食源性沙门氏菌耐药性检测及相关质粒

Identification of antimicrobial susceptibility of foodborne Salmonella and related plasmid

摘要:

【目的】测定390株沙门氏菌的抗生素药敏性，研究部分多重耐药株中质粒与其宿主耐药表型之间的关系及其在接合过程中对耐药性水平转移的影响。【方法】使用选择性培养基分离到沙门氏菌并通过PCR确认后，按照琼脂稀释法测定分离株对供试抗生素的药敏性，试剂盒提取代表性多重耐药株中的质粒，HindⅢ酶切，DPS软件分析电泳后质粒图谱。通过接合试验研究质粒在抗生素抗性水平转移中的作用。【结果】沙门氏菌分离株对四环素耐药最为普遍（58.2%），其次为链霉素（42.8%）、卡那霉素（39%）和氨苄青霉素（38.2%），对头孢西丁、氯霉素、庆大霉素、头孢曲松、阿莫西林甲氧苄啶、头孢替呋钠和萘啶酮酸的耐药率分别为27.2%、26.9%、21%、19%、18.2%、17.9%、14.6%和12.3%。抗性质粒编码的相同或相似沙门氏菌耐药表型与其中所含的耐药质粒并不呈现出严格的对应关系。质粒携带的抗性基因可通过接合作用转移，接合效率在2.4×10-4到5.6×10-1之间。【结论】食源性沙门氏菌对常用抗生素的多重耐药已经成为普遍现象，抗性质粒的同源性与其宿主耐药表型无直接相关性，其携带的耐药基因可通过接合作用在不同细菌种属之间高频传递。

Abstract:

[Objective] We tested the antimicrobial susceptibility of 390 Salmonella isolates. We also studied the relationship between plasmids in some multidrug resistant Salmonella isolates and the antibiotic resistance profile of their hosts, as well as conjugation test of some multidrug resistant Salmonellas. [Methods] Salmonella strains were isolated by using selective cultures, putative Salmonella was confirmed by PCR. Antimicrobial susceptibility was tested according to the National Committee for Clinical Laboratory Standards. Plasmid of some representative multidrug resistant strains was isolated by using QIAGEN Plasmid Mini Kit and digested with HindⅢ. The plasmid profiles were acquired by gel electrophoresis and analyzed by DPS. The conjugation test was done to illustrate the function of plasmid during the antibiotic resistance transfer. [Results] Of the Salmonella isolates, 58.2% were resistant to tetracycline, followed by resistance to streptomycin (42.8%), kanamycin (39%), ampicillin (38.2%), cefoxitin (27.2%), chloramphenicol (26.9%), gentamicin (21%), ceftriaxone (19%), amoxicillin-clavulanic (18.2%), trimethoprim-sulfamethoxazole (17.9%), ceftiofur (14.6%) and nalidixic acid (12.3%). There was no strict corresponding relationship between antibiotic resistance profile of the host Salmonella and its plasmid profile. The conjugation frequency of the plasmid was from 2.4×10-4 to 5.6×10-1. [Conclusion] Antimicrobial resistance is common in foodborne Salmonella, direct relativity does not exist between the homology of plasmids and their hosts’ antibiotic resistance phenotype, antibiotic resistant genes in the plasmid can transfer from donor to the recipient in interspecies and intraspecies with high frequency accompanying conjugation.