Antituberculosis drug resistance surveillance in Kenya, 1995

Twenty-two of the 42 administrative districts in Kenya.

To determine the prevalence of drug resistance in newly diagnosed patients with pulmonary tuberculosis, to determine possible risk factors associated with resistance, and to establish standard routine surveillance of drug resistance.

Cross-sectional study.

Sputum samples from newly diagnosed patients with smear-positive pulmonary tuberculosis were analysed using standard procedures.

Of 638 patients, 85% were culture positive for Mycobacterium tuberculosis. Of 491 patients tested for susceptibility to isoniazid, streptomycin, rifampicin and ethambutol, 90.8% had fully sensitive strains and 9.2% had a strain resistant to one or more drugs. Of 445 patients with no history of previous chemotherapy, 6.3% had a resistant strain. Of 46 patients with a history of previous chemotherapy, 37% had a resistant strain. No resistance to either rifampicin or ethambutol was detected. There was a strong association between previous chemotherapy and resistance. Resistance was not associated with age or sex. High concordance between Kenya's results and those of the Mycobacterium Reference Unit in the UK on both drug-sensitive and drug-resistant strains indicates that clinically significant and comparable data can be obtained from laboratories employing unsophisticated and inexpensive standard procedures.

Rates of initial drug resistance are still low in Kenya. The increase in acquired resistance to isoniazid requires monitoring.