Invasive Candidiasis Statistics
Candidemia is one of the most common bloodstream infections in the United States.1 During 2013–2017, the average incidence was approximately 9 per 100,000 people; however, this number varies substantially by geographic location and patient population. CDC estimates that approximately 25,000 cases of candidemia occur nationwide each year.2
Candidemia is the most common form of invasive candidiasis, but it does not represent all forms of invasive candidiasis because the infection can occur in the heart, kidney, bones, and other internal organs without being detected in the blood. In fact, the true burden of invasive candidiasis might be twice as high as the estimate for candidemia.
CDC performs surveillance for Candida bloodstream infections candidemia through the Emerging Infections Program (EIP), a network of 10 state health departments and their collaborators in local health departments, academic institutions, other federal agencies, public health and clinical laboratories, and healthcare facilities.
Active, population-based surveillance for candidemia is being conducted in 10 EIP sites: California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, and Tennessee (Table 1). CDC and its partners recruit laboratories and hospitals serving the counties under surveillance to submit reports of candidemia that develops in patients living within the surveillance area.
|Emerging Infections Program site||Current candidemia surveillance ongoing since (year)||Area under surveillance|
|Colorado||2017||5 counties in Metropolitan Denver|
|Georgia||2008||8 counties in Metropolitan Atlanta|
|Maryland||2008||Baltimore City and County|
|Minnesota||2017||7 counties in Minneapolis-St. Paul Metropolitan area|
|New Mexico||2017||Bernalillo County|
|New York||2016||Monroe County|
|Oregon||2011||3 counties in Metropolitan Portland|
|Tennessee||2011||17 counties that incorporate Knoxville and surrounding areas|
Through this program, CDC monitors epidemiologic trends in candidemia and performs species confirmation and antifungal susceptibility testing on all available Candida bloodstream isolates to meet these public health needs:
- Track incidence of candidemia and estimate the total burden
- Identify new risk factors for candidemia
- Detect the emergence and spread of antifungal resistance
- Understand and describe specific genetic mutations associated with resistance
- Identify areas where candidemia prevention and intervention strategies can be focused
CDC also collects data on healthcare-associated infections, including central line-associated Candida infections through the National Healthcare Safety Network (NHSN), the largest healthcare-associated infection reporting system in the United States.
CDC’s active, population-based surveillance for candidemia has been ongoing since 2008. Candidemia incidence declined during 2009–2013 and then stabilized at approximately 9 cases per 100,000 population during 2013-2017 (Figure 1). However, there are notable differences by site. It is possible that the observed declines in candidemia during 2008–2013 are related to healthcare delivery improvements such as those involving catheter care and maintenance.3 Increases in incidence in certain surveillance areas may be due to increases in the number of candidemia case related to injection drug use, which has recently been re-emerging as a risk factor for candidemia.4,5
Figure 1: Candidemia incidence rates per 100,000 people by site and surveillance year, 2009–2017
There have been important changes in the rates of candidemia by age group. Rates have decreased significantly in infants, but remain high compared with other groups.6,7 The reasons for the decline in candidemia rates in infants are not fully understood but might be related to factors such as fluconazole prophylaxis in high-risk pre-term babies or improved infection control practices, such as hand hygiene and catheter care. Candidemia rates are typically highest among people aged 65 and older (Figure 2). Candidemia rates are approximately twice as high in blacks as in non-blacks (Figure 3). The reasons for the difference in incidence by race may have to do with difference in underlying conditions, socioeconomic status, or other factors.
Figure 2: Candidemia incidence rates per 100,000 person-years, by age group, 2009–2017
Figure 3: Candidemia incidence rates per 100,000 person-years, by age group, 2009–2017
Trends in species distribution
Up to 95% of all invasive Candida infections in the United States are caused by five species of Candida: C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei. The proportion of infections caused by each species varies by geographic region and by patient population.8 C. albicans is the most common species causing invasive Candida infection, although the proportion of Candida infections caused by C. albicans has decreased during the last 20 years.9-11 Altogether, non-C. albicans species cause approximately two-thirds of candidemia cases in the United States.3,9 In some locations, C. glabrata is the most common species. An emerging species called C. auris is also an increasing cause of invasive Candida infections in United States since 2016.
Trends in antifungal resistance
Some types of Candida are increasingly resistant to the first-line and second-line antifungal medications, such as fluconazole and the echinocandins (anidulafungin, caspofungin, and micafungin). About 7% of all Candida bloodstream isolates tested at CDC are resistant to fluconazole (Figure 4). More than 70% of these resistant isolates are the species Candida glabrata or Candida krusei.9,12 CDC’s surveillance data indicate that the proportion of Candida isolates that are resistant to fluconazole has remained fairly constant over the past 20 years.9,13,14 Echinocandin resistance, however, appears to be emerging, especially among Candida glabrata isolates. Approximately 3% of Candida glabrata isolates are resistant to echinocandins, but the percentage may be higher in some hospitals. This is especially concerning because echinocandins are the first-line treatment for Candida glabrata, which already has high levels of resistance to fluconazole.12
Figure 4: Antifungal resistant Candida spp. isolates by year, 2009–2017
Invasive Candida infections are often associated with high rates of morbidity and mortality, as well as increases in cost and length of hospital stay. CDC’s surveillance data indicate that the in-hospital all-cause (crude) mortality among people with candidemia is approximately 25%. However, because people who develop invasive candidiasis are typically already sick with other medical conditions, it can be difficult to determine the proportion of deaths directly attributable to the infection. One study estimated the mortality attributable to candidemia to be 19–24%.15
Most cases of invasive candidiasis are not associated with outbreaks. However, sporadic outbreaks of C. parapsilosis infection have been reported for decades, including clusters of invasive candidiasis in neonatal intensive care units likely transmitted via healthcare workers’ hands.16-18 Recently, an emerging species called C. auris has caused outbreaks of invasive infections around the world likely because of its ability to colonize patient skin and persist on healthcare surfaces. Of concern, it is commonly resistant to antifungal medications, and some disinfectants used in healthcare settings do not kill C. auris. Read more about C. auris.
- Magill SS, O’Leary E, Janelle SJ, et al. Changes in Prevalence of Health Care-Associated Infections in U.S. Hospitals. The New England journal of medicine 2018;379:1732-44.
- Tsay S, Williams S, Mu Y, et al. National Burden of Candidemia, United States, Open Forum Infect Dis. 2018;5(Suppl 1):S142-43.
- Cleveland AA, Harrison LH, Farley MM, et al. Declining Incidence of Candidemia and the Shifting Epidemiology of Candida Resistance in Two US Metropolitan Areas, 2008-2013: Results from Population-Based Surveillance. PloS one 2015;10:e0120452.
- Poowanawittayakom N, Dutta A, Stock S, Touray S, Ellison RT, 3rd, Levitz SM. Reemergence of Intravenous Drug Use as Risk Factor for Candidemia, Massachusetts, USA. Emerging infectious diseases 2018;24.
- Zhang A, Shrum S, Williams S, et al. The Changing Epidemiology of Candidemia in the United States: Injection Drug Use as an Emerging Risk Factor for Candidemia. IDWeek. San Francisco, CA2018.
- Benedict K, Roy M, Kabbani S, et al. Neonatal and Pediatric Candidemia: Results From Population-Based Active Laboratory Surveillance in Four US Locations, 2009-2015. J Pediatric Infect Dis Soc 2018;7:e78-e85.
- Cleveland AA, Farley MM, Harrison LH, et al. Changes in incidence and antifungal drug resistance in candidemia: results from population-based laboratory surveillance in Atlanta and Baltimore, 2008-2011. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 2012;55:1352-61.
- Lockhart S. Current Epidemiology of Candida Infection. Clinical Microbiology Newsletter 2014;36:131-6.
- Lockhart SR, Iqbal N, Cleveland AA, et al. Species identification and antifungal susceptibility testing of Candida bloodstream isolates from population-based surveillance studies in two U.S. cities from 2008 to 2011. Journal of clinical microbiology 2012;50:3435-42.
- Pfaller M, Neofytos D, Diekema D, et al. Epidemiology and outcomes of candidemia in 3648 patients: data from the Prospective Antifungal Therapy (PATH Alliance(R)) registry, 2004-2008. Diagnostic microbiology and infectious disease 2012;74:323-31.
- Pfaller MA, Diekema DJ. Epidemiology of invasive candidiasis: a persistent public health problem. Clinical microbiology reviews 2007;20:133-63.
- Vallabhaneni S, Cleveland AA, Farley MM, et al. Epidemiology and Risk Factors for Echinocandin Nonsusceptible Candida glabrata Bloodstream Infections: Data From a Large Multisite Population-Based Candidemia Surveillance Program, 2008-2014. Open Forum Infect Dis 2015;2:ofv163.
- Hajjeh RA, Sofair AN, Harrison LH, et al. Incidence of bloodstream infections due to Candida species and in vitro susceptibilities of isolates collected from 1998 to 2000 in a population-based active surveillance program. Journal of clinical microbiology 2004;42:1519-27.
- Kao AS, Brandt ME, Pruitt WR, et al. The epidemiology of candidemia in two United States cities: results of a population-based active surveillance. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 1999;29:1164-70.
- Morgan J, Meltzer MI, Plikaytis BD, et al. Excess mortality, hospital stay, and cost due to candidemia: a case-control study using data from population-based candidemia surveillance. Infection control and hospital epidemiology : the official journal of the Society of Hospital Epidemiologists of America 2005;26:540-7.
- Clark TA, Slavinski SA, Morgan J, et al. Epidemiologic and molecular characterization of an outbreak of Candida parapsilosis bloodstream infections in a community hospital. Journal of clinical microbiology 2004;42:4468-72.
- Huang YC, Lin TY, Leu HS, Peng HL, Wu JH, Chang HY. Outbreak of Candida parapsilosis fungemia in neonatal intensive care units: clinical implications and genotyping analysis. Infection 1999;27:97-102.
- Lupetti A, Tavanti A, Davini P, et al. Horizontal transmission of Candida parapsilosis candidemia in a neonatal intensive care unit. Journal of clinical microbiology 2002;40:2363-9.