浙江5个地区2010~2012年沙门菌流行特征及分子分型研究

Epidemiological characters and molecular typing of Salmonella in 5 regions of Zhejiang province during 2010-2012

目的了解浙江部分地区沙门菌感染的流行病学特点,为防治提供科学依据。方法收集浙江省杭州、宁波、嘉兴、衢州、绍兴5个地区2010~2012年临床分离的沙门菌94株,对其进行血清分型、K-B纸片法药物敏感性试验。用二重PCR法检测毒力岛基因invA和毒力质粒基因spvB,并进行多位点序列分型;用多位点序列分型软件Dna SP version 5.0对7个管家基因进行核苷酸多态性分析。结果 94株沙门菌共测出18种血清型,其中肠炎沙门菌29株（30.9%）,鼠伤寒沙门菌27株（28.7%）,甲型副伤寒沙门菌10株（10.6%）,纽波特沙门菌和伊鲁慕沙门菌各5株（5.3%）,猪霍乱沙门菌4株（4.3%）,伤寒沙门菌和婴儿沙门菌各2株（2.1%）,其余10种血清型均各分离到1株。94株沙门菌耐药率最高的为氨苄西林47株（50.0%）,耐药率最低的为头孢吡肟1株（1.1%）;非耐药菌株占所有菌株的46.8%（44/94）。毒力岛基因invA和毒力质粒基因spvB阳性率分别为97.9%（92/94）和45.7%（43/94）。94株沙门菌经MLST分析分为24种ST型,以ST11型菌株最多,占29.8%（28/94）;上报网站http：//mlst.ucc.ie/mlst/新ST型5型,分别为ST1746、ST1747、ST1748、ST1749和ST1750。结论浙江5个地区临床分离的沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,质粒毒力基因spvB在这两种主要血清型中有较多的分布。94株沙门菌的耐药情况尚好,非耐药株数量接近半数。血清分型与多位点序列分型存在一定的联系。

Objective To understand the epidemiological characters of Salmonella in Zhejiang province so as to provide scientific evidences for controlling Salmonellosis.Methods A total of 94 Salmonella strains from five regions of Zhejiang province during 20102012 were clinically isolated and serotyped.The antibiotic susceptibility test was performed by using K-B method.The pathogenicity island gene invA and virulence plasmid gene spvB of Salmonella were detected by duplex PCR.The nucleotide polymorphism of seven housekeeping genes of Salmonella was analyzed by multiple locus sequence typing（MLST） with Dna SP 5.0 software.Results Among the 94 Salmonella isolates,18 various serovars were found including 29（30.9%） stains of Salmonella enteritidis,27（28.7%） of Salmonella typhimurium,10（10.6%） of Salmonella paratyphi,5（5.3%） of Salmonella newport,5（5.3%） of Salmonella irumu,4（4.3%） of Salmonella cholerae,2（2.1%） of Salmonella typhi,2（2.1%） of Salmonella infantis and 1（1.1%） of each strain for the rest of 10 serovars.The drug-resistance rate of ampicillin was the highest（50.0%,47 /94）,while cefepime was the most sensitive antibiotics with the resistant rate of 1.1%（1 /94）.The non-drug-resistant strains accounted for 46.8%（44 /94） of all the isolates.The positive rates of virulence genes invA and spvB were 97.9% and 45.7% respectively.Among the 94 isolates,24 sequence types（ST） were characterized by multilocus sequence typing（MLST） and ST11 as the most of strain accounted for 29.8%.Five new ST（ST1746,ST1747,ST1748,ST1749 and ST1750） were reported to the website of http： / /mlst.ucc.ie/mlst.Conclusion The main serovars among the 94 Salmonella strains isolated from five regions of Zhejiang province were Salmonella enteritidis and Salmonella typhimurium,in which the virulence plasmid gene spvB was widely distributed.No serious antibiotic resistance in these isolates was found and nearly half of them were non-drug-resistant strains.The results of MLST were generally associated with those of serotyping.