Antibiotic Resistant Bacteria

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The discovery of antibiotics was one of the greatest medical advances in history. Research into antibiotics began with Alexander Fleming, a British microbiologist, who observed a mold growing on an agar plate along with Staphylococcus aureus. It appeared that the growth of Staph aureus was inhibited in the presence of the mold. This led Fleming to theorize that a substance could be derived from the mold that would act against bacteria.

The mold was penicillin, and it did have components that inhibited bacterial growth. Further research with various types of molds has resulted in a wide variety of antibiotics that are effective against many bacteria. In fact,the development of antibiotics has been responsible for a substantial decrease in the number of deaths occurring from infection.

Antibiotic Therapy

In the past, antibiotics have been prescribed readily by physicians, when a patient presented with what appeared to be an infection. If it was a bacterial infection, the antibiotics generally helped. If it was viral, the antibiotics made no difference in the infection. In some cases, patients improved and discontinued taking the antibiotics, rather than completing the entire prescription as directed by their physician.

The overuse and misuse of antibiotics has inadvertently created what may be one of the greatest crises in western medicine - the development of antibiotic resistant bacteria. Because of this, some physicians are more hesitant to prescribe antibiotics for every infection.

Antibiotic Resistant Bacteria

Improper use of antibiotics, such as discontinuing the drug when the symptoms subside has led to antibiotic resistant bacteria. The weaker bacteria will be killed first, leaving the stronger bacteria to survive. The stronger bacteria reproduce, but they have developed the capacity to mutate, altering their DNA structure to change slightly so they are protected from antibiotic therapy. The evolution of bacteria is like the evolution of any other living thing - the strongest survive. During reproduction, bacteria pass on genetic material to their offspring, which may enable slight genetic variations from parent to offspring. This includes resistance to the antibiotic that has been used to treat the symptoms.

In addition, some antibiotics have been used to treat infections which were viral based, rather than bacterial based. In these cases, the infection was unaffected by the antibiotics; however, the antibiotic may still have been a stimulus for genetic mutation.


The name given to bacteria that become resistant to antibiotic treatment is superbugs. Superbugs are bacteria that have altered their DNA structure and are not susceptible to traditional antibiotic therapy.

One of the most prolific superbugs is Staphylococcus aureus, which normally lives on the surface of skin and mucus membranes. These are gram-positive cocci that can cause infections when introduced into a cut or sore, or by a breathing aparatus or catheter.

There are strains of Staphylococcus aureus that have developed high resistance to antibiotics. These are called methilcillin-resistant Staph aureus (MRSa). These antibiotic resistant bacteria are highly resistant to common drugs and are very difficult to treat, particularly if they are hospital acquired.

While most superbugs are hospital acquired and affect those individuals who are immunocompromised, the danger of wide-spread infection cannot be denied. Using antibiotics only when needed, and completing the entire prescribed treatment as directed, can help prevent further development of antibiotic resistant bacteria.


Wassenaar, T.M., Virtual Museum of Bacteria. “Evolution in Bacteria,”

National Network for Immunization Information.