Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.
Department of Medical Laboratory Science, Addis Ababa University, Addis Ababa, Ethiopia.
PLoS One. 2018 Feb 15;13(2):e0193083. doi: 10.1371/journal.pone.0193083. eCollection 2018.
Tuberculosis (TB) is caused by M. tuberculosis complex and remains a major global public health problem. The epidemic remains a threat to sub-Saharan Africa, including Ethiopia, with further emergence of drug resistant TB. We investigated the drug sensitivity pattern and molecular epidemiology of mycobacterial strains isolated from pulmonary TB patients in and around Ambo town in Oromia Region, Central Ethiopia.
A cross-sectional study was conducted involving 105 consecutive new smear positive pulmonary TB patients diagnosed at Ambo Hospital and surrounding Health Centers between May 2014 and March 2015 upon informed consent. Sputum samples were cultured on Löwenstein-Jensen (LJ) media using standard techniques to isolate mycobacteria. Region of difference 9 (RD9)-based polymerase chain reaction (PCR) and spoligotyping was employed for the identification of the isolates at species and strain levels. The spoligotype patterns were entered into the SITVIT database to determine Octal and SIT (Spoligotyping International Typing) numbers for each strain. The sensitivity of the isolates to isoniazid (INH), rifampicin (RIF), ethambutol (ETB) and streptomycin (STM) was evaluated on LJ-medium with the indirect proportion method.
Cultures were positive in 86/105 (82%) of newly diagnosed smear positive pulmonary TB cases. All of the 86 isolates were confirmed as M. tuberculosis. The majority (76.7%) of them were clustered into seven groups while the rest (23.3%) appeared unique. The most predominant Spoligotypes were SIT53 and SIT149, consisting of 24.4% and 20.9% of the isolates, respectively. Assigning of the isolates to family using SPOTCLUST software revealed that 45.3% of the isolates belonged to T1, 23.3% to T3 and 13% to CAS family. The majority (76.7%) of the M. tuberculosis isolates were susceptible to all the four drugs. Any resistance to any one of the four drugs was detected in 23.3% of the isolates. The highest proportion of any resistance was observed against isoniazid (9.3%) and ethambutol (7%). There was only a single case (1.2%) of multidrug resistant/rifampicin resistant (MDR/RR) TB.
The majority of the isolates were clustered suggesting on-going active transmission in the study area. Mono resistance is relatively prevalent while the magnitude of MDR/RR-TB was found to be lower than in previous studies.
结核病（TB）是由结核分枝杆菌复合体引起的，仍然是一个主要的全球公共卫生问题。该疾病在包括埃塞俄比亚在内的撒哈拉以南非洲仍然构成威胁，并且出现了更多的耐药结核病病例。我们研究了在埃塞俄比亚奥罗米亚地区安博镇及其周边地区新诊断的涂阳肺结核患者的分枝杆菌分离株的药敏模式和分子流行病学。
这是一项横断面研究，涉及 2014 年 5 月至 2015 年 3 月期间在安博医院和周围健康中心就诊并经知情同意的 105 例连续新诊断的涂阳肺结核患者。使用标准技术将痰液样本接种于 Löwenstein-Jensen（LJ）培养基上以分离分枝杆菌。采用基于差异区 9（RD9）的聚合酶链反应（PCR）和 spoligotyping 对分离株进行种属和菌株水平的鉴定。 spoligotype 模式被输入 SITVIT 数据库，以确定每个菌株的 Octal 和 SIT（ spoligotyping International Typing ）编号。使用间接比例法在 LJ 培养基上评估分离株对异烟肼（INH）、利福平（RIF）、乙胺丁醇（ETB）和链霉素（STM）的敏感性。
在 105 例新诊断的涂阳肺结核病例中，有 86/105（82%）的培养呈阳性。所有 86 株分离株均确认为结核分枝杆菌。其中大多数（76.7%）聚集成七个群组，其余（23.3%）则呈独特型。最主要的 spoligotypes 是 SIT53 和 SIT149，分别占分离株的 24.4%和 20.9%。使用 SPOTCLUST 软件对分离株进行家族分配，结果显示 45.3%的分离株属于 T1，23.3%属于 T3，13%属于 CAS 家族。大多数（76.7%）结核分枝杆菌分离株对四种药物均敏感。在 23.3%的分离株中检测到对任何一种药物的耐药性。对异烟肼（9.3%）和乙胺丁醇（7%）的耐药率最高。只有一例（1.2%）耐多药/利福平耐药（MDR/RR）结核病。
大多数分离株呈聚集性，提示研究地区正在发生持续的活动性传播。单耐药较为普遍，而耐多药/利福平耐药结核病的比例低于以往研究。
