Nontuberculous mycobacterial infections in continuous ambulatory peritoneal dialysis patients

Nontuberculous mycobacterial infections are a rare but clinically important cause of infections in continuous ambulatory peritoneal dialysis (CAPD) patients. We describe seven cases of catheter-related nontuberculous mycobacterial infections associated with CAPD. Six patients had Mycobacterium fortuitum infections and one had a Mycobacterium kansasii infection. Three patients presented with peritonitis, three presented with exit site infections, and one developed an infection at the exit site after catheter removal. There were no specific clinical findings that differentiated these infections from those caused by common bacterial pathogens. Initial routine peritoneal dialysis fluid and exit site cultures were negative in two patients and grew M fortuitum in four patients and M kansasii in one patient. M fortuitum and M kansasii were sensitive to amikacin, and M fortuitum was sensitive to ciprofloxacin when tested. Sensitivities to other antibiotics were variable. All patients were treated with a combination of antibiotics from 3 weeks to 6 months. Catheter removal was necessary for cure of the infection in all patients with peritonitis and in a majority of patients with exit site infections. The majority of patients changed to hemodialysis after catheter removal. Two patients remained on CAPD, with follow-up ranging from 2 months to 4 years. One patient has received a successful renal transplant. In conclusion, M fortuitum is the most common nontuberculous mycobacterial catheter-related infection in CAPD patients. Nontuberculous mycobacterial infections should be considered in the differential diagnosis of any culture-negative infection associated with CAPD. In patients with infections secondary to M fortuitum, our findings suggest that amikacin and ciprofloxacin are the initial antibiotics of choice until antibiotic sensitivities are available.