Kevin Garey, professor of pharmacy practice at the University of Houston
Photo Courtesy of the University of Houston

A recent study has found Clostridioides difficile (C. diff) is doing a fine job of surviving the threat of hospital-grade disinfecants, according to a press release from the University of Houston. 

The study was published in the Antimicrobial Agents and Chemotherapy journal of the American Society for Microbiology.

“We found no disinfectant was able to completely eliminate C. difficile embedded within biofilms, although we did note differences among disinfectants,” says Kevin Garey, chair of the College of Pharmacy Department of Pharmacy Practice and Translational Research at the University of Houston.

Overall, Clorox, Cidex OPA, and Virex were most effective at killing C. diff spores. Clorox and OPA were also effective at killing total vegetative cell growth, the cellular stage responsible for causing infections. Virex was found to be ineffective against vegetative cell growth in biofilms. Clorox and Virex were most effective in reducing biomass followed by Nixall, Cidex OPA and Vital oxide.

No previous studies have investigated chemical disinfection of C. diff spores embedded in biofilms. For the project, five unique C. diff strains, embedded in three different biofilm types grown for 72 or 120 hours, were exposed to seven different hospital disinfectants. 

In the center of a biofilm, a spot exists without oxygen, an attractive locale for the anaerobic C. diff spore, which dies when it touches oxygen. The first author of the research paper, Tasnuva Rashid, of the University of Texas School of Public Health, was able to get a spore to germinate and replicate itself within a biofilm while exposed to an oxygen-rich environment.

“This study helps explain why C. diff is so hard to eradicate from the environment and demonstrates the ability of these spores to be so omnipresent and self-propagate in the environment,” said Garey.

The survival of C. diff in hospitals and nursing homes is especially hazardous. The Centers for Disease Control and Prevention report that within a month of diagnosis, one in 11 people over age 65 died of a health care-associated C. diff infection. Garey reports that approximately 1 percent of all people over age 80, whether sick or not, will die of a C. diff infection.