Mycobacterium abscessus Peritonitis: An Uncommon Yet Significant Cause of Peritoneal Dialysis-Associated Peritonitis

Introduction: Peritoneal dialysis (PD) is generally safe and well tolerated, but peritonitis is a common complication. Mycobacterium (M) species associated peritonitis in PD patients is uncommon with complex treatment. Case Description: We report the case of a 79-year-old female with end-stage renal disease (ESRD) due to diabetic nephropathy on PD, breast cancer in remission, initially presented to our institution with abdominal pain and cloudy effluent. CT scan of her abdomen did not show any abnormalities; Initial analysis of PD fluid was negative, with no organism grown. Empirical PD peritonitis treatment with intra-peritoneal antibiotics did not improve her symptoms. Later, culture of PD fluid showed growth of acid-fast bacilli. She required intravenous antibiotics, PD catheter removal and a switch to hemodialysis. Cultures of the PD fluid later grew M abscessus, and the antibiotic regimen was changed appropriately to therapy with intravenous (IV) micafungin, linezolid, Eravacycline, azithromycin, imipenem, and amikacin, leading to clinical improvement. Auditory function was monitored by audiogram every two weeks due to potential ototoxicity of amikacin. Repeat imaging later revealed that the infection had caused a 2 cm abdominal wall abscess, necessitating a longer course of antimicrobials. She remained stable and was discharged on Eravacycline, Linezolid and Amikacin. Discussion: Mycobacterium abscessus-associated peritonitis in PD patients is an uncommon occurrence. Clinicians should maintain awareness of this possibility when patients fail to show clinical improvement despite treatment with standard broad-spectrum antibiotics, particularly in cases where PD fluid initially deemed to be culture negative. The complex treatment experienced by our patient underscores the importance of remaining vigilant against opportunistic infections, even among immunocompetent individuals without apparent risk factors. To effectively manage such cases, it is imperative to send PD fluid samples for acid-fast bacillus testing. If Mycobacterium species are detected, further analysis using genome-wide sequencing is recommended to confirm the specific strain of Mycobacterium involved. Prompt removal of the catheter along with peritoneal washout is crucial for achieving clinical improvement and preventing further complications.