Setchanova Lena Petrova, Alexandrova Alexandra, Dacheva Daniela, Mitov Ivan, Kaneva Radka, Mitev Vanio
1 Department of Medical Microbiology, Faculty of Medicine, Medical University of Sofia , Sofia, Bulgaria .
Microb Drug Resist. 2015 Feb;21(1):35-42. doi: 10.1089/mdr.2014.0076. Epub 2014 Jul 31.
A pneumococcal conjugate vaccine (PCV10) was introduced in Bulgarian national immunization program since April 2010. Clonal composition based on pulsed-field gel electrophoresis and multilocus sequence typing genotyping of 52 serotype 19A Streptococcus pneumoniae isolates was analyzed. These were invasive and respiratory isolates collected between 1992 and 2013 from both children (78.8% <5 years) and adults with pneumococcal infections. Multidrug resistance was found in 82.7% of all 19A isolates. The most prevalent genotype (63.5%) among serotype 19A pneumococcal strains was the multidrug-resistant clonal complex CC230, which is a capsular switched variant of the Denmark(14)-32 (ST230) global clone. The most frequent sequence type (ST) was ST230 (48.1%) and together with four other closely related STs (15.4%), belonging to ST1611, ST276, ST7466, and ST2013, which were single- and double-locus variants; they were included in the main CC230. The disappearance of highly drug-resistant ST663 clone and emergence of new clones as CC320 and CC199 was also observed among the rest 19A isolates. A comparison of clonal composition between invasive and noninvasive isolates did not show a great genetic diversity among both kinds of isolates. Continuous surveillance of serotype 19A population following the introduction of PCV10 is essential to evaluate the impact of the vaccine on the epidemiology of this serotype.
自2010年4月起,一种肺炎球菌结合疫苗(PCV10)被纳入保加利亚国家免疫规划。对52株19A血清型肺炎链球菌分离株进行了基于脉冲场凝胶电泳和多位点序列分型的克隆组成分析。这些分离株为1992年至2013年间收集的侵袭性和呼吸道分离株,来自患有肺炎球菌感染的儿童(78.8%<5岁)和成人。在所有19A分离株中,82.7%发现有多药耐药性。19A血清型肺炎球菌菌株中最常见的基因型(63.5%)是多药耐药克隆复合体CC230,它是丹麦(14)-32(ST230)全球克隆的荚膜转换变体。最常见的序列型(ST)是ST230(48.1%),与其他四个密切相关的STs(15.4%)一起,属于ST1611、ST276、ST7466和ST2013,它们是单一位点和双位点变体;它们被纳入主要的CC230。在其余19A分离株中还观察到高耐药性ST663克隆的消失以及新克隆CC320和CC199的出现。侵袭性和非侵袭性分离株之间的克隆组成比较未显示出这两种分离株之间有很大的遗传多样性。在引入PCV10后持续监测19A血清型群体对于评估疫苗对该血清型流行病学的影响至关重要。