tetC, rmtB, rmtD, aadA1, aac(3’)-ⅡC, sul1, and sul2 genes. Interestingly, one isolate carried 5 antibiotic resistance genes (tetB, tetC, flor, rmtB, sul1). The genes tetB, rmtB, and flor were the most prevalent resistance genes in H. parasuis in China. Alterations in the gyrA gene (S83F/Y, D87Y/N/H/G) were detected in 81% of the strains and parC mutations were often accompanied by a gyrA mutation. pulsed-field gel electrophoresis typing revealed 51 unique patterns in the isolates carrying antibiotic resistance genes indicating considerable genetic diversity and suggesting the genes were spread horizontally.

Discussion: The current study demonstrated that the high antibiotic resistance of H. parasuis in piglets is a combination of transferable antibiotic resistance genes and multiple target gene mutations. GyrA gene mutation also was the most important role in quinolone resistance. These data provide novel insights for the better understanding of the prevalence and epidemiology of antimicrobial resistance in H. parasuis.

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Information of separation site, separation time and resistance gene for H. parasuis

DOI: 10.7287/peerj.preprints.3386v1/supp-1