Which organisms are most commonly implicated in PD-related peritonitis?

• A. Skin flora, especially Staphylococcus aureus and coagulase-negative staphylococci
• B. Pseudomonas aeruginosa
• C. Streptococcus pneumoniae
• D. Candida albicans

Answer: (A)

Contamination during PD exchanges is the main driver of PD-related peritonitis. The peritoneal cavity becomes infected most often by organisms that live on the skin, which are carried into the abdomen during the exchange process. The two most frequently implicated skin flora are Staphylococcus aureus and coagulase-negative staphylococci. These organisms are common on the hands and catheter entry points, so strict hand hygiene and aseptic technique during every exchange are crucial to prevent infection.

While other pathogens can cause PD peritonitis, they are less common. Pseudomonas aeruginosa and Candida albicans can occur, often related to environmental exposure or prolonged catheter use with antifungal exposure, but they are not the typical culprits. Streptococcus pneumoniae is not a common cause of PD-related peritonitis.

This pattern—predominance of skin flora—also guides initial empiric therapy, which usually covers gram-positive organisms, with later adjustment based on culture results.