Conference Coverage

C. difficile travels on the soles of our shoes



NEW ORLEANS – For an explanation to the spread of Clostridium difficile, one needs to look to our soles.

Based on ribosomal analysis, C. difficile often is transmitted from the hospital into the community and back into the hospital on the soles of shoes, researchers have concluded, based on findings from thousands of samples from patients, hospital environments, and shoes.

This photograph depicts Clostridium difficile colonies after 48 hours of growth on a blood agar plate; Magnified 4.8X. CDC/D. Holdeman
Not all C. difficile isolates come from a health care setting; the community also acts as a reservoir. “I believe our total environment is contaminated with Clostridium difficile,” M. Jahangir Alam, PhD, said at the annual meeting of the American Society for Microbiology.

Dr. Alam of the University of Houston College of Pharmacy and his colleagues collected thousands of samples from the state of Texas to see how C. difficile strains in the community are related to clinical strains in the hospital.

The researchers collected 3,109 stool samples from people hospitalized with C. difficile, another 1,697 swabs taken from environmental surfaces in hospitals across the state, plus another 400 samples taken from the soles of shoes of clinicians and non–health care workers.

C. difficile was found in 44% of clinical stool samples, 13% of high-touch hospital environment surfaces, and 26% of community shoe sole samples. Among these positive C. difficile samples, toxigenic strains were detected in 93% of patient samples, 66% of hospital environment swabs and 64% of shoe samples. Importantly, the most predominant toxigenic strains appeared in all three sample types.

“When we collected some hospital environmental samples, we saw the isolate ribotypes perfectly matched the patient samples,” Dr. Alam said.

Further, “we saw the exact same ribotypes on our shoe bottoms, from these community, nonclinical sources,” Dr. Alam said. “Apparently, it seems, these dangerous pathogens are everywhere.”

In fact, “we may have brought many different strains from all over the world here to this meeting,” he added. “When we are taking antibiotics, we are susceptible to these different strains.”

Hospitals are cleaned daily, “but how many of us care about the shoes” on those who walk through the hospital, he asked. “We are loading the hospital with Clostridium difficile, and the hospital environment is also loaded with Clostridium difficile so we are bringing it into the community. We are spreading it everywhere.”

“Maybe we are blaming the doctors, nurses, and other staff, but [we are] not thinking about our shoes,” Dr. Alam added.

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