Can yeast isolation in peritoneal fluid be predicted in intensive care unit patients with peritonitis?

OBJECTIVE: To generate and validate a predictive score of yeast isolation based on independent risk factors of yeast isolation in intensive care unit patients with peritonitis.

DESIGN: Retrospective cohort study to determine independent risk factors of yeast isolation, generation of the score, and validation in a prospective cohort of patients with peritonitis.

SETTING: Tertiary-care, university-affiliated hospital.

PATIENTS: Two hundred twenty-one patients with peritonitis hospitalized in a surgical intensive care unit between 1994 and 1999 for the retrospective cohort and 57 patients in the prospective cohort (2000).

MEASUREMENTS AND MAIN RESULTS: Four independent risk factors of yeast isolation in peritoneal fluid (similar odds ratio) were found in the retrospective cohort: female gender, upper gastrointestinal tract origin of peritonitis, intraoperative cardiovascular failure, and previous antimicrobial therapy at least 48 hrs before the onset of peritonitis. A score based on the number of risk factors was constructed (grade A = zero or one risk factor, grade B = at least two risk factors, grade C = at least three risk factors, and grade D = four risk factors), and validated in the prospective cohort. For a grade C score, sensitivity was 84%, specificity was 50%, positive and negative predictive values were 67% and 72%, respectively, and overall accuracy was 71%.

CONCLUSIONS: Four independent risk factors of yeast isolation in the peritoneal fluid were identified in critically ill surgical patients with peritonitis. The presence of at least three of these factors (grade C score) was associated with a high rate of yeast detection. This approach could be helpful to initiate early antifungal therapy in this patient population.