广东省138株不可分型流感嗜血杆菌的病原学特征分析

Etiologic characteristics of 138 non-typeable Haemophilus influenzae isolates in Guangdong Province

目的 了解广东省138株不可分型流感嗜血杆菌临床分离株的分子血清分型、多位点序列分型(multilocus sequence typing, MLST)、耐药表型和耐药基因等病原学特征。方法 通过国家致病菌识别网监测收集广东省2018—2019年的138株来自不同医院门诊和住院患者的流感嗜血杆菌分离株为研究对象,采用PCR技术对荚膜基因和耐药基因进行检测,同时应用MLST分析菌株之间的群落分布关系并使用描述性流行病学对病例资料进行回顾性分析。结果 138株流感嗜血杆菌临床株男女检出比为1.68∶1,检出人群以儿童(52.90%)和老年人(30.43%)为主,发病季节集中在2—6月份;血清分型结果均为不可分型菌株,其中35.51%(49/138)菌株携带TEM耐药基因,耐药基因亚型可分为3个等位基因亚型(HAEM0118∶8、HAEM0118∶6、HAEM0118∶10),ROB基因未检出。MLST分型一共分成54个ST型,其中12个ST型为新发现的ST型,ST103、ST422、ST836和ST57为4个主要流行的ST型。结论 广东省138株不可分型流感嗜血杆菌在该省部分地区已成为流行的主导血清型,耐药基因携带率高。建议加强本市对不可分型流感嗜血杆菌临床感染株的病原学和耐药性监测,合理使用抗生素,重视并加快疫苗和药物的开发,防止其形成优势克隆后导致社区感染的暴发流行。

Objective To understand the molecular serotyping, multilocus sequence typing(MLST), drug resistance phenotypes and drug resistance genes of 138 clinical isolates of non-typeable Haemophilus influenzae(NTHi) in Guangdong Province. Methods A total of 138 isolates of Haemophilus influenzae isolated from outpatients and inpatients of different hospitals in Guangdong Province from 2018 to 2019 were collected by the National Pathogenic Bacteria Identification Network Surveillance. The capsular genes and drug resistance genes were detected by PCR technique. At the same time, MLST was used to analyze the community distribution among the strains, and descriptive epidemiological method was employed to perform a retrospective analysis on the case data. Results The male-to-female detection ratio in the 138 clinical strains of Haemophilus influenzae was 1.68:1. Most of them were detected in children(52.90%) and the elderly(30.43%). The onset season was mainly in February-June. Serotyping showed that all the 138 strains were NTHi isolates, of which 35.51%(49/138) carried the TEM resistance gene, and the resistance gene subtypes could be divided into three alleles(including HAEM0118:8, HAEM0118:6 and HAEM0118:10). No ROB gene was detected. There were 54 ST types in MLST typing, 12 of which were newly discovered ST types. ST103, ST422, ST836 and ST57 were the main prevalent ST types. Conclusion The major serotype of the 138 clinical isolates of Haemophilus influenzae in some areas of Guangdong Province was NTHi, with TEM type carrying high β-lactam enzyme resistance. The results suggest that it is necessary to strengthen the monitoring of etiology and drug resistance of NTHi clinical infection strains, rationally use antibiotics, and emphasize and accelerate the development of NTHi vaccine and drug so as to prevent the outbreak of community infection after the formation of dominant clone of NTHi.