分离自腹泻儿童志贺菌的耐药性及分子流行病学研究

摘要

Objective To investigate the prevalence and antibiotic resistance of Shigella isolated from children with diarrhea for the guidance of clinical treatment and prevention and control of bacillary dysentery.Method A total of 156 strains of Shigella were isolated from feces of children with diarrhea in Zhejiang Xiaoshan Hospital from January 2008 to December 2010.The antimicrobial resistance of the strains was detected by disk diffusion method and the extended-spectrum beta-lactamases (ESBLs) in these isolates were determined using phenotypic confirmatory test; the isolates of ESBLs producing Shigella sonnei were analyzed by REP-PCR.Result Among 156 strains of Shigella isolated,the most common groups were Shigella sonnei (130 strains,accounting for 83.3％) and Shigella fleaneri (26 strains,accounting for 16.7％),and 81 (51.9％) strains were identified as ESBLs producers,and the positive rates in 2008,2009 and 2010 were 32.0％,41.4％ and 59.8％,respectively.The results of antibiotic susceptibility test displayed that the resistance rates of ESBLs producing Shigella to ampicillin,cotrimoxazole,cefotaxime,piperacillin were higher than 90％.However,the resistance rates to cefepime,ceftazidime,levofloxacin and ciprofloxacin were low; The resistance of ESBLs producing strains to piperacillin (100％ vs.77.3％),cefotaxime(100％ vs.0),ceftazidime(14.8％ vs.0),cefepime(28.4％ vs.0),cotrimoxazole(95.1％vs.86.7％) was significantly higher than that of non-ESBLs producing strains (x2 =20.605,156.000,12.037,24.979,45.040,respectively ;P ＜ 0.05).No isolate was resistant to piperacillin/tazobactam and imipenem.There were 7 genotypes among 74 ESBLs producing Shigella sonnei,respectively type A (50),type B (12),type C (8),type D (1),type E (1),type F (1),and type G (1).Conclusion The isolation rate of ESBLs-producing isolate was high in Shigella from pediatric patients with diarrhea,and the number is going up year by year,and these ESBLs producing Shigella sonnei strains in genotype A are dominant in recent years,Piperacillin/tazobactam is the drug of choice for children with ESBLs producing Shigella infection.%目的 调查腹泻儿童临床分离志贺菌的流行及其耐药性,为细菌性痢疾临床治疗和感染控制提供理论依据.方法 收集2008年1月至2010年12月浙江萧山医院就诊的≤14岁腹泻患儿粪便分离的志贺菌156株,纸片扩散检测其抗菌药物的耐药性,纸片确认试验检测产超广谱β内酰胺酶(ESBLs)；采用细菌基因组重复序列聚合酶链反应(REP-PCR)检测产ESBLs宋内志贺菌的分子流行病学特征.结果 156株志贺菌中主要为宋内志贺菌(130株,占83.3％)和福氏志贺菌(26株,占16.7％),81株志贺菌产ESBLs,阳性率为51.9％,各年的阳性率分别为2008年32.0％、2009年41.4％、2010年59.8％.药敏结果显示,产ESBLs志贺菌对氨苄西林、复方新诺明、头孢噻肟、哌拉西林耐药率均＞90％,而对头孢吡肟、头孢他啶、左氧氟沙星、环丙沙星耐药率较低；产ESBLs志贺菌与非产ESBLs志贺菌相比,对哌拉西林(100％ vs.77.3％)、头孢噻肟(100％ vs.0)、头孢他啶(14.8％ vs.0)、头孢吡肟(28.4％ vs.0)、复方新诺明(95.1％ vs.86.7％)的耐药率均较高(x2值分别为20.605,156.000,12.037,24.979,45.040;P均＜0.05),未发现亚胺培南、哌拉西林-他唑巴坦耐药菌株.74株产ESBLs宋内志贺菌共分为7个基因型:A型50株,B型12株,C型8株,D、E、F、G型各1株.结论 分离自腹泻患儿的志贺菌产ESBLs阳性率较高,且有逐年增加的趋势；近年来宋内志贺菌存在同一克隆株A型的流行；哌拉西林-他唑巴坦可作为临床治疗儿童感染产ESBLs志贺菌的首选药物.