1例阿萨姆类芽胞杆菌感染病例调查分析

Survey on Paenibacillus assamensis infected case

目的对贵州省黔西南州兴义市患者关节液中分离的疑似土拉弗朗西斯菌(土拉菌)进行鉴定。方法将患者关节液中分离的1株革兰阴性菌(经全自动细菌鉴定及药敏分析系统检测,此菌株为土拉菌),接种到土拉菌选择性培养基上进行初步筛选。对新鲜培养的菌株进行土拉菌特异抗原乳胶凝集检测;并用16S rRNA的两对引物27f和1492r、8-27f和1500r对菌株进行菌种鉴定。采集患者血清,分别采用玻片法和试管法进行土拉菌特异抗体乳胶凝集检测。结果该菌在土拉菌选择性培养基上不生长。土拉菌特异抗原乳胶凝集检测为阴性,采用玻片法和试管法进行土拉菌特异抗体乳胶凝集检测,均为阴性。用两对引物扩增分别得到1 379 nt和1 429 nt的片段,经测序和比对分析,该菌株与阿萨姆类芽胞杆菌GPTSA 11的16S rRNA基因具有高度一致性,覆盖率为100%,E值为0。两个片段均含有类芽胞杆菌属特有的保守信号序列PAEN 515F和PAEN 862F。结论该病例排除土拉菌感染,为阿萨姆类芽胞杆菌引起感染,是首例阿萨姆类芽胞杆菌感染的临床病例。

Objective To identify a suspected Francisella tularensis strain isolated from the joint fluid of a patient in Xingyi of Qianxinan Prefecture,Guizhou province.Methods A gram-negative bacterium strain,which was identified as F.tularensis by automatic bacterial identification and drug sensitivity analysis system,was isolated from the joint fluid of a hospitalized patient in a hospital of traditional Chinese medicine of Qianxinan,and inoculated on the selective medium for screening.F.tularensis-specific antigen latex agglutination was performed for the fresh strain,and then the two pairs of primers,including 27 f and 1492 r,8-27 f and 1500 r,were used to identify the strain.In addition,the patient’s serum was used for F.tularensis specific antibody detection with slide and test tube.Results The strain did not grow on the selective medium for F.tularensis.The fresh strain was negative in F.tularensis-specific antigens in latex agglutination.The patient’s serum was negative for F.tularensis-specific antibodies in latex agglutination by slide and test tube.When the two amplicons involving1 379 nt and 1 429 nt were sequenced and aligned,the strain showed high homology with 16 S rRNA gene sequence of Paenibacillus assamensis GPTSA 11,the query cover was 100%and E value was 0.Moreover,both fragments contained the consensus signature sequence stretches of PAEN 515 F and PAEN 862 F,which are specific to Paenibacillus.Conclusion The result excluded F.tularensis infection and indicated that the case was infected with P.assamensis.This is the first clinical case of P.assamensis infection.