National surveillance of anti-tuberculosis drug resistance, Peru 2005-2006

Abstract

Objective. To determine the anti-tuberculosis drug resistance prevalence in Peru. Material and methods. We performed a conglomerated sampling in 33 health regions from Peru. We used a Canneti proportions method in solid medium L-J for testing Mycobacterium tuberculosis susceptibility with isoniazid (INH) rifampicin (RMP), streptomycin (SM) and ethambutol (EMB). Strains with TB MDR was evaluated to second line drug susceptibility by proportion methods in 7H10 agar in plates. Results. We analyzed 1809 cultures from new patients and 360 pre treated. 51.6 coming from Lima and 59.3% were males. The national prevalence of primary resistance was 23.2% (CI95%: 21.3 - 25.1) and acquired resistance was 41.7% (95% CI: 36.5 - 46.8). We detected 180 TB MDR cases, the prevalence of primary TB MDR was 5.3% (95%CI: 4.2 - 6.3) and acquired was 23.6% (95%CI: 19.2 - 28.0). 20% of never treated patients isolated were resistant to INH or RIf. Global resistance and primary TB MDR were more prevalent in Lima than rest of the country. TB XDR was present in 5.9% of patients with TB MDR and 36% of TB MDR strains were resistant at least one secondline drug. Conclusions. Compared with previous studies, primary and acquired anti-tuberculosis drug resistant have significantly increased in the last 10 years in Peru.