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Study of the antagonistic relationship between gene expression biofilm of Aspergillus niger and Staphylococcus aureus that cause otomycosis

Summary

Researchers studied how bacteria (S. aureus) and fungi (A. niger) interact when both infect the ear canal, a condition called otomycosis. They found that bacteria significantly suppress the fungus’s ability to form protective biofilms by reducing the expression of genes needed for fungal growth. This antagonistic relationship suggests that mixed infections might actually be easier to treat than pure fungal infections, offering new insights for managing ear infections.

Background

Otomycosis is a fungal infection of the outer ear commonly caused by Aspergillus niger and can be complicated by bacterial co-infections such as Staphylococcus aureus. Biofilms are microbial communities that provide protection and antimicrobial resistance in polymicrobial infections. Understanding the interactions between fungal and bacterial biofilms is important for managing complex ear infections.

Objective

This study aimed to investigate the antagonistic relationship between gene expression biofilms of A. niger and S. aureus in the context of otomycosis. The researchers sought to determine how S. aureus affects A. niger biofilm formation and the expression of genes involved in fungal biofilm development.

Results

A. niger biofilm formation was significantly inhibited when co-cultured with S. aureus, with optical density decreasing from 0.56 to 0.15 at 24h and 0.05 at 48h. Gene expression analysis showed that all six biofilm-related genes were markedly downregulated in co-culture conditions compared to A. niger alone at both time points, demonstrating S. aureus produces inhibitory effects on A. niger biofilm development.

Conclusion

This study demonstrates that S. aureus has a strong antagonistic effect on A. niger biofilm formation through suppression of fungal biofilm-related gene expression. The findings suggest that S. aureus produces diffusible antimicrobial compounds or exotoxins that inhibit fungal conidiation and hyphal growth. These results provide insights into polymicrobial interactions in otomycosis and may inform therapeutic strategies for managing mixed fungal-bacterial ear infections.
  • Published in:Current Medical Mycology,
  • Study Type:In vitro experimental study,
  • Source: PMID: 40662148, DOI: 10.22034/cmm.2024.345248.1586
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