How Long Did It Take For
MRSA Bacteria to Evolve?

Maybe you were just reading about MRSA bacteria on the MRSA symptoms page and wondered how long it might take for a Multi Resistant bacteria to evolve.

Just to start with a few quick basics - someone asked me "What is bacteria?" a common enough query - if grammatically dubious! Bacteria is of course a 'plural' noun so to be accurate we should ask "what are bacteria?"! A single member of this community is a 'bacterium'. Indeed all bacterium are essentially single, because unlike humans or more complex species they require no partner to reproduce!

Bacteria are also singular in that they are 'single cell organisms'. Each bacterium is just one cell. In a group they can appear as, say, a slime or a 'mold' or, within infected, moist regions of the human body can appear as a 'white mass' using a internal observation equipment.

Bacteria reproduce by 'binary fission' - that is when a single cell is mature and nourished, and at the right temperature, all of its component will begin to perfectly sub-divide. Eventually a sort of internal wall will completely surround each half of the components of the cell -- including a perfectly bisected nucleus. At this point the two halves will begin to separate completely until two perfect and complete bacteria exist where once there had been only one.

This efficient form of pro-creation will continue rapidly in the right conditions. Each bacterium sub-dividing again and again every half hour or so (some species even reproduce every 10 minutes!).

You'll have heard about 'viral e-mails' or the concept of viral growth perhaps. Because of binary fission bacteria reproduce in a perfect geometric progression, under the right conditions. That is to say:

...and so on....and remember, that is just from ONE bacterium!
All in somewhere between 2 and 5 hours!

But remember - MRSA bacteria, or any other kind, never do travel around alone! Singular they may be, but they are certainly gregarious. In fact taking the suggestion from http://archive.food.gov.uk/ that about a million bacteria would create a clump about the size of a pinhead...

One good wet un-contained sneeze...and you could have have potentially several hundred million Staphylococcal bacteria winging their way across the void to infect numerous sources! In so many millions, what chances that one or two might be potentially resistant types, or even MRSA bacteria, if put to the test?! They could become the progenitors of colonies of trillions!

Bacteria simply need food and warmth to start growing like wild fire. Some also need oxygen (aerobes) whilst others need the complete lack of oxygen (anaerobes)...

...But, I'm getting carried away, and I bought you here to consider the mathematics of evolution given the power of bacteria to reproduce so quickly and efficiently.

Let us assume first of all, for comparison, that Man has developed from cave dweller to the "fine, intelligent, designer-dressed" creature that s/he is today over a period of about 200,000 years or so. Indeed it is thought that Neaderthals, our early ancestors, may even have existed as long as 400,000 to 500,000 years ago.

Let us further assume that given a fair wind and good fortune Man has the potential to live to around 70 years of age, if not forestalled by accident or illness. Then for the whole on Man's existence approximately 210,000/70 = 30,000 lifetimes have passed. Or if we take the greater figure 420,000/70 - 60,000 lifetimes have passed!

If we compare this with MRSA bacteria - and consider how long 30 to 60 thousand lifetimes might be, we should get an idea of how long it takes for a single simple 'Neanderthal' bug to transform into a 'Superbug' -- shouldn't we?

Simple Staphylococcus aureus has 'become' a superbug -- namely MRSA bacteria -- and made its presence felt, in relatively recent times. So how long might it have taken to evolve.

If we reckon an a typical lifespan for MRSA bacteria is 30 minutes (after which it will have become 2 'new' bugs!!) And if we assume that it will take between 30 to 60 thousand lifetimes to evolve as much as Man has -- for the original Staph aureus to become a 'super' version of itelf...

then:

30,000 x 1/2 (30 mins = half an hour ;-D)= 15,000 hours!!

60,000 x 1/2 = 30,000 hours.

This implies it might take between:

15,000/24 = 1250

and

30,000/24 = 2500

Which equates to 3.4 to 6.8 years!

So now we simply need to ask...How long have antibacterial cleaners been being used in hospitals?

Of course it is a bit more complex than this. MRSA - or originally Methicillin Resistant Staph Aureus (common parlance now tends to call it Multi-Resistant, as various strains are resistant to more than just the overused penicillin related antibiotic of the 1970's!) was first noted in certain difficult infections, between 1961 and the late 1970's (depending on your sources). So naturally -- it was clear that sometimes Staphylococcus aureus infections were appearing that were resistant to antibiotics from as long ago as maybe 40 odd years!.

So, When you know that a resistant strain has appeared what do you do?

Well, it seems, throw every other anti biotic, and then every kind of antibacterial at it until you get a phenomenally intractable bacteria that is impossible to KILL it seems!

Isn't that clever of us?!

(P.S. As a matter of historical interest Dial (later known as Armour Dial) introduced the first antibacterial soap in 1948 in the US. By 1953 this was the biggest selling soap in America in dollar value and continues as a premier brand The company also lays claim to having introduced the first antibacterial liquid soap in 1987.

The liquid soap was formulated using Triclosan and anti bacterial agent that has now been banned in some countries. Whilst those with vested interests down play the problems that might develop from over use of Triclosan, numerous studies have suggested that a variety of potential issues might be related to its use.)

NOW - forget the MRSA Bacteria Math!! For comprehensive answers about MRSA - its diagnosis, treatment and those who have survived it - go here: