Introduction: Campylobacter spp. is the most frequent cause of bacterial gastroenteritis in humans globally. Campylobacter spp. infections are characterized by acute watery or bloody diarrhoea, fever, weight loss and abdominal cramps. Campylobacteriosis complications include extra-intestinal diseases such as Guillain-Barre Syndrome (GBS) or its variant the Miller Fisher Syndrome (MFS). Consumption of contaminated foods of animal origin including undercooked meat, contaminated dairy products has been associated with foodborne campylobacteriosis in humans. Cattle are considered an important reservoir of Campylobacter spp. and a source of foodborne Campylobacteriosis. Antimicrobial treatment failure in most bacterial infections including campylobacteriosis has emerged and led to the increase of animal and human health care costs. The use of antimicrobials in cattle for therapy in both cattle and humans and for growth promotion in exerts selective pressure on bacterial pathogens, which may result in the emergence of antimicrobial resistant Campylobacter spp. strains which can be transferred from animals to humans along the food chain or through contact between animals and humans. In South Africa, studies on the occurrence and antimicrobial resistance profiles of Campylobacter spp. of public health importance are lacking. The main objectives of this study were to: 1) investigate the occurrence of Campylobacter spp. in beef cattle on cow-calf operations in Gauteng and North West Provinces and 2) determine the antimicrobial resistance profiles of Campylobacter spp. isolates. The overall aim of the study was to contribute to monitoring and surveillance of Campylobacter spp. of public health importance in South Africa.
Methodology: A total of 537 fresh faecal samples from beef cattle consisting of 453 from adult cows and 102 from calves were collected on 5 cow-calf operations in Gauteng and North West provinces. The samples were screened for Campylobacter spp., including C. jejuni subsp. jejuni, C. coli and C. upsaliensis by culture and the polymerase chain reaction (PCR). Furthermore, 86 Campylobacter spp. isolates consisting of 46 C. jejuni subs. jejuni, 24 C. coli and 16 C. upsaliensis were tested for antimicrobial resistance against a panel of nine antimicrobial agents including azithromycin, ciprofloxacin, erythromycin, gentamicin, tetracycline, florfenicol, nalidixic acid, telithromycin and clindamycin by the broth microdilution method. Results: Out the 537 cattle faecal samples tested in this study, PCR revealed that 29.4% (158/537) [16.23%-42.57%] 95%CI of cattle carried Campylobacter spp. Among the 158 Campylobacter spp. positive cattle, 62.6% (99/158) carried C. jejuni subsp. jejuni, 25.3% (40/158) C. coli, 10.1% (16/158) C. upsaliensis and 3.1% (5/158) cows that had mixed infections. Three cows harbored both C. jejuni and C. coli, one cow carried C. jejuni and C. upsaliensis and one cow carried both C. coli and C. upsaliensis. Further antimicrobial resistance profiling of 86 Campylobacter spp. isolates (46 C. jejuni isolates, 24 C. coli and 16 C. upsaliensis) by the broth microdilution method revealed that the highest resistance rates for clindamycin (36%), nalidixic acid (19.7%), tetracycline (18.6%) and erythromycin (17.4%). However, lower resistance rates against florfenicol (3.4%), gentamicin (4.6%), telithromycin and ciprofloxacin (5.8%) were observed. The isolates were multidrug resistant against tetracycline/clindamycin, erythromycin/tetracycline/clindamycin, and nalidixic acid/clindamycin.
Conclusion: Little is known about the occurrence rates of Campylobacter spp. in beef cattle in South Africa. The prevalence of Campylobacter recorded in this study was consistent with various studies that have reported Campylobacter spp. prevalence rates within the same range in cattle in a number of countries with C. jejuni subsp. jejuni as the most predominant species. Campylobacter spp. isolates were mainly resistant to clindamycin, nalidixic acid and tetracycline. Findings from this study highlight the importance of beef cattle as a reservoir and a potential source of clinically relevant and antimicrobial resistant Campylobacter spp. isolates in South Africa.