Peritoneal Dialysis-Related Peritonitis from Nontuberculous Mycobacterium abscessus: A Rare Complication

Introduction: Nontuberculous Mycobacterium (NTM) accounts for 3% of Peritoneal dialysis (PD)-related peritonitis, mostly from M. Fortuitum. PD-related peritonitis caused by M. abscessus is exceedingly rare. Only 38 cases are reported in the literature since 1998 including just 3 previous cases from the USA. Mean interval between diagnosis and treatment initiation is 4 weeks as culture and antibiotic susceptibility results take weeks. Treatment is challenging and prognosis is poor with 25% mortality rate. Diagnosis requires a high index of suspicion. PD fluid should be stained for acid-fast bacilli. Here we report a case of M. abscessus causing PD-related peritonitis in a lung transplant recipient. Case Description: 69 year-old male with 10-year history of lung transplant presented with 4 days of abdominal pain, cloudy effluent and nausea. Admission labs showed CRP 72 mg/L (<10 mg/L), lactic acid of 3.16 mmol/L (<2 mmol/L), WBC count 9000/microL (4000-11000/microL). PD fluid studies showed 828 cells/mm3 with 94% neutrophils consistent with peritonitis. Broad-spectrum antibiotics were started. PD fluid culture grew gram-positive rods on day 8 and acid-fast bacilli on day 9. MTB complex PCR was negative. On day 13, he developed septic shock. PD fluid culture on day 17 grew M. abscessus. PD catheter was removed, and he was transferred to hemodialysis on day 18. He was discharged at 5 weeks on hemodialysis. He received 1 month of azithromycin, 1 month of linezolid, 6 months of intravenous cefoxitin and oral Omadacycline. He succumbed to lung infections 8 months later. Discussion: Gram-positive or gram-negative bacteria are most common causes of PD-related peritonitis. NTM-related infections are on the rise, but M. abscessus causing PD-related peritonitis is exceedingly rare. It is often mistaken for Corynebacterium species or diphtheroid on gram stain. Immunocompromised and solid organ transplant recipients are at increased risk, hence a high index of suspicion is required. PD fluid must be examined promptly for acid-fast bacilli using Zeihl-Nelson stain. Eradication is difficult and requires several months of antibiotics, longer in immunocompromised patients. Encapsulating peritoneal sclerosis is a serious complication. ISPD guidelines suggest removing the PD catheter. Prognosis with M. abscessus is poorer than with other NTM infections.