High Detection Rates of Urine Mycobacterium tuberculosis in Patients with Suspected Miliary Tuberculosis

Objective The utility of detecting Mycobacterium tuberculosis in urine samples from patients with pulmonary tuberculous with diffuse small nodular shadows (suspected miliary tuberculosis (MTB)) is still unclear in Japan. A retrospective cross-sectional study was conducted to investigate the detection rates of M. tuberculosis in urine of patients with suspected MTB. Methods Among 687 hospitalized patients with tuberculosis, 45 with culture-confirmed suspected MTB and the data of culture and polymerase chain reaction (PCR) for M. tuberculosis in urine and sputum samples were investigated. The detection rates of M. tuberculosis in urine using cultures and PCR were calculated. The detection rate of urine was then compared with that of bone marrow aspiration. Results Fourteen patients with suspected MTB were ultimately analyzed. A diagnosis of miliary tuberculosis was suspected in all patients before anti-tuberculosis chemotherapy. Positive results by PCR (11 [78.6%] cases) and culture (8 [57.1%]) were obtained from urine samples. In patients with suspected MTB, there was no significant difference in the detection rates between M. tuberculosis in urine using a combination of PCR and culture (85.6% [12/14 cases]) and bone marrow aspiration (66.7% [8/12 cases]) (p>0.05). Conclusion Using PCR and culture, we demonstrated high detection rates of M. tuberculosis in the urine of patients with suspected MTB. A combination of PCR and culture compared favorably with the detection rates achieved with bone marrow aspiration. We believe that detection of M. tuberculosis from urine and sputum samples may be easy and safe for patients with disseminated tuberculosis infections such as definitive MTB.