Download Due to natural variation, one or a small few of the millions of cells of

Due to natural variation, one or a small few of the millions of cells of a
particular pathogen may be lucky enough to be resistant to an antibiotic.
When this antibiotic is used many bacteria are killed leaving this lucky
pathogen cell alone to reproduce on its own - passing on its resistance. If
the antibiotic is overused then the number of antibiotic resistant cells will
grow in number. This most has most famously happened with the MRSA
bacteria, where overuse of the antibiotic methycillin has lead to a whole
strain of bacteria resistant to it!
It is important to remember that antibiotics work against bacteria
only.
Antibiotics have no effect against viral diseases.
Viruses reproduce inside human cells which makes them very difficult
to treat with drugs without damaging these cells as well – which can
lead to secondary infections.