尼泊尔肺炎链球菌带菌率：从偏远地区延迟运送样本方法的评估及其对疫苗实施的影响。
Streptococcus pneumoniae carriage prevalence in Nepal: evaluation of a method for delayed transport of samples from remote regions and implications for vaccine implementation.
机构信息
Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom; Patan Academy Paediatric Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal.
Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
出版信息
PLoS One. 2014 Jun 6;9(6):e98739. doi: 10.1371/journal.pone.0098739. eCollection 2014.
BACKGROUND
Pneumococcal disease is a significant cause of morbidity and mortality in young children in Nepal, and currently available pneumococcal conjugate vaccines offer moderate coverage of invasive disease isolates.
METHODS
A prevalence study of children aged 1.5 to 24 months in urban and rural Nepal was conducted. In the urban group, nasopharyngeal swabs (NPS) were transported using silica desiccant packages (SDP) with delayed processing (2 weeks), or skim-milk-tryptone-glucose-glycerin (STGG) with immediate processing (within 8 hours). Pneumococcal nasopharyngeal carriage prevalence, serogroup/type distribution and isolate genotypes (as defined by multilocus sequence typing) were determined.
RESULTS
1101 children were enrolled into the study: 574 in the urban group and 527 in the rural group. Overall carriage prevalence based on culture from specimens transported and stored in STGG was 58.7% (337/574), compared to 40.9% (235/574) in SDP. There was concordance of detection of pneumococcus in 67% of samples. Using the SDP method, pneumococcal carriage prevalence was higher in the rural population (69.2%; 364/526) compared to the urban population (40.9%; 235/574). Serogroup/type distribution varied with geographical location. Over half of the genotypes identified in both the urban and rural pneumococcal populations were novel.
CONCLUSION
The combination of delayed culture and transport using SDP underestimates the prevalence of pneumococcal carriage; however, in remote areas, this method could still provide a useful estimate of carriage prevalence and serogroup/type distribution. Vaccine impact is unpredictable in a setting with novel genotypes and limited serotype coverage as described here. Consequently, continued surveillance of pneumococcal isolates from carriage and disease in Nepali children following the planned introduction of pneumococcal conjugate vaccines introduction will be essential.
背景
肺炎球菌疾病是尼泊尔幼儿发病率和死亡率的重要原因，目前可用的肺炎球菌结合疫苗对侵袭性疾病分离株的覆盖范围有限。
方法
在尼泊尔城乡地区开展了一项年龄为 1.5 至 24 个月儿童的患病率研究。在城市组中，使用含有延迟处理（2 周）的硅干燥剂包装（SDP）或即时处理（8 小时内）的脱脂乳-胰蛋白酶-葡萄糖-甘油（STGG）运输鼻咽拭子（NPS）。确定了鼻咽部肺炎球菌携带率、血清型/型分布和分离株基因型（通过多位点序列分型定义）。
结果
共有 1101 名儿童入组研究：城市组 574 名，农村组 527 名。基于在 STGG 中运输和储存的标本进行培养的总体携带率为 58.7%（337/574），而 SDP 为 40.9%（235/574）。67%的样本检测结果一致。使用 SDP 方法，农村地区的肺炎球菌携带率（69.2%；364/526）高于城市地区（40.9%；235/574）。血清型/型分布随地理位置而变化。在城市和农村地区的肺炎球菌人群中，有一半以上的基因型是新的。
结论
使用 SDP 进行延迟培养和运输的组合低估了肺炎球菌携带率；然而，在偏远地区，这种方法仍然可以提供携带率和血清型/型分布的有用估计。在描述的新型基因型和有限血清型覆盖的情况下，疫苗的影响是不可预测的。因此，在计划引入肺炎球菌结合疫苗后，继续监测尼泊尔儿童从携带和疾病中分离的肺炎球菌分离株将是至关重要的。
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