Metabolites of Xenorhabdus bacteria are potent candidates for mitigating amphibian chytridiomycosis

• Published in: AMB Express Vol. 13; no. 1; p. 88
• Main Authors: Ujszegi, János, Boros, Zsófia, Fodor, András, Vajna, Balázs, Hettyey, Attila
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 24-08-2023; Springer Nature B.V; SpringerOpen
• Subjects: Amphibian pathogen; Amphibians; Antifungal activity; Antifungal treatment; Antimicrobial; Bacteria; Batrachochytrium; Bioaugmentation; Biodiversity; Biomedical and Life Sciences; Biotechnology; Cell culture; Chemical-free disinfection; Chytridiomycosis; Culture media; Dilution; Effectiveness; Fungicides; Life Sciences; Metabolites; Microbial Genetics and Genomics; Microbiology; Original; Original Article; Reptiles & amphibians; Secondary metabolites; Side effects; Skin microbiota; Toads; Xenorhabdus; Antimicrobial; Chemical-free disinfection; Skin microbiota; Antifungal treatment; Bioaugmentation; Amphibian pathogen
• ISSN: 2191-0855; 2191-0855
• DOI: 10.1186/s13568-023-01585-0

Chytridiomycosis, caused by the chytrid fungus
Batrachochytrium dendrobatidis
(Bd), has caused extreme losses in amphibian biodiversity. Finding bacteria that produce metabolites with antifungal properties may turn out to be invaluable in the fight against this devastating disease. The entomopathogenic bacteria,
Xenorhabdus szentirmaii
and
X. budapestensis
produce secondary metabolites that are effective against a wide range of fungal plant pathogens. To assess whether they may also be effective against Bd, we extracted cell-free culture media (CFCM) from liquid cultures of
X. szentirmaii
and
X. budapestensis
and tested their ability to inhibit Bd growth in vitro. As a second step, using juvenile common toads (
Bufo bufo
) experimentally infected with Bd we also tested the in vivo antifungal efficacy of
X. szentirmaii
CFCM diluted to 2 and 10% (v/v), while also assessing possible malign side effects on amphibians. Results of the in vitro experiment documented highly effective growth inhibition by CFCMs of both
Xenorhabdus
species. The in vivo experiment showed that treatment with CFCM of
X. szentirmaii
applied at a dilution of 10% resulted in infection intensities reduced by ca. 73% compared to controls and to juvenile toads treated with CFCM applied at a dilution of 2%. At the same time, we detected no negative side effects of treatment with CFCM on toad survival and development. Our results clearly support the idea that metabolites of
X. szentirmaii
, and perhaps of several other
Xenorhabdus
species as well, may prove highly useful for the treatment of Bd infected amphibians.
Key points
First report of high anti-Bd efficacy of
Xenorhabdus
metabolites in vitro.
Metabolites of
X. szentirmaii
can be applied effectively on live toads.
Application of
X. szentirmaii
metabolites on live toads was safe.