A case report of peritoneal dialysis–associated peritonitis caused by Mycobacterium mageritense

Non-tuberculous mycobacteria can result in peritoneal dialysis (PD)-associated peritonitis and PD catheter-related infections, including tunnel and exit site infection. We report the case of a 78-year-old male patient undergoing PD for end-stage renal failure due to diabetic nephropathy, with a medical history that includes PD catheter-related infections. He developed <i>Mycobacgerium mageritense</i> peritonitis secondary to a PD catheter-related infection. <i>M. mageritense</i> grew on blood agar, and its identification was confirmed using matrix-assisted laser desorption ionization-time of flight/mass spectrometer (MALDI-TOF/MS) and 16S rRNA sequencing. Based on susceptibility testing, treatment was initiated with trimethoprim/sulfamethoxazole (TMP/SMX) (80 mg/400 mg) 5 mg/kg every 24 hours in combination with minocycline 100 mg every 12 hours, which was subsequently changed to TMP/SMX plus faropenem 200 mg every 8 hours due to nausea caused by minocycline. However, the antimicrobial therapy proved to be ineffective, and the patient subsequently developed complicated PD-associated peritonitis, leading to the removal of the PD catheter. We switched to TMP/SMX, imipenem/cilastatin 500 mg every 12 hours, and used linezolid 600 mg every 12 hours, which was later replaced with amikacin, guided by therapeutic drug monitoring. Subsequent complications related to antimicrobial therapy included nausea caused by linezolid and hearing impairment due to amikacin. We treated the patient with TMP/SMX and sitafloxacin 100 mg every 24 hours, which was well-tolerated. The patient was treated for 18 months without a relapse. Our findings underscore the importance of suspecting non-tuberculous mycobacteria in PD catheter-related infection and considering the early inclusion of acid-fast bacillus culture. Given the diagnostic challenges and the complexity of managing multi-drug antimicrobial therapy in patients with renal dysfunction, we recommend early catheter removal.