Aggarwal Puneet, Singal Archana, Bhattacharya Sambit Nath, Mishra Kiran
Department of Dermatology & STD, University College of Medical Sciences and Guru Teg Bahadur Hospital, Delhi, India.
Int J Dermatol. 2008 Jul;47(7):681-7. doi: 10.1111/j.1365-4632.2008.03675.x.
Mycobacterial isolation from cutaneous tuberculosis on Löwenstein-Jensen (L-J) medium has been reported to be low. The radiometric BACTEC 460 TB culture system (BACTEC system) has shown better isolation rates in pulmonary tuberculosis. There has been a progressive increase in the prevalence of multidrug resistance in pulmonary tuberculosis, but similar studies are lacking for cutaneous tuberculosis. Therefore, this study was undertaken to compare mycobacterial isolation on conventional L-J medium vs. the BACTEC system, and to determine the prevalence of multidrug resistance in cutaneous tuberculosis.
Thirty-five untreated, clinically diagnosed, and histopathologically documented patients with cutaneous tuberculosis constituted the study material. Lesional skin biopsy specimens were cultured on both L-J medium and the BACTEC system. The isolates obtained were identified and subjected to sensitivity to rifampicin, isoniazid, ethambutol, and streptomycin using the BACTEC system.
Twenty-six mycobacterial isolates were recovered from 35 patients. Nine isolates (25.7%) grew on L-J medium after a mean period of 31.5 days, and 22 (62.8%) on the BACTEC system in 17.3 days. All of the isolates were identified as Mycobacterium tuberculosis. Drug susceptibility testing demonstrated 12 isolates to be resistant, seven multidrug resistant.
The BACTEC system demonstrated an improved mycobacterial isolation rate and substantially reduced detection time when compared with L-J medium. The combined isolation rate on both media was 74.3% (26/35), greater than that of either used separately. Drug resistance was observed in 46.2% of isolates.
Radiometric liquid culture medium together with conventional L-J medium may be recommended in practice to enable the institution of appropriate antituberculous therapy modifications in drug-resistant cases of cutaneous tuberculosis.
据报道，在罗-琴（L-J）培养基上从皮肤结核中分离出分枝杆菌的概率较低。放射性BACTEC 460结核培养系统（BACTEC系统）在肺结核中显示出更高的分离率。肺结核中多重耐药的患病率呈逐渐上升趋势，但皮肤结核缺乏类似研究。因此，本研究旨在比较传统L-J培养基与BACTEC系统上分枝杆菌的分离情况，并确定皮肤结核中多重耐药的患病率。
35例未经治疗、临床诊断且经组织病理学证实的皮肤结核患者构成研究材料。病变皮肤活检标本分别在L-J培养基和BACTEC系统上培养。对获得的分离株进行鉴定，并使用BACTEC系统检测其对利福平、异烟肼、乙胺丁醇和链霉素的敏感性。
35例患者中分离出26株分枝杆菌。9株（25.7%）在L-J培养基上平均31.5天后生长，22株（62.8%）在BACTEC系统上17.3天后生长。所有分离株均鉴定为结核分枝杆菌。药敏试验显示12株耐药，7株多重耐药。
与L-J培养基相比，BACTEC系统显示出更高的分枝杆菌分离率，且检测时间大幅缩短。两种培养基的联合分离率为74.3%（26/35），高于单独使用任何一种培养基的分离率。46.2%的分离株观察到耐药。
在实践中，可推荐使用放射性液体培养基和传统L-J培养基，以便在皮肤结核耐药病例中调整适当的抗结核治疗方案。
