下呼吸道感染患儿沙眼衣原体检测与初步基因分型

A STUDY ON DETECTION AND GENOTYPE OF CHLAMYDIA TRACHOMATIS(CT) IN INFANTS WITH RESPIRATORY INFECTIONS

研究下呼吸道感染患儿沙眼衣原体 (Ct)的检测情况、Ct分离株的初步基因分型及方法学评价。采用McCoy细胞培养、聚合酶链反应 (PCR)对下呼吸道感染患儿 2 48例鼻咽拭子 (其中 110例加下睑结膜刮取标本 )进行检测 ;8份患儿Ct标本经双链DNA直接测序法以及裂解酶片段长度多态性 (CFLP)基因分型。下呼吸道感染患儿鼻咽标本Ct检出率为 2 5 %(6 2 / 2 48) ,其中 110例新生儿鼻咽和结膜标本Ct总检出率为 40 9% (4 5 / 110 ) ,基因分型 :E型 4株 ,F、D和H型分别为 2、1和 1株 ,6株成人性病株中E型 3株 ,F、D和H型各 1株。取E型 3份 ,F型 2份作CFLP ,呈两类CFLP谱。提示同时取患儿鼻咽和结膜标本可提高Ct检出率 ,下呼吸道感染婴儿的Ct型别与成人性病Ct型别关系密切 ,双链DNA直接测序法及CFLP均可用于Ct基因分型。

To investigate the incidence of respiratory infections caused by Ct in infants,and the preliminary genotype of the Ct isolates.Two hundred and forty-eight infants with respiratory infections were detected by McCoy cell culture and PCR.Two different groups were investigated by direct double-stranded DNA sequencing and cleavase fragment length polymorphism(CFLP),group Ⅰ consisted of nasopharyngeal specimens from 8 infants with pneumonia,group Ⅱ consisted of urogenital specimens from 6 adults attending the outpatient department for sexually transmitted diseases.The total positive rate of Ct was 25%(62/248)in the specimens taken from the nasopharynxes,whereas the culture-positive rate of nasopharyngeal and/or conjunctival samples was 42 9%(48/112).The results of genotyping showed that type E,F,D and H(4,2,1 and 1,respectively)belonged to groupⅠ,while type E,F,D and H(3,1,1 and 1,respectively)belonged to group Ⅱ.Two kinds of CFLP patterns were revealed belonging to type E and F which were confirmed by DNA sequencing.The results showed that the detection rate of Ct could be increased by taking both nasopharyngeal and conjanctival samples in infants.Close relation exists betreen Ct types caused respiratory infection in infants and Ct types caused sexual transmitted disease in adults.Both methods of direct double-stranded DNA sequencing and CFLP were successfully used to genotype the Ct isolates.