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Antibiotic resistance alters through iron-regulating Sigma factors during the interaction of Staphylococcus aureus

Hamed Tahmasebi1, Sanaz Dehbashi2, Mohammad Reza Arabestani3

  • 1School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran.

Scientific Reports
|September 17, 2021
PubMed

Insights

Polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus alter iron regulation. This study reveals how sigma factors influence antibiotic resistance, impacting treatments for these common infections.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Immunology

Background:

  • Iron sequestration by hosts is a key defense during polymicrobial infections.
  • Pseudomonas aeruginosa and Staphylococcus aureus are common co-infecting pathogens.
  • Understanding their interaction is crucial for developing effective treatments.

Purpose of the Study:

  • To investigate the interplay between S. aureus and P. aeruginosa.
  • To determine how this interaction affects iron-related sigma factor regulation.
  • To elucidate the impact on antibiotic resistance.

Main Methods:

  • Utilized a L929 cell culture model for co-infection studies.
  • Quantified gene expression of P. aeruginosa sigma factors (pvdS, hasI) and S. aureus sigma factor (sigS) using Quantitative Real-Time PCR.
  • Assessed antibiotic resistance profiles of both bacterial species.

Main Results:

  • Co-culture led to downregulation of P. aeruginosa sigma factors pvdS and hasI.
  • A significant increase in susceptibility to carbapenems was observed (p < 0.0001).
  • A direct correlation was found between vancomycin resistance and the S. aureus sigS gene.

Conclusions:

  • Iron-related sigma factors in P. aeruginosa and S. aureus are implicated in modulating antibiotic susceptibility.
  • These findings highlight the role of sigma factors in resistance to carbapenems and vancomycin.
  • Understanding these mechanisms can inform strategies against polymicrobial infections.

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