Supplementary Material for: Peritoneal Dialysis-Associated Peritonitis Caused by Lautropia mirabilis and Concurrent Viral Infection: A Case Report

Lautropia mirabilis is a rare cause of peritonitis associated with peritoneal dialysis-associated peritonitis (PDAP). This is the first reported case of PDAP resulting from coinfection with Lautropia mirabilis, cytomegalovirus(CMV), and Epstein-Barr virus(EBV).
A 67-year-old woman with end-stage renal disease secondary to polycystic kidney disease, managed with continuous ambulatory peritoneal dialysis for three years, presented with PDAP. Initial peritoneal dialysis effluent (PDE) culture revealed Streptococcus salivarius. She was discharged after successful treatment, but was readmitted two days after intraperitoneal therapy for recurrent PDAP. Despite 18 days of empirical antibiotic therapy and repeated negative PDE cultures, the patient’s condition persisted. Upon transfer to our hospital, targeted next-generation sequencing (tNGS) of the PDE was performed on the first day of admission to detect Lautropia mirabilis (16,929 reads), CMV (944 reads), and EBV(285 reads). Within 48 h, the PDE white blood cell (WBC) count decreased markedly, and symptoms improved over the subsequent week. After one week of inpatient monitoring, the patient was discharged with a two-week course of oral moxifloxacin. At the two-week follow-up, the patient reported no abdominal pain, and the repeat PDE WBC count remained normal, confirming a favorable therapeutic outcome.
Conventional culture methods often fail to detect uncommon pathogens including Lautropia mirabilis. Culture-negative PDAP typically requires empirical antibiotic therapy, which is associated with a high risk of treatment failure and substantial economic cost. This case suggests that tNGS could be considered a complementary diagnostic tool in selected cases of refractory culture-negative PDAP, potentially aiding pathogen identification and guiding therapy.