Differences in Epidemiology of Invasive Candidiasis Between Academic and Community Hospitals Participating in the Candida Surveillance Study (cass)

Background:

Candida species are the fourth most common cause of nosocomial bloodstream infection in the United States. Of the various Candida species, Candida albicans caused the majority of infections during the 1980s. However, during the 1990s, the proportion of infections caused by C. albicans decreased, accounting for only 45% of bloodstream infections. The rise in non‐albicans species was mainly due to C. glabrata, which was responsible for 24% of invasive Candida infections. We undertook sentinel surveillance to monitor whether the shift away from C. albicans was continuing.

Methods:

Forty‐one U.S. academic and community hospitals submitted between 25 and 200 consecutive yeast isolates obtained from sterile body sites. Demographic and clinical data were collected on patients from whom the isolates were obtained. Species identification was performed at a central laboratory using ChromAgar to make a presumptive identification. Formation of germ tubes in serum was used to confirm C. albicans. To identify species other than C. albicans, microscopic morphology was determined on Cornmeal Tween agar and biochemical characteristics were analyzed using an API 20C (Bio‐Meriuex).

Results:

Between September 2004 and October 2006, 3447 isolates were collected and submitted for species identification. The proportions of disease caused by different species were: C. albicans, 44.9% (1547); C. glabrata, 24.3% (836); C. parapsilosis, 17.9% (618); C. tropicalis, 9.1% (314); C. krusei, 1.6% (54); and other species, 2.3% (78). Men accounted for 1828 of the cases (53.5%). Women were more likely to have an infection with C. glabrata than were men (relative risk [RR] = 1.46, 95% confidence interval (CI): 1.29‐1.64, P < .001). Of the 41 participating sites, 7 (17.1%) are considered community‐based hospitals and account for4851 (20.9%) of the 23,171 hospital beds in the surveillance network. Community hospitals accounted for 547 of the cases (15.6%), significantly fewer than those contributed from academic centers. There was no difference in species distribution between the academic centers and community hospitals. Patients from academic centers were more likely to have received any antifungal prophylaxis (RR = 1.04, 95% CI: 1.000‐1.088, P = .03), and these patients were less likely to have C. albicans (RR = 0.85, 95% CI: 0.74‐0.96, P = .008).

Conclusions:

Non‐albicans species continue to cause most cases of invasive candidiasis detected in our surveillance system. Academic centers accounted for a disproportionately larger number of cases relative to the number from community hospitals, but there was no difference in species distribution between the academic centers and the community hospitals. Patients who had received antifungal prophylaxis were more likely to be infected with a non‐albicans Candida species, and women were more likely to be infected with C. glabrata.

Author Disclosure:

M. Lyon, Merck & Co., Inc., research grants; Y. Adiri, None; P. Hoover, Merck & Co., Inc., employment (full‐ or part‐time); M. A. Abramson, Merck & Co., Inc., employment (full‐ or part‐time).