Relationship of fluconazole prophylaxis with fungal microbiology in hospitalized intra-abdominal surgery patients: a descriptive cohort study

Introduction: Historically, Candida albicans has represented the most common cause of candidemia. However, the proportion of bloodstream infections due to non-albicans Candida species has increased. Because of the risk for candidemia in intra-abdominal surgical patients, some experts advocate the use of fluconazole prophylaxis. The impact of this practice on the distribution of Candida species isolated in breakthrough fungal infections in this population is unknown. We examined the association of fluconazole prophylaxis with the distribution of Candida species in intra-abdominal surgery patients. Methods: We retrospectively identified cases with a positive blood culture (BCx) for Candida among hospitalized adult intra-abdominal surgery patients between July 2005 and October 2012. Distribution of Candida species isolated represented our primary endpoint. Qualifying surgical cases were determined based on a review of discharge International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Patients receiving low-dose fluconazole prior to the positive BCx with a known indication for prophylaxis including neutropenia, ICU exposure or history of organ transplantation were classified as prophylaxis. Appropriateness of fungal treatment was determined by the timing and selection of antifungal agent based on fungal isolate. Results: Among 10,839 intra-abdominal surgery patients, 227 had candidemia. The most common Candida species isolated was C. albicans (n = 90, 39.6%) followed by C. glabrata (n = 81, 35.7%) and C. parapsilosis (n = 38, 16.7%). Non-albicans Candida accounted for 57.7% of isolates among the 194 non-prophylaxis patients and 75.8% among the 33 prophylaxis patients (P = 0.001). C. glabrata, the most common non-C. albicans species, was more prevalent than C. albicans in persons given prophylaxis, but not in those without prophylaxis. A total of 63% of those with candidemia were treated inappropriately based on the timing and selection of antifungal administration. Conclusions: Selection pressure from fluconazole prophylaxis in at-risk surgical patients may be associated with a drift toward fluconazole-resistant species in subsequent candidemia. Tools are needed to guide appropriate treatment through the prompt recognition and characterization of candidemia.