| Activity of tea tree oil on methicillin resistant Staphylococcus aureus (MRSA) New methods for the control of methicillin?resistant Staphylococcus aureus (MRSA) are required to reduce the *increasing incidence of nosocomial MRSA infections and the increasing reservoir of MRSA within the community which lead to increasing numbers of colonized patients and staff. This is further complicated by the recent emergence of S. aureus with reduced susceptibility to vancomycin (VRSA),'which will strain our resources in the near future. Therapy for MRSA infections is available, but will become problematic as the frequency of VRSA within the hospitals increases, and with it, the need to control the carrier state more stringently. The eradication of MRSA carriage in-patients and staff can prove difficult for a number of reasons. This is due in part to the emergence of resistance to mupirocin, a topical agent used in the attempted eradication of MRSA carriage. Other agents such as chlorhexidine have proved problernatic, due to the patients' intolerance of them. Often the perception of being decontaminated can also lead to patients' non-compliance with topical treatments. Alternative approaches are thus required. Tea tree oil has been suggested as a possible topical agent with broad?spectrum antibacterial properties which could fulfil this role.2 It has been shown to be effective against clinical isolates of MRSA both in the UK and in Australia. We would like to report our findings from a study on 28 clinical isolates of MRSA, two NCTC S. aureus strains and eight clinical isolates of coagulase?negative staphylocci (CNS) from the Manchester Royal Infirmary. The minimum inhibitory concentrations (MICs) were determined by previously describe methods, and were repeated in triplicate. The MICs ranged from 0.25?0.51/4) tea tree oil for the MRSA. No resistant isolates were found. The MICs for the CNS ranged between 0.5?4% tea tree oil. The concentration of tea tree oil can be found at 2?5% in a range of cosmetic products. This range will inhibit methicillin?sensitive S. aureus and MRSA but may not inhibit CNS, thus preserving the skin flora. Presently, the antimicrobial agents such as mupirocin used in soaps and ointments are becoming less effective at eradicating MRSA because of resistance. Tea tree oil is cheap, natural and a possible alternative to the present antimicrobial agents used within hospitals. However, treating patients and staff with tea tree oil for MRSA carriage will require further studies on its efficacy, absorption and toxicity of the oil when applied topically. So far, tea tree oil appears to be a promising candidate in the eradication of MRSA carriage. Its image as a cosmetic product rather than a decontarninant may help improve compliance in usage. Our Study on a small number of clinical isolates confirms its efficacy under laboratory conditions, but further work is needed to confirm this in clinical trials. 3.5.6 C. H. Chan K. W. Loudon* Department of' Medical Microbiology 2nd Floor Clinical Sciences Building, Manchester Royal Infirmary Oxford Road, Manchester, M13 9WL, UK *Department o f Microbiology, Pilgrim Hospital, Sibsey Road, Boston, Lincolnshire PE21 90S, Ulf Chan, C.H., and K.W. Loudon. “Activity of tea tree oil on methicillin-resistant Staphylococcus aureus.” Journal of Hospital Infections 1998, 39:244-245. Carson, C.F., et al. “Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil Melaleuca alternafolia.” Journal of Antimicrobial Chemotherapy 1995, 35:421-424. Cox, S. D., et al. “Trea tree oil causes K+ leakage and inhibits respiration in Escherichia coli.” Letters in Applied Microbiology 1998, 26:355-358. |
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