Detection of Mycobacterium tuberculosis by PCR analysis of urine and other clinical samples from AIDS and non-HIV-infected patients.

A number of different clinical specimens, such as sputum, cerebrospinal fluid and blood, have been reported to be good substrates for the detection of Mycobacterium tuberculosis by PCR assay. We wanted to search for the presence of mycobacteria in other body fluids, such as urine. Urine samples and other samples obtained from AIDS patients and non HIV-infected patients were analysed by PCR. The results were compared with those obtained using conventional methods (Bactec 460 TB and AFB (acid fast bacilli strain)). We analysed 412 urine samples and 210 different other samples (sputum and cerebrospinal fluid) obtained from AIDS patients by PCR; almost identical levels of PCR-positive (14-17%) results were observed in all samples analysed. The results were then compared with those obtained with the Bactec 460 TB and AFB. PCR, Bactec 460 TB and acid fast stain were also used to analyse 190 urine samples and 230 other samples from non-HIV infected patients in the consumption ward of Sassari Hospital. The number of urine samples positive by PCR (6.3%) and Bactec 460 TB (2.1%) was half that obtained from samples taken from the AIDS patients. As expected, an increase in the number of positive sputum samples was observed with all methods. The results indicate that PCR analysis of urine samples represents a valid alternative for fast and sensitive detection of M. tuberculosis. This method can be routinely used in the clinical laboratory, especially in HIV-infected patients.