大连地区儿童肺炎链球菌耐药及血清分型研究

摘要

目的：研究大连地区住院儿童感染肺炎链球菌（SP）的耐药性及其血清分型。方法 SP菌株均从5岁以下儿童患者鼻咽抽吸物中分离。血清分型通过多重PCR方法鉴定，药敏试验通过 E-test方法来判断，而耐药基因 ermB及mefA／E则由PCR方法来检测。结果从2010年7月到2013年6月，共分离得到131例SP。药敏结果显示所有的131例菌株对红霉素以及克林霉素全部耐药，大约有39．8％的菌株对青霉素 G不敏感，而所有的菌株则均对左氧氟沙星和万古霉素敏感。此外，有129例（98．5％）属于多种耐药菌株。血清分型结果显示本地区 SP血清型以19F （28．2％）、19A （19．1％）、6B（17．6％）及23F（14．5％）为主。且在这些血清型中的 SP中，青霉素不敏感肺炎链球菌（PNSP）对阿莫西林、头孢曲松及头孢噻肟的不敏感性要显著高于青霉素敏感肺炎链球菌（PSSP）（P＜0．05）。7价疫苗（PCV7）和13价疫苗（PCV13）覆盖的血清型分别占68．7％和87．8％。此外，49株（37．4％）单独携带 ermB基因，而82株（62．6％）同时携带 ermB和mefA／E两种耐药基因。结论大多数分离的 SP对青霉素 G仍然相对敏感，所有菌株对左氧氟沙星和万古霉素敏感。本地区 SP血清型以19F、19A、6B及23F为主。鉴于19A血清型的高流行率，引入PCV13更能有效地预防儿童肺炎链球菌的感染和控制耐药菌株传播。%Objective To explore the antimicrobial susceptibility and serotypes distribution of pneumococci in hospi-talized children in Dalian.Methods The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5 years of age.The capsular serotypes were identified by multiplex polymerase chain reaction (PCR).Antimicrobi-al susceptibility was tested by E-test.The presence of ermB,mefA/E genes were detected by PCR.Results From July 2010 to June 2013,a total of 131 pneumococcal isolates were collected.All 131 strains were resistant to erythromycin and clindamycin,about 39.8% strains were non-susceptible to penicillin G,all strains were sensitive to levofloxacin and vancomycin.129 (98.5%)isolates were resistant to ≥3 types of antibiotics.Serotypes 19F (28.2%),19A (19.1%), 6B (17.6%)and 23F (14.5%)were the most common serotypes in all identified strains.As for 19F,19A,6B and 23F groups,penicillin non-susceptible S.pneumoniae(PNSP)strains were more resistant to amoxicillin,ceftriaxone and ce-fotaxime than penicillin non-susceptible S.pneumoniae(PSSP)strains (P<0.05).The serotypes coverage of PCV7 and PCV13 were 68.7% and 87.8%,respectively.49 (37.4%)strains carried the ermB gene,and 82 (62.6%)carried both ermB and mefA/E genes.Conclusion Most of SP strains were relatively sensitive to penicillin G,and all strains were sensitive to levofloxacin and vancomycin.Serotypes 19F,19A,6B and 23F were the most common serotypes of S.pneu-moniae stains in Dalian.Considering the high prevalence of serotype 19A,the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in Dalian.