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目的了解宁波市人工河水环境中沙门菌的血清型分布特征及耐药情况,为预防、控制相应食源性疾病发生提供科学根据。方法对河水样品进行离心浓缩、蛋白胨水增菌液增菌、亚硒酸盐胱氨酸增菌液选择性增菌和沙门菌显色平板分离沙门菌,对分离菌株采用系统生化和血清凝集进行鉴定,并采用纸片法检测菌株对8种抗生素的耐药性,对多重耐药菌株和耐β-内酰胺类抗生素菌株扩增主要相关耐药基因。结果 2014年1月至2015年12月,共采集48份河水样品,分离沙门菌株105株,主要血清型为鼠伤寒(26株)、德尔卑(14株)、里森(8株)、肠炎(4株)、阿贡纳(4株)、斯坦利(4株)、阿格玛(4株),其他及未分型沙门菌41株。70株(66.7%)耐至少一种抗生素,对抗生素的耐药率分别为氨苄西林53.3%、四环素42.9%、甲氧苄啶-磺胺甲恶唑32.4%、庆大霉素11.4%、环丙沙星4.8%、头孢噻肟4.8%和产超广谱β-内酰胺酶4.8%。β-内酰胺类抗生素相关耐药基因为TEM型(n=52)、OXA型(n=6)和CTX-M型(n=3),58.1%的菌株1类整合子基因阳性。结论人工河水环境中沙门菌检出率较高,且部分血清型为重要的食源性致病菌,检出菌也有较高的耐药性,携带多种耐药基因,提示食源性疾病防控中需关注环境细菌的危害。
Objective To understand the serotype distribution and drug resistance of Salmonella in artificial river water environment in Ningbo and to provide a scientific basis for preventing and controlling the occurrence of the corresponding foodborne diseases. Methods Centrifugal concentration of river water sample, enrichment of peptone water-added bacterium, selective enrichment of selenite cystine-enriched bacterium and Salmonella salmonellae were carried out by using colorimetric plate of Salmonella. Systemic biochemistry and serum agglutination were performed on the isolated strains The antibiotic resistance of the strains against 8 antibiotics was tested by the paper disc method. The major drug-resistant genes were amplified from the multidrug-resistant and β-lactam antibiotic-resistant strains. Results From January 2014 to December 2015, a total of 48 river samples were collected and 105 Salmonella isolates were isolated. The main serotypes were typhoid (26), Delphine (14), lister (8), enteritis (4 strains), Agonist (4 strains), Stanley (4 strains), Agmar (4 strains), other and non-typed Salmonella. 70 strains (66.7%) were resistant to at least one antibiotic. The rates of resistance to antibiotics were 53.3% for ampicillin, 42.9% for tetracycline, 32.4% for trimethoprim-sulfamethoxazole, 11.4% for gentamycin, 4.8% of the starfloxacin, 4.8% of the cefotaxime and 4.8% of the extended-spectrum beta-lactamase. The genes related to β-lactam antibiotics were TEM type (n = 52), OXA type (n = 6) and CTX-M type (n = 3). 58.1% of strains were positive for class 1 integron. Conclusions The detection rate of Salmonella in artificial river water environment is high, and some of the serotypes are important food-borne pathogens. The detection strains also have high resistance and carry multiple resistance genes, suggesting that the food-borne Disease prevention and control should pay attention to the harm of environmental bacteria.