One of the most common problems today associated with control of infection is the over prescribing of antibiotic drugs. Many infections that we are familiar with such as colds and flu are caused by viruses which cannot be treated by antibiotics. Only bacteria are susceptible to antibiotics. However it is often the case that patients expect antibiotic treatment and doctors may prescribe them as a precaution against a possible secondary infection. As a result we now see the development of super bugs or antibiotic resistant bacteria. But how does antibiotic therapy cause super bugs to evolve?

There are several mechanisms at play here the first one being Random Mutation. This is actually a completely normal process. In any bacterial growth a certain amount of mutation will occur. Sometimes a mutation will confer an advantage to a bacterial cell which causes it to be resistant to the effects of an antibiotic. In this situation the susceptible bacterial cells are killed by the antibiotic leaving the resistant cells free to replicate and form a new strain. This is a basic species survival mechanism leading to the rise of new resistant strains of bacteria.

Plasmids are another weapon in the bacteria’s arsenal against antibiotics. These are extra pieces of genetic material which exist independently within the bacterial cell. They are in a constant state of change, acquiring and losing genetic information. If the genetic information in a plasmid confers resistance to an antibiotic, it can replicate and be passed quickly from cell to cell. In this way antibiotic resistance can easily develop and spread within the colony.

A third mechanism which bacteria can avail of is the use of Transposons. These are even tinier pieces of DNA material. Transposons have often been called jumping genes. They can jump from a plasmid to a chromosome and vice versa. They can easily transfer resistant genes and pass this resistance on from cell to cell.

When we use antibiotics all of the above mechanisms come into play and combine to create the super bugs that we hear about from time to time. Of course it is absolutely necessary to use antibiotics to treat infection but using them when they are not strictly necessary actually contributes to the development of resistant super bug strains.