A scanning electron microscope image of the recently discovered extremophile fungus, E. alkalina, which produces an antimicrobial peptide with promising activity against biofilm-forming pathogenic bacteria.© Georgieva Marina, Pleiades Publishing
A peptide molecule produced naturally by a fungus to fight off bacteria could inspire new ways to treat life-threatening bacterial infections, new research published in the journal Applied Biochemistry and Microbiology has shown1. The peptide, isolated from a newly identified species of fungus found at the edge of soda lakes, can prevent bacteria from forming colonies called biofilms – an effect that makes it potentially potent against drug-resistant biofilm-forming bacteria.
Since their discovery 40 years ago, antimicrobial peptides (AMPs) have been shown to have a key role in the innate defence against microbial infection in animals, plants and fungi. With the growing threat in hospitals from antibiotic-resistant bacteria, AMPs are being studied as a promising new weapon.
“AMPs could be an alternative to conventional antibiotic therapies, due to their relatively low potential to elicit resistance,” says lead author Vera Sadykova from the Gause Institute of New Antibiotics in Moscow.
The largest group of AMPs, the peptaibols, consist of a peptide core attached to a nonpeptidic component. Peptaibols are produced by various fungi, and especially those of the Emericellopsis genus.
“Our scientific group recently isolated a new species of this genus, E. alkalina,” Sadykova says. “From E. alkalina, we carried out the isolation and structural and functional characterization of a new secreted peptaibol AMP called emericellipsin A.”
The team previously showed that emericellipsin A (EmiA) had strong activity against pathogenic fungal and yeast infections, while having low cytotoxicity to human cells. In their most recent study, in collaboration with researchers from other Russian institutions, they showed that EmiA could assist in efforts to find new ways to tackle multidrug-resistant bacterial infections.
The bacteria most commonly responsible for hospital-acquired infections tend to form biofilms – a collective colonization of a surface surrounded by a protective coating that makes the infection very difficult to eliminate. The team found that EmiA can prevent this.
“We showed the previously unknown ability of a fungal AMP from the peptaibol group to deprive bacteria from multidrug resistant strains of the ability to form biofilms,” Sadykova says.
The team found that the effect was most pronounced against gram-positive bacteria, and is currently studying whether any synergistic benefits could be found by combining EmiA with different commercial antifungal drugs to treat invasive fungal infections.
“We are also investigating the ability of a new synthetic analogue of the emericellipsins to show antifungal and antibiofilm effects,” Sadykova adds.
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