Patterns of resistance of Mycobacterium tuberculosis in Spanish patients infected with human immunodeficiency virus type 1 (HIV-1)

ObjectiveTo evaluate the resistance and mortality rates of multidrug-resistant tuberculosis (MDR-TB) in human immunodeficiency virus type 1 (HIV-1)-infected patients in a 1000-bed teaching hospital in inner-city Barcelona.MethodsA total of 311 patients, recruited between July 1991 and July 1993, had either tuberculosis (TB) with HIV (group A), TB without HIV (group B), or TB without HIV and previous exposure to antituberculosis drugs (group C). Mycobacterium tuberculosis was isolated radiometrically or using Lowenstein-Jensen media with p-nitro-a-acetylamino-B-hidroxypropiphenone (NAP) testing. Antibiograms to isoniazid, rifampicin, pyrazinamide, ethambutol and streptomycin were performed by the critical proportions method with only one strain per patient.ResultsOf 197 strains of M. tuberculosis isolated in group A, six (3%) were resistant to one agent and seven (3.5%) were multiresistant vs five (5.7%) and three (3.4%) of 88 strains, respectively, in group B, and three (11.5%) and seven (26.9%) of 26 strains, respectively, in group C.ConclusionsThe primary resistance rate of M. tuberculosis in Spain remains relatively low in both HIV-infected and non-HIV-infected patients in contrast to a nearly 30% or higher resistance rate among patients previously exposed to antituberculosis agents