Chauca José A, Palomino Juan-Carlos, Guerra Humberto
Instituto de Medicina Tropical "Alexander von Humboldt", Universidad Peruana Cayetano Heredia, PO Box 4314, Lima 100, Peru.
Mycobacteriology Unit, Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerp, Belgium.
J Med Microbiol. 2007 Mar;56(Pt 3):360-364. doi: 10.1099/jmm.0.46622-0.
Conventional methods for determining drug susceptibility of Mycobacterium tuberculosis require several weeks to obtain results, limiting their usefulness; automated methods and those based on molecular biology techniques have been able to reduce the turnaround time, but their high cost and need for sophisticated equipment restrict their use in developing countries. The goal of the present study was to evaluate the diagnostic accuracy of a rapid (3-4 days) low-cost test based on the use of mycobacteriophage D29 to determine the susceptibility of strains of M. tuberculosis to rifampicin (RIF) and isoniazid (INH). Results obtained show that susceptibility testing for RIF has a high diagnostic accuracy as compared to the standard indirect proportion method on Löwenstein-Jensen medium (sensitivity 100% and specificity 98%). Given the association between the resistance to RIF and INH, which define multidrug resistance (MDR), this test seems suitable for rapid detection of MDR tuberculosis strains (kappa=0.978). Susceptibility testing for INH using mycobacteriophage D29 had a good but lower diagnostic accuracy as compared to the standard method (sensitivity 80.4% and specificity 80.8%); the test would then be of limited usefulness in the management of tuberculosis patients. Further studies to determine the relationship of mycobacteriophage D29 tests to in vivo correlates of sensitivity to specific antituberculosis drugs are warranted.
传统的结核分枝杆菌药敏测定方法需要数周时间才能得出结果，这限制了它们的实用性；自动化方法以及基于分子生物学技术的方法能够缩短周转时间，但其高成本和对精密设备的需求限制了它们在发展中国家的使用。本研究的目的是评估一种基于分枝杆菌噬菌体D29的快速（3 - 4天）低成本检测方法在测定结核分枝杆菌菌株对利福平（RIF）和异烟肼（INH）药敏性方面的诊断准确性。所得结果表明，与在罗氏培养基上的标准间接比例法相比，利福平药敏试验具有较高的诊断准确性（敏感性100%，特异性98%）。鉴于对利福平和异烟肼的耐药性之间的关联定义了多重耐药（MDR），该检测方法似乎适用于快速检测耐多药结核菌株（kappa = 0.978）。与标准方法相比，使用分枝杆菌噬菌体D29进行异烟肼药敏试验具有较好但较低的诊断准确性（敏感性80.4%，特异性80.8%）；因此，该检测方法在结核病患者管理中的实用性有限。有必要进一步开展研究，以确定分枝杆菌噬菌体D29检测与对特定抗结核药物敏感性的体内相关因素之间的关系。
