UH Researcher Finds Clorox Comes Close,
but Nothing Eliminates Superbug
The deadly and notoriously stubborn superbug, Clostridioides difficile (C. diff), is putting up a winning fight against hospital-grade disinfectants meant to kill it, according to a University of Houston researcher.
“We found no disinfectant was able to completely eliminate C. difficile embedded within biofilms although we did note differences among disinfectants,” reports Kevin Garey, UH professor of pharmacy practice and translational research and pharmacy department chair.
These alarming results come from a recent study published in the Antimicrobial Agents and Chemotherapy journal of the American Society for Microbiology. Garey was the project’s principal investigator. The paper was the doctoral dissertation of Tasnuva Rashid of the University of Texas School of Public Health.
The C. diff bacterium causes colon inflammation with symptoms ranging from diarrhea to life-threatening sepsis and is most common among the elderly in hospitals and health care facilities. The Centers for Disease Control and Prevention report that within a month of diagnosis, 1 in 11 people over age 65 died of a health care-associated C. diff infection. Garey reports that approximately 1% of all people over age 80, whether sick or not, will die of a C. diff infection.
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 ineffective against vegetative cell growth in biofilms.
“Clorox is the best we have but is still quite caustic to the environment,” said Garey, who envisions development of superior disinfectants.
Clorox is the best we have
but is still quite caustic
to the environment.
Bacteria can grow on almost any surface and forms a complex biofilm, like a “suit of armor,” Garey describes it, where it can survive and thrive — think of slime inside an old garden hose or plaque on your teeth, biofilms both. More devastating, biofilms form on medical devices like catheters or injection ports, giving bacteria direct access to a patient.
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. Rashid 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,” Garey said.