Issue Brief

Clostridium difficile: Rapidly Emerging Bacteria that Flourish in the Face of Antibiotics

Note: For the most recent data on Clostridium difficile, visit the CDC's website.

Vital Statistics
• Nearly 45,000 Americans died from CDI between 1999 and 2009.1
• Seniors are especially at risk. More than 90 percent of deaths from CDI in 2009 occurred in those 65 years and older.2
• The estimated annual costs of CDI to the U.S. economy may reach $1.8 billion each year, with median per-patient costs as high as $40,000.3

What Causes C. Diff-Related Infections?
C. diff resides in the intestines of up to 3 percent of healthy adults without causing any symptoms.4, 5
When a patient takes antibiotics to treat another infection, those drugs may alter the normal balance of intestinal bacteria, allowing C. diff to flourish and release toxins that can cause severe diarrhea and inflammation of the colon.6
Reports of C. diff-related infections (CDI) are increasing in populations that include pregnant women, children, and those who have not been under medical care.7, 8, 9, 10

Treatment Options
• To treat CDI, antibiotic use must be restricted to metronidazole or, if that fails, vancomycin. Resistance to metronidazole and intermediate resistance to vancomycin has been reported.11, 12
• In May 2011, the U.S. Food and Drug Administration approved fidaxomicin, the first new antibiotic in more than 25 years to treat diarrhea caused by CDI.13, 14
• In severe cases, the only effective treatment for CDI is surgery to remove the infected portion of the patient's intestines.15


1 National Vital Statistics System, Centers for Disease Control and Prevention. “GMWKI: Total deaths for each cause by 5-year age groups, United States, 1999-2006+,” last modified November 12, 2009,; J. Xu et al., “Deaths: Final Data for 2007,” National Vital Statistics Reports 58, no. 19 (2010); K.D. Kochanek et al., “Deaths: Preliminary Data for 2009,” National Vital Statistics Reports 59, no. 4 (2011).
2 K.D. Kochanek et al., “Deaths: Preliminary Data for 2009.”
3 S.M. McGlone et al., “The Economic Burden of Clostridium difficile,” Clin Microbiol Infect (2011).
4 R. Ricciardi et al., “Increasing Prevalence and Severity of Clostridium difficile Colitis in Hospitalized Patients in the United States,” Arch Surg 142, no. 7 (2007): 624-31; discussion 31. 
5 F. Barbut and J.C. Petit, “Epidemiology of Clostridium difficile-Associated Infections,” Clin Microbiol Infect 7, no. 8 (2001): 405-10.
6 V.K. Viswanathan, M.J. Mallozzi, and G. Vedantam, “Clostridium difficile infection: An overview of the disease and its pathogenesis, epidemiology and interventions,” Gut Microbes 1, no. 4 (2010): 234-42.
7 H. Pituch, “Clostridium difficile is no longer just a nosocomial infection or an infection of adults,” Int J Antimicrob Agents 33 Suppl 1 (2009): S42-5.
8 “Severe Clostridium difficile-Associated Disease in Populations Previously at Low Risk—Four States, 2005,” MMWR Morb Mortal Wkly Rep 54, no. 47 (2005): 1201-5.
9 P.K. Kutty et al., “Risk Factors for and Estimated Incidence of Community-Associated Clostridium difficile Infection, North Carolina, USA,” Emerg Infect Dis 16, no. 2 (2010): 197-204.
10 A.N. Ananthakrishnan, “Clostridium difficile infection: epidemiology, risk factors and management,” Nat Rev Gastroenterol Hepatol 8, no. 1 (2011): 17-26.
11 T. Pelaez et al., “Reassessment of Clostridium difficile Susceptibility to Metronidazole and Vancomycin,” Antimicrob Agents Chemother 46, no. 6 (2002): 1647-50.
12 A. Dworczynski, B. Sokol, and F. Meisel-Mikolajczyk, “Antibiotic resistance of Clostridium difficile isolates,” Cytobios 65, no. 262-263 (1991): 149-53.
13 U.S. Food and Drug Administration, “FDA approves treatment for Clostridium difficile infection,” news release, May 27, 2011,
14 A. Pollack, “F.D.A. Approves Drug to Treat Hospital Scourge,” New York Times, May 27, 2011,
15 R.M. Dallal et al, “Fulminant Clostridium difficile: An Underappreciated and Increasing Cause of Death and Complications,” Ann Surg 235, no. 3 (2002): 363-72.
16 Based on data from, M.P. Heron et al., “Deaths: Final Data for 2006,” National Vital Statistics Reports 57, no. 14 (2009).