Abstract:
ObjectiveTo understand the distribution and pollution of Salmonella in rivers in Yuyao, Zhejaing province.
MethodsThe water samples were collected from 12 surveillance sites in Yuyao from January 2018 to December 2019, and then enrichment, isolation, biochemical identification, serotyping, drug sensitivity test and detection of drug resistance genes were carried out.
ResultsA total of 116 water samples containing Salmonella were detected in 192 river water samples, with a detection rate of 60.42%. The positive rate at Yaojiang bridge was highest (87.50%). A total of 177 Salmonella strains were detected in 116 positive water samples, which belonged to 25 serotypes, of which S.Typhimurium (16.38%), S. Derby (12.43%) and S.4,[5],12:i:- (11.30%) ranked top three. The number of serotypes detected at Sanguantang of Yaojiang river was highest. In seasonal distribution of the detection, more serotypes were detected in spring. Thirty nine strains showed extensive sensitivity to 16 antibiotics tested, while other strains showed resistance to at least one antibiotic. The resistance rates to penicillin and tetracycline were higher, the resistance rates to ampicillin, piperacillin and tetracycline were 72.31%, 51.41% and 66.10%, respectively. Thirty four strains were multi-drug resistant to three or more antibiotics. The detection rates of β-lactam antibiotic resistance gene tem, oxa and ctx-M were 67.23%, 6.78% and 12.43% respectively. The detection rates of tetracycline resistance gene tetA, tetB and tetG were 55.37%, 11.30% and 7.91%, respectively.
ConclusionThe detection rate of Salmonella in river environment of Yuyao was high, and the detected Salmonella strains had multi serotypes, serious drug resistance and complicated drug resistance mechanism. Therefore, it is suggested to pay close attention to the hazard of Salmonella from environmental sources in foodborne disease control.