Evaluation of Mycobacterium kansasii isolates from a clinical laboratory in a city hospital

Abstract

Fifteen isolates of Mycobacterium kansasii in Showa University Fujigaoka Hospital between 1982 and 1995 were investigated. Comparing by gender, 13 were isolated from male patients and only two were isolated from female patients. The average of cases was 48 years old and 14 out of 15 cases (93%) were isolated from respiratory tract specimens. The rate of the smear- and culture-positives was 64%, which was significantly higher than that (26%) of M. avium complex (p < 0.01 by chi 2 test). All 4 isolates were susceptible to rifampicin (10 micrograms/ml) by drug susceptibility testing using Ogawa egg medium, and only 1 was resistant to ethambutol (2.5 micrograms/ml). Seven out of 10 patients whose medical record was available were diagnosed as pulmonary infection with M. kansasii. Two out of 4 patients with primary infection type had underlying diseases such as diabetes mellitus and leukemia, while the remaining two patients did not have any underlying disease. Two out of 3 patients with secondary infection type had a medical history of tuberculosis and the remaining 1 patient had infected pulmonary cyst. Such as Pseudomonas aeruginosa, Enterobacter aerogenes and Flavobacterium spp., and Branhamella catarrhalis, associated with M. kansasii, bacteria more than 10(7) cfu/ml were isolated from the sputa of 3 patients with leukemia, infected pulmonary cyst and post-tuberculosis, respectively. M. kansasii, Stenotrophomonas maltophilia (10(7) cfu/ml) and Candida albicans were detected from the sputum of 1 patient with nephrosis, for which steroid (predonin) and antibiotics (piperacillin and latamoxef) were administrated, however, this patient was not diagnosed as a case of M. kansasii infection. These findings suggest the fact that M. kansasii inhabits among compromised hosts of a city hospital.