Trends in antifungal use and epidemiology of nosocomial yeast infections in a university hospital

Abstract

This report describes both the trends in antifungal use and the epidemiology of nosocomial yeast infections at the University of Iowa Hospitals and Clinics between fiscal year (FY) 1987-1988 and FY 1993-1994. Data were gathered retrospectively from patients' medical records and from computerized databases maintained by the Pharmacy, the Program of Hospital Epidemiology, and the Medical Records Department. After fluconazole was introduced, use of ketoconazole decreased dramatically but adjusted use of amphotericin B decreased only moderately. However, the proportion of patients receiving antifungal therapy who were treated with amphotericin B declined markedly. In FY 1993-1994, 26 patients of the gastrointestinal surgery service received fluconazole. Among these patients, fluconazole use was prophylactic in 16 (61%), empiric in 3 (12%), and directed to a documented fungal infection in 7 (27%). Rates of nosocomial yeast infection in the adult bone marrow transplant unit increased from 6.77/1,000 patient days in FY 1987-1988 to 10.18 in FY 1989-1990 and then decreased to 0 in FY 1992-1993. Rates of yeast infections increased threefold in the medical and surgical intensive care units, reaching rates in FY 1993-1994 of 6.95 and 5.25/1,000 patient days, respectively. The rate of bloodstream infections increased from 0.044/1,000 patient days to 0.098, and the incidence of catheter-related urinary tract infections increased from 0.23/1,000 patient days to 0.68. Although the proportion of infections caused by yeast species other than Candida albicans did not increase consistently, C. glabrata became an important nosocomial pathogen.

FIG. 1

Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections during each FY of the study period.

FIG. 2

Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections by unit during each year of the study period. (A) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the adult BMTU. (B) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the adult hematology unit. (C) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the MICU. (D) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the SICU. (E) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the solid-organ transplant unit. (F) Adjusted rates of antifungal use and adjusted rates of nosocomial yeast infections in the gastrointestinal surgery unit.

FIG. 3

Amphotericin B use in FY 1993–1994. (A) Amphotericin B use by each unit in FY 1993–1994 as a proportion of the total amount (grams) used (n = 225 g). Abbreviations: adult BMTU, A-BMTU; operating room, OR; adult hematology unit, A-Hem; pediatric BMTU, P-BMTU; general internal medicine unit, Medical; other units, Other. (B) Adjusted amphotericin use (grams per 1,000 patient days) by major units. Abbreviations: pediatric hematology unit, P-Hem; pulmonary unit, Pulm; burn unit, Burn.

FIG. 4

Fluconazole use in FY 1993–1994. (A) Fluconazole use by each unit in FY 1993–1994 as a proportion of the total amount (grams) used (n = 529 g). (B) Adjusted fluconazole use (grams/1,000 patient days) by major units. Abbreviations: adult BMTU, A-BMTU; adult hematology unit, A-Hem; pediatric BMTU, P-BMTU; general internal medicine unit, Medical; other units, Other; pediatric hematology unit, P-Hem; solid-organ transplant unit, Transplant; gastrointestinal surgery unit, GIS.

FIG. 5

Categories of patients who received fluconazole in FY 1993–1994. The total number of patients was 281. Adult BMTU patients (A-BMTU), adult patients with hematologic diseases (A-Hem), pediatric BMTU patients (P-BMTU), adult patients with general medical diseases (Medical), pediatric patients with hematologic diseases (P-Hem), patients undergoing solid-organ transplantation (Transplant), human immunodeficiency virus-infected patients (HIV), patients undergoing nononcologic operative procedures (Surgical), patients with solid-organ tumors who were undergoing medical or surgical treatment (Oncologic), and patients whose underlying conditions had not been determined (ND) were included.

FIG. 6

Distribution of nosocomial yeast infections by site during each year of the study period. Abbreviations: bloodstream infection, BSI; gastrointestinal infection, GI; surgical site infection, SSI.

FIG. 7

Proportion of nosocomial yeast infections caused by different yeast species during each year of the study period.