Transmission electron micrograph of Escherichia coli O157:H7. CDC/Peggy S. Hayes

Alarming increases in antimicrobial resistance around the world show no sign of slowing, warned clinicians and biologists today. To add to the dilemma, the development of new antimicrobial agents is unlikely to fill the gap in a hurry.

"Ten years ago there were more than 20 agents approved [by the FDA]," said Stephen Zinner, chair of the Department of Medicine at Mount Auburn Hospital in Cambridge, Massachusetts. "In the last year, only one or two agents have been approved."

The costs of bringing an anti-infective to the market place are prohibitive, says Zinner. A study by the Boston Consulting Group (BCG) suggests that the entire process costs in the region of $802,000,000. "Almost a billion dollars!" he exclaimed.

The same study estimated that the development process takes between 10 and 15 years. With a patent lifetime of only 20 years, says Zinner, "you can see the disincentives to drug development becoming more obvious."

And yet, he added, "antimicrobials have saved more lives than any other class of medicinal product."

Physicians and scientists must focus on the future if any headway is to be made, says Don Low, microbiologist-in-chief at Mount Sinai Hospital in Toronto. Low predicts an increase of about 20% in levels of resistance among important pathogens such as Eschirichia coli over the next 20 years.

Thus, antimicrobials will become progressively less useful, Low says. "We're going to see the loss of important compounds," he warned, "and we're not exactly answering the need with new products."

"The common theme for this battle of dealing with antimicrobial resistance is we have to have good surveillance," said Low.

Low praises the efforts of the pharmaceutical company Bayer, which has set up a worldwide antimicrobial-resistance surveillance service. The new Web-based surveillance service, called Libra, will provide access to local data on microbial resistance collected at different geographic locations.

"You can argue about the limitations of that kind of data because it's not done centrally, it's not done by one testing methodology," said Low, "but the scope of the data, the magnitude of the data, can give you some idea with regards to trends."

Once you have this broad picture, he says, then you can "dig down" and ask more important questions, such as what is driving the resistance or what mechanisms are giving rise to that resistance.

"That can then be done by having isolates from several different areas brought in centrally, characterized centrally by one testing methodology, and recorded," said Low.

Fifteen years ago, the US Centers for Disease Control decided it was no longer necessary to continue their surveillance program for resistance in pneumococci "because it wasn't an issue," recalled Low. The decision was eventually reversed, but the results were disastrous.

"Now resistance is no longer found in just certain hot-beds throughout the US," said Low, "but from coast to coast, with high level resistance intermediates and macrolide resistance." Pneumococcal resistance is now a "global crisis," he said, with resistance levels above 50% in parts of Asia.