Household Transmission of C difficile May Lead to Community-Associated Cases

Although Clostridium difficile infection (CDI) is traditionally considered a healthcare-associated infection, household transmission of CDI may be a source of community-associated cases, according to a study published in the Infection Control & Hospital Epidemiology.¹

Vivian Loo, MD, MSc, of McGill University Health Centre at McGill University in Montréal, Québec, Canada and colleagues conducted a prospective study from April 2011 to June 2013 including 3 tertiary care hospitals in Montréal, Québec, Canada.

Stool or rectal swab samples were obtained from 51 patients with CDI at the first home visit; samples were collected monthly for the next 4 months. Pulsed-field gel electrophoresis (PFGE) was performed to see if there was a transmission of CDI to other members of the household (67 humans and 15 pets). Transmission of CDI was defined as a household contact transitioning from a negative C difficile culture to a positive C difficile culture with a PFGE pattern “indistinguishable or closely related” to infected patients with CDI.

“Nine (13.4%) human household contacts of 67 were found to be culture positive for toxigenic C difficile at any follow-up visit,” the researchers reported. Of the 9 household contacts, 1 developed CDI; the remaining 8 were asymptomatic, including 5 infants in diapers.

“There were 15 domestic pets: 9 cats, 5 dogs, and 1 bird. Two cats and 2 dogs were found to be culture positive for C difficile during the follow-up visits,” the researchers noted. “All 4 pets found to be positive for toxigenic C difficile had indistinguishable or closely related PFGE profiles” to the patients with CDI, “suggestive of interspecies transmission between human and animals.”

“PFGE is not as discriminatory as whole genome sequencing to detect single nucleotide polymorphism, and may have overcalled isolated as being indistinguishable or closely related,” concluded Dr Loo and colleagues. While this study had a low participation rate, it was unique in that it “established an epidemiological link between” patients with CDI and “household contacts, both human and animal, with respect to C difficile transmission and carriage” and “confirmed inter-species transmission of C difficile between humans and pets, supported by molecular typing results.”

“Our research suggests that household transmission from patients with C difficile infection could be responsible for a bacterial reservoir for community-associated cases,” said Dr. Loo in a press release to the Society for Healthcare Epidemiology of America. “These infections, causing diarrhea and inflammation of the colon, can be serious, so it is important that everyone follows simple hygienic practices, like hand washing with soap and water, even in your own home.”²

References

1. Loo VG, Brassard P, Miller M. Household transmission of clostridium difficile to family members and domestic pets. Infect Control Hosp Epidemiol. 2016; 1:1-7. doi: 10.1017/ice.2016.178.
2. Pets and Children are a Potential Source of C. difficile in the Community [press release]. Arlington, VA: Society for Healthcare Epidemiology of America; August 29, 2016.