2015 Annual Report for the Emerging Infections Program for Clostridium difficile Infection

2015 Annual Report Print Version [PDF – 101 KB]

In 2015, a total of 17,354 cases of C. difficile infection (CDI) were reported to the Emerging Infections Program (EIP) in 35 counties in 10 US states (California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, New York, Oregon, and Tennessee).

The overall distribution of EIP CDI cases and crude incidence by selected demographic factors and epidemiologic classification are presented in Table 1. Data in this report are not intended to be directly compared to annual reports from other years, and should not be used to determine annual changes in EIP CDI incidence rates because single year calculations do not account for changes in testing practices by reporting facilities.

Table 1. Reported Number of CDI Cases and Crude Incidence by Sex, Age Group, Race, and Epidemiologic Classification Among the 10 EIP Sites^a

1. The epidemiologic classification was statistically imputed for 0.9% of the observed CDI cases, and race was statistically imputed for 16.8% of the observed CDI cases. The weighted frequency of cases in Colorado and Georgia was based on 33% random sampling..
2. A CDI case was classified as community-associated if the C. difficile-positive stool specimen was collected on an outpatient basis or within 3 days after hospital admission in a person with no documented overnight stay in a healthcare facility in the preceding 12 weeks.

Laboratory Characterization of C. difficile Isolates

In 2015, a total of 1,152 C. difficile isolates were submitted to CDC for further analysis. The total number of isolates received from each site ranged from 61 to 279, with a median of 99. The majority of the isolates (88%) were collected in metropolitan areas.

Among all isolates submitted, 133 distinct ribotypes were detected. Ribotype 106 was the most common ribotype among community-associated C. difficile isolates, followed by 027, 014 and 020 (Table 2). Among healthcare-associated C. difficile isolates, ribotype 027 predominated, followed by 106, 002 and 014 (Table 3). An increase in ribotype 027 occurred from 14% in 2014 to 19% in 2015 among healthcare-associated C. difficile isolates, although it was not statistically significant (p=0.08). Ribotype 027 remained relatively stable among community-associated C. difficile isolates between 2014 (7%) and 2015 (8%).

Twenty-six percent of the isolates harbored a deletion in tcdC. Twenty-six percent of the isolates were binary toxin-positive, and among these, ribotypes 027, 153_251, and 078 predominated.

Table 2. Frequency of Ribotypes Among Community-Associated C. difficile Isolates, 2014 (n=619)

Table 3. Frequency of Ribotypes Among Healthcare-Associated C. difficile Isolates, 2014 (n=504)