Growth Inhibition of an Opportunistic Yeast Pathogen <i>Trichosporon asahii</i> by <i>Staphylococcus epidermidis</i>

Abstract

In the co-culture of Staphylococcus epidermidis and Trichosporon asahii, a fungal pathogen, it was observed that live S. epidermidis inhibited the growth of T. asahii. Soluble active anti-T. asahii substances were speculated to be produced by S. epidermidis in culture medium. Using 1 H-and 13 C-NMR spectra and electron ionization-high resolution mass spectrometry (HR-negative-FAB-MS), we separated the active molecule and identified it as lactic acid. Commercially available L-lactic acid and D-lactic acid inhibited the growth of T. asahii. These results show that metabolites from bacterial populations are involved in the interactions of pathogenic fungi. The use of antibacterial agents to treat primary diseases could lead to the disruption of normal microbial communities and could cause opportunistic infections such as trichosporonosis.

Antagonistic Interaction of Staphylococcus aureus and Staphylococcus epidermidis with Rhizopus arrhizus Mediated by Phenol Soluble Modulins and Organic Acids

“…Lactic acid produced by S. epidermidis has also been implicated in the growth inhibition of T. asahii, an opportunistic yeast pathogen. 17 Butyric acid from S. epidermidis mediates its competitive interaction with Propionibacterium acnes, 35 although it was not detected in our study.…”

“…The <3 kDa active fraction also contained organic acids, which are produced as metabolites and could be important as antimicrobials. , Acetic acid, succinic acid, lactic acid, citric acid, and malic acid were detected in these fractions and demonstrated an inhibitory effect on R. arrhizus . Lactic acid produced by S. epidermidis has also been implicated in the growth inhibition of T. asahii , an opportunistic yeast pathogen . Butyric acid from S. epidermidis mediates its competitive interaction with Propionibacterium acnes , although it was not detected in our study.…”

“…and Aspergillus fumigatus . S. epidermidis is commonly coisolated with Candida albicans , and their mixed cultures exhibit higher biofilm formation as well as drug resistance. , Likewise, coculturing C. albicans with S. aureus increases the invasiveness, biofilm formation, and drug resistance of the bacteria and protects the fungus from immune response more effectively. − S. aureus is also isolated at a higher frequency in the cases of chronic rhino-sinusitis due to A. fumigatus , where it mediates the disease pathology via its superantigens and by increasing the fungal biofilm formation. − In contrast, antagonistic interactions occur with Cryptococcus neoformans , Trichosporon asahii , and Candida glabrata, wherein the bacteria inhibit fungal growth and even induce apoptosis. − To our knowledge, the influence of staphylococci on Mucorales remains uninvestigated. This study was planned to elucidate the interaction of a common pathogenic Mucorale, Rhizopus arrhizus ( R. arrhizus ), with S. aureus and S. epidermidis and identify the molecular mechanisms involved.…”