浙江省1例携带白喉棒状杆菌病例的病原学特征

Pathogen characteristics of one patient carrying Corynebacterium diphtheriae in Zhejiang province

目的对浙江省1例携带白喉棒状杆菌病例进行病原学诊断。方法采集患者咽拭子、鼻咽拭子和支气管肺泡灌洗液标本各1份,进行白喉棒状杆菌分离培养、涂片染色鉴定、生化和蛋白鉴定以及样本核酸的白喉棒状杆菌toxA和toxB毒力基因检测。结果从患者的支气管肺泡灌洗液分离到1株白喉棒状杆菌,革兰染色呈阳性,菌体排列呈棒状,粗细不一;奈瑟染色见菌体一端或两端特异性异染颗粒;生化和蛋白鉴定均提示99.0%以上概率属白喉棒状杆菌;患者的采集样本和分离菌株的核酸白喉棒状杆菌toxA和toxB毒力基因检测结果均为阴性。结论本病例携带的白喉棒状杆菌为不带有毒素生物结构基因编码菌,该病例为无毒白喉棒状杆菌带菌者。

Objective To clarify the pathogenic etiology in a patient in Zhejiang province carrying Corynebacterium diphtheriae.Methods We collected pharyngeal swab, nasopharyngeal swab and bronchoalveolar lavage fluid(BALF) from the patient for bacterial culture, smear staining, biochemical identification, and nucleic acid testing of toxA and toxB virulence genes. Results A strain of Corynebacterium diphtheriae was isolated from patient’s BALF, with Gram stain revealing a positive, rod-like arrangement with irregular thickness. Neisser staining showed characteristic metachromatic granules at one or both ends of the strain. Biochemical and spectrometric analyses showed that the strain was Corynebacterium diphtheriae with greater than a 99.0% possibility. Collected specimens and isolates were negative for nucleic acid of toxA and toxB Corynebacterium diphtheriae virulence genes. Conclusions The isolated Corynebacterium diphtheriae strain was a non-toxic bacterium without toxA and toxB virulence genes;thus, the patient was a carrier of a non-toxic Corynebacterium diphtheriae.