Antibiotic resistance

VOL 112 / NO 2 / AUGUST 2002 / POSTGRADUATE MEDICINE

Since the 1940s, antibiotics have been the mainstay of treatment of infections caused by bacteria. These medications kill specific types of bacteria and, when used correctly, are effective in curing infection. However, antibiotics can also be used inappropriately. In part because of their widespread use--and misuse--some bacteria have developed a resistance to these medications. When bacteria survive in spite of antibiotics, we are less able to recover from serious infections and certain diseases.

How antibiotic resistance develops
There are four main reasons why antibiotic resistance develops:

• Demand for and use of antibiotics when antibiotics are not appropriate. Researchers at the Centers for Disease Control and Prevention estimate that one third of all outpatient prescriptions for antibiotics are unnecessary. Antibiotics do not harm viruses. When you take antibiotics for viral illnesses, such as a cold or the "flu," they primarily attack the "good" bacteria that live in your body naturally. When you have fewer of these "good" bacteria, your body provides favorable conditions for "bad" bacteria to thrive.
• Failure to finish an antibiotic prescription. Even though an antibiotic is effective in attacking susceptible bacteria, some resistant ones may survive, especially if you don't take enough of the medication to do the job. These surviving resistant bacteria multiply as a resistant strain, or group, and are more difficult to treat. The drug-resistant bacteria can also spread from one person to another.
• Misuse and overuse of antibiotics in livestock and agriculture. Sometimes antibiotics are mixed into livestock feed in an effort to help the animals grow. Although the amounts are too little to treat infection in livestock, they may be just enough to keep resistant bacteria going strong. In addition, antibiotics may be sprayed on plants and trees to destroy bacteria on produce. The antibiotic residues left on these fruits and vegetables may attack the good bacteria in our intestines--and let the more powerful, resistant, and harmful strains survive.
• Availability of antibiotics without a prescription in some countries. Many people have taken antibiotics for colds and other minor "bugs," not knowing that the medication works only on bacterial infections. This overuse has led to the production of more drug-resistant strains of bacteria.

Treating resistant bacteria
If resistance develops to one antibiotic, your doctor will prescribe a different antibiotic in order to fight the infection. However, many bacteria are resistant to more than one antibiotic. In fact, infections involving a few kinds of resistant bacteria are untreatable.

Preventing antibiotic resistance

• Talk to your healthcare provider about how bacteria are different from viruses and when antibiotics should and shouldn't be used (see box on this page). Don't pressure your doctor to prescribe antibiotics to treat viral infections such as a cold or the flu. Instead, be open to remedies that may help relieve your symptoms. Let your cold run its course. It takes time to recover from a cold or the flu. Call your doctor if your illness lasts longer than 2 weeks.
• When given antibiotics, take them exactly as directed and complete the full course, even if you are feeling better. If you stop using the medication early, the surviving bacteria may come back stronger than ever.

Preventing the need for antibiotics

• Wash your hands thoroughly with soap and warm water before preparing or eating food and after using the toilet.
• Wash fruits and vegetables to remove any resistant bacteria or residue from antibiotic sprays.
• Avoid eating raw eggs and undercooked meat, especially in ground form.

When to use antibiotics

Illnesses that are caused by bacteria and can be treated with antibiotics:

• Some ear infections
• Sinus infections. Antibiotics should be used only for severe infections or infections that last longer than 2 weeks. Keep in mind that a runny nose plus discolored mucus does not always mean that you need an antibiotic.
• Strep throat. Your healthcare provider will do a throat swab to determine if you have this illness, which is caused by Streptococcus bacteria.
• Urinary tract infections
• Some coughs or bronchitis. If you have a problem with your lungs or an illness that lasts longer than usual, bacteria may be the cause. In this case, your doctor may prescribe an antibiotic.

Illnesses that are caused by viruses and cannot be treated with antibiotics:

• All colds and "flu"
• Most sore throats
• Some ear infections
• Most coughs or bronchitis

This information is not a substitute for medical treatment.

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