Tea tree is used medicinally as an antimicrobial, and when diluted, can be effective against a range of vaginal pathogens. The most effective type of oil comes from Australian and New Zealand tea tree plants (Melaleuca alternifolia).
New research is filtering in slowly, however more is required to establish just where the parameters of tea tree are. So far, it has been established that tea tree oil has antibacterial, antifungal, antiviral and antiprotozoal activity.
Lactobacilli are somewhat resistant to tea tree oil, with pathogens susceptible at lower concentrations. This means tea tree oil can be used with positive effect for killing pathogens in the vagina, while sparing lactobacilli to a certain degree.
Tea tree (M. alternifolia) is effective against the following vulvovaginal/urinary tract infection-associated bacteria:
- Acinetobacter baumannii
- Actinomyces viscosus
- Actinomyces spp.
- Bacillus subtilis
- Bacteroides spp.
- Corynebacterium sp.
- Enterococci (10 minutes to an hour)
- Enterococcus faecalis (10 minutes to an hour)
- Enterococcus faecium (10 minutes to an hour)
- Escherichia coli
- Fusobacterium nucleatum
- Gardnerella vaginalis
- Klebsiella pneumoniae (30 minutes)
- Lactobacillus spp.
- Micrococcus luteus
- Mobiluncus spp.
- Peptostreptococcus anaerobius
- Porphyromonas gingivalis
- Prevotella spp.
- Prevotella intermedia
- Propionibacterium acnes
- Proteus vulgaris
- Pseudomonas aeruginosa (depends on oil used, can be effective from 1 to 1.5 hours)
- Serratia marcescens
- Streptococcus pyogenes (Group A Strep)
- Staphylococcus aureus (takes about 30 minutes)
- Methicillin-resistant Staphylococcus aureus (MRSA) (takes 1.5 to 6 hours)
Tea tree (M. alternifolia) oil is effective against the following vulvovaginal/urinary tract infection-associated yeast/fungi:
- Aspergillus flavus
- Aspergillus fumigatus
- Aspergillus niger
- Candida albicans
- Candida glabrata
- Candida parapsilosis
- Candida tropicalis
- Cryptococcus neoformans
- Saccharomyces cerevisiae
- J. May, C. H. Chan, A. King, L. Williams, G. L. French; Time–kill studies of tea tree oils on clinical isolates, Journal of Antimicrobial Chemotherapy, Volume 45, Issue 5, 1 May 2000, Pages 639–643, https://doi.org/10.1093/jac/45.5.639
- Singh BR, Vadhana P, Bhardwaj M, Vinodh Kumar OR, Sinha DK, et al. (2016) Comparative Antimicrobial Activity of Tea Tree Oil (Melaleuca Oil) and Common Topical Antimicrobials against Bacteria Associated With Wound and Topical Infections. Pharm Anal Acta 7:513. doi: 10.4172/2153-2435.1000513
- Carson CF, Hammer KA, Riley TV. Melaleuca alternifolia (Tea Tree) oil: a review of antimicrobial and other medicinal properties. Clin Microbiol Rev. 2006;19(1):50-62.
- Hammer KA, Carson CF, Riley TV. In vitro susceptibilities of lactobacilli and organisms associated with bacterial vaginosis to Melaleuca alternifolia (tea tree) oil. Antimicrob Agents Chemother. 1999;43(1):196.