Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia.
Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Germany.
PLoS One. 2018 Sep 17;13(9):e0198054. doi: 10.1371/journal.pone.0198054. eCollection 2018.
Previous studies suggest the burden of pulmonary tuberculosis (PTB) in Ethiopia may be greater in university students relative to the overall population. However, little is known about the transmission dynamics of PTB among students and members of the communities surrounding university campuses in Eastern Ethiopia.
A cross sectional study was conducted in Eastern Ethiopia among prevalent culture-confirmed PTB cases from university students (n = 36) and community members diagnosed at one of four hospitals (n = 152) serving the surrounding area. Drug susceptibility testing (DST) was performed on Mycobacterium tuberculosis complex (MTBC) isolates using BD Bactec MGIT 960 and molecular genotyping was performed using spoligotyping and 24-loci MIRU-VNTR. MTBC strains with Identical genotyping patterns were assigned to molecular clusters as surrogate marker for recent transmission and further contact tracing was initiated among clustered patients.
Among all study participants, four MTBC lineages and 11 sub-lineages were identified, with Ethiopia_3 (Euro-American lineage) being most common sub-lineage (29.4%) in both cohorts and associated with strain clustering (P = 0.016). We further identified 13 (8.1%) strains phylogenetically closely related to Ethiopia_3 but with a distinct Spoligotyping pattern and designated as Ethiopia_4. The clustering rate of MTBC strains was 52.9% for university students and 66.7% for community members with a Recent Transmission Index (RTI) of 17.6% and 48.4%, respectively. Female gender, urban residence, and new TB cases were significantly associated with strain clustering (P<0.05). Forty-eight (30%) of the study participants were resistant to one or more first line anti TB drugs, three patients were classified as multidrug resistant (MDR).
We found evidence for recent transmission of PTB among Ethiopian university students and the local community in Eastern Ethiopia, mainly linked to strains classified as Ethiopia_3 sub lineage. Drug resistance didn't have a major impact on recent transmission but comprehensive molecular surveillance in combination with drug resistance profiling of MTBC strains is desirable to better characterize TB transmission dynamics in high risk congregate living environments such as university campuses and guide regional TB control programs.
先前的研究表明，与总人口相比，埃塞俄比亚大学生群体中的肺结核（PTB）负担可能更大。然而，人们对埃塞俄比亚东部大学校园周围学生和社区成员中 PTB 的传播动态知之甚少。
在埃塞俄比亚东部，对来自大学生（n=36）和为周边地区服务的四家医院之一诊断出的社区成员（n=152）的经培养确证的肺结核病例进行了一项横断面研究。使用 BD Bactec MGIT 960 对结核分枝杆菌复合群（MTBC）分离株进行药物敏感性试验（DST），并使用 spoligotyping 和 24 位 MIRU-VNTR 进行分子基因分型。具有相同基因分型模式的 MTBC 菌株被分配到分子簇中，作为近期传播的替代标志物，并在聚类患者中启动进一步的接触追踪。
在所有研究参与者中，确定了四个 MTBC 谱系和 11 个子谱系，其中埃塞俄比亚 3（欧美谱系）是两个队列中最常见的子谱系（29.4%），并与菌株聚类相关（P=0.016）。我们进一步确定了 13 株（8.1%）与埃塞俄比亚 3 密切相关的菌株，但 spoligotyping 模式不同，并指定为埃塞俄比亚 4。大学生中 MTBC 菌株的聚类率为 52.9%，社区成员为 66.7%，最近传播指数（RTI）分别为 17.6%和 48.4%。女性、城市居住和新结核病病例与菌株聚类显著相关（P<0.05）。48 名（30%）研究参与者对一种或多种一线抗结核药物耐药，3 名患者被归类为耐多药（MDR）。
我们发现埃塞俄比亚东部大学生和当地社区中存在肺结核的近期传播证据，主要与分类为埃塞俄比亚 3 子谱系的菌株有关。耐药性对近期传播没有重大影响，但需要综合分子监测和 MTBC 菌株耐药性分析，以更好地描述大学等高风险聚集居住环境中的结核病传播动态，并为区域结核病控制计划提供指导。
