Barcelona Institute for Global Health (ISGlobal), Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan.
BMC Infect Dis. 2020 Dec 9;20(1):940. doi: 10.1186/s12879-020-05674-4.
Pneumococcal nasopharyngeal colonization (PNC) generally precedes pneumococcal disease. The purpose of this study was to determine the prevalence of PNC and to identify the pneumococcal serotypes circulating among Bhutanese children under five years of age admitted with clinical pneumonia, before the introduction of pneumococcal conjugate vaccine (PCV13) in the country. We also aimed to contribute to the understanding of the interplay between PNC and viral co-infection among this population.
This was a prospective study conducted at the Jigme Dorji Wangchuck National Referral Hospital in Bhutan over 12 consecutive months. Children aged 2 to 59 months admitted with WHO-defined clinical pneumonia were eligible for recruitment. We collected blood for bacterial culture and molecular identification of S. pneumoniae, and nasopharyngeal washing for screening of respiratory viruses, and for the detection and capsular typing of S. pneumoniae by real-time polymerase chain reaction (RT-PCR).
Overall, 189 children were recruited, and PNC was tested in 121 of them (64.0%). PNC was found in 76/121 children (62.8%) and S. pneumoniae was identified in blood (both by culture and RT-PCR) in a single child. Respiratory viruses were detected in a similar proportion among children with (62/70; 88.6%) and without PNC (36/40; 90.0%; p = 1.000), but rhinovirus detection was less common among children with PNC (20/70; 28.6% versus 19/40; 47.5%; p = 0.046). Capsular typing identified 30 different serotypes. Thirty-nine children (51.3%) were colonised with two to five different serotypes. A third of the children presented with serotypes considered highly invasive. Over half of the children (44/76; 57.9%) were carrying at least one serotype included in PCV13.
This study provides baseline information on the status of PNC among Bhutanese children admitted with clinical pneumonia prior to the introduction of PCV13, which is valuable to monitor its potential impact. PCV13 could theoretically have averted up to 58% of the pneumococcal infections among the children in this study, suggesting a future role for the vaccine to significantly reduce the burden associated with S. pneumoniae in Bhutan.
肺炎球菌鼻咽部定植（PNC）通常先于肺炎球菌疾病。本研究的目的是确定五岁以下因临床肺炎入院的不丹儿童中 PNC 的流行率，并确定在该国引入肺炎球菌结合疫苗（PCV13）之前流行的肺炎球菌血清型。我们还旨在增进对这一人群中 PNC 与病毒合并感染相互作用的理解。
这是在不丹的吉格梅·多吉·旺楚克国家转诊医院进行的一项前瞻性研究，历时 12 个月。符合世界卫生组织定义的临床肺炎标准并入院的 2 至 59 个月大的儿童有资格参加。我们采集血液进行细菌培养和 S. pneumoniae 的分子鉴定，采集鼻咽冲洗液进行呼吸道病毒筛查，并通过实时聚合酶链反应（RT-PCR）检测和荚膜分型 S. pneumoniae。
总体而言，共招募了 189 名儿童，其中 121 名（64.0%）进行了 PNC 检测。在 121 名儿童中，76 名（62.8%）发现 PNC，在一名儿童的血液中同时通过培养和 RT-PCR 发现 S. pneumoniae。有 PNC 的儿童（70 名中的 62 名；88.6%）和无 PNC 的儿童（40 名中的 36 名；90.0%；p=1.000）呼吸道病毒检出率相似，但 PNC 儿童的鼻病毒检出率较低（70 名中的 20 名；28.6%比 40 名中的 19 名；47.5%；p=0.046）。荚膜分型鉴定出 30 种不同血清型。39 名儿童（51.3%）定植了两种至五种不同的血清型。三分之一的儿童携带被认为具有高度侵袭性的血清型。超过一半的儿童（76 名中的 44 名；57.9%）携带至少一种包含在 PCV13 中的血清型。
本研究提供了在引入 PCV13 之前不丹因临床肺炎入院的儿童中 PNC 现状的基线信息，这对于监测其潜在影响很有价值。PCV13 理论上可以避免本研究中儿童 58%的肺炎球菌感染，这表明该疫苗未来可以显著降低不丹肺炎球菌相关负担。
