Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Department of Science and Technology/National Research Foundation: Vaccine Preventable Diseases, Faculty Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Medical Research Council: Respiratory and Meningeal Pathogens Research Unit, Faculty Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Vaccine. 2018 May 31;36(23):3278-3285. doi: 10.1016/j.vaccine.2018.04.068. Epub 2018 Apr 27.
Nasopharyngeal bacterial colonization is a pre-requisite for developing bacterial mucosal and invasive disease. Pneumococcal conjugate vaccine (PCV) immunization of children reduces their risk of colonization by vaccine-serotypes, which could affect the biome of the nasopharynx in relation to colonization by other bacteria. This study evaluated the association of PCV immunization on the prevalence density of nasopharyngeal colonization by common, potentially pathogenic bacteria.
A multiplex qPCR assay was used to evaluate bacterial nasopharyngeal colonization by 7-valent PCV (PCV7) serotypes, non-vaccine serotypes (NVT), Haemophilus influenzae, Staphylococcus aureus, Moraxella catarrhalis, and Neisseria meningitidis in PCV7-vaccinated and PCV-unvaccinated African children at two time points.
PCV7 vaccination was associated with a higher prevalence of NVT and H. influenzae at 9 and 16 months, respectively. While the prevalence of S. aureus was higher in PCV7-vaccinated children at 9 months, no difference was found at 16 months. The density of PCV7 serotypes (3.8 vs. 3.4 log; p = 0.048), NVT (3.6 vs. 3.1 log; p = 0.018), H. influenzae (4.34 vs. 3.86 log; p = 0.008), M. catarrhalis (3.52 vs. 2.98 log; p < 0.001) and S. aureus (4.02 vs. 3.06 log; p = 0.02) was higher among PCV-vaccinated compared to PCV-unvaccinated children at 9 months, although, this difference diminished at 16 months of age.
The reduction in PCV7-serotype colonization impacted on colonization prevalence and density of other bacterial species of the nasopharynx. The clinical relevance of this needs further exploration in relation to mucosal and invasive disease outcomes, as well as for higher valency PCV vaccines.
鼻咽部细菌定植是发生细菌黏膜和侵袭性疾病的前提。儿童接种肺炎球菌结合疫苗（PCV）可降低疫苗血清型定植的风险，这可能会影响鼻咽部的微生物区系，进而影响其他细菌的定植。本研究评估了 PCV 免疫接种对常见潜在致病细菌鼻咽部定植流行密度的影响。
采用多重 qPCR 检测法评估 7 价 PCV（PCV7）血清型、非疫苗血清型（NVT）、流感嗜血杆菌、金黄色葡萄球菌、卡他莫拉菌和脑膜炎奈瑟菌在 PCV7 接种和未接种的非洲儿童鼻咽部的定植情况，分别于两个时间点进行检测。
PCV7 疫苗接种与 9 个月和 16 个月时 NVT 和 H. influenzae 的更高流行率相关。虽然 9 个月时 PCV7 疫苗接种组金黄色葡萄球菌的流行率更高，但 16 个月时无差异。PCV7 血清型（3.8 与 3.4 log；p=0.048）、NVT（3.6 与 3.1 log；p=0.018）、流感嗜血杆菌（4.34 与 3.86 log；p=0.008）、卡他莫拉菌（3.52 与 2.98 log；p<0.001）和金黄色葡萄球菌（4.02 与 3.06 log；p=0.02）的密度在接种组高于未接种组，尽管这种差异在 16 个月时缩小。
PCV7 血清型定植减少对鼻咽部其他细菌种属的定植流行率和密度产生影响。这种影响与黏膜和侵袭性疾病结局以及更高价 PCV 疫苗相关的临床意义需要进一步探索。
