Sachdeva Ranjana, Gadre D V, Talwar Vibha
Department of Microbiology, University College of Medical Sciences & Guru Tegh Bahadur Hospital, Delhi, India.
Indian J Med Res. 2002 Mar;115:102-7.
BACKGROUND & OBJECTIVES: There is a paucity of information on extrapulmonary tuberculosis as much of the attention is focussed on pulmonary tuberculosis. This prospective study aimed at identification and characterisation of mycobacterial isolates from extra pulmonary sites and the evaluation of the drug susceptibility patterns of Mycobacterium tuberculosis isolates from extrapulmonary sites using the conventional method and the E-test.
A total of 350 specimens from patients of extrapulmonary tuberculosis with varied presentation, were studied. Speciation and characterisation of isolates were done on the basis of growth and biochemical characteristics. Drug susceptibility testing for M. tuberculosis isolates was done by proportion method for isoniazid, rifampicin, ethambutol and pyrazinamide, whereas resistance ratio method was used for streptomycin. E-test (AB Biodisk, Sweden) was carried out to compare susceptibility patterns of the M. tuberculosis isolates for isoniazid and rifampicin with the conventional method.
Thirty two of 350 (9.14%) patients clinically suspected to have extrapulmonary tuberculosis were culture positive for mycobacteria. On characterisation, 20 of the 32 isolates were identified as M. tuberculosis and 12 as non-tubercular mycobacteria (NTM) with 5 of the 12 being Mycobacterium avium complex. Among M. tuberculosis isolates both initial and acquired resistance was highest for streptomycin followed by isoniazid, rifampicin and ethambutol. No strain showed resistance to pyrazinamide. Two strains were found to be multidrug resistant. Drug susceptibility patterns by conventional method corroborate with the E-test results.
INTERPRETATION & CONCLUSION: This study shows that the characterisation and species identification of mycobacterial isolates along with drug susceptibility testing help in better understanding of extrapulmonary tuberculosis. E-test had the advantage of being rapid and simple without need for additional equipment.
由于大部分注意力都集中在肺结核上，关于肺外结核的信息匮乏。这项前瞻性研究旨在从肺外部位鉴定和表征分枝杆菌分离株，并使用传统方法和E-test评估肺外部位结核分枝杆菌分离株的药敏模式。
共研究了350例表现各异的肺外结核患者的标本。根据生长和生化特征对分离株进行分类和表征。结核分枝杆菌分离株的药敏试验采用比例法检测异烟肼、利福平、乙胺丁醇和吡嗪酰胺，而链霉素采用耐药率法检测。采用E-test（瑞典AB Biodisk公司）与传统方法比较结核分枝杆菌分离株对异烟肼和利福平的药敏模式。
350例临床疑似肺外结核患者中，32例（9.14%）分枝杆菌培养阳性。经鉴定，32株分离株中20株为结核分枝杆菌，12株为非结核分枝杆菌（NTM），其中12株中有5株为鸟分枝杆菌复合群。在结核分枝杆菌分离株中，初始耐药和获得性耐药对链霉素最高，其次是异烟肼、利福平、乙胺丁醇。没有菌株对吡嗪酰胺耐药。发现两株为多重耐药。传统方法的药敏模式与E-test结果相符。
本研究表明，分枝杆菌分离株的表征、菌种鉴定以及药敏试验有助于更好地了解肺外结核。E-test具有快速、简单且无需额外设备的优点。
