Our grandparents’ generation first witnessed the wonders of antimicrobial agents. These drugs saved millions of lives and rendered harmless a number of previously untreatable fatal illnesses. But their overuse has led to antibiotic-resistant bacteria.

The causes of overuse include overprescribing in medicine and widespread use in agriculture. Did you know that an estimated 70% to 80% of antibiotics in the United States are used not to treat human disease but to prevent disease in swine, poultry, and beef cattle and to promote faster growth of these animals? About half of these antibiotics, including tetracycline, penicillin, and erythromycin, are in the same drug classes as those given to humans. Over a protracted period, low doses cause resistance that worsens over time, leading to more virulent diseases.

Agricultural antibiotic overuse creates other risks, too. Bacteria can pass to humans working in the livestock industry who handle the animals, their feed, or excrement, and these workers in turn can transmit resistant bacteria to others. Manure also contaminates ground and surface water, soil, and the air. Even more concerning, GI-tract bacteria can contaminate meat that reaches grocery stores.

Several groups are working actively to combat growing antibiotic resistance by reducing agricultural and medicinal use. “Keep Antibiotics Working: The Campaign to End Antibiotic Overuse” (www.keepantibioticsworking.com) seeks to contain the public health threat of antibiotic resistance by reducing overuse and misuse and banning the use in healthy farm animals of antibiotics important to human treatment. It also advocates education for consumers and providers about prudent antibiotic use. The Centers for Disease Control and Prevention (CDC), Food and Drug Administration, Union of Concerned Scientists, and World Health Organization also recognize this global public health threat and offer guidance on reducing antibiotic resistance.

Much of the responsibility rests with healthcare providers. The CDC’s “Campaign to Prevent Antimicrobial Resistance in Healthcare Settings” (www.cdc.gov/drugresistance/healthcare/default.htm) directs clinicians to diagnose and treat infections effectively, prevent infection and transmission, and use antimicrobials wisely. It focuses especially on patients more prone to infections—hospitalized adults and children, surgical patients, dialysis patients, and those in long-term care.

Hospitals contribute to antimicrobial resistance worldwide. Vulnerable patients on prolonged antibiotic therapy may develop infections with drug-resistant organisms. At least three organisms have become “superbugs” in hospitals because treatment with existing antibiotics has become ineffective—methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and Clostridium difficile (commonly called C. diff). Worldwide, other culprits include penicillin-resistant Streptococcus pneumoniae and multiresistant salmonellae and Mycobacterium tuberculosis.

In the last 5 years or so, the rate of infections has more than doubled and the C. diff organism is growing more prevalent and harder to control. Health­care workers must be sure to use appropriate precautions to prevent its spread.

Resistant infections significantly increase patients’ length of stay, morbidity, and mortality, which raises the costs of care. They also complicate placement of patients in facilities along the continuum of care. Many long-term care facilities struggle to provide sufficient staff to care for patients requiring isolation. Beyond the gowns and gloves, the social isolation separates patients from caregivers; care may be delayed or decreased to patients in isolation.

Consumers play a role, too. For a long time, they have inappropriately demanded anti­biotics for conditions such as the cold and flu. Direct-to-consumer advertising urges consumers to request newer and more expensive antibiotics with supposedly greater potency. Poor patient compliance with prescribed treatment also contributes to the spread of resistance. When patients forget to take medications or stop therapy early because they feel better or can’t afford the medication, the organisms that haven’t been killed can adapt.

Breaking the cycle of antibiotic resistance requires a global strategy that can be achieved through partnerships of governments, consumers, prescribers, dispensers, veterinarians, the pharmaceutical industry, and professional groups. The problem keeps growing, and now is a great time to take local action to reduce the consequences.