儿童感染侵袭性肺炎链球菌耐药基因和毒力基因携带分析

Drug resistance gene and virulence gene carriage of the children infected invasive Streptococcus pneumoniae

目的 了解河北省侵袭性肺炎链球菌耐药基因和毒力基因携带情况,为利用全基因测序手段研究耐药机制及致病机理打下基础。方法 对2017—2018年收集从儿童病例分离并保存河北省疾病预防控制中心的75株侵袭性肺炎链球菌,使用普通PCR方法检测侵袭性肺炎链球菌菌株研究报道较多的耐药基因和毒力基因,并分析携带情况。结果 青霉素耐药相关pbp2b基因携带率为0,红霉素耐药相关ermB、ermA和mefA/E基因携带率分别为96.00%、0和33.33%,四环素耐药相关tetM、tetL、tetK和tetO基因分别为94.67%、84.00%、0和0,左氧氟沙星耐药相关gyrA基因97.33%;主要毒力基因携带率自溶酶和神经氨酸酶表达相关基因lytA、lytB、nanA均为100.00%;与菌体侵入机体过程相关的pav、ply、hysA、iga基因分别为97.33%、98.67%、93.33%、96.00%;与细菌粘附相关的rrgA基因为29.33%;肺炎链球菌表面蛋白相关基因pspA与pspC携带率为0%。血清14、19F、6、23F型菌株mefA/E基因携带率较高,携带rrgA基因的株菌中19F型最多(9/22);不携带tetL基因的菌株中6型占33.3%。结论 河北省侵袭性肺炎链球菌携带ermB、tetM和tetL基因及gyrA基因比例较大,应警惕此类菌株对大环内酯类、四环素类、氟喹诺酮类抗生素的耐药性。lytA、lytB基因携带率高应慎用β-内酰胺类抗生素。菌株毒力基因携带率具有地区差异,建议结合临床表现,深入研究并长期监测。

Objective The drug resistance gene and virulence gene of local invasive Streptococcus pneumoniae in Hebei were detected by molecular biological methods,in order to lay a foundation for further study of drug resistance mechanism and pathogenesis by whole gene sequencing.Methods The virulence genes and drug resistance genes of 75 invasive strains were detected by ordinary PCR,the drug resistance genes and virulence genes with mature detection methods,more research frequency and comparable with other reported results were selected,and the carrying conditions were analyzed by summary and typing.Results The carrying rate of main drug resistance gene of 75 strains invasive Streptococcus pneumoniae isolated from children in a class Ⅲ hospital in Hebei Province from 2017 to 2018:Penicillin resistance related pbp2b gene 0;Erythromycin resistance related ermB gene 96.00%,Erma gene 0,mefA/E gene 33.33%;Tetracycline resistance related tetM gene 94.67%,tetL gene 84.00%,tetK and tetO gene 0;Levofloxacin resistance related gyrA gene was 97.33%.The carrying rate of main virulence genes:autolyase and neuraminidase expression related genes lytA,lytB and nanA genes were 100.00%;the process of bacteria invading the body related genes pav,ply,hysA,iga were 97.33%,98.67%,93.33%,96.00%;bacterial adhesion related rrgA gene was only 29.33%.Streptococcus pneumoniae surface protein related pspA and pspC genes were 0%.The mefA/E gene carrying rate of 14,19 F,6 and 23 F strains was higher,RrgA gene carrying strains of 19 F was the most(9/22).Genotype 6 accounted for 33.3% of strains that did not carry tetL gene.Conclusions The proportion of local invasive Streptococcus pneumoniae carrying of gene ermB,etM and tetL and gyrA were large.The antibiotic resistance of these strains to macrolides,tetracyclines and fluoroquinolones should be alerted.The high carrying rate of lytA and lytB warns us to be cautious when using β-lactam antibiotics.There are regional differences in the carrying rate of virulence genes of strains.It is suggested to conduct indepth research and long-term monitoring in combination with clinical manifestations.