Tuberculosis in Saudi Arabia: initial and secondary drug resistance among indigenous and non-indigenous populations.

Resistance to six anti-mycobacterial agents rifampicin, isoniazid, streptomycin, ethambutol, p-amino salicylic acid and cycloserine was studied. Variations in the resistance pattern among Saudi, non-Saudi and a stable National Guard King Khalid Hospital (NGKKH) population were investigated. A high percentage of relapse cases, 21%, was recorded. Among the NGKKH population this figure was much lower, 9.9%. Resistance to rifampicin alone was high at 7.2% followed by streptomycin 3.3%, isoniazid 1.8%, p-amino salicylic 1.2% and cycloserine 0.8%. Resistance to rifampicin alone was higher among 'new' cases whilst combined resistance to two or more drugs was seen more often in 'old' patients. Resistance was seen more frequently among non-Saudis, both 'old' and 'new'. An unusual finding was the prevalence of rifampicin resistance among non-pulmonary isolates.