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

2016 Annual Report Print Version Cdc-pdf[PDF – 2.41 MB]

In 2016, a total of 16,796 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 Sitesa

Reported Number of CDI Cases and Crude Incidence by Sex, Age Group, Race, and Epidemiologic Classification Among the 10 EIP Sites
Demographic Characteristic Population ≥1 Year of Age Community Associated CDIb
No.
Community Associated CDIb
Incidencec
Healthcare Associated CDIb
No.
Healthcare Associated CDIb
Incidencec
All
CDI
No.
All
CDI
Incidencec
Sex
Male 5762583 3016 52.34 4090 70.97 7106 123.31
Female 6014899 4899 81.45 4791 79.65 9690 161.10
Age group
1-17 years 2541378 631 24.83 254 9.99 885 34.82
18-44 years 4595566 1977 43.03 1078 23.45 3055 66.48
45-64 years 3085858 2563 83.06 2545 82.47 5108 165.53
≥65 years 1554680 2744 176.50 5004 321.87 7748 498.37
Race
White 7997290 6242 78.06 6522 81.55 12764 159.61
Non-white 3780192 1673 44.26 2359 62.40 4032 106.66
Total 11777482 7915 67.20 8881 75.41 16796 142.61
  1. The epidemiologic classification was statistically imputed for 1.0% of the observed CDI cases, and race was statistically imputed for 17.9% of the observed CDI cases. The weighted frequency of cases in Colorado and Georgia was based on 33% random sampling for cases aged ≥18 years.
  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. All CDI cases that do not meet the aforementioned criteria were classified as healthcare-associated.
  3. Cases per 100,000 persons.

Laboratory Characterization of C. difficile Isolates

In 2016, 969 C. difficile isolates were submitted to CDC for further analysis. The total number of isolates received from each site ranged from 26 to 278, with a median of 75.5. The majority of the isolates (97%) were collected in metropolitan areas.

Among all isolates submitted, 138 distinct ribotypes were detected. Ribotype 106 was the most common ribotype among community-associated C. difficile isolates, followed by 027, 002, and 014 (Table 2). Among healthcare-associated C. difficile isolates, ribotype 027 predominated, followed by 106, 014 and 020 (Table 3).

The prevalence of ribotype 027 among healthcare-associated C. difficile isolates was lower in 2016 (16%) than in 2015 (19%), although this difference was not statistically significant (p=0.25). Ribotype 027 remained relatively stable among community-associated C. difficile isolates between 2015 (8%) and 2016 (9%). In contrast, the prevalence of ribotype 106 among community-associated C. difficile isolates was higher in 2016 (13%) than in 2015 (9%), although this difference also was not statistically significant (p=0.08).

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, 019, and 078 predominated.

Table 2. Frequency of Ribotypes Among Community-Associated C. difficile Isolates, 2016 (n=460)

Frequency of Ribotypes Among Community-Associated C. difficile Isolates, 2016 (n=460)
Ribotype No of isolates % isolatesa
106 62 13%
027 42 9%
002 33 7%
014 27 6%
020 20 4%
056 18 4%
054 16 3%
019 16 3%
015 14 3%
087 12 3%
Others 200 43%
  1. Percentages may not add to 100% due to rounding.

Table 3. Frequency of Ribotypes Among Healthcare-Associated C. difficile Isolates, 2016 (n=509)

Frequency of Ribotypes Among Healthcare-Associated C. difficile Isolates, 2016 (n=509)
Ribotype No of isolates % isolatesa
027 79 16%
106 56 11%
014 35 7%
020 30 6%
002 30 6%
015 18 4%
056 14 3%
054 13 3%
078 12 2%
076 11 2%
017 11 2%
019 11 2%
Others 189 37%
  1. Percentages may not add to 100% due to rounding.