A. Several months ago, the U.S. Centers for Disease Control and Prevention released astunning report on the impact of resistant bacteria. According to the analysis, whichCDC officials said was conservative, more than 2 million people are infected in theUnited States each year by bacteria that are resistant to a wide array of the safest andmost effective antibiotics. Of those, at least 23,000 die. The illnesses and deaths costsociety some $55 billion annually--S20 billion from additional health-care spendingand $35 billion from lost productivity. "If we are not careful, we will soon be in apost-antibiotic era," said Dr. Tom Frieden, the director of the CDC. "And for somepatients and for some microbes, we are already there."
B. Resistant bacteria spread not only with cross-contamination from people who arealready sick or unknowingly carrying the microbes; they also come from foodAmericans eat. Indeed, a current multistate outbreak of a multi-drug-resistant straincalled Salmonella Heidelberg (海德堡沙门氏菌) was traced to Foster Farms brandchicken. At present, the microbe had infected more than 300 people in 20 states andPuerto Rico; more than one third of them required hospitalization.
C. In the past, drug-resistant bacteria were relatively easy to confront, with pharma-ceutical ( 制药品 ) companies pumping out ever-more sophisticated antibiotics. BigPharma isn't investing much time or effort in these lines of treatment these days--why commit hundreds of millions of dollars to research and develop a new antibioticthat will only be taken by a patient for a few days, when a breakthrough drug for, say,diabetes could be both unique and used by people for a lifetime?
D. "We have an increasing antimicrobial resistance across the world and we have adecreasing pipeline of new antibiotics," said Dr. Ed Septimus, a professor of internalmedicine at Texas A&M Health Science Center and Medical Director for the InfectionPrevention and Epidemiology Clinical Services Group at HCA Healthcare System. "Itis a perfect storm in which, for some patients, it will feel like we are going back to the pre-antibiotic era." What would it be like living in a world without antibiotics? You can say goodbye to many lifesaving procedures we now consider commonplace.
E. Take heart transplants--they can be performed only because surgeons are confident the antibiotics they give patients before the procedure will prevent a postoperative infection. The same holds true for other complex surgeries. Chemotherapy (化疗) severely inhibits the immune system, which is why chemo patients require antibiotics. "So many of these medical miracles that we take for granted are only possible because we have been able to deal with infectious complications," said Ruth Lynfield, the state epidemiologist ( 流行病专家 ) and medical director at the Minnesota Department of Health. "If we can't do that, those areas of medicine--surgery, transplants, intensive care, neonatal (新生儿 ) care——could be lost."
F. And it could be even worse. Several medical experts noted that while a virus causedthe influenza pandemic of 1918, most of the tens of millions of people who perished from the disease died of a bacterial infection in the lungs. With effective antibiotics, that complication can be treated. Given the scarcity of viral vaccines in much of the world, if a resistant bacteria takes hold, all anyone could do is find an effective way to dispose of the bodies. Given the stakes, it is astonishing to realize the causes of this threat are well-understood and the ways to attack it well-known. Even as far back as 1945, Alexander Fleming, a pioneer in antibiotics, said, "the misuse of penicillin( 青霉素 ) could be the propagation of mutant ( 突变) forms of bacteria that would resist the new miracle drug."
G. In essence, this crisis is looming because the world consumes too many antibiotics. In the United States, doctors prescribe them too often, many times because patients demand them for illnesses that are not bacterial and thus cannot be treated with antibiotics, such as colds and other sicknesses caused by viruses. The CDC found that the greatest use of antibiotics for humans occurs in the Southern states, a fact that medical experts struggle to explain. One thing the data and studies indicate, though, is that the areas with the highest use are most likely to experience the most resistant bacteria.
H. But the amount of antibiotics used humans for medical purposes pales in comparison to the quantities fed to American livestock--pigs, cattle, and the like. According to the Food and Drug Administration, about 80 percent of all antibiotics sold in 2011 were used on animals, primarily for spurting growth.
I. What makes the use of antibiotics for growth in meat and poultry ( 家禽 ) productionparticularly troublesome, experts say, is the low dosages. Using small amounts of antibiotics is more likely to create resistant bugs, the experts said, because the microbes are not wiped out. Instead, the bacteria are essentially trained to resist thedrugs. "It creates a reservoir of drug-resistant genes," said Dr. Henry Chambers, aprofessor of medicine at University of California San Francisco.
J. Antibiotics are also used for animals in the United States as aprophylactic ( 预防药品 ),to prevent infections likely to spread because of the meat and poultry productionprocess. These so-called "production diseases" are the result of a system which placesever larger numbers of animals into ever smaller containment areas, exposing them toeach other's feces, urine and--as a result--bacteria. "We need to change the animalproduction system, where animals are healthier and infections become the exceptionand not the norm," said Dr. Lance Price, a professor at the George WashingtonUniversity School of Public Health and Health Services who specializes in studyingresistant bacteria. "We should prevent infections in animals by not overcrowdingthem, not packing them in together and not exposing them to easy contamination."
K. The connection between antibiotic usage in animals and the development of resistantbacteria has long been recognized in Europe, which banned the use of the drugs asgrowth promoters in 2006. In the United States, the FDA only imposed voluntaryrestrictions in 2012, which, experts said, seems to have done little to decrease usageof antibiotics for livestock. "When you compare our use of antibiotics for animals towhat they're seeing in Europe," said Lynfield, "we are not doing well."
L. Despite the magnitude of the risk, many basic strategies for containing and identifyingthreats have not been adopted. For example, there is no comprehensive international surveillance of threats from antibiotic resistance; identification only occurs with the appearance of an outbreak rather than through examination of strains. According to the CDC, there is no systematic collection of detailed information about the use of antibiotics either in human health care or in agriculture in the United States. Without the ability to track, isolate and identify these pathogens (病原体 ) , the both state and government health officials are unable to act until people start showing serious signs of illness or dying.
M. Medical experts agree that the use of antibiotics to spur growth in animals or to prevent disease caused by processing techniques has to stop. They also say that up to half of the usage of antibiotics by humans is unnecessary. Programs to engage in what is known as "antibiotic stewardship"--training physicians on the proper uses of the drugs and even limiting the ability of doctors in hospitals who are untrained in infectious diseases to prescribe antibiotics--have begun to be implemented, although they are not yet widespread. Since large pharmaceutical companies have little economic incentive to develop antibiotics, the experts say, government has to step up, funding basic research into new treatments that would cut the cost for the development and sale of new drugs.
N. The hardest step could be restraining the international use of antibiotics. Many resistant strains are emerging in India and Southeast Asia, where antibiotics can be purchased without a prescription, according to Dr. Trevor Van Schooneveld, medical director of the Antimicrobial Stewardship Program at the University of
Nebraska Medical Center. The resistant strains that emerge in those locations easilyspread around the world; for instance, a resistant bacterium that causes urinary tractinfections emerged not long ago in New Delhi; it is now being found in the UnitedStates.
O. The failure to pursue these solutions have left infectious-disease specialists frustratedas they see the world moving further and further away from the promise offered somany decades ago by antibiotics. Governments, they fear, may not act forcefully untilthe problem becomes overwhelming. "We may have to wait until the deaths of somereally prominent and previously healthy people," said Relman. "It might be that onlyby shocking the public will we be able to have the world take this threat seriously."