Antibiotics (Nov 2022)

Study of SarA by DNA Affinity Capture Assay (DACA) Employing Three Promoters of Key Virulence and Resistance Genes in Methicillin-Resistant <i>Staphylococcus aureus</i>

  • Byungchan Kim,
  • Hong-Ju Lee,
  • Sung-Hyun Jo,
  • Min-Gyu Kim,
  • Yeonhee Lee,
  • Wonsik Lee,
  • Wooseong Kim,
  • Hwang-Soo Joo,
  • Yun-Gon Kim,
  • Jae-Seok Kim,
  • Yung-Hun Yang

DOI
https://doi.org/10.3390/antibiotics11121714
Journal volume & issue
Vol. 11, no. 12
p. 1714

Abstract

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Methicillin-resistant Staphylococcus aureus (MRSA), one of the most well-known human pathogens, houses many virulence factors and regulatory proteins that confer resistance to diverse antibiotics. Although they have been investigated intensively, the correlations among virulence factors, regulatory proteins and antibiotic resistance are still elusive. We aimed to identify the most significant global MRSA regulator by concurrently analyzing protein-binding and several promoters under same conditions and at the same time point. DNA affinity capture assay (DACA) was performed with the promoters of mecA, sarA, and sarR, all of which significantly impact survival of MRSA. Here, we show that SarA protein binds to all three promoters. Consistent with the previous reports, ΔsarA mutant exhibited weakened antibiotic resistance to oxacillin and reduced biofilm formation. Additionally, production and activity of many virulence factors such as phenol-soluble modulins (PSM), α-hemolysin, motility, staphyloxanthin, and other related proteins were decreased. Comparing the sequence of SarA with that of clinical strains of various lineages showed that all sequences were highly conserved, in contrast to that observed for AgrA, another major regulator of virulence and resistance in MRSA. We have demonstrated that SarA regulates antibiotic resistance and the expression of various virulence factors. Our results warrant that SarA could be a leading target for developing therapeutic agents against MRSA infections.

Keywords