Public Release: 

Cleaning procedure prevents therapy dogs from spreading MRSA to children with cancer

Simple cleaning procedure prevents therapy dogs from spreading bad bug MRSA to children and adolescents with cancer, study shows

Infectious Diseases Society of America

SAN FRANCISCO - Therapy dogs help ease stress in young patients with cancer, but can spread methicillin-resistant Staphylococcus aureus (MRSA), putting vulnerable kids at risk for a serious infection. Cleaning the dogs with special antibacterial shampoo and wipes reduces MRSA carriage and helps keep the kids safe, suggests a first-of-its-kind study presented at IDWeek 2018.

The therapy program in the study features specially trained dogs who visit with young patients receiving outpatient cancer treatment at Johns Hopkins Bloomberg Children's Hospital. The dogs participate in numerous one-on-one and group visits throughout the day, often moving between departments or other hospitals within the same day. The study was the first to analyze a new protocol to reduce the spread of MRSA by ridding the dogs of the bug - called decolonization - which included shampooing them with antibiotic chlorohexidine before the first visit of the day and using chlorohexidine wipes every five to 10 minutes during visits.

"It's amazing to watch just how excited the children get when they see the dogs for the first time, and they enjoy petting, hugging, kissing and playing fetch with them. The visits are really helpful in easing their anxiety and stress," said Kathryn Dalton, VMD, MPH, a PhD candidate in the Department of Environmental Health and Engineering at Johns Hopkins University Bloomberg School of Public Health, Baltimore. "But because they go from session to session the dogs can pick up and spread MRSA. We found this simple, low-cost intervention helps increase patient safety while still ensuring that young patients with cancer can benefit from these therapy dogs."

While MRSA carriage usually doesn't lead to infection in healthy people, the risk of infection is greater for people whose immune system is weakened, such as those who are being treated for cancer.

All 45 patients with cancer (ages 2 to 20) and 4 dogs in the study were tested for MRSA carriage before and after group therapy visits. The dogs were not decolonized for seven control sessions and the researchers found that 4 patients (15.4 percent) became MRSA carriers after a visit as did 3 (42.9 percent) of the dogs. In the 6 intervention sessions (for which the dogs were decolonized) 1 patient (4.5 percent) became a MRSA carrier after the visit as did 2 dogs (33.3 percent).

The study also found that patients who interacted closely with the dogs - such as by petting, hugging, brushing the fur and spending more time - were six times more likely to become MRSA carriers than those who didn't interact closely. But once the dogs were decolonized, the risk for becoming MRSA carriers was no different in the close interaction group.

"This intervention not only decreases MRSA transmission from the therapy dog to the patient, but also indirectly between patients or from the hospital environment to patients, with the dog as an intermediary," said Dr. Dalton. "Decolonization is inexpensive and fast - it can be done by hospital staff or even the dog handler - and improves patients' and dogs' safety."

Children with active MRSA infection are not allowed to participate in the dog therapy program. Further studies by the research team will look at whether any of the children who were colonized ultimately developed a MRSA infection, as well as to expand this intervention to other hospitals and departments to determine if the decolonization procedure works in other settings.


In addition to Dr. Dalton, co-authors of the study are Meghan Davis, PhD, DVM, MPH, Allen Chen, MD, PhD, MHS, Kathy Ruble, RN, NP, PhD, Alexandra DeLone, MA, MS, Pam Frankenfield, RN, Destiny Walker, BS, Shanna Ludwig, PhD, Tracy L. Ross, MT, Janice Jaskulski, MS, Karen C. Carroll, MD, Shelley Rankin, PhD, and Daniel Morris, DVM, MPH.

About IDWeek

IDWeek 2018TM is the annual meeting of the Infectious Diseases Society of America (IDSA), the Society for Healthcare Epidemiology of America (SHEA), the HIV Medicine Association (HIVMA) and the Pediatric Infectious Diseases Society (PIDS). With the theme "Advancing Science, Improving Care," IDWeek features the latest science and bench-to-bedside approaches in prevention, diagnosis, treatment, and epidemiology of infectious diseases, including HIV, across the lifespan. IDWeek 2018 takes place Oct. 3-7 at the Moscone Center in San Francisco. For more information, visit

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