Skilled nursing facilities provide a welcome home for a complex, interactive network of infectious “superbugs,” with antibiotics only fueling the fire, according to a new study from the University of Michigan.

Of 234 nursing home residents who participated in the study, 40% had more than one multi-drug-resisant organisms (MDROs) on their bodies, the result of “an ecosystem of resistance” that can spring up in SNFs.

“In short, every nursing home and likely every hospital in America is home to a natural experiment in the evolution of bacteria strains to become resistant to drugs and to survive on a host patent or travel between hosts,” a release announcing the findings noted.

The majority of the residents had been given some type of antibiotics during the study period, and all were using urinary catheters. Residents with certain combinations of MDROs were substantially more likely to develop urinary tract infections, the researchers found. But treatment with antibiotics actually increased the residents’ risk of getting an MDRO, which subsequently puts the patient at greater risk for getting a different type of drug-resistant organism in the future — a cascading chain of infection.

“We observed a complex network of interactions, with acquisition of each of six different MDRO species being influenced by different sets of antibiotics, and primary MDRO colonization in turn increasing the risk of acquisition and infection by other MDROs,” lead study author Joyce Wang said in the release.

Based on their research, the team developed a detailed map of the ways in which antibiotics and bacteria interact with each other in a clinical setting — with a longer-term goal of giving providers the ability to provide more targeted treatments and prevent the inadvertent spread of MDROs through well-intentioned antibiotic use.

Still, researchers warned that such a tactical use of antibiotics remains a ways off, and recommended nursing home staff continue to be judicious in their use of the drugs.

“We need to understand what clinical practices drive the spread of MDROs in health care facilities, and counterintuitively, it appears that a key factor is the use of certain antibiotics used against an individual organism that may impact other circulating organisms,” researcher Evan Snitkin said.

The full findings were published in the Proceedings of the National Academy of Sciences.

Written by Alex Spanko