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Prevalence, antimicrobial resistance, resistance genes and class 1 integrons of Salmonella serovars in leafy vegetables, chicken carcasses and related processing environments in Malaysian fresh food markets
- Abatcha, Mustapha Goni, Effarizah, Mohd Esah, Rusul, Gulam
- Food control 2018 v.91 pp. 170-180
- Salmonella, ampicillin, antibiotic resistance, cephalothin, chicken carcasses, chloramphenicol, green leafy vegetables, multiple drug resistance, resistance genes, sequence analysis, serotypes, streptomycin, sulfonamides, Malaysia
- This study was carried out to determine the prevalence, antibiotic resistance, resistance genes and class 1 integrons of Salmonella serovars in raw leafy vegetables, chicken carcasses and related environments. From April 2015 to May 2016, a total of 642 samples collected from fresh food markets in Peninsular Malaysia were examined. The overall occurrence of Salmonella species was 29.1% (187/642) with 37 different serovars detected. The most prevalent serovars were S. Corvallis (49/187), S. Brancaster (28/187), S. Weltevreden (17/187), S. Albany (15/187), S. Hvittingfoss (6/178), S. Paratyphi B (6/178) and S. Typhimurium (6/178). Among the Salmonella isolates, the highest antibiotic resistance was to streptomycin (66.6%), followed by tetracycline (44.3%), sulfonamides (44.3%), ampicillin (26.7%), chloramphenicol (29.1%) and trimethoprim-sulfamethoxazole (16.6%). All isolates of Salmonella were 100% susceptible to cephalothin. Fifty-five percent of the isolates (103/187) were multidrug-resistant. The multiple antibiotic resistance (MAR) index of Salmonella serovars ranged from 0.08 to 0.83, and the most prevalent resistance pattern was STeS₃. Eleven out of 16 resistant genes (tetA, tetB, blaTEM-1,temB, strA, strB, aadA, sul1, sul2, floR and cmlA) were detected among the resistant Salmonella isolates. None of the isolates was positive for tetC, tetG, cat1 and cat2. Seventeen isolates harboured class 1 integrons, which were grouped into 5 different integrons profiles (IPs). DNA sequencing analyses have identified dfrA1, dfrA12, aadA2, blaPSE−1, dfrA12-orf-aadA2 arrays of cassettes in variable regions on class 1 integrons.