Reduced triclosan susceptibility in methicillin-resistant Staphylococcus epidermidis

Area of Science:

• Microbiology
• Antimicrobial Resistance

Background:

• Triclosan is a widely used antimicrobial agent.
• Understanding bacterial susceptibility to triclosan is crucial for public health.
• Staphylococcus species are common human pathogens.

Purpose of the Study:

• To determine the minimal inhibitory concentrations (MICs) of triclosan against clinical isolates of Staphylococcus aureus and Staphylococcus epidermidis.
• To investigate potential differences in triclosan susceptibility between methicillin-resistant and methicillin-sensitive Staphylococcus epidermidis.

Main Methods:

• Minimal Inhibitory Concentration (MIC) determination was performed.
• Clinical isolates of Staphylococcus aureus (n=100) and Staphylococcus epidermidis (n=96) were tested.
• Susceptibility testing included differentiation between methicillin-resistant and methicillin-sensitive Staphylococcus epidermidis.

Main Results:

• Staphylococcus aureus isolates were highly susceptible to triclosan (MIC(50) = 0.12 microg/ml, MIC(90) = 0.25 microg/ml).
• Staphylococcus epidermidis isolates showed lower susceptibility (MIC(50) = 0.12 microg/ml, MIC(90) = 8 microg/ml).
• Decreased triclosan susceptibility was more common in methicillin-resistant Staphylococcus epidermidis compared to methicillin-sensitive strains.

Conclusions:

• Clinical isolates of Staphylococcus aureus remain highly susceptible to triclosan.
• Staphylococcus epidermidis demonstrates reduced susceptibility to triclosan, particularly methicillin-resistant strains.
• These findings highlight the need for ongoing surveillance of antimicrobial resistance patterns.