title: Prevalence of resistance to antituberculosis drugs in Riyadh and a review of previous reports.
abstract: BACKGROUND
  Resistance to antituberculosis drugs is an important cause of treatment failure. We evaluated the prevalence and pattern of antituberculosis drug resistance in the central region of Saudi Arabia, and reviewed previous reports from Saudi Arabia.
  
  
  METHODS
  We retrospectively examined the records of sputum smear and culture-positive pulmonary tuberculosis patients admitted consecutively from 1998 through 1999 in a main referral hospital in Riyadh, and analyzed drug sensitivity reports. We also reviewed previous reports on antituberculosis drug resistance in Saudi Arabia.
  
  
  RESULTS
  Of 515 patients with pulmonary tuberculosis, 80 (15.5%) had resistance to at least one antituberculosis drug. Resistance to streptomycin was most frequent (9.7% ), followed by rifampicin (9.5%), isoniazid (4.3%), and ethambutol (0.2%). Resistance to one antituberculosis drug was found in 8.9%, resistance to two drugs in 5.2%, resistance to three drugs in 1.2%, and resistance to four drugs in 0.2%. Multidrug resistance (defined as resistance to at least isoniazid and rifampicin) was found in 1.9% of patients. A literature review including 6114 patients in Saudi Arabia showed that resistance against streptomycin was most common (8.8%), followed by rifampicin (8%), and isoniazid (7.2%). Of the 6114 patients, 6.8% patients were resistant to only one drug, 3.6% were resistant to two drugs, and 3.7% to three drugs.
  
  
  CONCLUSIONS
  The high prevalence of rifampicin resistance and resistance to multiple drugs in the Riyadh region and in other parts of Saudi Arabia is a major challenge to the control of tuberculosis in this country. Efforts should be made to prevent the emergence of further antituberculosis drug resistance.
authors.affiliation: Department of Tuberculosis and Chest Diseases, Sahary Hospital, Riyadh, Saudi Arabia.
authors.forename: Rupak
authors.initials: R
authors.lastname: Singla
authors.forename: Nasser
authors.initials: N
authors.lastname: Al-Sharif
authors.forename: Mohammed
authors.initials: M
authors.lastname: Al-Sayegh
authors.forename: Mohammed
authors.initials: M
authors.lastname: Osman
authors.forename: M A
authors.initials: MA
authors.lastname: Shaikh