• Posted June 26, 2024

Drug-Resistant Fungi Found in Commercial Flower Bulbs, Compost, Soil

A tough-to-treat, drug-resistant fungal infection may be as close as your local garden center, new research shows.

Investigators at the University of Georgia (UGA) in Athens found high levels of multidrug-resistant fungi in compost, soil and flower bulbs sold at popular retailers.

“Gardening is a nice, stress-relieving hobby. But I’m nervous for people who may not be aware that working with compost and flower bulbs could pose a risk to their health," said study lead author Marin Brewer. She's a professor in UGA’s College of Agricultural and Environmental Sciences.

The fungus in question is Aspergillus fumigatus, which lives in soil naturally but can trigger illness if inhaled. People with healthy immune systems can probably fight off the fungus, but folks with compromised immune systems could get very sick and even die if they encounter a variant that's become resistant to multiple anti-fungal drugs.

People who may immunocompromised are those battling chronic obstructive pulmonary disease (COPD), cystic fibrosis, type 2 diabetes, HIV/AIDS and COVID-19. Anyone taking immunosuppressants -- for example, cancer patients or people who have undergone an organ transplant -- are also at risk.

A. fumigatus is already on health experts' radar: It's estimated that over 2 million people are infected globally, and the World Health Organization recently named the fungus as a critical threat to health.

Even in healthy people, A. fumigatus can trigger aspergillomas -- "clumps" within the lung. People often these clear on their own, but others may need anti-fungal meds.

In the new study, Brewer's team sampled store-bought compost, soil, flower bulbs and a variety of food products sold at big box retail stores from 2019 through 2021.

More than 500 different strains of A. fumigatus were found in the products, with over 90% of them found in flower bulbs, soil, compost and peanuts.

Strains that were drug-resistant were found in soil and compost made from manure and on flower bulbs, including daffodils, dahlias, gladioli and tulips, the team said.

“We found dozens of strains of resistant fungi in just 1 gram of compost,” Brewer said in a UGA news release. “Based on our findings, there could be tens of thousands of potentially resistant strains in one bag of compost.”

Because fungal spores can be inhaled, Brewer's team recommend that anyone with a compromised immune system wear N-95 masks when gardening.

Brewer added that, based on the findings, she'll be skipping any plans to plant flower bulbs and will avoid commercial compost.

Much of the drug resistance is coming from overuse of antifungals by the agriculture industry. According to the UGA team, industry representatives say companies are working to reduce the threat.

The findings were published recently in the journal Applied and Environmental Microbiology.

More information

Find out more about fungal infections at the Cleveland Clinic.

SOURCE: University of Georgia, Athens, news release, June 26, 2024