I spotted the article below recently and stored it away for reference at a later stage. I’ve now decided to reproduce it here as I feel it’s a useful explanation of how MRSA (methicillin-resistant Staphylococcus aureus) survives despite exhaustive attempts at infection control.
With thanks to the author whose identity escapes me.
Why does MRSA exist?
It’s all about survival of the fittest – the basic principle of evolution, and bacteria have been around a lot longer than us, so they’re pretty good at it.
There are countless different strains of a single type of bacteria, and each has subtle natural genetic mutations which make it different from the other.
In addition, bacterial genes are constantly mutating.
Some strains’ genetic make-up will give them a slight advantage when it come to fighting off antibiotic attack.
So when weaker strains encounter antibiotics, they die, while these naturally resistant strains may prove harder to kill.
This means that the next time you encounter Staph, it is more likely to be one which has survived an antibiotic encounter i.e. a resistant one.
The advice from doctors who give you antibiotics is always to finish the entire course – advice which many of us ignore.
When you don’t finish the course, there’s a chance that you’ll kill most of the bugs, but not all of them – and the ones that survive are of course likely to be those that are most resistant to antibiotics.
Over time, the bulk of the Staph strains will carry resistance genes, and further mutations may only add to their survival ability.
Strains that manage to carry two or three resistance genes will have extraordinary powers of resistance to antibiotics.
The reason that hospitals seem to be hotbeds for resistant MRSA is because so many different strains are being thrown together with so many doses of antibiotics, vastly accelerating this natural selection process.
Clever things bugs aren’t they! You too can do your bit to keep them at bay. Always finish the entire course of an antibiotic and make sure you wash your hands properly to prevent the spread of germs. After all, this is all about the survival of the fittest.