广州地区患儿流感嗜血杆菌分离株荚膜基因分型的研究

Capsular Genotyping of Haemphilus influenzae Isolated from Pediatric Patients in Guangzhou

目的用PCR方法进行流感嗜血杆菌荚膜编码基因分型,调查儿童急性呼吸道感染患儿流感嗜血杆菌的感染情况。方法以流感嗜血杆菌荚膜编码基因(bexA)和荚膜分型编码基因(Hi-a、Hi-b)作为靶基因设计引物,用PCR方法扩增标准菌株为ATCC9006、ATCC49247、EQA0609的3个编码基因并测序,在此基础上对临床分离的43株流感嗜血杆菌进行荚膜基因分型研究。结果PCR结果显示标准菌株ATCC49247未扩增出bexA编码基因,ATCC9006扩增出bexA和Hi-a编码基因,EQA0609扩增出为bexA和Hi-b编码基因,并且PCR产物序列与GenBank公布的序列一致性高。临床分离菌株Hi未扩增出bexA、Hi-a及Hi-b编码基因。结论本实验研究表明广州地区儿童急性呼吸道感染患儿所分离的流感嗜血杆菌主要是不可分型的无荚膜菌株。

Objective To investigate the epidemic of the child acute respiratory tract infection with H.influenzae by capsular genotyping with the PCR method. Method The standard strains ATCC9006, ATCC49247, EQA0609, and 43 clinical isolates of H.influenzae were analyzed by PCR. The target genes selected in this study were bexA, Hi-a, and Hi-b. Result We succeeded in amplifying the genes bexA and Hi-a from ATCC9006, bexA and Hi-b from EQA 0609. The genes bexA, Hi-a, and Hi-b were not detected from ATCC49247. All the sequences of PCR products have a high degree of identity with the genes deposited in GenBank. All these genes were not detected in the 43 clinical isolates of H.influenzae. Conclusion Our study suggests that H.influenzae isolated from acute respiratory infection in children are almost non-typeable capsular strains.