Original Research

Genetic characterisation of antimicrobial resistance and virulence genes in Staphylococcus aureus isolated from commercial broiler chickens in the Durban metropolitan area, South Africa

Nelisiwe Mkize, Oliver T. Zishiri, Samson Mukaratirwa
Journal of the South African Veterinary Association | Vol 88 | a1416 | DOI: https://doi.org/10.4102/jsava.v88i0.1416 | © 2017 Nelisiwe Mkize, Oliver T. Zishiri, Samson Mukaratirwa | This work is licensed under CC Attribution 4.0
Submitted: 13 April 2016 | Published: 04 May 2017

About the author(s)

Nelisiwe Mkize, School of Life Sciences, University of KwaZulu-Natal, South Africa
Oliver T. Zishiri, School of Life Sciences, University of KwaZulu-Natal, South Africa
Samson Mukaratirwa, School of Life Sciences, University of KwaZulu-Natal, South Africa

Abstract

Antimicrobial resistance of Staphylococcus aureus in human and veterinary medicine is a serious worldwide problem. The aim of this study was to investigate the prevalence of S. aureus in commercial broiler chickens as well as to establish antimicrobial susceptibility and the distribution of genetic determinants conferring resistance and virulence. One hundred and ninety-four samples were aseptically collected from broiler chicken slaughterhouses and retail outlets around the Durban metropolitan area in South Africa. Microbiological and molecular methods were used to detect the presence of S. aureus as well as its resistance- and virulence-associated genes. Polymerase chain reaction (PCR) was used to confirm the presence of S. aureus by amplifying the nuc gene. Approximately 54% of 194 samples were positive for S. aureus. The disc diffusion technique was used to investigate antimicrobial susceptibility profiles of the S. aureus isolates to a battery of 10 antimicrobial agents, namely ampicillin, chloramphenicol, gentamicin, erythromycin, cefoxitin, kanamycin, streptomycin, tetracycline, vancomycin and trimethoprim. The results demonstrated that S. aureus isolates of abattoir origin had a high level (79.4%) of resistance to tetracycline, followed by ampicillin, vancomycin, cefoxitin, trimethoprim, erythromycin and streptomycin with resistance rates of 65.1%, 61.9%, 60.3%, 58.7%, 57.1% and 46.0%, respectively. Staphylococcus aureus isolates of retail origin exhibited higher antimicrobial resistance prevalence rates than those of abattoir origin. Tetracycline had the highest resistance rate (100%), followed by cefoxitin (91.7%), erythromycin (83.3%), streptomycin (83.3%) and kanamycin (66.7%). All isolates were resistant to two or more antimicrobial agents. Out of the four virulence genes that were screened, only two were detected (coagulase and protein A); however, their prevalence rates were very low. All antimicrobial resistance genes screened were detected (mecA, BlaZ and tetK), although their prevalence did not correspond with antimicrobial susceptibility testing.

Keywords

staphylococcus aureus; virulence; antimicrobial resistance; methicillin; broiler chicken

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Crossref Citations

1. Environmental antimicrobial resistance and its drivers: a potential threat to public health
Samreen, Iqbal Ahmad, Hesham A. Malak, Hussein H. Abulreesh
Journal of Global Antimicrobial Resistance  vol: 27  first page: 101  year: 2021  
doi: 10.1016/j.jgar.2021.08.001