肺炎球菌结合疫苗对摩洛哥婴幼儿急性中耳炎中肺炎链球菌携带的影响

文献信息

中文摘要

背景： 尽管已有肺炎球菌结合疫苗（PCVs），肺炎链球菌仍是儿童感染的主要原因。在摩洛哥，PCV10和PCV13的同时使用为评估其对鼻咽部携带和血清型分布的影响提供了独特机会。
目的： 描述卡萨布兰卡急性中耳炎（AOM）幼儿鼻咽菌群中的肺炎球菌血清型，并根据疫苗接种状态比较血清型分布。
方法： 在这项前瞻性、多中心、横断面研究（2020-2024年）中，对6-36月龄AOM患儿进行鼻咽拭子采集。分离株通过Quellung反应和PCR进行血清分型，并分类为疫苗型（VTs）或非疫苗型（NVTs）；流感嗜血杆菌分离株通过玻片凝集进行血清分型。
结果： 在442名儿童中，回收172株肺炎球菌（携带率为38.9%），代表18种血清型。PCV10血清型占49.4%，额外的PCV13血清型占21.5%；主要非PCV13血清型为11A、15B和10A。理论覆盖率PCV15达到73.8%，PCV20达到92.4%。在136株检测的分离株中，两株对青霉素完全耐药（MIC >2 mg/L）。在74株流感嗜血杆菌分离株中，10.8%为b型，20.3%为f型；10.8%发现产β-内酰胺酶，六株（8.1%）为BLNAR表型。
结论： 疫苗型携带持续存在以及非疫苗血清型的出现表明摩洛哥的血清型替换不完全。PCV13比PCV10提供更广泛的覆盖，主要通过血清型19A和3。大多数非PCV13血清型包含在PCV20中，支持其潜在纳入国家免疫规划并持续进行血清型监测。

英文摘要

BACKGROUND: Streptococcus pneumoniae remains a major cause of pediatric infections despite pneumococcal conjugate vaccines (PCVs). In Morocco, the concurrent use of PCV10 and PCV13 offers a unique opportunity to evaluate their impact on nasopharyngeal carriage and serotype distribution.
OBJECTIVE: To describe pneumococcal serotypes in the nasopharyngeal flora of young children with acute otitis media (AOM) in Casablanca and to compare serotype distribution according to vaccination status.
METHODS: In this prospective, multicenter, cross-sectional study (2020-2024), children aged 6-36 months with AOM had a nasopharyngeal swab performed. Isolates were serotyped by Quellung reaction and PCR and classified as vaccine (VTs) or non-vaccine types (NVTs); Haemophilus influenzae isolates were serotyped by slide agglutination.
RESULTS: Of 442 children, 172 pneumococci were recovered (carriage rate of 38.9%), representing 18 serotypes. PCV10 serotypes accounted for 49.4% and additional PCV13 serotypes for 21.5%; the main non-PCV13 serotypes were 11 A, 15B, and 10 A. Theoretical coverage reached 73.8% for PCV15 and 92.4% for PCV20. Among 136 isolates tested, two were fully penicillin-resistant (MIC >2 mg/L). Of 74H. influenzae isolates, 10.8% were serotype b and 20.3% serotype f; β-lactamase production was found in 10.8%, and a BLNAR phenotype in six isolates (8.1%).
CONCLUSION: Persistent vaccine-type carriage alongside emerging non-vaccine serotypes indicates incomplete serotype replacement in Morocco. PCV13 provided broader coverage than PCV10, mainly through serotypes 19 A and 3. Most non-PCV13 serotypes were included in PCV20, supporting its potential integration into the national immunization program and continuous serotype surveillance.