山西省肠炎沙门菌耐药分析与分子分型研究

Characteristics of drug resistance and molecular typing of Salmonella enteritidis isolated in Shanxi Province

目的了解山西省肠炎沙门菌的耐药状况与脉冲场凝胶电泳（PFGE）分子分型特征，为沙门菌的临床治疗及食源性疾病暴发溯源提供依据。方法收集2015年4月—2018年3月分离于食源性疾病监测点的标本，进行系统生化鉴定、血清凝集；采用微量肉汤稀释法对64株肠炎沙门菌进行药敏试验；应用PFGE技术进行分子分型。结果64株肠炎沙门菌对萘啶酸的耐药率最高，为95.31%，其次为氨苄西林和氨苄西林/舒巴坦，分别为90.63%和81.25%，对6种抗菌药物（头孢唑林、头孢噻肟、四环素、头孢他啶、甲氧苄啶/磺胺甲恶唑、环丙沙星）耐药率较低（3.13%～23.44%），对氯霉素、头孢西丁、阿奇霉素、亚胺培南及庆大霉素均敏感；比较散发菌株与暴发菌株对剩余9种抗菌药物的耐药率，差异均没有统计学意义（P〉0.05）。64株肠炎沙门菌经XbaⅠ酶切后共分为33种带型（E1～E33），各带型包含菌株数为1～10株不等，带型相似度在54.6%～100.0%之间。结论山西省肠炎沙门菌耐药状况应引起重视，相关部门应加强抗生素的规范使用；肠炎沙门菌PFGE带型之间具有显著的遗传多态性，但PFGE在用于分析菌株之间的亲缘关系，及时确认和溯源食源性疾病暴发事件有重要意义。

ObjectiveTo investigate the antimicrobial resistance status and pulsed field gel electrophoresis （PFGE） patterns of Salmonella enteritidis （S.enteritidis） in Shanxi Province in order to provide references for the treatment of Salmonella infection and for tracing the source of outbreaks of foodborne diseases.MethodsSixty-four S. enteritidis strains were collected by monitoring sites for foodborne diseases from April 2015 to March 2018. Biochemical identification system and serotyping analysis were used for bacterial identification. Drug susceptibility patterns were analyzed with micro-broth dilution method. PFGE was used for molecular typing.ResultsThe antimicrobial resistance rate of 64 S. enteritidis strains to nalidixic acid （95.31%） was the highest, followed by that to ampicillin （90.63%） and to ampicillin/sulbactam （81.25%）. They had lower resistance rates to cefazolin, cefotaxime, tetracycline, ceftazidime, trimethoprim/sulfamethoxzole and ciprofloxacin （3.13%-23.44%） and were all sensitive to chloramphenicol, cefotaxime, azithromycin, imipenem and gentamicin. No statistically significant difference in drug resistance rates was found between the sporadic strains and the outbreak strains （P〉0.05）. All 64 S. enteritidis strains digested with XbaⅠwere divided into 33 molecular patterns by PFGE. The numbers of bacteria contained in each pattern ranged from 1 to 10 strains. The similarity among patterns was between 54.6% and 100%.ConclusionMore attention should be paid to the drug resistance status of S. enteritidis in Shanxi Province. It is necessary to strengthen the standardized administration of antibiotics. The PFGE patterns of S. enteritidis reveal the presence of significant genetic polymorphism. PFGE is of great significance in analyzing the genetic relationship among S. enteritidis strains and in identifying and tracing the source of outbreaks of foodborne diseases.