An alarming number of residents in nursing homes for veterans are susceptible to acquiring a superbug after admission, with over one-third already carrying these drug-resistant pathogens into the facilities and spreading them through routine activities, according to a new study. The findings have important implications for nursing homes in general.

The study conducted by the Department of Veteran Affairs (VA) on superbugs – also known as multidrug-resistant organisms (MDROs) – suggests that efforts to improve infection prevention and control of MDROs in nursing homes need to focus on shared spaces and resident movement, not just individual rooms.

Among those residents who did not have a MDRO infection when they arrived, about 41%, acquired a new MDRO while in the nursing home, the study found. And, it took just under 15 days for a resident to acquire one of these organisms on average.

Moreover, about 36.5% of nursing home residents were already colonized with an MDRO at the time of admission, the study suggests.

Published in the journal Nature, the study was conducted at three VA nursing homes in Michigan and Ohio. It tracked 197 newly admitted residents from April 2021 to September 2023. Researchers collected thousands of samples over 6,400 days during the course of the study.

Of the 182 residents, who had a follow-up visit, about 65.4% had been colonized with at least one MDRO.

Researchers aimed to understand how often residents carried and spread MDROs, including drug-resistant Staphylococcus aureus (commonly called MRSA), Enterococcus bacteria (also known as VREs), and other drug-resistant bacterial strains. Infections caused by VREs, which are usually linked to infections in the bloodstream, urinary tract and wounds, were the most commonly acquired.

Almost 40% of resident rooms had at least one surface contaminated with one of these organisms, most often the bedrail, bed control, or privacy curtain.

“These in-depth studies are hard to conduct but very important to ultimately develop interventions and strategies for improvement,” Dr. Lona Mody, lead author of the study, noted in the VA department’s article on the study. “We now establish a novel framework to understand transmission, outline resources that are required and the expertise it takes.”

The study also focused on 345 “interactive visits,” during which residents left their rooms for activities like therapy, meals, or appointments. MDRO transmission was observed in 16% of these visits, with most occurrences happening during therapy sessions. 

Resident hands were identified as a major source of transmission, particularly when they were contaminated with VRE, which spread to surfaces 44% of the time.

Additionally, residents with longer hospital stays or recent antibiotic use were more likely to be colonized at admission or acquire an MDRO during their stay.

As for infection at the time of leaving the nursing home, despite the colonization, about 37% of residents who had an MDRO at admission were no longer colonized at discharge, while 20% of residents without an MDRO at admission left with one.