Clostridium difficile, 2016

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 healthcare facilities, where environmental contamination by C. difficile spores and exposure to antimicrobial drugs are common. The primary risk factor for development of CDI in healthcare settings is recent use of antimicrobials, particularly clindamycin, cephalosporins, and fluoroquinolones. Other risk factors for CDI acquisition in these settings are age >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 outbreaks in Quebec first reported in March 2003. During this period, Quebec hospitals reported a 5-fold increase in healthcare-acquired CDI. These and other healthcare facility (e.g., long-term care facilities) outbreaks have been associated with the emergence of a 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 of CDI 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 healthcare settings (i.e., community-associated) have also been receiving increased attention. Community-associated (CA) CDI data from 2009- 2011 across 10 EIP sites showed that 64% of CA CDI patients received prior antibiotics, and 82% had some outpatient healthcare exposure.

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 healthcare facility-onset (HCFO) if the initial specimen was collected >3 days after admission to a healthcare facility. Community-onset (CO) cases who had an overnight stay at a healthcare facility in the 12 weeks prior to the initial specimen are classified as CO-HCFA, whereas CO cases without documented overnight stay in a healthcare facility in the 12 weeks prior to the initial specimen result are classified as CA. A more detailed set of case definitions is available upon request.

In 2016, 903 incident cases of CDI were reported in the five sentinel counties (227 per 100,000 population), an increase from 202 per 100,000 population in 2015. Fifty-eight percent of these cases were classified as CA, 25% as CO-HCFA, and 17% as HCFO. The median ages for CA, CO-HCFA, and HCFO cases were 52 years, 63 years, and 75 years, respectively. Fifty-two percent of CA cases were prescribed antibiotics in the 12 weeks prior to stool specimen collection compared to 75% of HCFO cases and 78% of CO-HCFA cases. Of the 524 putative CA cases eligible for interview, 342 were interviewed and confirmed as CA cases. Fifty-four 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 (27%); dental procedures (13%); urinary tract infections (14%); and skin infections (9%).

• For up to date information see>> Clostridium Difficile
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2016