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Revenge of the MicrobesAwake!—1996 | February 22
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The Limitations of Medical Science
Other reasons why infectious diseases are making a comeback relate to medical science itself. Many bacteria now defy antibiotics that once killed them. Ironically, antibiotics themselves have helped to create this situation. For example, if an antibiotic kills only 99 percent of the harmful bacteria in an infected person, the surviving one percent that resisted the antibiotic can now grow and multiply like a superstrain of weeds in a newly plowed field.
Patients aggravate the problem when they do not finish a course of antibiotics prescribed by their doctor. Patients may stop taking tablets as soon as they begin to feel better. While the weakest microbes may have been killed, the strongest survive and quietly multiply. Within a few weeks, the disease reoccurs, but this time it is harder, or impossible, to cure with drugs. When these drug-resistant strains of microbes invade other people, a serious public-health problem results.
Experts at WHO stated recently: “Resistance [to antibiotics and other antimicrobial agents] is epidemic in many countries and multi-drug resistance leaves doctors with virtually no room for manoeuvre in the treatment of an increasing number of diseases. In hospitals alone, an estimated one million bacterial infections are occurring worldwide every day, and most of these are drug-resistant.”
Blood transfusions, used increasingly since the second world war, have also helped to spread infectious diseases. Despite the efforts of science to keep blood free of deadly microbes, blood transfusions have contributed significantly to the spread of hepatitis, cytomegalovirus, antibiotic-resistant bacteria, malaria, yellow fever, Chagas’ disease, AIDS, and many other dreadful diseases.
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Revenge of the MicrobesAwake!—1996 | February 22
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When Microbes Fight Back
A small microbe known as a bacterium “weighs as little as 0.00000000001 gram. A blue whale weighs about 100,000,000 grams. Yet a bacterium can kill a whale.”—Bernard Dixon, 1994.
Among the most feared bacteria found in hospitals are drug-resistant strains of Staphylococcus aureus. These strains afflict the sick and the weak, causing deadly blood infections, pneumonia, and toxic shock. According to one count, staph kills about 60,000 people in the United States each year—more than those who die in car accidents. Over the years, these strains of bacteria have become so resistant to antibiotics that by 1988 there was only one antibiotic effective against them, the drug vancomycin. Soon, however, reports of vancomycin-resistant strains began to surface from around the world.
Yet, even when antibiotics do the job they’re supposed to do, other problems may arise. In mid-1993, Joan Ray went to a hospital in the United States for a routine operation. She expected to be home in just a few days. Instead, she had to remain in the hospital for 322 days, primarily because of infections she developed after surgery. Doctors fought the infections with heavy doses of antibiotics, including vancomycin, but the microbes fought back. Joan says: “I couldn’t use my hands. I couldn’t use my feet. . . . I couldn’t even pick up a book to read it.”
Doctors struggled to find out why Joan was still sick after months of antibiotic treatment. Laboratory work showed that in addition to staph infection, Joan had another kind of bacteria in her system—vancomycin-resistant enterococcus. As the name suggests, this bacteria was unharmed by vancomycin; it also seemed to be immune to every other antibiotic.
Then doctors learned something that flabbergasted them. The bacteria not only resisted the drugs that should have killed it but, contrary to what they expected, it actually used vancomycin to survive! Joan’s doctor, an infectious-disease specialist, said: “[The bacteria] need that vancomycin in order to multiply, and if they don’t have that they won’t grow. So, in a sense, they’re using the vancomycin as food.”
When the doctors stopped giving Joan vancomycin, the bacteria died, and Joan got better.
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