Antibiotic Resistance in Healthy Adults

Misuse of Antibiotics Leads to Increased Amounts of Resistant 'Super' Bugs

Oct. 9, 2003 -- The public has turned a deaf ear on warnings about antibiotic overuse. But antibiotic-resistant staph infections are on the rise, and it's happening in otherwise healthy people. In fact, four children have died.

Several new studies address this issue -- pointing to people's misconceptions about antibiotic resistance and their own risk.

The reports are being presented at the annual Infectious Diseases Society of America meeting in San Diego this week.

One serious problem: Commonly called staph infection, Staphylococcus aureus used to be found mostly in hospitals and was easily treated with antibiotics. But since the mid-1980s, staph has become increasingly resistant to antibiotics and has shown up outside of hospitals.

As infections with these resistant bacteria increase in frequency, doctors become more and more limited in their options to treat them.

"It's happening throughout the country," says Stuart H. Cohen, MD, professor of medicine at the University of California, Davis, School of Medicine and Medical Center, in a news release. "It's probably been smoldering for years, but recently, it's almost like a switch got triggered. ... It rings a warning bell that physicians and patients need to address antibiotic resistance head-on."

It's potentially life threatening: Four healthy children who contracted resistant bacteria died because doctors did not realize the seriousness of the infection. The children didn't get appropriate treatment in time.

Risk factors for children include having a family member who is hospitalized, being in day care, or having taken many antibiotics, experts say.

Understanding Staph

Actually, many people have staph bacteria "colonized" -- living naturally -- in their bodies yet don't feel any ill effects from it, according to the CDC. But if these people get cut or get a cold, -- anything that shakes up their immunity -- a staph infection can set in.

Others who do not carry staph bacteria can also get infected if exposed to it. These infections may be caused by antibiotic-resistant staph bacteria.

Many of these antibiotic-resistant staph infections can cause deep skin infections and create an abscess that needs to be surgically drained. When staph bacteria are determined to be resistant to the antibiotic methicillin, doctors have to decide which other antibiotic to prescribe -- some are given intravenously, while others are very expensive.

The antibiotic vancomycin is very good in treating methicillin-resistant staph infections. "But we're very worried that if we use it a lot, we'll start seeing resistance to it," says researcher Gloria P. Heresi, MD, professor of pediatric infectious diseases at The University of Texas Medical School in Houston, in the news release.

Methicillin-Resistant Infections

Cohen's study of 1,637 staph infections showed that 21% were resistant to the antibiotic methicillin. Of 176 resistant bacteria studied, 59% were acquired in the community and 42% were hospital-acquired.

About one in five patients with community-acquired resistant infections did not have diabetes or use intravenous drugs, which heightens risk for antibiotic-resistant infections.

"In the next few years, the routine antibiotics used to treat staph infection in healthy folks likely will not work anymore," says Cohen. "We may need to use more expensive drugs, or those with more side effects."

More Methicillin Resistance

In Houston's hospitals, 60 children were treated for community-acquired staph infections. Of those, 45% turned out to have methicillin-resistant infections.

Another not-yet-completed study shows that, in upcoming years, nearly 70% of staph infections will be resistant to methicillin, says Heresi. "It seems as though the bacteria are more virulent," she says.

One child developed a serious hip infection and, as a result, developed a blood clot in the leg that could have been fatal.

Penicillin, Erythromycin, Cotrimoxazole Resistance

One group of researchers tested three antibiotics -- penicillin, erythromycin, and cotrimoxazole -- for resistance to S. pneumoniae, a bacterium that causes pneumonia, ear infections, and sinusitis.

In 1992, researchers detected virtually no resistance to all three antibiotics. But in 2001, more than one in five (21%) infections were antibiotic-resistant.

Other studies have shown that one in four children had resistance to all three antibiotics.

Resistance to amoxicillin has remained relatively stable at about 9%. However, resistance to some of the newer antibiotics -- like erythromycin -- is higher, about 28% and increasing, reports researcher Robertino M. Mera, a professor at Louisiana State University Health Sciences Center in New Orleans.

Experts' advice:

  • Not every infection requires antibiotics. Many infections are viral and antibiotics will do nothing to eradicate them.
  • When an antibiotic is prescribed, patients should finish all the medication -- even if they feel better before they have taken all the pills.

The problem of antibiotic resistance has become serious, they say. It's no longer just a concern for the elderly or hospitalized people.

Show Sources

SOURCES: 41st Annual Meeting of the Infectious Diseases Society of America, San Diego, Oct. 9-12, 2003. News release, Infectious Diseases Society of America.
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