Essential oils from plants such as tea tree (Melaleuca alternifolia), peppermint (Mentha piperita), and eucalyptus (Eucalyptus camaldulensis) have demonstrated antibacterial properties against multidrug-resistant bacteria through their ability to damage bacterial cell membranes and disrupt cellular functions. These essential oils represent promising alternatives or adjuncts to conventional antibiotics for treating infections caused by multidrug-resistant pathogens like MRSA and ESBL-producing E. coli and Klebsiella. Further research is needed to better understand their synergistic effects when combined with antibiotics to potentially enhance antibacterial activity.

1. COMBATING MULTIDRUG
RESISTANT BACTERIA WITH
ESSENTIAL OILS
Miguel Diaz

2. MICROBIAL COMPETITION
http://www.livescience.com/
• Competition for limited resources
• Excretion of chemicals that are toxic
and inhibit growth
http://virtuallaboratory.colorado.edu

3. COEVOLUTION
• Intrinsic resistance
• Spontaneous mutations
http://learn.genetics.utah.edu/

4. PATHOGENS
• Disease causing organisms
www.cdc.gov
http://www.bacteriainphotos.com/bact
eria-photo-gallery.html

5. BACTERIA
• Bacterial Classification
• Gram Positive
• Gram Negative

6. DISCOVERY OF ANTIBIOTICS
• 1928 Alexander Fleming discovered
Penicillin
• Antibiotics have had a significant
impact on human health and life
• “Wonder” drug
http://sciencenational.tumblr.com/

7. MODES OF ACTION
• Selective for bacterial cells
• Unique processes
• Metabolic pathways
• Bacteriostatic vs Bactericidal
• Narrow vs Broad Spectrum

8. ANTIBIOTICS
• Treat bacterial infections
• Life saving
• extending the human lifespan
• Naturally, Synthetic, Semi-Synthetic
• Zone of inhibition
• Minimum Inhibition Concentration
(MIC)

9. ERA OF ANTIBIOTICS
• Overuse
• Misuse
"The thoughtless person playing with penicillin
treatment is morally responsible for the death of
the man who succumbs to infection with the
penicillin-resistant organism.”
A. Fleming

10. RESISTANCE
• Intrinsic Evolutionary event
• Genes chromosomal or plasmid
• HGT
• R plasmids
https://www.niaid.nih.gov

11. R-PLASMIDS
https://classconnection.s3.amazonaws.com
• Plasmids
• Non-chromosomal DNA
• Housekeeping genes
• Some carry resistant genes
• R-plasmids

12. ANTIBIOTIC RESISTANCE

13. MECHANISM OF RESISTANCE
• Modify and inactivate
• ẞ-lactams
• Penicillin
• Prevent drug uptake
• Chloramphenicol
• Pump it out
• Efflux Pump
• Tetracycline

14. HORIZONTAL GENE TRANSFER
• Sharing of genetic material
• across different genera
• 3 mechanisms
• Transformation
• uptake of DNA from the
environment
• Transduction
• Virus mediated
• Conjugation
• cell to cell sharing
• type IV pili

15. MULTIDRUG RESISTANCE
http://www.moleculin.com/
Multidrug Efflux Pump
http://evolution.berkeley.edu/
• R-plasmid with many resistant genes

16. MULTIDRUG RESISTANCE
• ESKAPE Pathogens
• Enterococcus faecium (VRE)
• Staphylococcus aureus (MRSA)
• Klebsiella and Escherichia coli producing ESBL
• Acinetobacter baumannii
• Pseudomonas aeruginosa
• Enterbacteriaceae

17. POST ANTIBIOTIC ERA?
• Little research and development
• Mutations can happen quickly and
are easily shared
• What now?
“ We are headed to a post antibiotic era, in which common infections and minor
injuries can once again kill” WHO 2015
http://bk.asia-city.com

18. ESSENTIAL OILS
http://www.questnetproxy.com/
• Traditional medicine
• Topical or inhaled
• Some toxic if ingested
• Generally safe
• Chemotype
• Changes in chemical
phenotype
• Steam distillation

19. ESSENTIAL OIL: MODES OF ACTION
http://www.mdpi.com/pharmaceuticals
• Degrade cell wall
• Damage cytoplasmic membrane
• Increase permeability
• Leakage of cell contents
• Damage membrane proteins
• Coagulation of cytoplasm
• Depletion of proton motor force

20. TERPENOIDS
• Secondary plant metabolite
• Isoprene subunits
• Volatile Compounds
• Easley evaporated
• Give plants fragrance (essence)

21. MELALEUCA ALTERNIFOLIA
http://www.teamessence.com.my/
• Native to Australia
• Aboriginals use it for treating infections
• Know for its antiseptic, antibiotic
properties
• Main constituents
• terpinen-4-ol
• -terpineol

22. TEA TREE OIL
• Cell Membrane Permeability
• Leak K+
• E. coli and S. aureus
• Cell Respiration
• Decrease O2 consumption rate

23. TEA TREE
Lee et al. 2014

24. MENTHA PIPERITA
https://www.tuinplant.nl
• Native to Europe and Middle
East
• Menthol and Mentone
• Medicinal Uses
• Analgesic, cooling,
antiemetic
• muscle rubs
Bakkali et al. 2008

25. PEPPERMINT OIL
Singh et al. (2011)

26. PEPPERMINT OIL
Bazargani and Rohloff (2016)
• Anti-plasmid activity
• Menthol 96%
• In combo with promethazine 100%
Anti-biofilm

27. EUCALYPTUS CAMALDULENSIS
https://upload.wikimedia.org/wikipedia/commons/8/82/Eu
calyptus_trunk_zebra_pattern.jpg
• Indigenous to Australia
• Medicinal Purpose
• anesthetic, antiseptic, astringent
• Constitutes
• p-cymene (35.0%)
• cryptone (13.7%)
• tanins (11%)
• terpinen-4-ol (5.7%)

28. EUCALYPTUS
http://www.mdpi.com/molecules
Jazani et al. 2012

29. OTHER ESSENTIAL OILS

30. ESSENTIAL OILS AND MDRO
• Essential oils can reduce the use of antibiotic
• Preventative measures
• Reduce inflammation response
• Antiseptic
• Cleaning hospital surfaces
• Alternative treatments
• Effective against a broad spectrum of bacteria
• Synergistic effects
• In combination with antibiotics
• Decrease MIC
• Increase zone inhibition

31. REFRENCES
• Bazargani MM, Rohloff J. 2016. Antibiofilm activity of essential oils and plant extracts against Staphylococcus
aureus and Escherichia coli biofilms. Food Control 61:156–164.
• www.cdc.gov
• Cox.S.D. 2000. The model of antimicrobial action of the essential oil of Melaleuca alternifolia. J. Appl.
Microbiol. 88:170–175.
• Jazani NH, Mikaili P, Shayegh J, Haghighi N, Aghamohammadi N, Zartoshti M. 2012. The hydro-alcoholic
extract of leaves of Eucalyptus camaldulensis Dehnh. has antibacterial activity on multi-drug resistant bacteria
isolates. J. Appl. Biol. Sci. 6:37–40.
• Knezevic P, Aleksic V, Simin N, Svircev E, Petrovic A, Mimica-Dukic N. 2016. Antimicrobial activity of
Eucalyptus camaldulensis essential oils and their interactions with conventional antimicrobial agents against
multi-drug resistant Acinetobacter baumannii. J. Ethnopharmacol. 178:125–136.
• Lee RLP, Leung PHM, Wong TKS. 2014. A randomized controlled trial of topical tea tree preparation for MRSA
colonized wounds. Int. J. Nurs. Sci. 1:7–14.
• Singh R, Shushni MAM, Belkheir A. 2015. Antibacterial and antioxidant activities of Mentha piperita L. Arab. J.
Chem. 8:322–328.