大连地区儿童肺炎链球菌耐药及血清分型研究

Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolated from the children in Dalian

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 hospitalized children in Dalian.Methods The pneumococci were isolated from the nasopharyngeal aspirates of children less than 5years of age.The capsular serotypes were identified by multiplex polymerase chain reaction（PCR）.Antimicrobial susceptibility was tested by E-test.The presence of ermB,mefA/E genes were detected by PCR.Results From July2010 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≥3types 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 19 F,19A,6Band 23 F groups,penicillin non-susceptible S.pneumoniae（PNSP）strains were more resistant to amoxicillin,ceftriaxone and cefotaxime than penicillin non-susceptible S.pneumoniae（PSSP）strains（P〈0.05）.The serotypes coverage of PCV7 and PCV13were 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 19 F,19A,6Band 23 Fwere the most common serotypes of S.pneumoniae stains in Dalian.Considering the high prevalence of serotype 19 A,the introduction of PCV13 may be a promising preventive strategy to control the increasing trend of clonal spread in Dalian.