Varghese Rosemol, Neeravi Ayyanraj, Subramanian Nithya, Pavithra B, Kavipriya A, Kumar Jones Lionel, Girish Kumar C P, Jeyraman Yuvraj, Karthik G, Verghese Valsan P, Veeraraghavan Balaji
Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India.
Department of Paediatrics, Christian Medical College, Chennai, Tamil Nadu, India.
Indian J Med Microbiol. 2019 Jul-Sep;37(3):358-362. doi: 10.4103/ijmm.IJMM_19_348.
Pneumococcal pneumonia is one of the major causes of mortality in children less than 5 years in Asia, especially in India. Available PCVs have less serotype coverage in India compared to western countries. Moreover, the baseline pneumococcal serotype and sequence type data is limited and available data doesn't represent the entire India. With this background we aimed to characterize invasive and carriage isolates of S. pneumoniae from a tertiary care hospital in South India.
A total of 221 S. pneumoniae isolates, invasive (n=138) and carriage (n=83) between the time period of 2012-2018 were included. Isolates was identified and confirmed using standard laboratory protocols. Serotyping was performed by Customized sequential multiplex PCR and MLST as described in www.pubmlst.org.
The major serotypes were 19F, 6B, 14, 6A and 19A and the sequence types (ST) were ST63, 236 and 230. Predominant STs in invasive was ST 63 whereas in carriage were ST4894 and 1701. High level ST diversity in carriage was observed. Majority of the STs were SLVs or DLVs of previously reported STs or PMEN clones. Phylogenetic analyses of the STs revealed gradual expansion of three PMEN CCs CC320, 63 and 230.
The vaccine serotypes were the predominant ones found to be associated with IPD, PMEN clones, new STs and antimicrobial resistance. Accordingly, PCV13 is expected to provide invasive serotype coverage of 75% in Indian children less than 5 years. This study provides baseline serotype and sequence type data prior to the introduction of PCV in South India.
肺炎球菌肺炎是亚洲5岁以下儿童死亡的主要原因之一，在印度尤为如此。与西方国家相比，印度现有的肺炎球菌结合疫苗（PCV）血清型覆盖率较低。此外，肺炎球菌血清型和序列型的基线数据有限，现有数据不能代表整个印度。在此背景下，我们旨在对印度南部一家三级护理医院的肺炎链球菌侵袭性和携带分离株进行特征分析。
纳入2012年至2018年期间的221株肺炎链球菌分离株，其中侵袭性分离株（n = 138）和携带分离株（n = 83）。使用标准实验室方案对分离株进行鉴定和确认。如www.pubmlst.org所述，通过定制的序列多重PCR和多位点序列分型（MLST）进行血清分型。
主要血清型为19F、6B、14、6A和19A，序列型（ST）为ST63、236和230。侵袭性分离株中主要的ST是ST63，而携带分离株中是ST4894和1701。观察到携带分离株中ST多样性较高。大多数ST是先前报道的ST或肺炎球菌致病克隆（PMEN）的单一位点变异株（SLV）或双位点变异株（DLV）。对ST的系统发育分析显示三个PMEN克隆复合体CC320、63和230逐渐扩展。
疫苗血清型是发现与侵袭性肺炎球菌疾病（IPD）、PMEN克隆、新的ST和抗菌药物耐药性相关的主要血清型。因此，预计PCV13可为印度5岁以下儿童提供75%的侵袭性血清型覆盖率。本研究提供了在印度南部引入PCV之前的基线血清型和序列型数据。
