New research conducted by the University of Georgia has shed light on a concerning discovery - common commercial gardening products such as soil, compost, and flower bulbs harbor high levels of multidrug-resistant Aspergillus fumigatus. This fungus, classified as a significant fungal threat by the World Health Organization (WHO), poses a critical risk to individuals with weakened immune systems, emphasizing the serious health hazards associated with gardening.

Aspergillus fumigatus has been identified by the WHO as a critical public health threat due to its potential lethality, especially to immunocompromised individuals. The recent study conducted by the University of Georgia raises concerns about the soil and compost found in stores, as they may carry hidden dangers. Researchers have found significant concentrations of multidrug-resistant fungi in commercial gardening products, including soil and flower bulbs.

In particular, Aspergillus fumigatus, a common fungus found in soil, can pose a significant hazard to human health when inhaled. The risk is especially severe for individuals with weakened immune systems, who could face a mortality rate close to 100% if infected by a multi-drug resistant strain of the fungus. Lead author of the study, Marin Brewer, who is a professor in UGA's College of Agricultural and Environmental Sciences, highlighted the need for awareness, stating, "People don't think of tulips as deadly, but they could be."

The vulnerable individuals who face the highest risk include those with chronic obstructive pulmonary disease (COPD), cystic fibrosis, Type 2 diabetes, HIV/AIDS, and even COVID-19. Additionally, cancer patients and individuals taking immunosuppressant drugs are also at risk. Furthermore, research indicates that more people are susceptible to developing fungal infections than ever before.

Aspergillus fumigatus has recently been classified by the World Health Organization as one of the most critical fungal threats worldwide. Each year, this fungus infects over 2 million people globally. Aspergillosis, the disease caused by the fungus, is a leading cause of death in immunocompromised patients, with an alarming 80% mortality rate.

Although less common, even individuals with healthy immune systems can face threats from this fungus. Aspergillomas, clumps of the fungus that form on the lungs, can occur in healthy individuals. While some may clear the infection with minimal symptoms, others require medications or surgery to prevent the infection from spreading. However, the effectiveness of treatments is diminishing, as they rely on the same mechanisms used in agricultural settings.

The University of Georgia's study analyzed various products, including soil, compost, flower bulbs, and food items sold at major retailers from 2019 to 2021. Surprisingly, researchers found over 500 strains of Aspergillus fumigatus in the samples, originating from different brands. Of the 525 samples, 90% contained the fungus, primarily in flower bulbs, soil, compost, and peanuts. Most of the drug-resistant strains were detected in manure-based compost, soil, and flower bulbs such as daffodils, dahlias, gladioli, and tulips.

Lead author Marin Brewer expressed concerns about the findings, stating, "We found dozens of strains of resistant fungi in just 1 gram of compost. Based on our findings, there could be tens of thousands of potentially resistant strains in one bag of compost."

To mitigate the risks, the researchers strongly advise individuals with compromised immune systems to take precautions when gardening and to consult with their physicians regarding the potential dangers. Additionally, wearing N-95 masks can provide some protection to dedicated gardeners.

While the agricultural industry attempts to address the issue, Brewer herself has chosen to refrain from planting flower bulbs and using commercial compost. The situation calls for heightened awareness and caution, as individuals must prioritize their health and take necessary measures to safeguard against this multidrug-resistant fungus found in common gardening products.

Reference: "Azole resistance mechanisms and population structure of the human pathogen Aspergillus fumigatus on retail plant products" by Caroline Wang, Natalie Miller, Douglas Vines, Paul M. Severns, Michelle Momany, and Marin T. Brewer, 23 April 2024, Applied and Environmental Microbiology.