A new serotype 14 variant of the pneumococcal Spain9V-3 international clone detected in the central region of Argentina
A new serotype 14 variant of the pneumococcal Spain9V-3 international clone detected in the central region of Argentina
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DOI：
10.1099/jmm.0.2008/000505-0
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发表时间：
2008-08-01
影响因子：
3
通讯作者：
Echenique, Jose R.
中科院分区：
文献类型：
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作者：
Albarracin Orio, Andrea G.;Cortes, Paulo R.;Echenique, Jose R.
肺炎链球菌的青霉素抗性西班牙(9V)-3克隆广泛存在，并呈现出源自荚膜基因重组的不同血清型变异体。在这项工作中，通过多位点序列分型 (MLST) 评估了从阿根廷中部地区（科尔多瓦、布宜诺斯艾利斯、圣达菲和拉潘帕省）分离的 29 种侵袭性肺炎球菌的遗传相关性。研究的所有青霉素不敏感分离株 (21/29) 均属于 Spain(9V)-3 克隆的血清型 14 变体。该克隆占主导地位，表明它是该地区青霉素耐药性传播的原因。有趣的是，这种血清型 14 变体（名为 Cordoba S14V）可以通过其 pbp1a 基因与欧洲变体区分开来，这表明荚膜基因存在不同的重组替代。对假定的重组位点进行了分析，结果显示近端交叉点明确位于 spr0309 基因中，而远端位点仅限于 recU 基因，从而证实了不同的重组事件。对这些菌株的dexB、cpsB、aliA和pbp1a基因的分析显示与Spain(14)-5克隆的相应基因高度相似，表明荚膜基因是由该国际克隆提供的。建议对 pbp1a (nt 1473-1922) 和 spr0309 (nt 1-790) 基因的遗传多态性进行分析作为流行病学工具，以帮助识别 Spain(9V)-3 克隆的 Cordoba S14V。另一方面，对血清型 14 菌株进行的基于 BOX 重复的 PCR 和 MLST 分析揭示了 Cordoba S14V 的不同流行病学，表明并非近期在儿科人群中传播。建议这项分子流行病学工作可为监测西班牙S14Vs(9V)-3的进化、新克隆的出现以及阿根廷肺炎球菌疫苗接种计划的影响提供参考。
The penicillin-resistant Spain(9V)-3 clone of Streptococcus pneumoniae is widespread and presents different serotype variants originating from recombination of the capsular genes. In this work, the genetic relatedness of 29 invasive pneumococci isolated from the central region of Argentina (Cordoba, Buenos Aires, Santa Fe and La Pampa provinces) was assessed by multilocus sequence typing (MLST). All of the penicillin-non-susceptible isolates studied (21/29) belonged to a serotype 14 variant of the Spain(9V)-3 clone. This clone was predominant, suggesting that it was responsible for the penicillin resistance spread in this region. Interestingly, this serotype 14 variant (named Cordoba S14V) could be differentiated from the European one by its pbp1a gene, suggesting a different recombinational replacement of the capsular genes. The putative recombination sites were analysed, resulting in the proximal crossover point being clearly localized in the spr0309 gene, with the distal site restricted to the recU gene, confirming a different recombination event. Analysis of the dexB, cpsB, aliA and pbp1a genes from these strains showed a high similarity with the corresponding genes of the Spain(14)-5 clone, suggesting that the capsular genes were provided by this international clone. Analysis of the genetic polymorphisms of the pbp1a (nt 1473-1922) and spr0309 (nt 1-790) genes is proposed as an epidemiological tool to help recognize the Cordoba S14V of the Spain(9V)-3 clone. On the other hand, BOX-repeat-based PCR and MLST analyses of serotype 14 strains revealed a divergent epidemiology of the Cordoba S14V, suggesting a non-recent dissemination in the paediatric population. It is suggested that this molecular epidemiology work will be a reference for monitoring the evolution of S14Vs of Spain(9V)-3, the emergence of new clones and the impact of pneumococcal vaccination programmes in Argentina.