Interaction between biofilms formed by Staphylococcus epidermidis and quinolones

Area of Science:

• Microbiology
• Pharmacology
• Biomedical Engineering

Background:

• Staphylococcus epidermidis is a common cause of biofilm-related infections, particularly on medical devices.
• Fluoroquinolones are broad-spectrum antibiotics with potential anti-biofilm activity.

Purpose of the Study:

• To investigate the efficacy of pefloxacin, ciprofloxacin, norfloxacin, and ofloxacin against Staphylococcus epidermidis biofilms.
• To evaluate the impact of fluoroquinolones on bacterial adhesion and biofilm eradication.

Main Methods:

• Studied interaction of four fluoroquinolones with Staphylococcus epidermidis biofilms from clinical isolates.
• Assessed biofilm optical density and bacterial adhesion in vitro, including a vascular catheter model.
• Utilized scanning electron microscopy to visualize anti-biofilm activity.

Main Results:

• Subinhibitory concentrations (1/2-MIC and 1/8-MIC) reduced biofilm optical density significantly (22-74%).
• Higher concentrations (12.5-400 microg/mL) reduced preformed biofilm optical density by 45-77%.
• Fluoroquinolones inhibited bacterial adhesion to plastic and catheter surfaces, with higher concentrations eradicating established biofilms.

Conclusions:

• Subinhibitory fluoroquinolone concentrations effectively inhibit Staphylococcus epidermidis adhesion.
• Higher fluoroquinolone concentrations demonstrate potent eradication of preformed biofilms on vascular catheters.
• These findings suggest fluoroquinolones as potential agents for preventing and treating S. epidermidis biofilm infections.