Peritoneal Dialysis-Related Peritonitis Caused by Lysinibacillus sphaericus

Area of Science:

• Microbiology
• Nephrology
• Infectious Diseases

Background:

• Peritonitis is a significant complication for patients undergoing peritoneal dialysis (PD).
• While Staphylococcus species are common causes, unusual organisms are increasingly reported, necessitating understanding of their clinical characteristics and management.
• Effective treatment and outcome data for peritonitis caused by rare pathogens are crucial for patient care.

Observation:

• A 72-year-old female PD patient presented with symptoms of peritonitis, including fever, abdominal pain, and cloudy dialysate.
• Initial treatment with intraperitoneal ceftazidime and vancomycin showed improvement within 48 hours.
• Blood and PD fluid cultures ultimately identified Lysinibacillus sphaericus, a Gram-positive bacillus susceptible to vancomycin.

Findings:

• Lysinibacillus sphaericus peritonitis was successfully treated with a 14-day course of intraperitoneal vancomycin.
• The patient experienced rapid clinical improvement, with PD effluent clearing and cell counts normalizing within 3 days post-treatment.
• No recurrence of peritonitis was observed after completing antibiotic therapy.

Implications:

• This case highlights Lysinibacillus sphaericus as a potential, albeit rare, cause of peritonitis in PD patients.
• The successful treatment underscores the importance of accurate microbial identification and appropriate antibiotic selection.
• Environmental exposure, such as gardening, may be a potential source of infection, suggesting preventative measures for PD patients.