ObjectiveTo investigate the contamination and characteristics of enterotoxins and drug resistance of Staphylococcus aureus in raw milk in shanghai.
MethodsA total of 306 raw milk were collected from 4 dairy farms in Shanghai.The isolation and identification of Staphylococcus aureus and determination of toxin were performed according to GB4789.10.The detected Staphylococcus aureus was treated according to the CLSI recommended microdilution method for sensitive test, quantitative determination of the minimum inhibitory concentration (MIC).
ResultsA total of 32 strains of Staphylococcus aureus were detected, with a detection rate of 10.5%.Among them, 17 strains were positive for enterotoxigenicity with a positive rate of 53.1%, then drug resistance was tested in 12 antibiotics.The most serious resistance was penicillin, ampicillin, erythromycin and tetracycline, and the resistant rates were 78.1%, 65.6%, 53.1% and 21.9% respectively, showing a variety of resistance spectrum.
ConclusionThe Staphylococcus aureus contamination, enterotoxigenic ability, and their drug resistance in raw milk in Shanghai are serious, which is related to the process of dairy cattle breeding antibiotic exposure.It is recommended to expand the drug screening range for treatment of cow mastitis in Shanghai.According to the results of drug-sensitive test should be made the reasonable choice of antimicrobial drugs for the treatment of cows′mastadenitis.
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