Document Type : Original Articles
Author
Biology, Science, Al-Muthanna University, Samawa city, Iraq
10.22034/cmm.2025.345304.1586
Abstract
Background and Purpose: Various species of microorganisms interact in a variety of ecological niches, sometimes leading to infection. A biofilm of one or more species may form during the infectious process. Otomycosis can be brought on by etiologic agents such as Staphylococcus aureus and Aspergillus niger. This study aims to survey of the antagonistic relationship between the gene expression biofilms of Aspergillus niger and S. aureus in the context of otomycosis-related biofilm formation.
Materials and Methods: we examined single-species biofilms of A. niger and S. aureus, as well as mixed-species biofilms of A. niger-S. aureus, over 24 and 48 hours. The expression of A. niger biofilm-related genes (eng1, xynB, exo, eglA, eglB, and eglC) was analyzed using Real-time polymerase chain reaction. The impact of S. aureus on the gene expression of A. niger was evaluated and compared to the gene expression of A. niger alone, which served as the control.
Results: Biofilm formation assays showed that A. niger biofilm formation was significantly inhibited when co-cultured with S. aureus, with optical density values dropping from 0.56 (alone) to 0.15 at 24 hours and 0.05 at 48 hours. Real-time PCR analysis revealed that the expression of A. niger biofilm-related genes (eng1, xynB, exo, eglA, eglB, and eglC) increased significantly in single-species biofilms, reaching (2.5, 3, 1.5, 3.5, 2, 1.7) at 24 hours and (3.5, 4, 2, 4.2, 3, 2) at 48 hours. However, in co-culture with S. aureus, gene expression was markedly reduced to (0.8, 0.5, 0.4, 0.9, 0.6, 0.5) at 24 hours and (0.5, 1, 0.2, 0.8, 0.6, 0.3) at 48 hours, demonstrating a strong inhibitory effect of S. aureus on A. niger biofilm formation and gene expression.
Conclusion: This study describes the antagonistic relationship between S. aureus and A. niger on the gene expression biofilm that causes otomycosis, as well as the antibiosis relationship between the two during in vitro biofilm formation. These findings provide new insights into the complex interactions between these microorganisms during infection and may have implications for understanding and managing otomycosis.
Keywords
Main Subjects
)