鸡肉源沙门氏菌血清型、药敏性及部分耐药基因研究

Serotyping, Antibiotic Susceptibility and Some Genes Associated with Quinolones and Fluoroquinolines Resistance of Chicken-Borne Salmonella

目的:研究432株分离于陕西省杨凌及周边城市零售鸡肉中沙门氏菌的血清型分布、药敏性及其与(氟)喹诺酮类抗菌药物抗性相关耐药基因的流行状况。方法:按照玻片凝集法鉴定血清型,使用临床和实验室标准协会推荐的琼脂稀释法测定沙门氏菌的药敏性,聚合酶链式反应(polymerase chain reaction,PCR)方法确定沙门氏菌中与(氟)喹诺酮类抗生素耐药相关基因。结果:432株沙门氏菌中除36株血清型未定外,其余396株沙门氏菌共涵盖37个血清型,其中鼠伤寒沙门氏菌(Salmonella typhimurium,检出率17.93%)、汤普森沙门氏菌(Salmonella thompsons,检出率12.88%)、埃森沙门氏菌(Salmonella essen,检出率8.84%)和婴儿沙门氏菌(Salmonellainfants,检出率6.57%)等血清型比较常见。沙门氏菌对磺胺异噁唑(耐药率89.81%)耐药最为普遍,对磺胺甲噁唑、萘啶酮酸、四环素、氨苄西林、氯霉素和阿莫西林-克拉维酸等抗生素的耐药率均在50%以上。aac(6’)-Ib-cr基因检出率(16.67%)最高,qnr B、qnr S和qnr A的检出率分别为10.19%、6.71%和1.62%,且该4种基因在不同血清型菌株中分布不同。菌株携带qnr和aac(6’)-Ib-cr基因越多,对(氟)喹诺酮类和氨基糖苷类协同耐药性越强。结论:陕西省杨凌及周边城市零售鸡肉源沙门氏菌的血清型种类繁多,耐药比较普遍。

Objective:In this study,the serotyping,antibiotic susceptibility and some genes associated with quinolone and fluoroquinolones resistance of432chicken-borne Salmonella isolates in and around Yangling,Shaanxi province were studied for better understanding the epidemiological characteristics of Salmonella serovars.Methods:Salmonella serovars were determined using slide agglutination method.Antibiotic susceptibility was tested by the agar dilution method recommended by the Clinical and Laboratory Standards Institute(CLSI).The resistant genes of qnrA,qnrB,qnrS and aac(6')-Ib-cr,commonly carried by plasmid and associated with resistance to quinolone and fluoroquinolones,were identified using PCR and DNA sequencing.Results:Totally37serotypes were identified among396Salmonella isolates,and the other36isolates were unidentified.The most prevalent serotype was Salmonella typhimurium(17.93%),followed by S.thompson(12.88%),S.essen(8.84%)and S.infantis(6.57%).Among432Salmonellae isolates,antibiotic resistance was commonly found to sulfafurazole(89.81%),and approximately50%of the isolates were resistant to sulfamethoxazole,naladixic acid,tetracycline,ampicillin,chloramphenicol,and amoxicillin/clavulanate potassium.aac(6')-Ib-cr(16.67%)was most frequently detected,and the detection rates of qnrB,qnrS and qnrA were10.19%,6.71%and1.62%,respectively.The distribution of these four genes differed in different serotypes of isolates.More qnr and aac(6')-Ib-cr genes were detected in the isolates found to be more resistant to both fluoroquinolones and aminoglycosides.Conclusion:The serotype of Salmonella isolates from retail chicken in Yangling and its surrounding areas was diverse,and qnr and aac(6')-Ib-cr genes were commonly found in these isolates that were resistant to many antibiotics.