Objective: Inventory of patients with a Mycobacterium kansasii infection.
Design: Descriptive, retrospective.
Setting: Academic Medical Centre, Amsterdam, the Netherlands.
Method: Review of the medical records of all patients with a bacteriologically confirmed infection with M. kansasii from January 1987 until the end of December 1996.
Results: M. kansasii was isolated from 17 patients. Of 15 HIV-tested patients 13 were seropositive. Their median CD4 count was 10 x 10(6)/l. Ten HIV-positive individuals used trimethoprim-sulfamethoxazole prophylaxis. In 1 HIV-seropositive and in 1 HIV-seronegative patient no chest X-rays were made. Caverns were present in none of 12 HIV-positive patients and in 1 of 3 HIV-negative patients. Of the HIV-positive patients 1 fulfilled the criteria for pulmonary infection of the American Thoracic Society (ATS). According to these criteria 9 of the HIV-positive patients were colonized with M. kansasii. In 6 of these patients there were indications of infection: regression of pulmonary infiltrates with therapy (n = 3), positive histology and culture of lung tissue at autopsy (n = 1), and dissemination (n = 2). Disseminated infection occurred in a total of 4 HIV-infected patients.
Conclusion: HIV-infected patients are at an increased risk for M. kansasii infection. Trimethoprim-sulfamethoxazole does not offer protection against this infection. The diagnostic criteria of the ATS are not applicable to these patients. M. kansasii infection confirmed by isolation in an HIV-positive individual should always be treated.