牡蛎污染耐药性细菌调查及整合子检测

A study to characterize the integrons and drug resistance of bacteria from oysters

目的对水产品牡蛎污染耐药性细菌进行调查,并检测其携带整合子类型,为细菌耐药机制研究提供依据。方法利用抗性培养基平板筛选牡蛎标本中的耐药性细菌,用K-B法进行药敏试验,PCR法扩增Ⅰ型、Ⅱ型和Ⅲ型整合酶基因。结果 34份牡蛎标本分离出76株耐药株,其中超过90%的分离菌对四环素、氨苄西林耐药,诺氟沙星、左氧氟沙星、复方新诺明、环丙沙星、头孢唑啉和氯霉素耐药>50%,有2株对耐亚胺培南细菌。整合酶基因检测结果显示80.26%耐药细菌携带Ⅰ型整合子,其中6株同时携带Ⅱ型整合子,未检测到Ⅲ型整合子。所有携带整合子的耐药细菌是多重耐药,不携带整合子耐药细菌中多重耐药占60%。结论牡蛎污染细菌的耐药性严重,且多重耐药与携带整合子有关,携带整合子细菌更易产生多重耐药,提示整合子可作为食品分离菌的耐药性检测靶标。

Objective To use drug-resistant bacterial strains isolated from oysters in order to investigate the relation ship between integrons and multidrug resistance. Methods Drug-resistant bacterial strains were cultured on plate medi- um with different antibiotics. PCR was used to detect class I, class II, and class III integrases. The K-B test was used to detect drug resistance. Results More than 90% of the bacteria were resistant to TE and AMP. More than 50% of the bacteria were resistant to NOR, LEV, SXT, CIP, KZ, and C. Two strains of IMP resistant bacteria were detected. Eighty-point two-six percent of the resistant bacteria had a class I integron, and 6 of those strains had a class II integron. However, no bacteria were found to have a class III integron. All of the resistant bacteria with a class I integron were multidrug-resistant. In contrast, only 60% of the bacteria without integrons were multidrug-resistant. Conclusion The current results revealed that oysters were seriously contaminated with drug-resistant bacteria. Class I integrons were often found in multidrug-resistant bacteria isolated from oysters in Shanghai.