Occurrence of methicillin-resistant staphylococci in the pig-production chain in Ibadan, Nigeria.

Opeyemi U Lawal,Abimbola O Adekanmbi,Olawale O Adelowo

doi:10.4102/ojvr.v88i1.1959

Opeyemi U Lawal, Abimbola O Adekanmbi + Show 1 more

Open Access

https://doi.org/10.4102/ojvr.v88i1.1959

Copy DOI

Abstract

Staphylococcus species colonises humans and animals and is a major food contaminant with public health significance. Here, we assessed the occurrence of methicillin-resistant staphylococci (MRS) in the pig-production chain in Ibadan, Nigeria. Nares of 120 pigs and 10 farmers were sampled with sterile swabs whilst 54 pork samples were collected from a retail slaughterhouse. Staphylococcus species were isolated using enrichment, cefoxitin–aztreonam selective broth and Mannitol salt agar. Isolates were tested for susceptibility to cefoxitin (30 μg), oxacillin (1 μg) and vancomycin (30 μg). Methicillin-resistant staphylococci isolates were characterised using conventional biochemical tests. From 184 samples, 364 staphylococcal isolates were obtained. Amongst the 54 pork samples, 44.0% were contaminated with Staphylococcus species. Overall, 9 (2.5%) MRS were obtained and presumptively identified as Staphylococcus xylosus (n = 3), Staphylococcus sciuri (n = 3), Staphylococcus warneri (n = 2) and Staphylococcus cohnii (n = 1). There was no relationship between the prevalence of MRS between pigs and pig handlers in the farms, but Farm 2 had the highest frequency of 66.7% (p < 0.05). Piglets had the highest prevalence of 66.7% (p < 0.05) whilst MRS was absent in workers and pork samples. This study raises concerns about the cross-contamination of staphylococci in the food chain. Constant surveillance is imperative to ensure food safety.

Highlights

Staphylococcus species colonises humans and animals and is one of the major food contaminants of public health importance (Becker, Heilmann & Peters 2014)
The five farms selected for this study were involved in pig production but lack accurate history of the type and quantity of antimicrobials used on the farms
High contamination rate of the pig production chain by Staphylococcus species Using three-step method, all the samples recovered from pigs and pig handlers were positive for mannitol-positive http://www.ojvr.org

Summary

Introduction

Staphylococcus species colonises humans and animals and is one of the major food contaminants of public health importance (Becker, Heilmann & Peters 2014). Methicillin-resistant staphylococci (MRS) emerged in a variety of livestock animals, apparently through different mechanisms (De Boer et al 2009). The close proximity amongst humans, livestock and antimicrobial use in animals presumably facilitates the emergence and spread of MRS (Bouchami et al 2020). Methicillin-resistant staphylococci have been recovered from various retail products (Bouchami et al 2020; De Boer et al 2009) leading to an interest in MRS colonisation and infection in animals. Piglets are reported to be more vulnerable to MRS colonisation and infection because of the fragility of their immune system (Verhegghe et al 2013)

Objectives

Methods

Results

Conclusion