2018 Annual Report for the Emerging Infections Program for Clostridioides difficile Infection

2018 Annual Report Print Version [PDF – 3 pages]

In 2018, a total of 15,591 cases of C. difficile infection (CDI) were reported to the Emerging Infections Program (EIP) in 35 counties in 10 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 is 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.

1. The epidemiologic classification was statistically imputed for 1.5% of the observed CDI cases, and race was statistically imputed for 18.7% 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. Subcategories may not add to total due to rounding.
4. Cases per 100,000 persons.

In 2018, 87% of participating laboratories reported routinely using a nucleic acid amplification test (NAAT) either alone or as part of a multistep testing algorithm for CDI diagnosis. Among all CDI cases identified in 2018, 23% were toxin positive (diagnosed by toxin enzyme immunoassay or cell cytotoxicity assay), 22% were NAAT positive but toxin negative, 55% were positive by NAAT but no information was available regarding toxin-positivity (e.g., diagnosed by a laboratory that only utilized NAAT), and 0.1% were diagnosed by other methods (e.g., culture).

In 2018, a total of 1076 C. difficile isolates were submitted to CDC for further analysis. The total number of isolates received from each site ranged from 23 to 278, with a median of 76.5. The majority of the isolates (97%) were collected in metropolitan areas.

Among all isolates submitted, 137 distinct ribotypes were detected. Ribotype 106 was the most common ribotype among community-associated C. difficile isolates, followed by 002, 014, and 076 (Table 2). Among healthcare-associated C. difficile isolates, ribotype 027 predominated, followed by 106, 002 and 014 (Table 3). An overall decline in ribotype 027 has been observed since 2012 among both community-associated (17% vs. 4%; p<0.0001) and healthcare-associated (21% vs. 16%; p=0.06) isolates. In contrast, our data demonstrate a continued increase in ribotype 106 among community-associated isolates between 2012 and 2018 (9% vs 16%; p=0.0007).

Twenty-two percent of the isolates harbored a deletion in tcdC. Twenty percent of the isolates were binary toxin-positive, and among these, ribotypes 027, 078, and 019 predominated.

An initial chart review was performed on all CDI cases in eight EIP sites and on a random sample of cases in the two remaining EIP sites with the largest surveillance catchment areas (CO and GA).¹ A subsequent comprehensive chart review was performed on all community-associated cases and a subset of healthcare-associated cases. Of 7418 cases with data available, 7091 (95.6%) received CDI treatment. These included 4798 (67.7%) cases treated with vancomycin (excluding vancomycin tapers), 366 (5.2%) with vancomycin tapers, 3268 (46.1%) with metronidazole, and 188 (2.7%) with fidaxomicin. Bezlotoxumab was administered to 7 cases. Overall, the average duration of therapy was 14 days (range: 1–104 days).

Of the 7091 treated cases, 3334 (47.0%) either required hospitalization for their CDI or were already hospitalized at the time of their CDI diagnosis. The average length of hospital stay was 8 days (range: 0–365 days). Among 3126 hospitalized cases with treatment dates available: 2664 (85.2%) were treated with vancomycin (excluding vancomycin taper), and on average, received 49.5% (range: 0% to 100%) of their therapy as inpatient and 50.5% (range: 0% to 100%) as outpatient; 1443 (46.2%) were treated with metronidazole, and on average, received 76.2 % (range: 0% to 100%) of their therapy as inpatient and 23.8% (range: 0% to 100%) as outpatient; and 72 (2.3%) were treated with fidaxomicin, and on average, received 61.7% (range: 0% to 100%) of their therapy as inpatient, and 38.4% (range: 0% to 100%) as outpatient.

¹ Centers for Disease Control and Prevention. Healthcare-Associated Infections – Community Interface (HAIC). Clostridioides difficile infection (CDI) tracking. Available at: https://www.cdc.gov/hai/eip/cdiff-tracking.html Accessed November 17, 2020.

* The appendix Includes results of special analyses that are requested or of interest during a particular surveillance year.

Note: Data in this report were generated on March 17, 2020. Diagnostic testing information and laboratory data were updated on March 31, 2022.