Take the Antibiotics Quiz

Antibiotics kill only bacteria. They do not have any effect on viruses. Sometimes, when you take an antibiotic, the bacteria may be resistant or become resistant, the CDC says. Resistant bacteria do not respond to the antibiotic and continue to cause infection. You should take antibiotics only when necessary. Each time you take an antibiotic unnecessarily (for a viral infection, for example) or improperly (taking a partial dose, for example), you increase your chance of developing drug-resistant bacteria. Because of resistant bacteria, diseases such as tuberculosis, pneumonia and meningitis that once were easy to treat with antibiotics are now becoming much more difficult to treat. Once a particular type of bacteria has developed resistance to a drug, it can pass on that resistance to other types of bacteria.

Viruses cause all colds and influenza, as well as most coughs and most sore throats. Antibiotics cannot kill viruses. Taking an antibiotic for a cold or the flu will not affect the course of your illness and may contribute to bacterial resistance. (In children, this is especially critical, because children often play in close contact and can easily pass resistant bacteria onto others, spreading the problem.) Your doctor will probably prescribe an antibiotic if you have an ear infection, sinus infections, strep throat or a urinary tract infection. Many of these infections are caused by bacteria.

These antibiotics are called "narrow-spectrum" antibiotics. The other major category of antibiotics is called "broad-spectrum." These antibiotics are used to treat more severe infections that don't respond to the narrow-spectrum type. Unfortunately, more and more doctors have turned to the broad-spectrum antibiotics for less severe infections, a recent study says. Experts fear that overuse of these broad-spectrum antibiotics will lead to more bacterial resistance. These broad-spectrum antibiotics are more expensive than narrow-spectrum antibiotics. Antibiotics also are classified as fighting gram-positive or gram-negative bacteria, or as fighting anaerobic organisms or aerobic organisms.

It's important to take the full dose of medicine prescribed for your illness. If you stop taking the medicine before you have completed the dose, some of the bacteria that caused your illness may still be in your body. If the bacteria are exposed to only a small dose of an antibiotic or if an antibiotic is not given enough time to kill the bacteria, the bacteria will develop resistance to the antibiotic. The next time the antibiotic is given, the bacteria will not be susceptible to it. They can then multiply in number and cause your illness to recur. They can transfer their drug resistance to the next generation of bacteria.

You should not take antibiotics left over from a previous illness. These antibiotics would make up only a partial dose, which would not be enough to fight off a bacterial infection and could create bacterial resistance. More important, your current illness may not be caused by bacteria, which would make the antibiotics useless. Always check with your health care provider before taking any antibiotic.

That's why taking an antibiotic can cause symptoms associated with loss of good bacteria such as diarrhea, vaginal yeast infections, oral thrush, and an inflammation of the small intestine and colon called enterocolitis. If you have any of these side effects, be sure to tell your health care provider.

Improper use of antibiotics contributes to bacterial resistance to these drugs. Half of the 100 million prescriptions written in this country each year are unnecessary because they are prescribed for the common cold and other viral infections, the CDC says. Ask your health care provider why an antibiotic was not prescribed for your illness, but don't demand one. Your health care provider is the best source of information on antibiotic use.

Although many antibiotics are safe to take if you are pregnant or breast-feeding, some are not. Some of these drugs can affect your growing fetus. Your health care provider will make the correct choice of medication for you. Be sure to tell your health care provider if you are breast-feeding.

Although hospitals and other medical facilities use antibacterial soaps, they follow strict guidelines for their use, according to the Alliance for the Prudent Use of Antibiotics. Some health experts are concerned that using antibacterial soaps at home can increase bacterial resistance to these soaps. Studies have not proved that these soaps work any better than ordinary soaps to eliminate bacteria.

Although many people mistakenly believe this, it is not true. It is the bacteria themselves, not the person who harbors the bacteria, that become resistant to antibiotics.