Time-kill studies of tea tree oils on clinical isolates

Area of Science:

• Microbiology
• Pharmacology
• Natural Products

Background:

• Tea tree oil is recognized for its topical antimicrobial properties.
• It holds potential for clinical use in hospitals and communities for infection control.
• Applications include reducing methicillin-resistant Staphylococcus aureus (MRSA) carriage and hand disinfection.

Purpose of the Study:

• To determine the kill rate of two chemically distinct tea tree oils against multidrug-resistant organisms (MDROs) and sensitive microorganisms.
• To compare the antimicrobial activity of a standard tea tree oil with a specially bred clone (Clone 88).
• To assess the influence of organism susceptibility patterns and Gram reaction on the kill rate.

Main Methods:

• Time-kill kinetic studies were employed.
• Two types of tea tree oil were tested: standard and Clone 88.
• The oils were tested against a panel of MDROs, including MRSA, vancomycin-resistant enterococci, and Gram-negative bacteria, as well as sensitive strains.

Main Results:

• Both tea tree oils exhibited rapid killing times (under 60 minutes) against most tested isolates.
• The cloned tea tree oil (Clone 88) displayed enhanced antimicrobial activity compared to the standard oil.
• MRSA isolates were found to be killed more slowly than other tested organisms.
• The kill rate was largely independent of the organism's Gram reaction or susceptibility pattern.

Conclusions:

• Tea tree oil is an effective antimicrobial agent against a broad spectrum of microorganisms, including MDROs.
• Clone 88 tea tree oil offers superior antimicrobial activity and may be a valuable tool for infection prevention.
• Further research may explore its role in decolonization protocols and as a disinfectant in healthcare settings.