Clostridium difficile, 2014

Clostridium difficile is an anaerobic, spore-forming, Gram-positive bacillus that produces two pathogenic toxins: A and B. C. difficile infections (CDI) range in severity from mild diarrhea to fulminant colitis and death. Transmission of C. difficile occurs primarily in health care facilities, where environmental contamination by C. difficile spores and exposure to antimicrobial drugs are common. The primary risk factor for CDI in health care settings is recent use of antimicrobials, particularly clindamycin, cephalosporins, and fluoroquinolones. Other risk factors for CDI are age greater than 65 years, severe underlying illness, intensive care unit admission, nasogastric intubation, and longer duration of hospital stay.

In the early 2000s, a marked increase in the number of CDI cases and mortality due to CDI was noted across the United States, Canada, and England. Most notable was a series of large-scale protracted outbreaks in Quebec first reported in March 2003. During this period, Quebec hospitals reported a 5-fold increase in health care-acquired CDI. These and other health care facility (e.g., long-term care facilities) outbreaks have been associated with the emergence of a new more virulent strain of C. difficile, designated North American PFGE type 1 (NAP1), toxinotype III.

In 2009, in an effort to better understand the burden in Minnesota, as part of EIP, MDH initiated population-based, sentinel surveillance for CDI at clinical laboratories serving Stearns, Benton, Morrison, and Todd Counties; in 2012 Olmsted County was added.

CDIs that occur outside the traditional health care settings (community-associated) have also been receiving increased attention. Community-associated (CA) CDI data from 2009 -2011 across 10 EIP sites showed that 36% of CA CDI patients did not receive prior antibiotics and 82% had some outpatient health care exposure. Patients with CA CDI commonly have outpatient health care exposures and reduction of antibiotic use alone may not prevent over 1/3 of CDI in the community.

A CDI case is defined as a positive C. difficile toxin assay on an incident stool specimen from a resident (≥ 1 year of age) of one of the five counties. A CDI case is classified as health care facility-onset (HCFO) if the initial specimen was collected greater than 3 days after admission to a health care facility. Community-onset (CO) cases who had an overnight stay at a health care facility in the 12 weeks prior the initial specimen are classified as CO-HCFA, whereas CO cases without documented overnight stay in a health care facility in the 12 weeks prior the initial specimen result are classified as CA. A more detailed set of case definitions is available upon request.

In 2014, 718 incident cases of CDI were reported in the five sentinel counties (183 per 100,000 population). Fifty-five percent of these cases were classified as CA, 25% as CO-HCFA, and 20% as HCFO. The median ages for CA, CO-HCFA, and HCFO cases were 54 years, 59 years, and 71 years, respectively. Fifty-eight percent of CA cases were prescribed antibiotics in the 12 weeks prior to stool specimen collection compared to 84% of HCFO cases and 86% of CO-HCFA cases. Of the 396 putative CA cases eligible for interview, 280 were interviewed and confirmed as CA cases. Forty-nine percent of CA cases reported antibiotic use in the 12 weeks prior to illness onset date. Most common uses of antibiotics included treatment of ear, sinus, or upper respiratory infections (31%); skin infections (14%); dental procedures (13%); and urinary tract infections (12%).

• For up to date information see>> Clostridium Difficile
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2014