Peritoneal Dialysis-Related Peritonitis Caused by Lysinibacillus sphaericus

Peritonitis is the major complication of peritoneal dialysis (PD) patients. Staphylococcus is the leading causative organism of PD-related peritonitis. However, there were more reports of unusual organisms causing peritonitis. Clinical features, management, and outcome of peritonitis from unusual organisms are important information. We reported herein a 72-year-old female patient who presented with fever, abdominal pain, and cloudy dialysate for 3 days. Upon admission, ceftazidime and vancomycin were given intraperitoneally. A preliminary report of blood and PD fluid culture showed the presence of Gram-positive bacilli. Her clinical status improved 48 hours after the commencement of the antibiotics. Subsequently, culture reports of blood and PD fluid showed Lysinibacillus sphaericus which was susceptible to vancomycin at a minimal inhibitory concentration of less than 0.25 μg/mL. The patient was given intraperitoneal vancomycin for a total of 14 days. Then, the PD effluent was clear, and its cell count was below 100 cells/mm3 in 3 days. The patient did not have a recurrence of peritonitis after antibiotic discontinuation. The possibility of this organism infection is environmental contamination related to the patient’s gardening activities.