Exploring Microbiome Changes Associated with C. diff to Prevent or Reverse Colonization

The burden of Clostridium difficile (C. diff) continues to grow in health care facilities throughout the United States and around the world. Gaining a better understanding of sources and risk factors for C. diff can help reverse colonization and transmission or prevent it altogether, authors of a new paper suggest.

“This is a review/commentary article that provides a high-level overview of the literature dealing with C. diff colonization and the microbiome changes associated with C. diff colonization,” author Silvia Munoz-Price, MD, PhD, from the Medical College of Wisconsin in Milwaukee told our sister publication MD Magazine.

After reviewing the literature, authors of the study postulated that when it comes to the potential for C. diff colonization, exposure to and transmissions of the virus occurs outside of hospitals. In fact, it seemed like most of the patients became symptomatic during their hospital stay, rather than acquiring the virus while hospitalized.

For example, the investigators cited one study from Canada that had been conducted from 2006 to 2007 where more than 4000 patients were screened for C. diff colonization upon hospitalization, during their stay (on a weekly basis) and at discharge. They found that 4% of the patients were colonized upon hospitalization and 3% acquired C. diff during their stay in the hospital.

The authors also found evidence indicating that community-acquired C. diff appears to be on the rise. The authors discuss a decade-long study which took place in Minnesota where community-acquired C. diff infection rates rose from 2.8 to 14.9 per 100,000-person-years within the 10-year span. The patients in that study more likely to acquire C. diff were younger, female, and healthier than patients with hospitalization acquired C. diff. The reviewers also said that rates of community-acquired C. diff have also been rising in Finland, Australia, and England, according to published studies.

Most of the common risk factors for community-acquired C. diff infections still applied, the researchers found, including antibiotic exposure, household contact, and animals. A 2013 study showed that two-thirds of community-acquired C. difficile patients were exposed to antibiotics in the preceding 12 weeks of their infection, and about one-third had been exposed to proton pump inhibitors.

While studies examining transmissibility within households are difficult to come by, the study authors found one review from Quebec. The review consisted of 2222 cases of C. diff diagnosed between 1998 and 2009, and investigators found that 8 cases were designated to be transmitted by household contacts. However, the researchers noted, confirmation using strain typing was not performed in that study.

Looking at farm livestock, a 2013 Dutch study showed that individuals with daily contact with pigs showed rates of C. diff positivity of 25%; in those with weekly contact, it was 14%. In the same study, C. diff was found in the manure from all the farms in 10% to 80% of the samples per farm. The reviewers also said that C. diff has been found in the stool of farm chickens, calves, and retail ground meat. Dogs and cats are also known to culture positive for C. diff, and the researchers wrote that the bacteria can also be present in vegetables and water (tap water, swimming pools, as well as rivers, lakes, and seas). They hypothesized that the presence of C. diff in vegetables may come from the use of organic fertilizer.

“We envision that in the future we should be able to take advantage of our increasing knowledge about microbiome changes so that we will be able to: identify patients at risk for de novo C. difficile colonization during their hospitalization and manipulate our patients' microbiome to prevent or reverse C. difficile colonization,” Dr. Munoz-Price said.

“Different from what we do now, the latter would be accomplished not by withholding or changing antibiotics but by correcting the deficient flora of a patient in an individualized fashion. This new approach would revolutionize the field of Infection Control and Antibiotic Stewardship,” she concluded.

A previous version of this article has been published on MDMagazine.com.