10
May
Scientists Zero In on “Rapidly Evolving” Human Pathogenic Fungi, May Be Tied to Widespread Fungicide Use
(Beyond Pesticides, May 10, 2023) Scientists are uncovering more information about a fungal pathogen behind a disease outbreak in Indian hospitals that sickened 10 pre-term infants. According to a study published in mBIO late last month, the yeast pathogen Lodderomyces elongisporus was the causative agent of this outbreak and is rapidly evolving resistance to control measures. There is growing concern globally over the spread of fungal pathogens, with scientists increasingly identifying agriculture as the driver behind pathogenic mutations and resistance.
Scientists in Delhi, India were called to investigate an outbreak of L. elongisporus that sickened ten infants with low birthweight in the neonatal intensive care unit (NICU) from September 2021 to February 2022. L. elongisporus is more commonly known for attacking severely immunocompromised adults, including those with heart conditions or a history of intravenous drug use. However, there are an increasing number of reports of fungal infections in neonatal care units. Further, the fungus appears to be spreading globally, with reports of infections in the Middle East, Europe, Australia, and North America.
“This yeast is among a growing list of fungi capable of causing severe infections among humans,” said lead study author Jianping Xu, PhD a professor at McMaster University in Canada to ETHealthworld. “The genetic mechanisms underlying their adaptations to humans, and to hospital and natural environments warrant further investigation and measures to contain their spread and persistence.”
Researchers aimed to determine the origin of the yeast in the NICU, how it came to infect neonates, and its current genetic makeup and potential resistance to control measures and treatments.
As part of the outbreak investigation, scientists learned that one infant was initially sickened, and treated with common antifungals, but, after isolating the infection and determining it to be L. elongisporus, switched to a more intensive treatment. After a second case was found, prevention practices and cleaning increased, and only two cases occurred over the next couple months. Then a cluster of four neonates were sickened, resulting in environmental sampling of the NICU. Researchers found two locations where L. elongisporus remained – on the railing of the neonate open care warmer (a machine that houses neonatal infants) and on its temperature control panel. This information and more strict protocols on handwashing and disinfection contained the outbreak. Nine of the ten patients sickened survived treatment with an antifungal known as amphotericin B, a very strong antifungal that itself has severe and potentially lethal side effects.
Further environmental sampling and genetic sequencing determined that stored apples outside of the hospital contained a similar, though not exact, strain of L. elongisporus. Testing on the hospital strain and apple strain showed significant diversity between how samples responded to antifungal drugs. Most concerningly, scientists found evidence of recombination in all samples. This indicates that this fungus is evolving rapidly.
“The findings are worrisome because the hospital environment seems to be selecting for stress-resistant fungal pathogens. They are adapting and evolving very, very quickly,” said Dr. Xu to ETHealthworld.
While scientists found that L. elongisporus was able to be killed by antifungals, its susceptibility to disinfectants is another story. The fungus is surprisingly resistant to bleach employed to clean hospital rooms of infectious agents.
Lodderomyces elongisporus appears to be speed running a virulent path similar to that of Candida auris and Aspergillus fumigatus. C. auris has been rapidly spreading across the world over the last decade, posing significant risks to public health. A 2022 study published on the spread of A. fumigatus found a direct connection between fungicide use on farms and growing resistance and virulence in the hospital setting. Such a pathway with a more genetically diverse and rapidly evolving fungus is a chilling prospect for global public health.
Despite these dangers, regulators and politicians are not responding with the urgency that scientists say is needed. The U.S. Environmental Protection Agency’s guidance released on the rise of drug-resistant Candida auris is case in point. The agency failed to consider the resistance impacts of pesticides that are not used for public health purposes; EPA only evaluated the efficacy of antimicrobial compounds whose use patterns classify them as human-health-related.
At the international level, a Freedom of Information Act request reveals officials at the U.S. Department of Agriculture (USDA) working on behalf of the chemical industry to downplay the role of synthetic fungicide use in chemical agriculture as a factor in the rise of drug-resistant fungal infections. Evidence reveals officials within the industry trade group Croplife America urging USDA to “make certain” that the United Nation’s (UN) Codex Alimentarius, a set of international guidelines and standards established to protect consumer health, made no mention of how fungicides contribute to antibiotic resistance. Government agencies in the U.S. are thus not only failing to take action, but actively blocking efforts to address this issue.
Evidence shows that the only true way to eliminate resistance is to stop using the material that is causing resistance to occur in the first place. Organic agriculture is the best response to rising resistance, placing strong controls on allowed materials. This ensures that life-saving medication will be retained to protect people’s health, not grow crops. For more reasons to go organic, see Beyond Pesticides Why Organic webpage.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: ETHealthworld, mBIO
