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7/5/2001

Antimicrobial Resistance Is Nearing 'Tipping Point'

Kate Traynor

The health care community's attempts at solving the problem of antimicrobial resistance may be nearing a "tipping point," said Emory University epidemiologist John E. McGowan, Jr., M.D., referring to a phrase made popular last year by writer Malcolm Gladwell.

"The tipping point," McGowan said, "involves contagious behavior. A small number of people who have wide influence start behaving differently, and that behavior spreads to many others."

In this case, the contagious behavior can be traced to clinicians who published important research findings and spread the word about effective ways of fighting antimicrobial resistance.

"In the last year or so," McGowan said, "a number of different groups have provided Web sites that allow hospitals and health care systems throughout the United States to benchmark and compare their efforts and their results both for resistance and for antimicrobial use."

Supplementing research reports and benchmarking, McGowan said, is the proliferation of clinical practice guidelines aimed at reducing antimicrobial resistance. "We can have significant improvements in the way we use antibiotics by using...guidelines," he said. "A number of professional societies are now bringing us combined and cooperative guidelines, and I think this is an advance in dealing with resistance....

"These changes have been happening in the margins. But at the tipping point, their impact is dramatic."

McGowan was in Washington, D.C., for a June 26 press conference sponsored by the National Foundation for Infectious Diseases.

Despite his optimism about recent progress toward overcoming antimicrobial resistance, McGowan cited serious issues that clinicians still face. One alarming finding is that bacterial resistance to vancomycin is on the rise.

"Today, we see some disturbing reports about pneumococcal isolates that are starting to show ways of getting around this important drug," he said. He advised clinicians also to be on the lookout for vancomycin-resistant Staphylococcus aureus. "We don’t have clinical examples of vancomycin-resistant Staph aureus yet, but we’re seeing them in the laboratory," he said. "This, in fact, could be a challenge for us, because Staphylococcus aureus represents a relatively virulent organism."

Another disturbing trend is the appearance in the community of drug-resistant organisms that were once confined to health care institutions. For example, community-acquired infections with methicillin-resistant Staphylococcus aureus are "something that we’ve seen with increasing frequency in the last few years," he said.

One way to deal with resistance to drugs such as vancomycin or methicillin is to develop new antimicrobial drugs. "Industry is beginning to respond to this need," McGowan said. "We had a relative drought for a number of years in new agents that could target some of these [resistant] bacteria...but now we’re seeing more of these developed."

He said researchers are focusing on ways to prevent bacterial infections, not just treat them. Preventive measures include the use of standard infection-control practices and, in the case of Streptococcus pneumoniae, vaccination.

"If you can prevent the occurrence of...resistant organisms," he said, "you don’t have to deal with the difficulty of treating them."

Recent research into the genetic mechanisms of antimicrobial resistance has brought both good and bad news, McGowan said. To illustrate the bad news, he described a recent report of a bacterial isolate with "five different genes that conferred resistance to beta-lactam antibiotics."

"Most of these resistance genes were encoded on one single, large, transferable plasmid," he said, adding that this mechanism could help spread the resistance factors to other bacteria. And other researchers have described a tiny genetic "resistance determinant" in methicillin-resistant Staphylococcus aureus that may be transferred by a molecular mechanism "that we don't know much about preventing."

The good news about such resistance genes, McGowan said, is that "we had no idea that that was the problem until the work was done."

Even though researchers have uncovered some disturbing news about antimicrobial resistance, McGowan viewed the accumulation of scientific information as a good thing. "We now have the data that says we know how to deal with many of these areas of infection, and we’re making progress in [controlling] antibiotic resistance."