Sharew Bekele, Moges Feleke, Yismaw Gizachew, Mihret Adane, Abebe Wondiwossen, Fentaw Surafal, Tessema Belay
Department of Medical Microbiology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Wollo University, Dessie, Ethiopia.
Infect Drug Resist. 2021 Mar 2;14:787-794. doi: 10.2147/IDR.S293578. eCollection 2021.
In Ethiopia, pneumococcal conjugate vaccine 10 (PCV10) was introduced in 2011 in the national vaccination program. This study was aimed to assess serotype distribution of invasive and non-invasive isolates using whole-genome sequencing.
A hospital-based prospective study was conducted from 2018 to 2019 at Addis Ababa and Amhara region referral hospitals, from all patients. Clinical Samples were collected and initially cultured onto 5% sheep blood agar at 37°C in a 5% CO atmosphere. Sequencing was done using the Illumina NextSeq 500 and SeroBA was used to predict serotypes from whole-genome sequencing raw data.
Of the 57 isolates, there were 32 circulating serotypes. The most common serotypes were 15A/B/C (n=5, 8.8%), 6A (n=4, 7.0%), 10A/F (n=4, 7.0%), 23A (n=4, 7.0%) and 7C (n=3, 5.3%). The serotype coverage of PCV10 and PCV13 were 12.3% and 26.3% respectively. The most common invasive serotypes were 15A/B/C (n=5, 8.8%) and 6A (n=4, 7.0%), and non-invasive serotypes were 23A (n=4, 7.0%) and 10A/F (n=3, 5.3%). The most prevalent serotype obtained from PCV10 eligible children was 3 (n=2, 3.5%). The prevalent serotype obtained from PCV10 non-eligible patients were type 23A (n=4, 7%) and type 6A (n=3, 5.2%). The most common serotypes among children ≤18 years old were 10A/F, 7C, 35A/B, 16F, 19A, 3 and 38. However, the proportions of some non-vaccine serotypes (11A/B and 15A/B/C) were higher in adult patients.
In this study a shift in the distribution of non-vaccinated serotypes increases in the population, and PCV10 serotype coverage was reduced as compared to PCV13. Therefore, it is important to continue monitoring serotype changes among all patients in addition to assessing the impact and effectiveness brought by vaccines and provides a foundation for prevention strategies and vaccine policies.
在埃塞俄比亚，2011年肺炎球菌结合疫苗10（PCV10）被纳入国家疫苗接种计划。本研究旨在通过全基因组测序评估侵袭性和非侵袭性分离株的血清型分布。
2018年至2019年在亚的斯亚贝巴和阿姆哈拉地区转诊医院开展了一项基于医院的前瞻性研究，纳入所有患者。收集临床样本，最初接种于5%绵羊血琼脂平板，在37°C、5%二氧化碳环境中培养。使用Illumina NextSeq 500进行测序，并使用SeroBA从全基因组测序原始数据预测血清型。
57株分离株中，有32种流行血清型。最常见的血清型为15A/B/C（n = 5，8.8%）、6A（n = 4，7.0%）、10A/F（n = 4，7.0%）、23A（n = 4，7.0%）和7C（n = 3，5.3%）。PCV10和PCV13的血清型覆盖率分别为12.3%和26.3%。最常见的侵袭性血清型为15A/B/C（n = 5，8.8%）和6A（n = 4，7.0%），非侵袭性血清型为23A（n = 4，7.0%）和10A/F（n = 3，5.3%）。PCV10适用儿童中最常见的血清型为3型（n = 2，3.5%）。PCV10不适用患者中常见的血清型为23A（n = 4，7%）和6A（n = 3，5.2%）。≤18岁儿童中最常见的血清型为10A/F、7C、35A/B、16F、19A、3型和38型。然而，一些非疫苗血清型（11A/B和15A/B/C）在成年患者中的比例较高。
本研究中未接种疫苗血清型在人群中的分布发生变化，且与PCV13相比，PCV10血清型覆盖率降低。因此，除评估疫苗带来的影响和效果外，持续监测所有患者的血清型变化很重要，可为预防策略和疫苗政策提供依据。
