高致病力解脲脲支原体临床分离株毒力基因筛查

Screening of virulence genes in highly pathogenic clinical isolates of Ureaplasma urealyticum

目的探讨解脲脲支原体(UU)临床分离株毒力基因与致病性之间的关系,明确其致病性遗传背景。方法收集2012年12月-2016年12月医院解脲脲支原体感染人群的样本2661份,筛选分离201株高致病力解脲脲支原体临床菌株,分别来源于女性不孕症、胎膜早破、先兆流产和泌尿系统疾病,本研究设计4个较为保守的解脲脲支原体管家基因(ftsH,rpL22,valS,thrS)及2个可变毒力基因(ureG and mbanp1)上下游引物,进行聚合酶链反应(PCR)检测6个基因并测序。结果 201株高致病解脲脲支原体临床分离株经PCR扩增,产物测序均为目的基因,两个毒力基因(ureG and mbanp1)阳性率分别为93.1%,90.6%;药敏试验显示,201株高致病力解脲脲支原体耐药性高于总体人群,其中氧氟沙星、罗红霉素和阿奇霉素最高,分别为21.2%vs15.2%、12.5%vs6.9%与10.9%vs3.5%;2012-2016年本院UU检测患者感染阳性率趋于一致,近两年呈逐年下降趋势。结论 201株解脲脲支原体大多携带ureG、mbanp1基因,可见高致病性临床分离株存在的共同致病基因,本地区近年来解脲脲支原体感染阳性率未见明显上升迹象,而201株高致病株耐药性明显高于普通菌株,临床医师需加强对于致病性解脲脲支原体的鉴别,并根据药敏试验合理选用抗菌药物进行治疗,防止临床解脲脲支原体耐药性增强。

OBJECTIVE To explore the relationship between virulence genes in clinical isolates of Ureaplasma urealyticum（Uu）and pathogenicity so as to clarify the genetic background of pathogenicity.METHODS A total of 2661 specimens were collected from patients with Uu infections who were treated in hospitals from Dec 2012 to Dec2016,totally 201 strains of highly pathogenic Uu were screened and isolated,which were isolated from female patients with infertility,premature rupture of fetal membranes,threatened abortion and urinary system disease.The downstream primers of 4 conservative housekeeping genes of Uu（ftsH,rpL22,valS,thrS）and 2 variable virulence genes（ureGand mbanp1）were designed,and the 6 genes were detected and sequenced by using polymerasechain-reaction（PCR）.RESULTS Totally 201 clinical isolates of highly pathogenic Uu were amplified by PCR,all of the amplified products were target genes through the sequencing,and the positive rates of ureGand mbanp1 were93.1% and 90.6%,respectively.The result of drug susceptibility testing showed that the drug resistance rate of the 201 strains of highly pathogenic Uu was higher than that of the strains isolated from overall population,the drug resistance rates to levofloxacin,roxithromycin and azithromycin were the highest,which were respectively21.2%vs15.2%,12.5%vs6.9%and 10.9%vs3.5%.The positive rate of Uu infection tended to be same in the hospital from 2012 to 2016 and showed downward trend in recent two years.CONCLUSION Most of the 201 strains of Uu carry with the ureGand mbanp1 genes,showing that the highly pathogenic clinical isolates have the pathogenic genes in common.The positive rate of Uu infection does not show a sign of significant rise in this area in recent years,however,the drug resistance rate of the 201 strains of highly pathogenic Uu is remarkably higher than that of the common strains.It is necessary for the clinicians to strengthen the identification of the pathogenic Uu strains and reasonably use antibiotics based on the result of drug susceptibility testing so as to prevent the increase of drug resistance rate of the clinical isolates of Uu.