[Resistant tuberculosis in a prison population during 1991-1993].

BACKGROUND: To know the prevalence of resistant tuberculosis and the characteristics of the same in the penitentiary medium in the Madrid area (Spain). METHODS: From March 1, 1991 to August 31, 1993 a prospective study was carried out in patients with isolations of Mycobacterium tuberculosis resistant to some of the common antituberculous drugs within the context of tuberculosis in a penitentiary population attended in the Hospital General Penitenciario (Madrid). Demographic, clinical, analytical, and microbiological data were collected as was that on the antituberculous treatment used. The study of sensitivities was performed by the proportions method. RESULTS: Tuberculosis was diagnosed in 275 patients according to strict microbiological criteria (positive Lowenstein culture). The antibiogram was performed in 218 isolations. Twenty strains resistant to some first line antituberculous drug (9%) (confidence interval [CI] p < 0.05:6-14), 9 of which were found to be multiresistant, were detected in 20 patients. Out of the patients in whom the sensitivity of the isolate was known, 173 had not previously undergone antituberculous treatment. Six of these patients were found to be resistant to isoniazide (3.5%) (CI p < 0.05:1.4-7.7) and 2 patients were resistant to rifampicin (1.2%) (CI p < 0.5:0.2-4.5). The other 45 patients had previously undergone antituberculous drugs with 8 isolates presenting resistance to isoniazide and 11 to rifampicin. Eighty-four percent of the patients with resistant tuberculosis and 90% of the sensitive cases were coinfected with HIV infection with the differences not being statistically significant. The HIV positive patients with resistant tuberculosis showed a mean CD4 positive lymphocytes of 0.76 x 10(9)/l (CI p < 0.5:0.028-0.213) and those with sensitive tuberculosis had 0.165 x 10(9)/l (CI p < 0.05:0.133-0.196) (p < 0.01). CONCLUSIONS: Tuberculosis resistant to common antituberculous drugs was detected in a Spanish penitentiary population. The level of the resistance of the isolations of Mycobacterium tuberculosis should be monitored both inside and outside of the penitentiary medium in an attempt to avoid the progression of resistant tuberculosis within the Community.