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November 7, 2002

KILLER BACTERIA: What you and your doctor should know

With another cold and flu season approaching, many physicians will be prescribing antibiotics to help patients cope with aches, chills, coughs and sniffles.

There are two problems with this:

• Antibiotics are useless against viral infections such as the common cold, influenza and most sore throats.

• Overuse of antibiotics is the leading promoter of antibiotic-resistant bacteria, according to the federal Centers for Disease Control (CDC) and Prevention.

Infections involving antibiotic-resistant bacteria kill at least 40,000 Americans each year, the CDC estimates.

Antibiotic resistance occurs when bacteria evolve in ways that reduce or eliminate the effectiveness of drugs designed to cure or prevent infections.

For one-celled organisms, bacteria have proven to be amazingly creative in acquiring resistance since the discovery of antibiotics in the 1940s — “as if the bacterial world was mirroring humanity’s own ever-quickening pace of development,” wrote Michael Shnayerson and Mark J. Plotkin in their book, “The Killers Within: The Deadly Rise of Drug-Resistant Bacteria” (Little, Brown and Co., 2002).

“Some [bacteria] succeeded in making their cell walls impermeable to antibiotics. Others created tiny pumps that actually vomited them out of the cell,” noted Shnayerson and Plotkin. “Many antibiotics targeted one enzyme or another of the cell wall itself, attaching to it just as the bacterium was making more cell enzymes in order to replicate; yet many bugs had figured out how to change or replace those enzymes so that the drug failed to attach. Still other bugs’ enzymes attacked the drug itself, slicing its chemical rings. The broad-spectrum antibiotics that most doctors reached for first were the ones likeliest to provoke these mechanisms.”

According to the CDC, “Today, virtually all important bacterial infections in the United States and throughout the world are becoming resistant,” and lethally resistant bacteria now reside in every hospital and nursing home in the world.

Especially at risk are the old and chronically ill; the very young, whose immune systems are immature, and patients such as cancer survivors and recipients of transplanted organs whose resistance to infection has been lowered by immunosuppressive drugs.

Bacteria flourish around, in and on us. Billions colonize our skin, noses, throats, stomachs and gastrointestinal tracts. Most of these bacterial strains are helpful (aiding digestion, for example) or benign. But some — such as S. aureus, the most virulent of the staphylococci, or “staph” bacteria — can cause pneumonia as well as deadly infections, given access to the bloodstream of a weakened host through, say, a cut in the skin. Some 20-40 percent of all humans are believed to carry S. aureus bacteria on their skin or in their noses.

To prevent antibiotic resistant infections, the CDC recommends the following:

• Talk with your health care provider about antibiotic resistance. Ask specifically whether an antibiotic is likely to be beneficial for your illness.

• Do not take an antibiotic for a viral infection such as a cold or the flu. The CDC estimates that up to 40 percent of the antibiotics prescribed in doctors’ offices each year in the United States are for viral infections. “There are many reasons for this, including demand from patients, time pressure on physicians, and diagnostic uncertainty,” wrote Richard Besser, medical director for CDC’s National Campaign for Appropriate Antibiotic Use, on the CDC’s website at <>. “The patient wants to get back to work or get the child back to school, and the doctor wants the patient to feel satisfied with treatment. The result is over-prescribing of antibiotics, resulting in the development of resistant bacteria.”

• Take an antibiotic exactly as your doctor tells you. Do not save some of your antibiotic for the next time you get sick.

• Do not take an antibiotic that is prescribed for someone else.

Pitt’s David L. Paterson, director of UPMC Health System’s new Antibiotic Management Program, added two recommendations:

• Avoid buying antibiotics in foreign countries, especially in Asia, Latin America (including Mexico) and eastern Europe, where antibiotics — often counterfeit or less than full-strength — are sold over the counter.

“If you’re not getting full-strength antibiotics, you’re not necessarily killing all of the germs,” Paterson said. “We know that, in a test tube, the best way to create antibiotic resistance is to give bacteria a less-than-killing dose of antibiotic. It makes the bacteria stronger and more able to resist the drug.”

• Especially in a hospital, ask health care providers to wash their hands before touching you.

“The No. 1 reason that antibiotic resistance occurs in hospitals is patient-to-patient transmission of resistant bacteria, usually on the hands of doctors and nurses,” Patterson said. “Doctors and nurses sometimes get too busy to wash their hands. It’s inexcusable but it is a fact of life in busy clinical medical settings. My advice to patients is: Be assertive. Ask if your doctor and nurse have washed their hands before allowing them to touch you. If necessary, insist that they wash their hands.”

When it’s suggested to him that many patients are reluctant to order their doctors around, Paterson laughed. “It’s not an easy issue,” he acknowledged. “It takes time for patients to become assertive, but it can be done.”

Like a growing number of other U.S. health care organizations, UPMC has installed dispensers of a waterless, alcohol-based, disinfectant liquid throughout its hospitals. “Doctors and nurses can clean their hands in 30 seconds using this liquid,” Paterson said, “whereas surveys show it takes three or four times that long using soap and water, not counting the time it takes to find a sink.”

Nutritionists and epidemiologists offer still more advice: Watch what you eat and how you cook it.

A study published in the March 1998 issue of Scientific American reported that of the 50 million pounds of antibiotics used in the United States each year, nearly half was being consumed by chickens, cows and other livestock.

Feeding livestock a steady (often daily) diet of antibiotics protects the animals against diseases and may promote growth, the agriculture industry maintains. Scientists say the latter claim is unproven and that animals, like humans, suffer in the long run from antibiotic overuse.

Overuse of antibiotics in livestock, scientists argue, is a sure way to breed resistant bacteria that can be passed on to people who handle the animals or eat undercooked meat.

And bacteria don’t respect international borders. Molecular biologists have traced the spread of bacterial pathogens such as antibiotic-resistant Salmonella (increasingly found in agricultural products) around the world.

— Bruce Steele

Filed under: Feature,Volume 35 Issue 6

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