Changes in antibiotic susceptibility in staphylococci habituated to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia)

M. A. S. McMahon, M. M. Tunney, J. E. Moore, I. S. Blair, D. F. Gilpin, D. A. McDowell

    Research output: Contribution to journalArticle

    40 Citations (Scopus)

    Abstract

    Aims: To investigate the effect of sub-lethal challenge with tea tree oil (TTO) on the antibiotic resistance profiles of staphylococci. Methods and Results: Isolates of methicillin-resistant/-sensitive Staphylococcus aureus (MRSA and MSSA) and coagulase-negative staphylococci (CoNS) were habituated to sub-lethal concentrations of TTO (72 h). Following habituation, the minimum inhibitory concentrations (MIC) of antibiotics and TTO were determined. Habituated MRSA/MSSA cultures had higher (P < 0.05) MIC values than control cultures for the examined antibiotics. Habituated MRSA/MSSA cultures also displayed decreased susceptibility to TTO. Although the MIC of habituated MRSA/MSSA for the examined antibiotics reverted to control values after subsequent culture in the absence of TTO, the increased MIC against TTO were maintained. When compared with control cultures, habituated CoNS cultures had higher (P < 0.05) MIC values against three-fifths of the antibiotics examined; no changes in TTO MIC were observed. Conclusions: TTO habituation `stress-hardens' MRSA and MSSA, evidenced by transient decreased antibiotic susceptibility and stable decreased TTO susceptibility. Although TTO habituation did not decrease susceptibility of CoNS to TTO, such cultures showed transient decreased antibiotic susceptibility. Significance and Impact of the Study: Application of TTO at sub-lethal concentrations may reduce the efficacy of topical antibiotics used with TTO in combination therapies.
    LanguageEnglish
    Pages263-268
    JournalLetters in Applied Microbiology
    Volume47
    Issue number4
    DOIs
    Publication statusPublished - Oct 2008

    Fingerprint

    Melaleuca
    Tea Tree Oil
    Staphylococcus
    Anti-Bacterial Agents
    Microbial Sensitivity Tests
    Methicillin-Resistant Staphylococcus aureus
    Coagulase
    Microbial Drug Resistance

    Keywords

    • CoNS
    • MRSA
    • MSSA
    • staphylococci
    • tea tree oil

    Cite this

    McMahon, M. A. S. ; Tunney, M. M. ; Moore, J. E. ; Blair, I. S. ; Gilpin, D. F. ; McDowell, D. A. / Changes in antibiotic susceptibility in staphylococci habituated to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia). In: Letters in Applied Microbiology. 2008 ; Vol. 47, No. 4. pp. 263-268.
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    title = "Changes in antibiotic susceptibility in staphylococci habituated to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia)",
    abstract = "Aims: To investigate the effect of sub-lethal challenge with tea tree oil (TTO) on the antibiotic resistance profiles of staphylococci. Methods and Results: Isolates of methicillin-resistant/-sensitive Staphylococcus aureus (MRSA and MSSA) and coagulase-negative staphylococci (CoNS) were habituated to sub-lethal concentrations of TTO (72 h). Following habituation, the minimum inhibitory concentrations (MIC) of antibiotics and TTO were determined. Habituated MRSA/MSSA cultures had higher (P < 0.05) MIC values than control cultures for the examined antibiotics. Habituated MRSA/MSSA cultures also displayed decreased susceptibility to TTO. Although the MIC of habituated MRSA/MSSA for the examined antibiotics reverted to control values after subsequent culture in the absence of TTO, the increased MIC against TTO were maintained. When compared with control cultures, habituated CoNS cultures had higher (P < 0.05) MIC values against three-fifths of the antibiotics examined; no changes in TTO MIC were observed. Conclusions: TTO habituation `stress-hardens' MRSA and MSSA, evidenced by transient decreased antibiotic susceptibility and stable decreased TTO susceptibility. Although TTO habituation did not decrease susceptibility of CoNS to TTO, such cultures showed transient decreased antibiotic susceptibility. Significance and Impact of the Study: Application of TTO at sub-lethal concentrations may reduce the efficacy of topical antibiotics used with TTO in combination therapies.",
    keywords = "CoNS, MRSA, MSSA, staphylococci, tea tree oil",
    author = "McMahon, {M. A. S.} and Tunney, {M. M.} and Moore, {J. E.} and Blair, {I. S.} and Gilpin, {D. F.} and McDowell, {D. A.}",
    year = "2008",
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    language = "English",
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    Changes in antibiotic susceptibility in staphylococci habituated to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia). / McMahon, M. A. S.; Tunney, M. M.; Moore, J. E.; Blair, I. S.; Gilpin, D. F.; McDowell, D. A.

    In: Letters in Applied Microbiology, Vol. 47, No. 4, 10.2008, p. 263-268.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Changes in antibiotic susceptibility in staphylococci habituated to sub-lethal concentrations of tea tree oil (Melaleuca alternifolia)

    AU - McMahon, M. A. S.

    AU - Tunney, M. M.

    AU - Moore, J. E.

    AU - Blair, I. S.

    AU - Gilpin, D. F.

    AU - McDowell, D. A.

    PY - 2008/10

    Y1 - 2008/10

    N2 - Aims: To investigate the effect of sub-lethal challenge with tea tree oil (TTO) on the antibiotic resistance profiles of staphylococci. Methods and Results: Isolates of methicillin-resistant/-sensitive Staphylococcus aureus (MRSA and MSSA) and coagulase-negative staphylococci (CoNS) were habituated to sub-lethal concentrations of TTO (72 h). Following habituation, the minimum inhibitory concentrations (MIC) of antibiotics and TTO were determined. Habituated MRSA/MSSA cultures had higher (P < 0.05) MIC values than control cultures for the examined antibiotics. Habituated MRSA/MSSA cultures also displayed decreased susceptibility to TTO. Although the MIC of habituated MRSA/MSSA for the examined antibiotics reverted to control values after subsequent culture in the absence of TTO, the increased MIC against TTO were maintained. When compared with control cultures, habituated CoNS cultures had higher (P < 0.05) MIC values against three-fifths of the antibiotics examined; no changes in TTO MIC were observed. Conclusions: TTO habituation `stress-hardens' MRSA and MSSA, evidenced by transient decreased antibiotic susceptibility and stable decreased TTO susceptibility. Although TTO habituation did not decrease susceptibility of CoNS to TTO, such cultures showed transient decreased antibiotic susceptibility. Significance and Impact of the Study: Application of TTO at sub-lethal concentrations may reduce the efficacy of topical antibiotics used with TTO in combination therapies.

    AB - Aims: To investigate the effect of sub-lethal challenge with tea tree oil (TTO) on the antibiotic resistance profiles of staphylococci. Methods and Results: Isolates of methicillin-resistant/-sensitive Staphylococcus aureus (MRSA and MSSA) and coagulase-negative staphylococci (CoNS) were habituated to sub-lethal concentrations of TTO (72 h). Following habituation, the minimum inhibitory concentrations (MIC) of antibiotics and TTO were determined. Habituated MRSA/MSSA cultures had higher (P < 0.05) MIC values than control cultures for the examined antibiotics. Habituated MRSA/MSSA cultures also displayed decreased susceptibility to TTO. Although the MIC of habituated MRSA/MSSA for the examined antibiotics reverted to control values after subsequent culture in the absence of TTO, the increased MIC against TTO were maintained. When compared with control cultures, habituated CoNS cultures had higher (P < 0.05) MIC values against three-fifths of the antibiotics examined; no changes in TTO MIC were observed. Conclusions: TTO habituation `stress-hardens' MRSA and MSSA, evidenced by transient decreased antibiotic susceptibility and stable decreased TTO susceptibility. Although TTO habituation did not decrease susceptibility of CoNS to TTO, such cultures showed transient decreased antibiotic susceptibility. Significance and Impact of the Study: Application of TTO at sub-lethal concentrations may reduce the efficacy of topical antibiotics used with TTO in combination therapies.

    KW - CoNS

    KW - MRSA

    KW - MSSA

    KW - staphylococci

    KW - tea tree oil

    U2 - 10.1111/j.1472-765X.2008.02420.x

    DO - 10.1111/j.1472-765X.2008.02420.x

    M3 - Article

    VL - 47

    SP - 263

    EP - 268

    JO - Letters in Applied Microbiology

    T2 - Letters in Applied Microbiology

    JF - Letters in Applied Microbiology

    SN - 0266-8254

    IS - 4

    ER -