Infection due to resistant Mycobacterium tuberculosis in a hospital population. Longitudinal survey of incident cases at Fundacion Jimenez Diaz (1991-1997)

Objective. Evaluation of epidemiologic, clinical and prognostic characteris tics in cases of resistant tuberculosis (MRTB), Methods. Retrospective longitudinal and observational study of resistant ca ses of tuberculosis at Fundacion Jimenez Diaz (1991-1997), Statistical anal ysis of conventional tests and significance, level at p < 0.05. Results. Twenty patients out of 558 with recovery of Mycobacterium tubercul osis showed resistance to some drugs (isoniazid, rifampicin, ethambutol, st reptomycin or pyrazinamide). Information was gathered from 19 patients: eig ht (42%) HIV-positive patients; eight (42%) with the antecedent of tubercul osis (2 abandoned treatment). There were eleven cases (58%) of secondary re sistance and eight of primary resistance but only five (25%) with multi-res istance criteria (1 primary and 4 secondary); five cases showed primary res istance to isoniazid. The number of resistances and HIV-seropositivity or a ntecedent of prophylaxis was not statistically significant. In contrast, th e higher number of resistances and tuberculosis antecedent were indeed stat istically significant. Conclusions. There was a low resistance rate at our institution. All multi- resistant cases had antecedents of therapy or prophylaxis abandon or previo us tuberculosis. Only one case was MRTB. The relevance of complying with a proper therapy is emphasized (consider therapies directly monitored if ther e is risk of abandon). In patients with epidemiologic risk factors suscepti bility studies should be performed and also start therapy with four drugs. The objective is to decrease the percentages of resistance and morbi-mortal ity.