A An infectious disease is an attack by a microbe on human health. It is usually caused by a virus, a bacterium, or less often, a fungus or parasite.

Q What is an antibiotic?

A An antibiotic is a chemical compound made by one organism to fend off another.

Q What is antibiotic resistance?

A Antibiotic resistance occurs when the target of the antibiotic mutates and no longer is harmed by the antibiotic.

Q Why are bacteria becoming resistant to antibiotics? How does this happen?

A It is a natural process of natural selection, but it is accelerated when the environment has two elements: lots of microbes and lots of antibiotics.

QWhy should we be concerned about antibiotic resistance?

A Increasing resistance limits the number of antibiotics doctors have to fight infection.

Q What can we do to prevent antibiotic-resistant infections?

A We can lessen the use of unnecessary or prolonged antibiotics. One of the biggest threats is the increasing use of antibiotics for colds, and those are almost always due to viruses and antibiotics do not affect viruses.

Luther V. Rhodes III MD, FIDSA, FACP, FSHEA is the chief of the Division of Infectious Diseases at the Lehigh Valley Health Network.