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目的了解1997至2010年分离自北京儿童医院急性呼吸道感染患儿的19F型肺炎链球菌的抗生素敏感性及分子流行病学特征。方法于1997—2006年以及2010年在北京儿童医院门诊病例中分离19F型肺炎链球菌,以120株经荚膜肿胀实验鉴定为19F型的肺炎链球菌为研究对象,采用E-test法和纸片扩散法检测菌株对9种抗生素的敏感性,聚合酶链式反应(PCR)检测红霉素耐药基因ermB和mefA,采用多位点序列分型(MLST)确定其序列分型(ST)。结果 120株19F型肺炎链球菌中青霉素不敏感菌株5株,占4.2%,均为中介。红霉素不敏感率高达99.2%。从1997年到2010年头孢类抗生素敏感性逐年降低,头孢曲松敏感性从1997至1998年的100%下降到2010年的68.0%,头孢克洛敏感性则从100%下降到4.0%。在119株耐红霉素菌株中,115株(95.8%)携带ermB基因,64株(53.3%)携带mefA基因,60株(50.4%)同时携带两种耐药基因。MLST共分出31种ST,ST983最常见(共39株,占32.5%),其次是ST271(共13株,占10.8%)。从1997到2010年,克隆群CC983的构成比下降(从1997至1998年的64.3%降为2010年的0),CC271的构成比升高(从14.3%升为92%),耐药性分析发现CC271对β-内酰胺类抗生素耐药率明显高于CC983。结论 1997—2010年19F型在肺炎链球菌中分离率升高,对β-内酰胺类抗生素耐药性增强,上述变化与抗生素选择压力下,高β-内酰胺类抗生素耐药性的国际流行克隆群CC271的输入和播散有关。
Objective To investigate the antibiotic susceptibility and molecular epidemiological characteristics of 19F Streptococcus pneumoniae isolated from children with acute respiratory tract infection in Beijing Children’s Hospital from 1997 to 2010. Methods Streptococcus pneumoniae 19F was isolated from outpatients in Beijing Children’s Hospital from 1997 to 2006 and in 2010, and 120 strains of Streptococcus pneumoniae identified as 19F by capsular swelling test were used as research objects. E-test and paper The susceptibility of the strains to 9 antibiotics was tested by piece diffusion assay. The erythromycin resistance genes ermB and mefA were detected by polymerase chain reaction (PCR) and sequenced by multiple locus sequencing (MLST) . Results There were 5 penicillin-insensitive strains in 120 strains of 19F Streptococcus pneumoniae, accounting for 4.2%, all of which were mediators. Erythromycin insensitive rate as high as 99.2%. From 1997 to 2010, the sensitivity of cephalosporin antibiotics decreased year by year. The sensitivity of ceftriaxone decreased from 100% in 1997 to 1998 to 68.0% in 2010, while the cefaclor sensitivity decreased from 100% to 4.0%. Of the 119 erythromycin resistant strains, 115 (95.8%) carried ermB, 64 (53.3%) carried mefA and 60 (50.4%) carried two resistance genes simultaneously. MLST was divided into 31 kinds of ST, ST983 the most common (a total of 39 strains, accounting for 32.5%), followed by ST271 (13 strains, accounting for 10.8%). From 1997 to 2010, the composition ratio of cloned population CC983 decreased (from 64.3% in 1997-1998 to 0 in 2010), the constituent ratio of CC271 increased (from 14.3% to 92%), and resistance analysis The results showed that the resistance rate of CC271 to β-lactam antibiotics was significantly higher than that of CC983. Conclusions 19F genotype 19F increased in Streptococcus pneumoniae from 1997 to 2010, and its resistance to β-lactam antibiotics was enhanced. These changes were associated with the international prevalence of high β-lactam antibiotic resistance under antibiotic selection pressure The input of clone CC271 is related to dissemination.