Brhane Mussie, Kebede Ameha, Petros Yohannes
Department of Tuberculosis Culture and DST Laboratory, Harar Health Research and Regional Laboratory, Harar, Ethiopia.
Department of Biology, College of Computational and Natural Sciences, Haramaya University, Haramaya, Ethiopia.
Infect Drug Resist. 2017 Mar 9;10:75-83. doi: 10.2147/IDR.S127903. eCollection 2017.
Molecular methods that target drug resistance mutations are suitable approaches for rapid drug susceptibility testing to detect multidrug-resistant tuberculosis (MDR-TB). The aim of the study was to determine MDR-TB cases and to analyze the frequency of gene mutations associated with rifampicin (RIF) and/or isoniazid (INH) resistance of among smear-positive pulmonary tuberculosis patients.
Institution-based cross-sectional study design was employed. Sputum specimens were collected, and using a pretested questionnaire, data for associated risk factors for drug resistance were collected from 105 consecutive smear-positive pulmonary tuberculosis patients in Karamara General Hospital. Specimens were transported to Harar Health Research and Regional Laboratory, Harar, where molecular drug susceptibility testing was performed using GenoType MTBDRplus assay.
Of the total 105 sputum specimens, 98 (93.3%) gave interpretable results, in which 67 (68.4%) were new cases and 31 (31.6%) were previously treated cases. Of these, 80 (81.6%) were sensitive to both drugs and 18 (18.4%) were resistant to RIF and/or INH. The prevalences of MDR-TB in total cases, new, and previously treated cases were 10 (10.2%), 3 (4.5%), and 7 (22.6%), respectively. Among the ten total RIF-resistant specimens, eight (80%) had resulted because of absence of WT8 and presence of MUT3 and in all specimens, the amino acids changed were . Of the 18 total INH-resistant specimens, 15 (83.3%) had mutations in the gene ( MUT1, ), indicating high-level resistance, while 3 (14.7%) had mutations in the promoter gene (), indicating low-level resistance.
Among the mutations associated with resistance to RIF and INH, the majority were in codon 531 of the gene and codon 315 of the gene. Relatively high prevalence of MDR-TB was observed in the study.
针对耐药突变的分子方法是用于快速药物敏感性检测以发现耐多药结核病（MDR-TB）的合适方法。本研究的目的是确定MDR-TB病例，并分析涂片阳性肺结核患者中与利福平（RIF）和/或异烟肼（INH）耐药相关的基因突变频率。
采用基于机构的横断面研究设计。收集痰标本，并使用预先测试的问卷，从卡拉马拉综合医院连续105例涂片阳性肺结核患者中收集耐药相关危险因素的数据。标本被运送到哈拉尔的哈拉尔健康研究和区域实验室，在那里使用GenoType MTBDRplus检测法进行分子药物敏感性检测。
在总共105份痰标本中，98份（93.3%）给出了可解释的结果，其中67份（68.4%）是新病例，31份（31.6%）是先前治疗过的病例。其中，80份（81.6%）对两种药物敏感，18份（18.4%）对RIF和/或INH耐药。MDR-TB在总病例、新病例和先前治疗病例中的患病率分别为10例（10.2%）、3例（4.5%）和7例（22.6%）。在总共10份RIF耐药标本中，8份（80%）是由于缺乏WT8和存在MUT3导致的，并且在所有标本中，改变的氨基酸是 。在总共18份INH耐药标本中，15份（83.3%）在 基因（MUT1， ）中有突变，表明高水平耐药，而3份（14.7%）在 启动子基因（ ）中有突变，表明低水平耐药。
在与RIF和INH耐药相关的突变中，大多数位于 基因的第531密码子和 基因的第315密码子。本研究中观察到MDR-TB的患病率相对较高。
