一例无毒力白喉棒状杆菌携带者的临床特征和病原学诊断分析

Clinical Characteristics and Etiological Diagnosis of A Case of Nontoxic Corynebacterium Diphtheria Carrier

目的对上海市某医院收治的1例携带白喉棒状杆菌的病例进行病原学诊断分析,为白喉的感控提供临床依据。方法采集患者痰液进行培养及质谱鉴定、涂片染色鉴定、宏基因组测序(metagenomic sequencing,mNGS),纯培养物行16S rDNA基因测序进行病原学诊断,同时采用PCR方法检测白喉棒状杆菌毒力基因toxA和toxB表达情况。结果患者痰液培养48h后分离到单一灰白色菌落,经质谱鉴定、涂片镜下及16S rDNA鉴定均提示为白喉棒状杆菌,mNGS提示白喉棒状杆菌较高序列数,PCR结果显示toxA和toxB毒力基因为阴性。结论该病例为白喉棒状杆菌携带患者,虽为无毒力感染者,仍当引起重视。

Objective To analyze the etiological diagnosis of a Corynebacterium diphtheria carrier case in a hospital of Shanghai,to provide clinical basis for the control of diphtheria.Methods Sputum samples were collected for culture,mass spectrum identification,smear staining identification,and metagenomic sequencing(mNGS).The pure cultures were sequenced with 16S rDNA gene for pathogen diagnosis.Meanwhile,PCR was used to detectvirulence genes toxA and toxB of Corynebacterium diphtheria.Results A grayish white colony was isolated from the sputum of the patient after incubation for 48 hours.Corynebacterium diphtheria was identified by mass spectrum identification,smear microscopy,and 16S rDNA identification.A high number of Corynebacterium diphtheria sequences were detected onmNGS.PCR results showed that virulence genes toxA and toxB were negative.Conclusion The patient in this case was Corynebacterium diphtheria carriers,non-toxic infection,but it should still be taken seriously.