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

2015 Annual Report Print Version [PDF – 5.53 MB]

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 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
Number
Community Associated CDIb
Incidence per 100,000 persons
Healthcare Associated CDIb
Number
Healthcare Associated CDIb
Incidence per 100,000 persons
All CDI
Number
All CDI
Incidence per 100,000 persons
Male 5717797 2787 48.74 4305 75.29 7092 124.03
Female 5964630 4901 82.17 5361 89.88 10262 172.05
1-17 years 2537415 595 23.45 189 7.45 784 30.90
18-44 years 4580200 1964 42.88 1136 24.80 3100 67.68
45-64 years 3064141 2412 78.72 2667 87.04 5079 165.76
≥65 years 1500671 2717 181.05 5674 378.10 8391 559.15
White 7979542 6116 76.65 7054 88.40 13170 165.05
Non-white 3702885 1572 42.45 2612 70.54 4184 112.99
Total 11682427 7688 65.81 9666 82.74 17354 148.55

 

  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, 2015 (n=614)

Frequency of Ribotypes Among Community-Associated C. difficile Isolates, 2015 (n=614)
Ribotype No of isolates % isolates
106 58 9%
027 52 8%
014 46 7%
020 40 7%
002 35 6%
015 21 3%
054 20 3%
005 19 3%
056 18 3%
046 17 3%
Others 288 47%

Table 3. Frequency of Ribotypes Among Healthcare-Associated C. difficile Isolates, 2015 (n=538)

Frequency of Ribotypes Among Healthcare-Associated C. difficile Isolates, 2015 (n=538)
Ribotype No of isolates % isolates
027 102 19%
106 48 9%
002 40 7%
014 36 7%
020 30 6%
015 18 3%
001_072 17 3%
056 17 3%
017 15 3%
005 14 3%
Others 201 37%
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