[Incidence of tuberculostatic-resistant Mycobacterium tuberculosis. Clinical aspects and impact on therapy and clinical course].
BACKGROUND: To know the incidence of Mycobacterium tuberculosis resistant to anti-tuberculin drugs in addition to the clinical features, treatment and evolution of the patients. METHODS: This was a retrospective study of the clinical histories of patients with isolation of Mycobacterium tuberculosis with some type of resistance studied from January 1980 to April 1992. RESULTS: During the period studied 470 patients were diagnosed with tuberculosis by cultures. In 30 of these cases (6.4%) Mycobacterium tuberculosis resistant to Isoniazide (8), Streptomycin (6), Isoniazide + Rifampicin (4), Isoniazide + Streptomycin (3), Isoniazide + Ethambutol (2), Isoniazide + Rifampicin + Streptomycin (2), Isoniazide + Rifampicin + Ethambutol (2), Rifampicin (1), Ethambutol (1), Isoniazide + Pyrazinamide (1) and Isoniazide + Rifampicin + Streptomycin + Ethambutol (1) were isolated. Clinical information was obtained on 23 patients, with the most frequent clinical pictures being those of respiratory infection (15). Five cases occurred in HIV+ patients. The resistance was considered as primary in 58.97% of the cases with modifications in empiric treatment being necessary in 6 cases. In 15 out of the 19 patients from whom the data of the follow up was obtained the evolution was good. CONCLUSIONS: Resistance to Mycobacterium tuberculosis was 6.4%, with the high number of strains resistant to Rifampicin being of note. In 79% of the cases in which follow up data was obtained the resistance had no impact on treatment due to the good evolution of the patients in relation with the treatment used.