Bags of compost and flower bulbs from the hardware store contain dangerous multi-resistant fungi

Bags of compost and flower bulbs from the hardware store contain dangerous multi-resistant fungi

For example, it is home to the fungus Aspergillus fumigatus, which is classified by the WHO as a serious threat to public health.

Summer is in full swing – and that means many people are back in their gardens. But be careful with that bag of compost you bought at the hardware store. It may contain more than just soil. “Gardening is a relaxing and enjoyable activity,” says researcher Marin Brewer. “But I worry about people who are not aware of the health risks that can come with working with compost and flower bulbs.”

Multi-resistant fungi
New research has shown that commercially available compost, soil and flower bulbs contain multi-resistant fungi. And that is quite worrying. “Especially because we found them in such large quantities, without people being aware of the risks,” Brewer tells“Our findings indicate that there could be tens of thousands of potentially resistant fungal strains in just one bag of compost.”

The researchers draw this disturbing conclusion after sampling various products such as compost, soil, flower bulbs and various foods. These samples were taken between 2019 and 2021 in large retail chains. The team discovered more than 500 strains of the fungus Aspergillus fumigatus in different products, from different brands. Most multi-resistant fungal strains were found in soil, manure compost and flower bulbs such as daffodils, dahlias, gladioli and tulips. “We were relieved that we did not encounter multi-resistant strains of Aspergillus fumigatus “We found it in store-bought foods and nuts,” says Brewer. “But its high presence in compost and flower bulbs is concerning. People don’t associate tulips with something deadly, but that could be the case.”

It is not surprising that researchers are sounding the alarm. A few years ago, the World Health Organization (WHO) published a catalogue containing The 19 Most Worrying Fungi That Are a Growing and Underappreciated Threat to Public Health. And one of the fungi mentioned was Aspergillus fumigatusThe WHO is particularly concerned about resistance, or the fact that this fungus is becoming increasingly resistant to existing medicines. There are only a handful of antifungal drugs and more and more fungi are proving less and less impressed by them. There is Aspergillus fumigatus so a good example of. Every year, Aspergillus fumigatus more than two million people worldwide. Aspergillosis, the disease caused by this fungus, is a leading cause of death in immunocompromised patients. But the fungus also targets people with chronic obstructive pulmonary disease (COPD), cystic fibrosis, type 2 diabetes, HIV/AIDS and even COVID-19. Cancer patients and people taking immunosuppressive medications are also at risk.

Meer over Aspergillus fumigatus
Aspergillus fumigatus is a ubiquitous fungus. It is thought that we inhale hundreds of spores of this species every day. Aspergillus fumigatus is found everywhere in the environment and is also found in the nose, throat and pharynx of healthy people. Although it does not always cause noticeable health problems, it still causes millions of people to become ill every year. The fungus can cause bronchopulmonary allergic aspergillosis in people with weakened immune systems. Symptoms include fever, weakness, chest pain, unexplained weight loss, headache, heart murmur, blood in the urine or abnormal urine color, and straight, narrow lines of broken blood vessels under the nails. Because the infection cannot be treated with existing remedies, this fungus regularly claims people’s lives: about eight out of ten patients with aspergillosis do not survive.

Or do Dutch compost bags also contain the fungus? According to Brewer, that cannot be ruled out. “I can’t say with 100 percent certainty, but it is very likely,” she notes.

The question is how exactly does this dangerous fungus end up in compost bags? “This fungus is found in decomposed plant material,” Brewer explains when asked. “It is very heat-tolerant and therefore thrives in compost piles. Research has shown that this fungus has become multi-resistant due to the use of fungicides in agriculture that have similar mechanisms of action.” And that is bad news. “There are strains of Aspergillus fumigatus “We have discovered that are resistant to voriconazole, itraconazole, and posaconazole,” Brewer said. “This is a significant public health concern because these drugs are often the first line of treatment for aspergillosis.”

Precautionary measures
Preventing infection with the fungus is particularly challenging. “The fungus is widespread in nature and is found in many places,” says Brewer. Moreover, you can become infected by inhaling the spores of the fungus. The researchers therefore strongly advise that people with weakened immune systems take precautions when gardening and discuss the possible risks with their doctor. Avid gardeners can also wear a face mask to protect themselves to some extent.

The agricultural sector is working to address this issue. In the meantime, Brewer has personally indicated that she will not plant flower bulbs and will probably not use commercial compost. At the same time, she hopes that this study will raise awareness of the potential dangers of multi-resistant pathogens in garden produce, so that more people will be aware of the risks and can take steps to protect themselves.