Our bodies are covered with bacteria. Even the most fastidious among us provides a home for about one trillion of the tiny organisms, comprising about one-twentieth of our body weight! Most of these creatures are harmless, like those within our intestinal tracts that help us digest food. But others can make us really sick. Forty-four thousand Americans die each year from bacterial infections, twice the number who die from AIDS in the United States.

For decades, drugs known as antibiotics have been the major weapon against bad germs. But health experts are growing increasingly concerned about the dramatic rise in drug-resistant bacteria in the United States and around the globe.

Mark Plotkin writes scary stories about people attacked by aggressive superbugs. Take the case of Evangeline Ames Murray, who nearly met her fate on a New York commuter train when flesh-eating bacteria entered her body and began to munch away at her arm. "Who needs science fiction when you have necrotizing fasciitis? This is a bug that attacks you, that eats your flesh and if you don't get to the doctor in a hurry you die," says Mr. Plotkin.

Evangeline Ames Murray got to the doctor in time. She was lucky. The drugs worked. Other patients do not respond to antibiotic treatment and die.

Mark Plotkin and co-author Michael Shnayerson explore the dilemma in their new book, The Killers Within: The Dramatic Rise of Drug Resistant Bacteria. Mark Plotkin says "bacteria have been around for at least 3.5 billion years: "living, killing, and mutating without the slightest regard for us." "Of course they don't have brains, but what they do have is the ability to evolve and evolve in a hurry. They create a new generation every twenty minutes," he says. "What they have learned to do is thicken their cell wall to keep antibiotics out, to vomit the antibiotics out once they get in there. They are incredibly clever little beasts, which is why they have been able to survive for three billion years."

Before the age of antibiotics, millions of people died routinely from staph, strep and tuberculosis infections. Then, during the World War II, the world's first "miracle drug," penicillin, was introduced to cure battlefield infections like gangrene, septicemia and pneumonia. "We began to beat these bad bugs back. It was like the atom bomb," he says. "The bacteria [were] on the run. But in fact within three years of it hitting the market, resistance began to appear."

Ethnobotanist Mark Plotkin says with each new miracle drug - streptomycin, erythomycin, methicillin, or vancomycin - bacteria resistance is not far behind. While hospitals are the largest breeding ground for these drug resistant strains, bacteria are everywhere.

Mr. Plotkin says an antibiotic that is used incorrectly when people take it in too small a dose, for example, or for too short a time allows bacteria to develop mutations or to import drug resistance from other bacteria. "The reason that they have done that is that all of us who have been given a course of antibiotics and after four days we have said, 'Our cold is gone, and so I am not going to take the next three days," he says. "In fact I am going to give it to my neighbor because he seems to have the same symptoms.' So, this not listening to the doctor lets the resistant bugs take over the playing field because the bugs susceptible to the drugs were killed off by the antibiotics. If you had taken all seven days you would have stood a greater chance of killing off all of them."

Over-prescription of antibiotics is another reason for the dramatic rise in drug resistant bacteria. New research says one-third of the 150 million outpatient prescriptions each year in the United States are unnecessary.

Pamela Parker faces this issue everyday in her pediatric medical practice in the Washington suburbs. About 20 percent of the sick children she sees during winter months have ear infections.

Parker: "The children who come in after a sleepless night with pain and a fever are put on an antibiotic."
Skirble: "How do you know when a child comes in whether they have a virus or a bacterial [infection]?"
Parker: "There is the dilemma of the pediatric practice. You go by what researchers have delineated and that is with coughs and colds and runny noses, most likely in the first two or three weeks of coughing and a runny nose it is all a viral process. Less than five percent will turn into a bacterial secondary infection, sinusitis pneumonia. But in small children, many more colds and flu will lead to an ear infection. So in small children you end up using antibiotics for ear infections when they appear, but you can see an ear infection."

The United States produces 23 million kilograms of antibiotics a year. Half that amount is administered to farm animals - chickens, cows and pigs - partly to treat or reduce infections, but mainly as a livestock growth promoter. Mark Plotkin is critical of this non-therapeutic use of antibiotics.

He says the practice breeds drug-resistant bacteria and he argues for the drugs' removal from the food supply, a precaution already adopted by some European countries. "I realize there is a cost, but I also point out that there is a successful model that shows that the money saved on antibiotics can be spent on hygiene and [to] create a product that isn't ridden with drug-resistant bacteria."

Co-author Mark Plotkin says that as activists wage war on antibiotics in food, scientists continue to engage in medical assaults on drug resistant germs. "And the way you stay ahead of the bacteria is that you find and develop new antibiotics. You develop better hygiene. You do genomics and understand how their genes fit together. But, also you look for new approaches."

Some of the new approaches that Mr. Plotkin explores in The Killers Within, include finding new anti-bacterial compounds in Nature. For example, researchers have discovered a germicidal protein in the thick saliva of Indonesian Komodo dragons, and the skins of African clawed frogs, shark bellies and silk moths. Co-author Mark Plotkin says it is this natural bounty that offers the greatest hope for treatment, not just of bacterial infections, but all diseases.