All In The Family: How MRSA Bacteria Spread At Home | St. Louis Public Radio

All In The Family: How MRSA Bacteria Spread At Home

Dec 8, 2019

People treated for drug-resistant MRSA often develop infections again and again — even multiple times in a single year.

Part of the problem is the hardiness of the bacteria responsible, which can live on household surfaces for months.

Washington University researchers report family members who share specific items, including towels and bedsheets, are more likely to pass the bacteria to each other. The team, which spent a year collecting bacteria samples from St. Louis families, also found that children who attend day care were often the ones who brought MRSA bacteria home. 

Meticillin-resistant Staphylococcus aureus, or MRSA, causes painful skin and tissue infections that can resemble pus-filled boils. 

“These infections are really burdensome for people,” said Stephanie Fritz, associate professor of pediatrics at Washington University. “They’re super painful, especially for little kids.” 

Fritz, an expert in pediatric infectious diseases, said she’s treated many children with recurrent MRSA infections in recent years at St. Louis Children’s Hospital. 

She’s among a growing group of researchers studying how staph bacteria live inside the home, continually reinfecting patients and their families.

To track the ways staph bacteria enter the home and spread among family members, Fritz and her team visited more than 100 families in the St. Louis region five times over a year. The families had one thing in common: Each had at least one child who had been treated for a MRSA infection. 

John Morelli, now a fourth-year medical student at Creighton University School of Medicine, swabs a bathroom sink for staph bacteria.
Credit Stephanie Fritz | Washington University

Armed with cotton swabs, the researchers collected staph samples from about 20 household surfaces, including the TV remote, door handles and light switches.

But they didn’t stop there. The team also swabbed the armpits, nostrils and groins of each family member — and the nostrils and fur of household pets. 

Patrick Hogan, a clinical research specialist at Washington University, quickly learned the subtle art of “wrangling the pets.” 

“There were nine pets in one house that we had to swab,” Hogan said. “Finding the cats in the basement was especially tricky.” 

They found various strains of staph bacteria, including MRSA, on many household surfaces. Family members who shared towels, razors and other personal hygiene items were much more likely to pass the bacteria back and forth.

“It's the surfaces that are touched by many people but not washed very often,” Fritz said, adding that the TV remote was often a highly contaminated surface. 

Over the one-year study, the team found MRSA on nearly half of the people sampled and one-third of the pets. Household pets, contrary to the researchers’ expectations, were more likely to pick up the staph bacteria from humans than transmit it. 

In most cases, children who attend day care were most likely to bring home new strains of staph bacteria. 

Stephanie Fritz, left, and Patrick Hogan examine a bacterial sample. The pair were part of a research team investigating transmission of staph bacteria among family members in the home.
Credit Washington University

Perhaps most important, Hogan said, the study was able to draw a direct link between families contracting new strains and developing future skin infections.

“If this germ is on your skin or your table and nobody gets sick from it, then so what?” Hogan said. “But we were able to show that people who got a new strain that they didn't previously have were more likely to get an infection later.”

Justin Knox, a postdoctoral researcher at Columbia University who has studied household transmission of MRSA in Manhattan, said it can be difficult to pinpoint exactly which strains are causing infections.

“Oftentimes for infections, we rely on self-reports,” Knox said. “We don’t have a single-payer health care system, so they’re not necessarily going to go visit the same hospital or same provider. Once we get out of the hospital setting, it’s a much more complex and dynamic situation that you’re trying to describe.” 

For families that have struggled with recurrent staph infections, study co-author Stephanie Fritz said simple preventative measures appear to be the best defense, such as frequent handwashing and using separate towels.

“They don’t have to turn their world upside down in order to stop this problem,” Fritz said. “These are subtle things that people can do.”

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