Peritoneal dialysis-associated peritonitis caused by Ureaplasma urealyticum: A case report

Ureaplasma urealyticum is a rare cause of peritoneal dialysis-associated peritonitis (PDAP) that may be missed by routine culture. Here, we report a culture-negative case in which targeted next-generation sequencing (tNGS) supported rapid pathogen identification and treatment adjustment.

A 41-year-old woman receiving continuous ambulatory peritoneal dialysis for >10 years presented with acute abdominal pain, cloudy dialysate, fever, and neutrophilic dialysate leukocytosis. The patient was diagnosed with PDAP.

Repeated bacterial and fungal cultures and acid-fast staining were negative. tNGS of peritoneal dialysate detected U urealyticum, which is considered the most likely causative pathogen.

Empirical vancomycin plus ceftazidime, followed by vancomycin plus meropenem, was ineffective. The treatment was changed to oral doxycycline plus intraperitoneal levofloxacin after the tNGS results became available. A vaginal U urealyticum isolate was subsequently resistant to levofloxacin; therefore, levofloxacin was replaced with intravenous azithromycin.

The abdominal pain resolved, the dialysate cleared, inflammatory markers decreased, the PD catheter was retained, and no recurrence occurred during the 1-month follow-up period.

In persistent culture-negative PDAP that does not respond to cell wall-active antibiotics, clinicians should consider cell wall-deficient organisms such as Ureaplasma. tNGS may complement conventional microbiological testing, but the results should be interpreted in the clinical context and, when possible, confirmed by an independent method.