Garedew Legesse, Mihret Adane, Ameni Gobena
Faculty of Veterinary Medicine, University of Gondar, Gondar, Ethiopia.
Scand J Infect Dis. 2013 Jul;45(7):512-8. doi: 10.3109/00365548.2013.773068. Epub 2013 Mar 11.
Extrapulmonary tuberculosis (EPTB) constitutes about 10% to 20% of all cases of tuberculosis in immunocompetent patients and more than 50% of the cases in HIV-positive individuals worldwide. Little information is available on the clonal diversity of Mycobacterium species in Ethiopia from EPTB.
This study was carried out on smear-negative EPTB patients to molecularly characterize Mycobacterium tuberculosis complex strains. A questionnaire, smear staining, culture, deletion typing, and spoligotyping were employed.
The proportional distribution of EPTB and isolates did not vary substantially (p > 0.05) amongst the socio-demographic parameters considered in the current investigation. Out of 98 fine needle aspirates processed for culture, 36.7% (36/98) were positive for mycobacterial growth. Further speciation of those culture-positive isolates showed that 88.9% were M. tuberculosis and the remaining could be non-tuberculous mycobacterial species. Spoligotyping revealed 16 clusters out of which 2 were new to the SITVIT database. The most dominant spoligotypes were SIT54, SIT53, and SIT149 in decreasing order. SIT54, SIT134, SIT173, SIT345, SIT357, SIT926, SIT91088, and SIT1580 were reported for the first time in Ethiopia. The family with the highest frequency identified was M. tuberculosis family T1, followed by family 33. Most of the strains belonged to Euro-American (61.4%) and Indo-Oceanic (36.3%) lineages.
The present study shows the importance of M. tuberculosis as a major cause of EPTB in the study area. Moreover, the majority of isolates of M. tuberculosis were found in clusters, suggesting the possibility of the existence of recent transmission. This warrants strengthening of the control programs for EPTB in the study area.
肺外结核病（EPTB）在免疫功能正常的患者中约占所有结核病病例的10%至20%，在全球艾滋病毒阳性个体中则超过50%。关于埃塞俄比亚EPTB中分枝杆菌物种的克隆多样性，可用信息很少。
本研究针对涂片阴性的EPTB患者开展，以对结核分枝杆菌复合群菌株进行分子特征分析。采用了问卷调查、涂片染色、培养、缺失分型和间隔寡核苷酸分型。
在本研究调查的社会人口统计学参数中，EPTB及其分离株的比例分布没有显著差异（p>0.05）。在98份用于培养的细针穿刺抽吸物中，36.7%（36/98）的分枝杆菌生长呈阳性。对那些培养阳性分离株的进一步菌种鉴定表明，88.9%为结核分枝杆菌，其余可能是非结核分枝杆菌物种。间隔寡核苷酸分型显示有16个簇，其中2个对SITVIT数据库来说是新的。最主要的间隔寡核苷酸分型依次为SIT54、SIT53和SIT149。SIT54、SIT134、SIT173、SIT345、SIT357、SIT926、SIT91088和SIT1580在埃塞俄比亚首次被报道。鉴定出的频率最高的家族是结核分枝杆菌家族T1，其次是家族33。大多数菌株属于欧美谱系（61.4%）和印度洋谱系（36.3%）。
本研究表明结核分枝杆菌是研究区域EPTB的主要病因。此外，大多数结核分枝杆菌分离株呈簇状分布，表明存在近期传播的可能性。这就需要加强研究区域EPTB的防控项目。
