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Antiseptic prevents therapy dogs from spreading MRSA among pediatric cancer patients
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Researchers found that a low-cost cleaning procedure could prevent therapy dogs from spreading MRSA among pediatric cancer patients — presenting a possible solution to the danger that therapy animals pose to at-risk patients.
The decolonization procedure involved washing dogs with chlorohexidine-based shampoo before their first visit with patients and cleaning their fur with chlorohexidine wipes every 5 to 10 minutes during sessions.
Kathryn Dalton, VMD, MPH, a PhD candidate in the department of environmental health and engineering at Johns Hopkins Bloomberg School of Public Health, and colleagues evaluated the intervention in children receiving outpatient cancer treatment at Johns Hopkins Children’s Center and reported that it reduced the number of children and dogs with detectable MRSA following visits.
The pilot study was conducted during 13 group therapy visits by dogs — six sessions in which the dogs underwent decolonization and seven control sessions. It included 45 patients aged 2 to 20 years being treated for cancer and four therapy dogs. All children and dogs were tested for MRSA carriage before and after visits. Dalton and colleagues hypothesized that the dogs — as an “intermediary fomite” — may facilitate transmission from MRSA-positive patients to noncolonized patients.
They found that in control groups, patients who interacted closely with dogs were six times more likely to have detectable MRSA at the end of a visit than those who did not. However, when dogs were decolonized according to the procedure, the risk among patients was the same regardless of their interaction with the dogs.
“It essentially removed the dog from the equation,” Dalton said at a news conference.
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According to the CDC, around 33% of people carry Staphylococcus bacteria in their nose — usually without becoming sick — and 2% carry MRSA. Companion animals are known to carry MRSA, and there has been at least some apprehension about the potential infection risk that therapy dogs pose for patients, especially those with weakened immune systems, such as patients being treated for cancer.
Concerned about the possibility that therapy dogs could facilitate transmission of resistant organisms among patients, Allen Chen, MD, PhD, MHS, a pediatric oncologist and vice chair for quality, safety and service at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, initiated the collaboration that led to the study.
“We are excited to have pilot data that show it will be feasible to detect these bacteria using an assay more sensitive than the clinical test, and that the intervention shows some promise,” Chen told Infectious Disease News. “This small pilot study was the basis for a definitive randomized clinical trial that may allow us to expand participation in the animal-assisted therapy program to our more immunocompromised patients.”
Study author Meghan Davis, PhD, DVM, MPH, assistant professor in the department of environmental health and engineering at Johns Hopkins Bloomberg School of Public Health, told Infectious Disease News that hospitals should not make changes to their programs based on such a small pilot study.
“For example, we found that many patients went from having detectable MRSA before they visited with the dog to leaving the session without detectable MRSA, and we are still looking into this,” Davis noted. She said animal-assisted intervention programs should continue to follow Society for Healthcare Epidemiology of America guidelines.
Rather than pointing out a problem that was assumed to exist, Chris Nyquist, MD, MPH/MSPH, a professor of pediatrics at the University of Colorado School of Medicine, said the study provides a starting point for a conversation about how to balance the safety of patients and the benefits that therapy dogs provide. In addition to their primary findings, Dalton and colleagues reported that interacting with the dogs lowered patients’ blood pressure and heart rate and improved their mental health.
“This study really speaks to me in an important way,” said Nyquist, who is the medical director for infection prevention and control at Children’s Hospital Colorado, which has a long-standing pet therapy program. “We have limited [therapy dogs] [for] our oncology patients because of concerns about transmission of infection, which is really sad because they’re the patients who are in the hospital the longest. We also don’t allow dogs into the operating room. This study really brings a method for us to expand the ability for pet therapy dogs potentially to areas where they haven’t been able to go.”
Overall, regardless of the level of interaction with the dogs, Dalton said the intervention led to a 90% decreased risk to acquire detectable MRSA in patients. She said the research team has secured additional funding to conduct a larger study in multiple hospitals to explore whether the intervention could be used in other settings. If it becomes standard practice, there is some question as to who would clean the dogs. During the study, Dalton said handlers took care of the previsit shampooing and she performed the wiping.
“This is something that could feasibly be done either by the dog handler or hospital staff,” she said.
According to Nyquist, humans remain the larger problem when it comes to the spread of MRSA. Recent studies have shown that most hospital privacy curtains are contaminated with MRSA and that the pathogen can be commonly found on hospital floors. The CDC recommends standard precautions to control the spread of MRSA in hospitals in most instances, including routine hand-washing.
“This is a way to wash the dogs,” Nyquist said. – by Gerard Gallagher
- Reference:
- Dalton K, et al. Abstract 160.
Disclosures: Dalton, Davis and Nyquist report no relevant financial disclosures.