Cao Huiluo, Chiu Kelvin Hei-Yeung, Chiu Susan S, Jiang Shuo, Chow Kin-Hung, Ho Pak-Leung
Carol Yu Center for Infection and Department of Microbiology, University of Hong Kong, Hong Kong, China.
Department of Microbiology, Queen Mary Hospital, Hong Kong, China.
Int J Med Microbiol. 2021 Dec;311(8):151543. doi: 10.1016/j.ijmm.2021.151543. Epub 2021 Nov 30.
Pneumococcal conjugate vaccines (PCVs) successfully decreased the incidence of invasive pneumococcal disease in children. However, many countries have reported serotype replacement and a rebound in diseases from non-vaccine serotypes. Here, we report the genomic investigation of a Streptococcus pneumoniae strain M215 that caused severe meningoencephalitis in an infant in 2019. The strain was assigned to serotype 24F using the bioinformatic pipeline SeroBA and pneumococcal type specific anti-sera. The strain was resistant to cotrimoxazole from mutations in both folA and folP genes. It was susceptible to penicillin and other non-β-lactam antibiotics. Phylogenetically, it belongs to Global Pneumococcal Sequence Cluster (GPSC) 6 and multi-locus sequence type 162. A total of 38 virulence genes were detected in the genome of M215. Upon comparison of the profile of virulence genes, GPSC6 but not non-GPSC6 strains of serotype 24F and related serotypes were found to possess the major virulence determinant, pilus islet-1, comprising genes encoding sortases (srtB, srtC, srtD), pilus proteins (rrgA, rrgB and rrgC) and one transcriptional regulator (rlrA), which was previously described to be characteristic feature of international clones in the pre-PCV era. In our locality, this represented the first detection of serotype 24F and GPSC6/ST162 causing serious pneumococcal disease. The emergence of the non-vaccine serotype 24F GPSC6/ST162 lineage with molecular feature of high virulence is concerning and emphasizes the need for full characterization of strains causing severe disease.
肺炎球菌结合疫苗（PCV）成功降低了儿童侵袭性肺炎球菌疾病的发病率。然而，许多国家报告了血清型替换以及非疫苗血清型疾病的反弹。在此，我们报告了一株肺炎链球菌M215的基因组研究，该菌株于2019年在一名婴儿中引起严重脑膜脑炎。使用生物信息学管道SeroBA和肺炎球菌型特异性抗血清将该菌株鉴定为24F血清型。该菌株因folA和folP基因的突变而对复方新诺明耐药。它对青霉素和其他非β-内酰胺类抗生素敏感。在系统发育上，它属于全球肺炎球菌序列簇（GPSC）6和多位点序列类型162。在M215的基因组中总共检测到38个毒力基因。在比较毒力基因谱时，发现24F血清型和相关血清型的GPSC6菌株而非非GPSC6菌株拥有主要毒力决定因素菌毛岛-1，其包含编码分选酶（srtB、srtC、srtD）、菌毛蛋白（rrgA、rrgB和rrgC）和一个转录调节因子（rlrA）的基因，这在PCV时代之前被描述为国际克隆株的特征。在我们当地，这是首次检测到24F血清型和GPSC6/ST162引起严重的肺炎球菌疾病。具有高毒力分子特征的非疫苗血清型24F GPSC6/ST162谱系的出现令人担忧，并强调了对引起严重疾病的菌株进行全面鉴定的必要性。
