Incidence of Candidemia is Decreasing, But Not for Some Drug-Resistant Species

First large-scale study on trends in invasive candidiasis finds species distribution of isolates varied between blood and nonblood sterile sites.

Invasive candidiasis is a serious infection that can affect the blood, heart, brain, eyes, bones, and other parts of the body. Despite newly available antifungal agents, mortality for invasive candidiasis remains high.

About half of invasive candidiasis cases historically have been caused by C albicans. Recent changes in species epidemiology and increased incidence of drug resistance call for a stronger understanding of how specific Candida species contribute to the infection; however, species and site-specific trends have not been reported on a large scale—until now.

Using a large electronic medical record database, investigators examined trends in invasive candidiasis and found that the although the incidence of candidemia is decreasing overall, incidence of drug-resistant species, such as C glabrata, are not.

Results of the study were shared on October 4, 2018 during a Poster Abstract Session at ID Week 2018, held this year in San Francisco, California.

In an exclusive interview Emily Ricotta, PhD, ScM, a research analyst in the epidemiology unit in the Division of Intramural Research at the National Institutes for Allergy and Infectious Disease, and lead author of the study discussed the overall decrease of C albicans infections in the United States and the rise of more susceptible incidences with Contagion® (see video).

Dr. Ricotta and the team of investigators used the Cerner Health Facts electronic health record dataset to identify inpatient hospitalizations that had any Candida species isolated from blood or sterile sites (SS) between 2009 and 2015. Patient characteristics were described by species. Using chi-squared or exact binomial tests, the investigative team evaluated significant relationships (P≤.05). They used Poisson regression to evaluate the annual percent change in invasive candidiasis incidence by site and species.

A total of 19,310 Candida isolates were identified in 10,313 patients. The majority of the isolates (46%) were C albicans, 22% were C glabrata, 14% were C parapsilosis, and 7% were C tropicalis: 11% of isolates were classified as other. None of the isolates were identified as C auris.

The overall incidence of invasive candidiasis was 99 cases/100,000 patients. Notably, isolation of other Candida species was 35% more frequent from blood, and 43% and 30% less frequent from non-blood abdominal and non-abdominal SSs, respectively, compared with C albicans.

“It’s very important to look and determine what site your isolate is from,” Dr. Ricotta stressed, “because that can give you an indication of what pathogens specifically you’ll have which can then give you an idea of the susceptibility profile that you’ll probably see.”

The study authors noted that a total annual increase of 1% (95% confidence interval [CI] = 0.2%-2%) in incidence of invasive candidiasis. They noted a significant annual increase of 6% in abdominal invasive candidiasis (range 4%-8%) as well as a 11% annual increase in SS invasive candidiasis (range 9%-13%), but a significant annual decrease of 4.5% in candidemia incidence (range 3%-6%). Specifically, among C albicans infections, candidemia decreased by 6.5% (range 5%-8%) annually, while abdominal and SS infections increased by 5% (range 3%-8%) and 10% (range 7%-13%), respectively. For other species, incidence of candidemia remained unchanged. For all species, SS infections increased, while increases in abdominal infections were noted in all species except C parapsilosis.

Species distribution of invasive candidiasis isolates varied between blood and non-blood isolates. Although incidence of candidemia was reported to be decreasing, according to the study authors, incidence of drug-resistant species such as C glabrata is not and they continue to pose treatment challenges.

Dr. Ricotta explained that until the driving factors of whats causing this shift in epidemiology can be identified, it is important to promote Candida awareness. Dr. Ricotta also emphasized the need for health care providers to be cognizant of the types of antibiotics that are being prescribed. (See video).

Patients with multidrug-resistant Candida infections have few remaining treatment options, and thus, are less likely to survive compared with patients who do not have resistant candidemia and can be treated with available antifungal medications, according to the US Centers for Disease Control and Prevention. Action is needed to prevent further resistance from developing and to prevent spread of infection.

“Our study can help providers know when they are looking at a particular source of a pathogen or if they get a particular type of pathogen, what treatment would be better for them to use; whether they have a more susceptible pathogen, a more resistant pathogen, whether they should start with an echinocandin versus and azole and knowing this will hopefully help moderate what sort of resistance we’re going to see going forward,” Dr. Ricotta concluded.

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