The Virulence Potential of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Cultured from the Airways of Cystic Fibrosis Patients

Toxins (Basel). 2020 May 30;12(6):360. doi: 10.3390/toxins12060360.

Abstract

Staphylococcus aureus is one of the most common pathogens that infects the airways of patients with cystic fibrosis (CF) and contributes to respiratory failure. Recently, livestock-associated methicillin-resistant S. aureus (LA-MRSA), usually cultured in farm animals, were detected in CF airways. Although some of these strains are able to establish severe infections in humans, there is limited knowledge about the role of LA-MRSA virulence in CF lung disease. To address this issue, we analyzed LA-MRSA, hospital-associated (HA-) MRSA and methicillin-susceptible S.aureus (MSSA) clinical isolates recovered early in the course of airway infection and several years after persistence in this hostile environment from pulmonary specimens of nine CF patients regarding important virulence traits such as their hemolytic activity, biofilm formation, invasion in airway epithelial cells, cytotoxicity, and antibiotic susceptibility. We detected that CF LA-MRSA isolates were resistant to tetracycline, more hemolytic and cytotoxic than HA-MRSA, and more invasive than MSSA. Despite the residence in the animal host, LA-MRSA still represent a serious threat to humans, as such clones possess a virulence potential similar or even higher than that of HA-MRSA. Furthermore, we confirmed that S. aureus individually adapts to the airways of CF patients, which eventually impedes the success of antistaphylococcal therapy of airway infections in CF.

Keywords: LA-, HA-MRSA; MSSA; biofilm; cystic fibrosis; cytotoxicity; hemolysis; invasion; virulence.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Zoonoses / drug therapy
  • Bacterial Zoonoses / microbiology*
  • Bacterial Zoonoses / transmission
  • Biofilms / drug effects
  • Biofilms / growth & development
  • Cross Infection / drug therapy
  • Cross Infection / microbiology*
  • Cross Infection / transmission
  • Cystic Fibrosis / drug therapy
  • Cystic Fibrosis / microbiology*
  • Drug Resistance, Bacterial
  • Hemolysis
  • Humans
  • Livestock / microbiology*
  • Methicillin-Resistant Staphylococcus aureus / drug effects
  • Methicillin-Resistant Staphylococcus aureus / growth & development
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification
  • Methicillin-Resistant Staphylococcus aureus / pathogenicity*
  • Rabbits
  • Respiratory System / microbiology*
  • Respiratory Tract Infections / drug therapy
  • Respiratory Tract Infections / microbiology*
  • Respiratory Tract Infections / transmission
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / microbiology*
  • Staphylococcal Infections / transmission
  • Virulence

Substances

  • Anti-Bacterial Agents