摘要目的：研究临床分离胥伐成格隆沙门菌的抗菌药物敏感性和毒力基因特征,为防治感染和了解其流行趋势提供依据。方法收集2014年5月至10月我院肠道门诊急性腹泻患者的临床资料,采集患者粪便标本进行沙门菌分离培养、生化鉴定、血清型分型,对鉴定得到的胥伐成格隆沙门菌进行抗菌药物敏感性检测、脉冲场凝胶电泳(PFGE)分型和多位点序列分型(MLST),PCR扩增沙门菌毒力岛SPI1-5代表性基因和调节基因、毒力质粒基因和细胞致死膨胀毒素( CDT )基因,对cdtB、pltA和pltB的扩增产物进行序列分析。结果共检测到108株非重复非伤寒沙门菌,其中16株(14.8%)为胥伐成格隆沙门菌。16株胥伐成格隆沙门菌对氟喹诺酮、氨苄西林、头孢曲松、复方新诺明等11种常用抗菌药物敏感率为100%,PFGE分型结果为A克隆14株、B克隆1株和C克隆1株, A克隆中有8例患者有明确的共同饮食来源,提示为感染暴发；16株胥伐成格隆沙门菌MLST分型均为ST241型,SPI1-5代表性基因invA、sitC、hilA、sseL、sifA、mgtC、siiE、sopB和调节基因phoP以及CDT基因cdtB、pltA和pltB均阳性,毒力质粒基因pefA、prot6E、spvB均为阴性；本研究中的胥伐成格隆沙门菌CDT基因与伤寒沙门菌相应基因的DNA和氨基酸序列相似均大于97%。结论本研究分离到多克隆ST241型胥伐成格隆沙门菌临床株,虽对常用抗菌药物尚保持敏感,但携带SPI1-5毒力基因和伤寒毒素CDT基因,应关注胥伐成格隆沙门菌临床感染在我国的变化趋势和危害,开展持续监测和研究。

abstractsObjective To investigate the antibiotic susceptibilities and the profiles of virulence genes of clinically isolated Salmonella enterica serovars Schwarzengrund ( S. Schwarzengrund) strains for bet-ter understanding the epidemiological trend of this type of non-typhoidal Salomonella and to provide guide-lines for the prevention and treatment of S. Schwarzengrund infection. Methods Stool samples and clinical data of patients with acute diarrhea who received treatment in the Second Hospital of Tianjin Medical Univer-sity during May, 2014 to October, 2014 were collected for this study. Enrichment culture and biochemical identification were used to isolate and identify the S. Schwarzengrund strains. The isolated strains were fur-ther analyzed with serotyping analysis, drug susceptibility test, pulsed field gel electrophoresis ( PFGE) and multiple locus sequence typing ( MLST ) . The representative genes carried by Salmonella pathogenicity islands (SPI) 1-5, SPI regulators and virulence plasmids were amplified by PCR. The coding genes of CdtB-islet, which were cdtB, pltA and pltB were amplified and sequenced. Results In total, 16 (14. 8%) out of 108 non-typhoidal Salmonella strains were identified as S. Schwarzengrund strains and all of them were sus-ceptible to 11 kinds of antibiotics such as fluoroquinolone, ampicillin, ceftriaxone and trimethoprim-sulfame-thoxazole. PFGE categorized the 16 S. Schwarzengrund strains into 3 clusters including A clone ( 14 strains), B clone (1 strain) and C clone (1 strain). The strains that isolated from 8 patients who ate the same food belonged to one cluster ( A clone ) , suggesting that it was an outbreak of infection. The 16 S. Schwarzengrund strains showed identical MLST type, which was ST241. The representative genes carried by SPI1-5 ( invA, sitC, hilA, sseL, sifA, mgtC, siiE and sopB) , the regulatory gene ( phoP) and the cytole-thal distending toxin islet (CdtB-islet) coding genes (cdtB, pltA and pltB) were positive, while the genes carried by virulence plasmids (pefA, prot6E and spvB) were negative. The similarities in CdtB-islet coding genes and amino acids sequences between Salmonella typhi and S. Schwarzengrund strains in this study were more than 97% and 98%, respectively. Conclusion In this study, polyclonal S. Schwarzengrund strains of ST241 type were isolated from the patients. They were susceptible to common antibiotics, but carried the virulence genes contained in SPI1-5 and CdtB-islet coding genes and might cause an outbreak of infection. Attention should be paid to the tendency and threat of clinical S. Schwarzengrund infection and continuous surveillance and investigation should be performed.