C. Diff Carriers Are Source of Infections in Hospitals

Clostridioides difficile is a spore-forming, gram-positive anaerobic bacillus spread by fecal–oral transmission of spores, which remain viable for long periods of time ex vivo. Although C. difficile carriers do not have diarrhea, they do shed spores that can contaminate environmental surfaces.

Annually, there are more than 400,000 cases and almost 30,000 deaths from C.difficile–associated diarrhea occur in the USA. Efforts to reduce the spread of C. difficile have focused on reducing transmission from patients with symptomatic C. difficile–associated diarrhea. Asymptomatic carriers may serve as a reservoir and spread C. difficile to those around them.


Medical scientists associated with the Montefiore Medical Center (The Bronx, NY, USA) performed a prospective cohort study on a sample of patients being admitted to a large university hospital between July 2017 and March 2018. The team tested 220 patients who showed no symptoms of C. difficile infection when they were admitted. Perirectal swabs (Copan Diagnostics, Murrieta, CA, USA) were completed within 24 hours of admission, and the patients were followed for six months.

Two testing methodologies were used for all specimens: C. difficile Quik Chek Complete (Abbott, Chicago, IL, USA) to test for glutamate dehydrogenase (GDH) and toxins A and B and XPert C. difficile/Epi (Cepheid, Sunnyvale, CA, USA) real-time polymerase chain reaction (PCR) assay that detects the toxin B gene. All specimens were also tested by toxigenic culture using spore-enriched specimens in cultures with selective chopped meat broth incubated for 48–72 hours followed by repeat GDH and toxin A/B testing.

The scientists reported that of the 220 subjects, 21 (9.6%) were C. difficile carriers, including 10.2% of the nursing facility residents and 7.7% of the community residents. Among the 21 C. difficile carriers, eight (38.1%) progressed to symptomatic C. difficile, but only four (2.0%) of the 199 non-carriers progressed to symptomatic C. difficile.

The authors concluded that asymptomatic carriers may represent a significant reservoir for transmission of C. difficile, and progression from asymptomatic carriage to symptomatic C. difficile infection (CDI) may account for a significant proportion of CDI that is classified as “healthcare-facility onset.” Therefore, identification of asymptomatic carriers could reduce the spread of C. difficile. Specific environmental, isolation, and stewardship strategies to prevent spread of C. difficile from carriers to uninfected patients as well as prevent progression to symptomatic CDI warrant further study.

Sarah Baron, MD, MS, an Assistant Professor of Medicine and lead author of the study, said, “It has generally been assumed that patients get the bacteria during their stay in the hospital. However, when we tested patients being admitted to the hospital, we found that many of them were carrying the bacteria that cause this diarrhea in their bodies already and often went on to develop the infection.” The study was published on December 11, 2019 in the journal Infection Control & Hospital Epidemiology.

Related Links:
Montefiore Medical Center
Copan Diagnostics
Abbott
Cepheid