Moore Catrin E, Giess Adam, Soeng Sona, Sar Poda, Kumar Varun, Nhoung Pheakdey, Bousfield Rachel, Turner Paul, Stoesser Nicole, Day Nicholas P J, Parry Christopher M
Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Angkor Hospital for Children, Siem Reap, Cambodia.
PLoS One. 2016 Jul 22;11(7):e0159358. doi: 10.1371/journal.pone.0159358. eCollection 2016.
The 13-valent pneumococcal vaccine (PCV13) was introduced in Cambodia in January 2015. There are limited data concerning the common serotypes causing invasive pneumococcal disease (IPD). Knowledge of the circulating pneumococcal serotypes is important to monitor epidemiological changes before and after vaccine implementation.
All episodes of IPD defined by the isolation of Streptococcus pneumoniae from blood, cerebrospinal fluid or other sterile site in Cambodian children admitted to the Angkor Hospital for Children in Siem Reap, Northwestern Cambodia, between 1st January 2007 and 1st July 2012 were retrospectively studied. Streptococcus pneumoniae isolates that could be retrieved underwent phenotypic typing and whole genome sequencing.
There were 90 Cambodian children hospitalized with IPD with a median (IQR) age of 2.3 years (0.9-6.2). The case fatality was 15.6% (95% CI 8-23). Of 50 Streptococcus pneumoniae isolates available for further testing, 46% were penicillin non-susceptible and 8% were ceftriaxone non-susceptible, 78% were cotrimoxazole resistant, 30% were erythromycin resistant and 30% chloramphenicol resistant. There were no significant changes in resistance levels over the five-year period. The most common serotypes were 1 (11/50; 22%), 23F (8/50; 16%), 14 (6/50; 12%), 5 (5/50; 10%) and 19A (3/50; 6%). Coverage by PCV7, PCV10 and PCV13 was 44%, 76% and 92% respectively. We identified novel multilocus sequence types and resistotypes using whole genome sequencing.
This study suggests IPD is an important disease in Cambodian children and can have a significant mortality. PCV13 coverage of the serotypes determined in studied strains was high and consistent with another recent study. The phenotypic resistance patterns observed were similar to other regional studies. The use of whole genome sequencing in the present study provides additional typing and resistance information together with the description of novel sequence types and resistotypes.
13价肺炎球菌疫苗（PCV13）于2015年1月在柬埔寨引入。关于引起侵袭性肺炎球菌疾病（IPD）的常见血清型的数据有限。了解循环肺炎球菌血清型对于监测疫苗实施前后的流行病学变化很重要。
对2007年1月1日至2012年7月1日期间在柬埔寨西北部暹粒省吴哥儿童医院住院的柬埔寨儿童中，因从血液、脑脊液或其他无菌部位分离出肺炎链球菌而定义的所有IPD发作进行回顾性研究。对可获取的肺炎链球菌分离株进行表型分型和全基因组测序。
有90名柬埔寨儿童因IPD住院，中位（IQR）年龄为2.3岁（0.9 - 6.2）。病死率为15.6%（95%CI 8 - 23）。在50株可供进一步检测的肺炎链球菌分离株中，46%对青霉素不敏感，8%对头孢曲松不敏感，78%对复方新诺明耐药，30%对红霉素耐药，30%对氯霉素耐药。在这五年期间，耐药水平没有显著变化。最常见的血清型为1型（11/50；22%）、23F型（8/50；16%）、14型（6/50；12%）、5型（5/50；10%）和19A 型（3/50；6%）。PCV7、PCV10和PCV13的覆盖率分别为44%、76%和92%。我们通过全基因组测序鉴定了新的多位点序列类型和耐药型。
本研究表明IPD在柬埔寨儿童中是一种重要疾病，且可导致显著死亡率。PCV13对研究菌株中确定的血清型的覆盖率很高，与另一项近期研究一致。观察到的表型耐药模式与其他区域研究相似。本研究中使用全基因组测序提供了额外的分型和耐药信息，以及对新序列类型和耐药型的描述。
