Peritoneal dialysis-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii: a case series and literature review

Background: As there is no established standard of care for non-tuberculous mycobacterium (NTM) peritoneal dialysis (PD)-related peritonitis, its treatments have to be case-dependent, which is often difficult. Additionally, several reported cases were accompanied by encapsulated ascites, adhesive ileus, and encapsulating peritoneal sclerosis, suggesting treatment difficulties. We report two cases of PD-related peritonitis with encapsulated ascites due to Mycobacterium abscessus subsp. massilience and subsp. bolletii. To the best of our knowledge, this is the first case series to report PD-related peritonitis caused by Mycobacterium abscessus subsp. bolletii. Case presentation: The first case is that of a 74-year-old male patient who started PD six years ago for end-stage renal failure due to diabetic nephropathy. In February 2021, he presented with signs of infection at the exit-site and swelling of the tunnel. Mycobacterium abscessus subsp. massilience was detected in the culture of the exit-site exudate; thus, he was diagnosed with tunnel infection (caused by NTM). Subsequently, fever, abdominal pain, and increased cell counts in the PD drainage fluid were observed, and he was judged to have NTM peritonitis. His general condition improved after PD catheter removal in addition to antimicrobial treatment and encapsulated ascites drainage. The second case is that of a 52-year-old man who commenced PD for end-stage renal failure due to nephrosclerosis 12 years ago. In May 2022, he was diagnosed with PD-related peritonitis based on signs of infection at the exit-site, encapsulated ascites on computed tomography, and a cloudy PD drainage fluid. Mycobacterium abscessus subsp. bolletii was detected in the culture of the exit-site exudate, which led to the diagnosis of NTM peritonitis. In addition to antimicrobial treatment, PD catheter removal and encapsulated ascites drainage were performed. The patient also had adhesive bowel obstruction due to peritonitis and required decompression therapy with the insertion of a gastric tube. Conclusions: PD catheter removal and encapsulated ascites drainage might have improved inflammation and treatment outcomes. Additionally, Mycobacterium abscessus might be prone to forming encapsulated cavities and/or intestinal adhesions; however, further accumulation of cases clarifying “subspecies” of Mycobacterium abscessus is necessary to confirm this hypothesis.