What is Drug Resistance?

Antimicrobial resistance is the ability of microbes, such as bacteria, viruses, parasites, or fungi, to grow in the presence of a chemical (drug) that would normally kill it or limit its growth.

Credit: NIAID

Diagram showing the difference between non-resistant bacteria and drug resistant bacteria. Non-resistant bacteria multiply, and upon drug treatment, the bacteria die. Drug resistant bacteria multiply as well, but upon drug treatment, the bacteria continue to spread.

• Many infectious diseases are increasingly difficult to treat because of antimicrobial-resistant organisms, including HIV infection, staphylococcal infection, tuberculosis, influenza, gonorrhea, candida infection, and malaria.
• Between 5 and 10 percent of all hospital patients develop an infection. About 90,000 of these patients die each year as a result of their infection, up from 13,300 patient deaths in 1992.
• According to the Centers for Disease Control and Prevention (April 2011), antibiotic resistance in the United States costs an estimated $20 billion a year in excess health care costs, $35 million in other societal costs and more than 8 million additional days that people spend in the hospital.
• People infected with antimicrobial-resistant organisms are more likely to have longer hospital stays and may require more complicated treatment.

To prevent antimicrobial resistance, you and your healthcare provider should discuss the appropriate medicine for your illness. Strictly follow prescription medicine directions, and never share or take medicine that was prescribed for someone else. Talk with your healthcare provider so that he or she has a clear understanding of your symptoms and can decide whether an antimicrobial drug, such as an antibiotic, is appropriate.

Do not save your antibiotic for the next time you get sick. Take the medicine exactly as directed by your healthcare provider. If your healthcare provider has prescribed more than the required dose, appropriately discard leftover medicines once you have completed the prescribed course of treatment. For more information about how to properly dispose of unused medications, visit the Food and Drug Administration Web site.

Healthy lifestyle habits, including proper diet, exercise, and sleeping patterns as well as good hygiene, such as frequent hand washing, can help prevent illness, therefore also preventing the overuse or misuse of medications

Diagnostic tests are designed to determine which microbe is causing infection and to which antimicrobials the microbe might be resistant. This information would be used by a healthcare provider to choose an appropriate antimicrobial treatment. However, current diagnostic tests often take a few days or weeks to give results. This is because many of today’s tests require the microbe to grow over a period of time before it can be identified.

Oftentimes, healthcare providers need to make treatment decisions before the results are known. While waiting for test results, healthcare providers may prescribe a broad-spectrum antimicrobial when a more specific treatment might be better. The common practice of treating unknown infections with broad-spectrum antimicrobials can accelerate the emergence of antimicrobial resistance.

If you think you have an infection of any type—bacterial, viral, or fungal—talk with your healthcare provider. Some infections will go away without medical intervention. Others will not and can become extremely serious. Ear infections are a good example: Some middle ear infections are caused by a virus and will get better without treatment. However, other middle ear infections caused by bacteria can cause perforated eardrums, or worse, if left untreated.

The decision to use antimicrobials should be left to your healthcare provider. In some cases, antimicrobials will not shorten the course of the disease, but they might reduce your chance of transmitting it to others, as is the case with pertussis (whooping cough).

Antibiotics are designed to kill or slow the growth of bacteria and some fungi.  Antibiotics are commonly used to fight bacterial infections, but cannot fight against infections caused by viruses.

Antibiotics are appropriate to use when

1. There is a known bacterial infection
2. The cause of the infection is unknown and bacteria are suspected. In that case, the consequences of not treating a condition could be devastating (e.g., in early meningitis).

Of note, the color of your sputum (saliva) does not indicate whether you need antibiotics. For example, most cases of bronchitis are caused by viruses. Therefore, a change in sputum color does not indicate a bacterial infection.