一起不典型症状宋内志贺菌暴发疫情的实验室诊断

目的分析本实验室对1起由宋内志贺菌引起的不典型临床症状、疑似不明原因发热暴发疫情的实验室检测过程,为类似事件的实验室诊断提供参考。探讨通过增菌前后Ct值变化,荧光PCR用作病原菌确诊方法的可能性。方法采用总大肠菌群酶底物法测定总大肠菌群和大肠埃希菌,常规培养法和荧光PCR法测定患者咽拭和肛拭样品以及水样中病原微生物,用MIC法对分离菌株进行体外药敏试验。结果 10份饮用水中6份总大肠菌群和大肠埃希菌,不符合GB5749-2006的要求。常规培养9份肛拭均检出宋内志贺菌,而10份水样均未检出肠道致病菌。荧光PCR结果 9份肛拭和5份水样检出志贺菌核酸,5份水样增菌后Ct值较增菌前有明显下降。肛拭中分离的9株菌对青霉素类抗生素中的阿莫西林、哌拉西林、替卡西林100%耐药,对磺胺类、β-内酰胺类、头孢菌素类(1-4代)、氨基糖苷类等存在不同程度耐药。结论实验室应用指标菌检测、常规培养和荧光PCR技术,48 h即找到引起疫情暴发的原因,为疫情的控制提供了及时科学的依据。药敏试验为患者治疗提供了正确的药物选择依据。

Laboratory Diagnosis in An Outbreak of Shigella Sonnei Infection With Atypical Clinical Symptoms

Objective To analyze the laboratory diagnosis progress in a suspected unexplained fever outbreak of Shigella sonnei with atypical clinical symptoms,as a case sample for similar incidents;and to investigate the role of the fluorescent PCR in pathogens diagnosis by the change of Ct values through the enrichment of pathogens.Methods The throat swab,rectal swab samples from patients and suspected water samples were collected and detected with enzyme substrate technique for total coliforms,conventional culture and fluorescent PCR,then the vitro susceptibility test was carried out for the isolates with MIC(minimal inhibitory concentration) method.Results Six out of 10 water samples did not meet the GB5749-2006 in total coliforms and Escherichia.coli,all the 9 rectal swabs were Shigella sonnei positive and water samples negative by conventional culture,and all the 9 rectal swabs were Shigella sonnei positive by fluorescent PCR.Besides,5 water samples were Shigella sonnei positive and changes of Ct values were observed after bacteria culture by fluorescent PCR.According to the MIC results,9 isolates were 100% resistant to amoxicillin,piperacillin,ticarcillin,partly resistant to β-lactams,cephalosporins(1-4 generation) but 100% senstinve to carbopenems.Conclusions Indicator bacteria testing,conventional culture and fluorescent PCR method were carried out synchronous,providing the laboratory diagnosis timely in 48h,which was meaningful for the outbreak control.The vitro susceptibility test guided the clinical medication as well.