Monday, November 18, 2013

The antibiotics crisis


Why are antibiotics so important?
Without them, modern medicine would not be possible. Arguably the most important factor in the 30-year jump in American life expectancy in the 20th century, these "wonder drugs" allow us to fight the whole gamut of bacterial illness, from everyday ear infections to diseases such as syphilis, typhoid, and tuberculosis that used to kill millions of people. Their discovery about 100 years ago also revolutionized the world of surgery: As antibiotics drastically reduced the number of post-operative infections, standard operations that used to be considered perilous — such as appendix removals — became safe and routine. But as life expectancy climbed, Alexander Fleming, who discovered penicillin, sounded an alarm. "There is the danger," he said in his 1945 Nobel Prize acceptance speech, "that the ignorant man may easily underdose himself and by exposing his microbes to nonlethal quantities of the drug make them resistant."

Was he right?
Yes, unfortunately. Thousands of Americans are now dying every year from infections that used to be curable. The Centers for Disease Control and Prevention recently warned that drug-resistant bacteria kill at least 23,000 people annually in America and cost the U.S. health-care system $20 billion a year. Three "nightmare" superbugs, the CDC says, have become of "urgent" concern (see box). The crisis has become so pressing that CDC official Dr. Arjun Srinivasan has warned that we could be entering a "post-antibiotic era." If that proves true, the repercussions would be devastating. Treatments we take for granted — like organ transplants, premature-infant care, and chemotherapy, which weakens the patient's immune system — would be put in jeopardy. Even routine medical procedures like the placement of a catheter could be considered too dangerous. In a post-antibiotic world, said Margaret Chan, director-general of the World Health Organization, in 2012, "things as common as strep throat or a child's scratched knee could once again kill."

How did superbugs develop?
Through evolution. Over time, some bacteria develop genetic mutations that make them immune to antibiotics used against them. When a particular type of antibiotic is used again and again, those tougher, resistant bacteria survive while their susceptible counterparts die off. Eventually, the resistant bacteria begin to outnumber the vulnerable bacteria and, in effect, take over — rendering that particular generation of antibiotic ineffective. That gives rise to infectious diseases that can't be treated. Though this process is natural, humans have accelerated it enormously.

How are we making it worse?
As Fleming feared, antibiotics are being widely misused. Fully half of human antibiotic use is inappropriate, estimates the CDC. A lot of people underuse antibiotics, stopping their treatment as soon as they start feeling better, before all the target bacteria are killed off, leaving the tougher residual microbes to grow and spread. But by far the worst negligence comes through overuse. Too many patients demand antibiotics from their doctors, even if they have viral illnesses that these drugs can't treat, such as the common cold or the flu. Though only 10 percent of adults with sore throats have a bacterial infection, doctors prescribe antibiotics in about 60 percent of sore throat cases. Factory farms make even more profligate use of antibiotics. A staggering 80 percent of the antibiotics sold in this country are fed to farm animals, to plump them up and keep them alive in their overcrowded habitats. This practice exposes vast armies of bacteria to antibiotics, making them more and more resistant.

Why not just develop new antibiotics?
Pharmaceutical companies say that it's too expensive. Antibiotics require billions of dollars to develop, but people usually take them for just a few days, with a single course of most antibiotics selling for a few hundred dollars. Including the cost of discovery and development, the average new antibiotic loses $50 million, according to the federal Office of Health Economics. Drug companies can make billions, however, developing medications for chronic diseases such as diabetes and heart disease, which are taken by patients for the rest of their lives. As a result, there have been no major new antibiotics since 1987. "We're losing ground because we are not developing new drugs in pace with superbugs' ability to develop resistance to them," said Helen Boucher from the Infectious Diseases Society of America.

Can this crisis be solved? 
It can, but only if pharmaceutical companies are given sufficient financial incentive to create new antibiotics. Last year, Congress passed the GAIN Act hoping to encourage new antibiotic development. The law extends patents for new antibiotics, so that inventors can maximize their profits before generics get in on the game, and fast-tracks approval for antibiotics that target certain pathogens. But the industry says the new law is only a "first step." Companies are urging Congress to approve tax credits to help cover the costs of research and development. Even if new antibiotics are eventually developed, the problem will reoccur unless livestock farmers stop pumping their animals full of antibiotics, and doctors and patients stop misusing the drugs for nonbacterial illnesses. The alternative, says Chan, "is the end of modern medicine as we know it."

The threat of super gonorrhea
Three nightmare superbugs have become so virulent that they pose an "urgent" risk to the health of Americans, says the CDC. The first is C. difficile, a deadly diarrhea-causing infection; the second, a bloodstream infection that kills half the people it infects; and the third, a drug-resistant form of gonorrhea — an age-old sexually transmitted disease that's evolved to become resistant to the last drug available against it, raising the prospect of a sexually transmitted global epidemic. This "super gonorrhea" tends to spread through unprotected oral sex. The microbes sit in the throat, multiply, and can enter the bloodstream, infecting the skin, heart valves — and even the brain. Some public officials predict that super gonorrhea will be widespread in five to eight years, and that we'll be powerless to fight it. "We're getting closer and closer to the edge of the cliff," warns CDC Director Tom Frieden.

http://theweek.com/article/index/252858/the-antibiotics-crisis

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