Non-Tuberculous Mycobacterium Peritoneal Dialysis-Associated Peritonitis: A Case Report of Mycobacterium neoaurum.

Peritoneal dialysis (PD) related peritonitis is a common cause for PD technique failure. In up to 20% of cases conventional cultures are negative, and nontuberculous mycobacteria are rarely identified as a cause. A 60-year-old man treated with peritoneal dialysis as kidney replacement therapy presented to care with two months of malaise, abdominal pain, and cloudy PD effluent. Effluent analysis demonstrated a marked neutrophil-predominant pleocytosis, but no organisms were identified on Gram stain or on initial cultures after 72 hours of incubation. He was admitted to the hospital and intraperitoneal vancomycin was initiated for presumed PD-associated peritonitis. After five days, his symptoms and neutrophil-predominant effluent pleocytosis persisted. Repeat effluent Gram stain identified a beaded, Gram-positive bacilli. Subsequent auramine rhodamine stain revealed acid-fast bacilli, ultimately speciating to Mycobacterium neoaurum; initial cultures ultimately demonstrated the same bacterium. Intraperitoneal vancomycin was changed to oral doxycycline and moxifloxacin, the PD catheter was removed, and the patient initiated intermittent hemodialysis. There was gradual improvement in presenting symptoms after changing antimicrobials. He was discharged on a 6-month course of doxycycline and moxifloxacin, with repeat clinic visits over 10 months showing resolution of weakness, increase in dry body weight, and no evidence of recurrent disease on cross-sectional imaging. Non-tuberculous mycobacteria PD peritonitis should be considered in patients with a subacute clinical course, initially negative effluent cultures, and lack of response to conventional antimicrobials. M. neoaurum has only rarely been associated with PD peritonitis; this case contributes to the evidence of this pathogen's association with implanted devices.