TAMMY BISCHOFF
Advisor, Tilahun Adera, Ph.D., M.P.H.
Preceptor, Michael Edmond, M.D., M.P.H.

Objectives: To describe and analyze secular trends and characteristics of nosocomial candidemia in the United States over a five-year time period.

Methods: The Surveillance and Control of Pathogen of Epidemiologic Importance (SCOPE) Project database consisting of 20,020 cases of nosocomial bloodstream infections for the period 1996-2000 from 40 hospitals throughout the United States was analyzed. Rates were calculated based on number of reported infections and total hospital admissions. Pairwise analysis, Student’s T-test and simple linear regression were performed to assess the association of patient and hospital characteristics to candidemia.

Results: 1557 (7.8%) nosocomial bloodstream infections were caused by Candida while 18,463 (92.2%) were caused by other pathogens. The overall rate of candidemia was 4.9/10,000 hospital admissions, which ranked Candida as the fourth most common nosocomial bloodstream pathogen. The annual rate of candidemia ranged from 4.4 to 6.2/10,000 admissions during this period, with the highest rate noted in 2000. The incidence rates of candidemia among the 4 US regions ranged from 3.1-7.4/10,000 admissions with the highest rate in the Southeast (SE). Of the 1557 isolates causing nosocomial bloodstream infections, C. albicans accounted for 53.2% followed by C. glabrata (18.7%), C. tropicalis (11.8%), C. parapsilosis (11.1%) and C. krusei (2.5%). The proportion of nonalbicans isolates varied with geographic region and ranged from 3 5.8% in the SW to 52% in the NE. The overall incidence rate of C. albicans, C. glabrata and C. parapsilosis increased over the 5-year period. Univariate predictors for candidemia were age <1 year, total parenteral nutrition, mechanical ventilation and the presence of a central venous catheter. Two specific hospital services, organ transplantation (p<.000) and level 1 trauma center (p<.000) were significantly associated with higher incidence rates of candidemia. In a simple linear regression model, the number of hospital beds was significantly related to the incidence rate of candidemia (p.OO8). The comparison of crude mortality rates revealed that individuals with candidemia had a 1.8 greater chance of dying than those with nosocomial bloodstream infections caused by other pathogens.

Conclusion: Candida consistently ranks among the top pathogens causing nosocomial bloodstream infections throughout the United States and is associated with the highest crude mortality rate among all pathogens causing nosocomial bloodstream infections. Advanced therapeutics typical of the intensive care unit setting are risk factors for these infections. The incidence of nonalbicans species causing nosocomial candidemia appears to be increasing. Finally, hospitals offering the most sophisticated medical services have the highest incidence of these infections.