Antimicrobial 'good' and 'bad' bacteria

                        I think this is a numbers thing. The zones of inhibition visible in aromatograms certainly must affect both good and bad bacteria but they impact most on the 'bad' bacteria which are trying to proliferate and now find they cant in the presence of the essential oil constituents.

                       Antibacterial/Antimicrobial EO's only impacts "bad" not "good"?

Q.  I'm looking for a better understanding of this concept. If anyone can help me with a explanation or a reference I'd really appreciate it. I'm a student of aromatherapy and I understand a handful of oils have constituents that are effective for some nasty bacteria strains. The question is how have these EO's become so smart that they know to leave our "good" bacteria in tact and only go after the "bad/nasty" ones? Or do you have a opinion that they go after good AND bad when they are doing their job?  so I'm trying to understand if the EO's containing antimicrobial actions would basically have the same effect (externally or internally used).

A.  Just a wild guess, I am no microbiologist but my thought is that 'bad' bacteria are doing something 'bad' in a differant way to good bacteria. There is a difference of intent and behaviour. For example once the 'bad' bacteria detect a weakness with the body's defences by detecting enough of their fellows around they start to form colonies and rapidly proliferate giving off toxins and disrupting the bodies cells and tissues.

Then there is an issue of action. Inhibition or destruction. I guess the EO constituents are as much disrupting the bad bacteria's communications as actually disrupting their cell membranes. The 'good' bacteria are keeping their heads down anyway. They are inhibited but only as long as the EO constituents around and then its life as normal. They must be replicating but not in such numbers as to necessitate an immune response.

The good bacteria are not wildly proliferating anyway so are not affected by this disruption of communications. Certainly there is some chemical intelligence at work because the body is sensing at a micro level the difference between good and bad bacteria and attacking the bad bacteria with the immune system.

In a sense the 'bad' bacteria are not eliminated but go back to being good(ish) bacteria again. This is an issue I have with the medical orthodoxy that an active ingredient can in all cases effect a 'cure'. Once a pathogen is introduced to the body the sad fact is that on the whole they dont go away even though health is restored.

When we look at the more chronic impacts of the 'bad bacteria' we look at the formation of plaques which the body's immune system constituents and antibiotics are too big to penetrate. Eo constituents are small enough to do penetrate the biofilms and inhibit the bacteria. These biofilms are no differant from the plaque on our teeth but forming in the heart arteries and in the brain they can be very damaging and of course you cant brush them away.

Turning to the chemistry...............

 It is the sesquiterpene lactones which first caught my eye and some display this bicyclic 7 carbon ring, 5 carbon ring azulene structure
http://en.wikipedia.org/wiki/Sesquiterpene_lactone
as do other better known anti-inflammatory constituents
http://en.wikipedia.org/wiki/Chamazulene (blue)
http://en.wikipedia.org/wiki/Vetivazulenehttp://en.wikipedia.org/wiki/Guaiazulene
and working back to the antibacterial theme
di-aldehyde
http://en.wikipedia.org/wiki/Velleral
sesquiterpene alcohol
http://en.wikipedia.org/wiki/Carotol
Caratol is some 40% of carrot oil and that certainly isnt blue. However it seems active properties of some important essential oils both anti-inflammatory and antibacterial may derive from the 7, 5 structure of azulene which certainly food for thought.
Are good bacteria as affected by the behaviour of these constituents as bad ones. Having identified the chemical structure of interest we can now delve into the research to see if anyone has subjected differant bacteria to azulene or its derivatives. Maybe a research project in there alright!


Ian Brealey