Antimicrobial Resistance

Antibiotics and similar drugs, together called antimicrobial agents, have been used for the last 70 years to treat patients who have infectious diseases. Since the 1940s, these drugs have greatly reduced illness and death from infectious diseases. Antibiotic use has been beneficial and, when prescribed and taken correctly, their value in patient care is enormous. However, these drugs have been used so widely and for so long that the infectious organisms the antibiotics are designed to kill have adapted to them, making the drugs less effective. Many fungi, viruses, and parasites have done the same. Some microorganisms may develop resistance to a single antimicrobial agent (or related class of agent), while others develop resistance to several antimicrobial agents or classes. These organisms are often referred to as multidrug-resistant or MDR strains. In some cases, the microorganisms have become so resistant that no available antibiotics are effective against them.

Drug Resistance Is Everywhere
Antimicrobial drug resistance occurs everywhere in the world and is not limited to industrialized nations. Hospitals and other healthcare settings are battling drug-resistant organisms that spread inside these institutions. Drug-resistant infections also spread in the community at large. Examples include drug-resistant pneumonias, sexually transmitted diseases (STDs), and skin and soft tissue infections.

The Effects of Antimicrobial Drug Resistance Are Far-Reaching
People infected with drug-resistant organisms are more likely to have longer and more expensive hospital stays, and may be more likely to die as a result of the infection. When the drug of choice for treating their infection doesn’t work, they require treatment with second- or third-choice drugs that may be less effective, more toxic, and more expensive. This means that patients with an antimicrobial-resistant infection may suffer more and pay more for treatment.
 
Trends in Drug Resistance
Reports of methicillin-resistant Staphylococcus aureus (MRSA)—a potentially dangerous type of staph bacteria that is resistant to certain antibiotics and may cause skin and other infections—in persons with no links to healthcare systems have been observed with increasing frequency in the United States and elsewhere around the globe.
Multi-drug resistant Klebsiella species and Escherichia coli have been isolated in hospitals throughout the United States.
Antibiotic-resistant Streptococcus pneumoniae infections have significantly declined, but remain a concern in some populations.
Antimicrobial resistance is emerging among some fungi, particularly those fungi that cause infections in transplant patients with weakened immune systems.
Antimicrobial resistance has also been noted with some of the drugs used to treat human immunodeficiency virus (HIV) infections and influenza.
The development of antimicrobial resistance to the drugs used to treat malaria infections has been a continuing problem in many parts of the world for decades. Antimicrobial resistance has developed to a variety of other parasites that cause infection.

http://www.cdc.gov/drugresistance/about.html