Peritoneal Dialysis-Associated Peritonitis Caused by Lautropia Mirabilis and Concurrent Viral Infection: A Case...

Lautropia mirabilis is a rare cause of peritonitis associated with peritoneal dialysis-associated peritonitis (PDAP). We report the first documented case of PDAP caused by coinfection with L. mirabilis, cytomegalovirus (CMV), and Epstein-Barr virus (EBV).

A 67-year-old woman with end-stage renal disease secondary to polycystic kidney disease, on continuous ambulatory peritoneal dialysis for 3 years, developed PDAP. Initial peritoneal dialysis effluent (PDE) culture grew Streptococcus salivarius, and symptoms resolved with treatment. However, she was readmitted 2 days later with recurrent PDAP. Despite 18 days of empirical antibiotic therapy and repeated negative PDE cultures, the patient's symptoms persisted. Upon her transfer to our hospital, PDE white blood cell (WBC) count was 110 × 10⁶/L. Targeted next-generation sequencing (tNGS) of the PDE performed on day one detected L. mirabilis (16,929 reads), CMV (944 reads), and EBV (285 reads). Therapy with intravenous moxifloxacin, intraperitoneal gentamicin, and oral ganciclovir led to rapid WBC decline and clinical improvement within 48 h. After 1 week of inpatient monitoring, the patient was discharged with a 2-week course of oral moxifloxacin. At the 2-week follow-up, the patient was asymptomatic with normal PDE WBC counts.

Conventional culture methods may fail to detect uncommon pathogens, such as L. mirabilis. Culture-negative PDAP often necessitates empirical antibiotic therapy, carrying a high risk of failure and increased healthcare costs. This case suggests that tNGS could be used as a complementary diagnostic tool in selected cases of refractory, culture-negative PDAP, potentially aiding the identification of pathogens and guiding therapy.