Peritoneal dialysis-associated peritonitis due to Nocardia farcinica: A case report

<i>Nocardia</i> spp. are Gram-positive aerobic actinomycetes that are widely found in everyday environments, such as soil, vegetables, and water. They are known to cause infections in the lungs, central nervous system, and skin. However, peritonitis caused by <i>Nocardia</i> spp. is rare. We report a case of peritoneal dialysis-associated peritonitis caused by <i>Nocardia farcinica</i> in a 53-year-old woman. She had been undergoing peritoneal dialysis (PD) for approximately two years because of diabetic nephropathy. Gram staining of the PD effluent revealed the presence of Gram-positive rods. Because species-level identification could not be achieved using and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, next-generation sequencing was performed and the isolate was identified as <i>N. farcinica</i>. The PD catheter was removed and hemodialysis was initiated. She received intravenous amikacin, sulfamethoxazole/trimethoprim (SMX/TMP), and imipenem/cilastatin for approximately two months, followed by oral SMX/TMP and minocycline for four months after discharge. The <i>N. farcinica</i> isolate from our patient showed good antimicrobial susceptibility to various antimicrobials, including SMX/TMP (minimum inhibitory ≤40 µ g/mL). This case highlights that <i>N. farcinica</i> can cause peritoneal dialysis catheter-associated peritonitis. Although reports of <i>N. farcinica</i>-related peritonitis are extremely limited, the species is associated with a higher mortality rate than other <i>Nocardia</i> spp. Therefore, appropriate source control and at least six months of antimicrobial therapy are recommended. Additionally, SMX/TMP monotherapy should be avoided as empiric therapy because <i>N. farcinica</i> may exhibit resistance.