社区获得性腹泻患者中志贺菌的感染耐药状况及基因分型

目的调查武汉市社区获得性腹泻患者中志贺菌感染和流行状况,分析志贺菌血清型分布及耐药性,为社区获得性腹泻治疗和该菌的基因分型提供客观依据。方法菌株来自2004年夏秋季武汉市4所大型医院门诊腹泻患者的粪便标本;药物敏感试验采用琼脂稀释法和纸片扩散法;结果分析采用WHONET5.3软件和SPSS12.0软件;基因分型采用重复基因外回文序列-聚合酶链式反应(REP-PCR)。结果5079份粪便标本分离出29株志贺菌,占所检出病原菌总数的23%,血清分型涉及B群和D群,D群占59%。志贺菌对头孢他啶和头孢吡肟的敏感率最高,为100%;其次为氨曲南、呋喃妥因和氟喹诺酮(诺氟沙星、环丙沙星、左氧氟沙星和莫西沙星),敏感率为93.1%～96.6%;对头孢曲松、头孢噻肟、卡那霉素和庆大霉素的敏感率为75.0%～82.8%;对氯霉素、氨苄西林、萘啶酸、四环素和大观霉素的敏感率均小于50%;未发现复方新诺明敏感株。耐药模式多达20种,最多为12种联合耐药;各群有各自的优势耐药模式。REP-PCR基因分型结果提示16株D群志贺菌有7种指纹图谱,12株B群志贺菌有2种指纹图谱。结论武汉地区因志贺菌感染导致社区获得性腹泻的比例较低,D群感染占优势。头孢他啶、头孢吡肟、氨曲南和氟喹诺酮有较好的抗菌活性。B群和D群对氨苄西林、阿莫西林/克拉维酸和氯霉素的敏感性差异有极显著性意义。多重耐药普遍存在,耐药模式繁多。武汉市志贺菌有相同或相似的克隆,血清型单一的D群有多种基因型,B群中f2a比f4c的遗传多样性高。

Infection, Drug Resistance and Genotype of Shigella spp. Isolated from Patients with Community Acquired Diarrhea

Objective To investigate shigellosis and epidemic situation among patients with community acquired diarrhea in Wuhan and analyze serotype distribution,drug resistance and genotype of Shigellae.Methods Stains were isolated from stool samples of outpatients with diarrhea from 4 big hospitals during summer and autumn in 2004.Agar dilution method and disc diffusion test were used to study the antimicrobial resistance.WHONET 5.3 and SPSS 12.0 were applied for analysis.REP-PCR was used for genotyping.Results Twenty-nine strains of Shigellae were isolated from 5079 samples and serotyping involved group B and D.All the stains were susceptible to ceftazidime and cefepime;The susceptibility to aztreonam,nitrofurantoin and fluroquinolones(norfloxacin,ciprofloxacin,levofloxacin and moxifloxacin) was 93.1%-96.6%;The susceptibility to ceftriaxone,cefetaxime,gentamicin and kanamycin's susceptible rates was 75.0%-82.8%;The susceptibility to ampicillin,spectinomycin,tetracycline,chloramphenicol and nalidixic acid was less than 50%.No strains were sensitive to trimoxazole.There were 20 kinds of resistance patterns with co-resistance to 12 drugs at the most.Each serogroup had its superiority resistance pattern.REP-PCR revealed that 16 Shigella sonnei strains had 7 fingerprinting patterns,while 12 Shigella flexneri had two patterns.Conclusion Community acquired diarrhea caused by Shigella spp.accounts for 0.57% in Wuhan region,and infection of D group was popular.Ceftazidime,cefepime,aztreonam,nitrofurantoin and fluroquinolones have the better antimicrobial activities.There were significant differences between group B and D of Shigella spp.in the susceptibility to ampicillin,amoxicillin-clavulanic acid and chloramphenicol.Multiply antibiotic resistance is widespread and resistance patterns were complicated.Sporadic isolates prevalent in Wuhan during summer and autumn in 2004 have the same or similar clones.Shigella sonnei with single serotype presents gene diversity and serotype 2a shows more gene diversity than 4c among Shigella flexneri.