Prevalence and Characterisation of Class 1 and 2 Integrons in Multi-drug Resistant Staphylococcus Aureus Isolates from Pig Farms in Chongqing, China

Chao Ye; Fengqing Hou; Dongyi Xu; Qingyuan Huang; Xia Chen; Zheng Zeng; Yuanyi Peng; Rendong Fang

doi:10.2478/jvetres-2020-0061

Prevalence and Characterisation of Class 1 and 2 Integrons in Multi-drug Resistant Staphylococcus Aureus Isolates from Pig Farms in Chongqing, China

J Vet Res. 2020 Sep 16;64(3):381-386. doi: 10.2478/jvetres-2020-0061. eCollection 2020 Sep.

Authors

Chao Ye¹, Fengqing Hou^{1

2

3}, Dongyi Xu¹, Qingyuan Huang¹, Xia Chen³, Zheng Zeng², Yuanyi Peng¹, Rendong Fang¹

Affiliations

¹ College of Animal Science and Technology, Southwest University, Beibei District, Chongqing, 400715, China.
² Chongqing Animal Disease Prevention and Control Center, Laboratory of Quality & Safety Risk Assessment for Animal Products on Biohazards, Ministry of Agriculture, Chongqing 401120, China.
³ Animal Husbandry and Aquatic Products Station of Yubei District, Chongqing 401120, China.

Abstract

Introduction: Integrons are mobile DNA elements that allow for acquisition and dissemination of antibiotic-resistance genes among pig farm-derived bacteria. Limited information is available on integrons of Staphylococcus aureus from pig farms. The aim of this study was to characterise and investigate the prevalence of class 1 and 2 integrons in multi-drug resistant (MDR) S. aureus isolates from pig farms.

Material and methods: A total of 724 swabs were collected from 12 pig farms in Chongqing, China, and examined by conventional microbial and molecular methods.

Results: In total, 68 isolates were S. aureus, 57 of which were methicillin resistant (MRSA). All 68 isolates were MDR strains and carried integrons, of which 88.2% (60/68) harboured both class 1 and 2. In addition, 85.3% (58/68) of the class 2 integron-positive isolates carried the β-lactam resistance gene (bla_TEM-1 ), and 66.7% (40/60) of the class 1 integron-positive isolates carried the aadA1c, aadA1 or dfrA1 gene for respective streptomycin and spectinomycin or trimethoprim resistance.

Conclusions: Class 1 and 2 integrons are common among the pig farm-derived S. aureus isolates. On account of their significance for public health, the prevalence of the integrons and their associated resistance genes in pig farm-derived S. aureus isolates should be paid special attention.

Keywords: Staphylococcus aureus; antibiotic resistance; integrons; pig; resistance gene cassettes.