Carried pneumococci in Massachusetts children: the contribution of clonal expansion and serotype switching.
Carried pneumococci in Massachusetts children: the contribution of clonal expansion and serotype switching.
复制标题
DOI：
10.1097/inf.0b013e318201a154
复制
发表时间：
2011-04
期刊：
影响因子：
--
通讯作者：
Finkelstein JA
中科院分区：
文献类型：
--
作者：
Hanage WP;Bishop CJ;Huang SS;Stevenson AE;Pelton SI;Lipsitch M;Finkelstein JA
背景：针对肺炎链球菌7种血清型的疫苗接种导致了疾病和无症状携带中疫苗血清型的几乎灭绝。方法：采用多位点序列分型技术对294株沙门氏菌进行分型。pneumoniae携带的马萨诸塞州儿童（年龄，3个月-7岁），并检查结果的血清型转换和与抗菌药物resistance.Results的关联：86个不同的序列类型（ST）被发现，其中10个表现出的血清型以外，这将是预期从以前的运输样品。我们将其解释为过去或最近血清型转换的证据。转换变体包括ST 320，这是该社区中常见且日益增加的多药耐药来源。血清组内的转换事件比预期的偶然事件更常见（Monte Carlo方法P= 0.043）。利用多位点序列分型数据和eBURST分析，我们还描述了重要的替换血清型19 A、15 B/C、35 B和最近描述的6C内的克隆动态。结论：一些由血清型转换产生的菌株在携带人群中越来越重要。在19 A的情况下，似乎大部分增加是由于ST 320，最近报告的转换变体。这可能会对ST造成侵袭性肺炎球菌疾病的后果。
Background:Vaccination against 7 serotypes of Streptococcus pneumoniae has led to the near extinction of vaccine serotypes in both disease and asymptomatic carriage. In carriage, vaccine serotypes have been replaced by nonvaccine serotypes.Methods:We used multilocus sequence typing to analyze a sample of 294 isolates of S. pneumoniae carried by Massachusetts children (aged, 3 months–7 years) and examine the results for serotype switching and association with antimicrobial resistance.Results:Eighty-six distinct sequence types (STs) were found, 10 of which exhibited a serotype other than that which would be expected from previous carriage samples. We interpret this as evidence of past or recent serotype switching. Switched variants include ST 320, which is a common and increasing source of multidrug resistance in this community. Switching events within serogroups were more common than expected by chance (P= 0.043 by a Monte Carlo approach). Using multilocus sequence typing data and eBURST analysis, we also describe clonal dynamics within the important replacement serotypes 19A, 15B/C, 35B, and the recently described 6C.Conclusions:Some strains generated by serotype switching are increasingly important parts of the carriage population. In the case of 19A, it appears that the majority of increase is due to ST 320, a recently reported switched variant. This may have consequences for the STs causing invasive pneumococcal disease.