RESISTANCE OF NON-TYPHOIDAL SALMONELLA STRAINS ISOLATED FROM BROILER PRODUCTS TO ANTIBIOTICS
Keywords:Non-typhoidal Salmonella, Antibiotics, Broiler, Disk diffusion, Resistance genes
This study was conducted to evaluate the resistance of non-typhoidal Salmonella strains (NTS) isolated from broiler products marketed in North-West Province, South Africa, to various antibiotics. A total of sixty (60) NTS isolates recovered from raw broiler products and confirmed by PCR were evaluated for antimicrobial resistance by disk diffusion method, using a panel of ten antibiotics. The NTS isolates that were identified and used in this study include S.typhimurium (n = 20), S. enteritidis (n = 20) and S. newport (n = 20). The antibiotics used were ampicillin (10 µg), chloramphenicol (30 µg), ciprofloxacin (5 µg), amikacin (30 µg), trimethoprim-sulphamethoxasole (25 µg), tetracycline (30 µg) cefotaxime (30 µg), meropenem (10 µg), gentamicin (10 µg) and erythromycin (15 µg). All the strains tested were resistant to two or more antibiotics. However, all isolates were susceptible to cefotaxime, meropenem, gentamycin and amikacin.Whereas, all were resistant to tetracycline, resistance to trimethoprim-sulphamethoxasole, ciprofloxacin and chloramphenicol was low, being 8.3, 13.3 and 20% respectively. Multi-drug resistance was discovered only in nine S.typhimurium strains, representing 15% of the tested isolates. Analysis of multiple antibiotic resistance (MAR), revealed seven phenotypes, with resistance to ampicillin, tetracycline and erythromycin as the most common pattern. The observations of this study indicate that NTS strains isolated from broiler products are resistant to multiple antibiotics, and may pose significant health risks to the consumers.