Repeated Peritonitis in a Peritoneal Dialysis Patient: An Unusual Case of Bacillus licheniformis With Vancomycin Failure Despite Sensitivity.

Bacillus licheniformis (B. licheniformis) is an aerobic, gram-positive, spore-forming rod typically found in soil, decaying organic matter, vegetables, and water, and occasionally part of normal gut flora. This report highlights a case of unusual repeated peritonitis caused by B. licheniformis, with three episodes occurring over six months, all of which were sensitive to vancomycin yet presented an unclear cause for recurrence. Peritonitis represents a significant cause of mortality, hospitalization, and failure of peritoneal dialysis catheters, leading to forced transitions to hemodialysis. The rarity of B. licheniformis as a pathogen in human infections emphasizes the critical need for precise microbial identification and customized therapeutic strategies.