The molecular characterizations of the first 40 Mycobacterium tuberculosis isolates from Chad revealed a high proportion of isolates of the Cameroon family (33%), of which one isolate showed a monodrug resistance. In total, 9/33 (27%) isolates were resistant to isoniazid. The implications of these findings are discussed.In Chad, the annual incidence rate of pulmonary tuberculosis was estimated at 60 to 120 of 100,000 in 1990 (12) but increased to 370 of 100,000 in 2000 (19), making Chad a highincidence country. The recommended WHO treatment strategy for patients with open and extrapulmonary tuberculosis is directly observed chemotherapy, which has been adopted in most African countries, including Chad, where its coverage was 25% in 2003 (20). An increase in drug resistance due to noncompliance during treatment is feared; however, the lack of baseline data on drug resistance from these countries makes monitoring difficult.Drug resistance testing, molecular characterization, and fingerprinting of Mycobacterium tuberculosis complex members have become common practices in most mycobacterial laboratories. A variety of molecular genetic typing tools for M. tuberculosis complex isolates have been developed (18), with the most widely used, IS6110 restriction fragment length polymorphism typing, as the gold standard. More recently, spoligotyping (8) has shown advantages over IS6110 typing. It is more cost-effective, easier to perform, and possible to compare results between laboratories.The outcome of the drug resistance tests and molecular characterization by spoligotyping of the first M. tuberculosis isolates from Chad are presented and implications for treatment control discussed.Between March and July 2001 and February and October 2002, a total of 357 sputum and 282 urine samples were collected from tuberculosis patients at the National Reference Hospital (HGRNT) in the Chadian capital, NЈDjaména, and at four rural health centers that were 50 to 200 kilometers away from NЈDjaména. All specimens (sputum and urine) were decontaminated (9) and inoculated onto two Löwenstein-Jensen slants, one containing 0.75% glycerol and the other containing 0.6% sodium pyruvate. In addition, liquid Middlebrook 7H9 medium containing oleic acid-albumin-dextrose-catalase and polymyxin-amphotericin B-nalidixic acid-trimethoprim-azlocillin was used. The inoculated media were incubated at 37°C without CO 2 for 8 weeks. Smears were made from the sediment and were stained by the Ziehl-Neelsen method (9). Growth of mycobacteria was confirmed by smear. Acid-fast-bacillus-positive colonies were subcultured on three Löwenstein-Jensen slants and a Middlebrook 7H10 agar plate. Three biochemical tests (nitrate, niacin, and 68°C catalase) (9) were used to identify M. tuberculosis complex (MTC) from nontuberculous mycobacteria. The Lebek method was used as an additional phenotypic test to distinguish between MTC members (7), and in addition the standard method for molecular identification of MTC isolates, real-time PCR (10), was performed. Genotyping ...
