Authors:

Sylvia Khalil

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About Paper:

antimicrobial activity Co-Author(s): Caitlin Kowalski, Matt Barber Human skin contains many microbes, termed the microbiome, that secrete antimicrobials to prevent infection; in response, pathogens may adapt to overcome these defenses. Staphylococcus aureus, a bacterial pathogen of the skin, is a major concern due to its antibiotic resistance. Our lab discovered 184 UNIVERSITY OF OREGON • 2023 UNDERGRADUATE RESEARCH SYMPOSIUM a host resident-fungi Malassezia, often overlooked in the microbiome, has bactericidal properties against S. aureus. When exposed to Malassezia, S. aureus develops resistance through activation of the sigma factor SigB. This study focuses on downstream mechanisms of S. aureus resistance to Malassezia beyond SigB. We aim to characterize the resistance mechanism, identify consequences of resistance, and help identify toxic effector(s). To accomplish this, we generated S. aureus mutations based on resistance evolved in the absence of SigB and relevant literature, then investigated their resistance to the yeast. We found sizable contributions to resistance through an evolved stp1 allele and activity of the regulator SarA. Both SigB and the stp1 evolved allele provide resistance through increased activation of SarA; this resistance is coupled with resistance to antibiotics and antimicrobial fatty acids. Currently, SarA is central to our research. We intend to study downstream components of SarA to complete this mechanism. Our work contributes to understanding how the microbiome prevents infection and can drive pathogen evolution, while aiding in the fight against antibiotic resistance.

Source:

University of Oregon / 2023

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No topics listed

Co-authors:

Sylvia Khalil