Data from: Aboriginal and non-Aboriginal children in Western Australia carry different serotypes of pneumococci with different antimicrobial susceptibility profiles

Background: Carriage of Streptococcus pneumoniae is considered a precursor to pneumococcal diseases including pneumonia. As part of the Kalgoorlie Otitis Media Research Project, we characterised pneumococci isolated from the nasopharynx of Western Australian Aboriginal and non-Aboriginal children. Methods: Between 1999 and 2005, 100 Aboriginal and 180 non-Aboriginal children were followed from birth to two years, with nasopharyngeal aspirates collected at ages 1–3 and 6–8 weeks, then at 4, 6, 12, 18 and 24 months. Introduction of 7-valent pneumococcal conjugate vaccine (7vPCV) in 2001 enabled evaluation of its impact on carriage in study participants according to vaccines doses received. Pneumococcal serotyping was performed by Quellung and antimicrobial susceptibility by disk diffusion and Etest®. Molecular epidemiology of pneumococcal isolates was investigated by pulse-field gel electrophoresis and multilocus sequence typing. Results: Overall, the prevalence of 7vPCV serotypes was similar for Aboriginal and non-Aboriginal children (19 % vs. 16 %), but the prevalence of non-vaccine serotypes was higher in Aboriginal children (22 % vs. 7 %). A multi-resistant 6B clone (ST90) was found only in non-Aboriginal children. Aboriginal children who received three doses of 7vPCV had lower odds of carrying 7vPCV serotypes (odds ratio [OR] 0.19, 95 % CI 0.08–0.44) and higher odds of carrying non-vaccine serotypes (OR 2.37, 95 % CI 1.13–4.99) than unvaccinated Aboriginal children; this finding was not observed in non-Aboriginal children. Conclusions: This unique study shows important differences in pneumococcal serotypes, genotypes, and antimicrobial susceptibility between Aboriginal and non-Aboriginal children living in the same geographic area before widespread 7vPCV use, and highlights the need for ongoing post-vaccination surveillance in outback Australia.背景：肺炎链球菌（Streptococcus pneumoniae）定植被认为是包括肺炎在内的各类肺炎球菌疾病的前驱感染阶段。作为卡尔古利中耳炎研究项目（Kalgoorlie Otitis Media Research Project）的组成部分，本研究对从西澳大利亚原住民与非原住民儿童鼻咽部分离获得的肺炎球菌进行了分型表征。 方法：1999年至2005年间，研究团队对100名原住民儿童及180名非原住民儿童开展了从出生至2岁的前瞻性队列随访，分别于1~3月龄、6~8月龄，以及4、6、12、18、24月龄时采集鼻咽抽吸物。2001年7价肺炎球菌结合疫苗（7vPCV，7-valent pneumococcal conjugate vaccine）的免疫接种计划正式实施，使得本研究得以评估该疫苗对不同接种剂量受试者的肺炎球菌定植影响。肺炎球菌血清分型采用奎伦（Quellung）法，抗菌药物敏感性检测采用纸片扩散法与Etest®。研究通过脉冲场凝胶电泳（pulse-field gel electrophoresis）与多位点序列分型（multilocus sequence typing）对肺炎球菌分离株开展分子流行病学分析。 结果：总体而言，原住民与非原住民儿童的7vPCV血清型定植率相近（19% vs 16%），但原住民儿童的非疫苗血清型定植率显著更高（22% vs 7%）。仅在非原住民儿童中检出了一株多重耐药的6B型克隆株（ST90）。相较于未接种的原住民儿童，接种3剂7vPCV的原住民儿童携带7vPCV血清型的比值比（OR）更低（OR 0.19，95%置信区间[CI] 0.08~0.44），而携带非疫苗血清型的比值比更高（OR 2.37，95%CI 1.13~4.99）；这一关联在非原住民儿童中未被观察到。 结论：本项独具特色的研究表明，在7vPCV广泛应用之前，居住于同一地理区域的澳大利亚原住民与非原住民儿童，其肺炎球菌的血清型、基因型与抗菌药物敏感性存在显著差异；同时强调了澳大利亚内陆偏远地区需持续开展疫苗接种后的监测工作。