Identificação e determinação da susceptibilidade a drogas de micobactérias isoladas de pacientes com a síndrome da imunodeficiência adquirida atendidos em hospital de referência para AIDS em Goiás, Brasil

Abstract

Detection, identification and susceptibility to antimycobacterial drugs of mycobacteria from patients with the acquired immunodeficiency syndrome at an AIDS Reference Hospital in Goiás, Brazil. ln the present study, 116 samples, including cerebrospinal fluid, sputum, bronchoscopy specimens, lymph node biopsy, urine, blood, tiver biopsy, bone marrow aspirate and pleural liquid were obtained from AIDS in-patients or out-patients followed-up at Hospital de Doenças Tropicais do Estado de Goiás (HDT). Samples were processed for detection of mycobacteria. Acid­fast bacillus (AFB) was detected by conventional Ziehl-Neelsen method and cultures were performed by inoculation into a solid medium, Lõwenstein­Jensen (L-J), and biphasic system (BI), consisting of a solid medium (L-J) associated to a liquid medium (7H9). Before culturing, samples were digested and decontaminated with sodium dodecyl sulphate (SOS) and by the Petroff method. Species identification was based on growth in the presence of inhibitory agents, growth rates, colony pigmentation and biochemical tests. M tubercu/osis isolates were tested for susceptibility to antimycobacterial drugs. Tests were performed on L-J by the proportion method established by Canetti. The 116 samples yielded 12 isolates (10,3%). These 12 isolates, included nine M tubercu/osis (from eight patients) and three M avium complex (MAC) strains (from two patients). M. tuberculosis recovered from cerebrospinal fluid was resistant to streptomycin and another one, from a smear-negative sputum, was resistant to rifampicin, isoniazid, pirazinamid, streptomycin, ethambutol and ethionamid. Of 12 culture-positive samples, six were smear-negative and two MAC strains were recovered only after sample decontamination by SOS method. There were no differences between L-J medium and BI on recovery rates of the cultured materiais.