Peritonitis caused by Mycobacterium kansasii in a patient undergoing continuous ambulatory peritoneal dialysis.

Mycobacterium kansasii was isolated from the peritoneal fluid, peritoneal biopsy, and the Tenckhoff catheter of a 62-year-old woman undergoing continuous ambulatory peritoneal dialysis (CAPD) who presented with the clinical picture of peritonitis. To the best of our knowledge, this is the first case of CAPD-associated peritonitis caused by M kansasii. Routine susceptibility tests using standard concentrations of isoniazid indicated isoniazid resistance; however, the organism was inhibited in vitro by a higher concentration of this drug. The patient responded to combination therapy with isoniazid and rifampin, as well as removal of the catheter. This report emphasizes the importance of mycobacterial cultures, in certain circumstances, in patients with CAPD-associated peritonitis and the utility of quantitative in vitro susceptibility testing.