Nationwide survey on the prevalence of anti-tuberculosis drug resistance in the Republic of Yemen, 2004.

OBJECTIVES To determine the prevalence of resistance to the four major anti-tuberculosis drugs, isoniazid, rifampicin, streptomycin and ethambutol, in Yemen. METHODS Cluster sampling with probability proportionate to size was applied. Susceptibility to four major anti-tuberculosis drugs was examined. The proportion method using Löwenstein-Jensen medium or Ogawa medium was carried out. RESULTS A total of 790 primary culture isolates from tuberculosis (TB) cases enrolled at the National Tuberculosis Institute, Yemen, were examined. In the confirmation culture at the supranational reference laboratory, 227 of them failed to grow on the secondary culture or were proved to be mycobacteria other than Mycobacterium tuberculosis and were excluded from further analysis. Among 563 cultures, 510 were obtained from new cases and 53 from previously treated cases. The prevalence of resistance to any four drugs was 9.8% (95%CI 7.0-12.5) among new cases and 17.4% (95%CI 12.0-33.5) among previously treated cases. The prevalence of multidrug-resistant TB was 3.0% (95%CI 1.5-4.5) among new cases and 9.4% (95%CI 0.2-18.7) among previously treated cases. CONCLUSION The first nationwide prevalence survey on resistance to the four major anti-tuberculosis drugs in Yemen showed a relatively low prevalence of drug-resistant cases, but a high prevalence of multidrug resistance among new cases.