Hospitals across the country are beginning to restrict the use of their most potent antibiotics and isolate their sickest patients to try to stop the evolution of “super bugs” - germs that resist all known drugs.
Of special concern is the emergence of resistance to vancomycin, an antibiotic that is the sole remaining weapon against some of the most lethal microbes.
The spread of drug-resistant germs is the No. 1 topic among the 12,000 infectious-disease experts at this week’s Interscience Conference on Antimicrobial Agents and Chemotherapy, sponsored by the American Society for Microbiology.
“We really are running out of therapeutic options for common diseases,” said Dr. Michael Scheld, the conference’s program chairman.
For patients, the rise of drug-resistant germs means that the medicine they get for their infection may not make them better. Often, this is little more than an inconvenience. More than 100 antibiotics are now on the market, and if one fails to work, doctors can always switch to another.
However, many fear the time is growing near when there will be no alternative antibiotic to turn to.
Since people are most likely to catch antibiotic-resistant germs in hospitals, many are developing strategies to control their spread.
Some hospitals, for example, are experimenting with limiting doctors’ ability to prescribe vancomycin, since indiscriminate use of the medicine is likely to speed up the evolution of resistant bugs.
Already, some strains of a relatively harmless form of bacteria called Enterococcus faecium are resistant to all antibiotics. Occasionally, these germs cause lethal bloodstream infections. However, they are usually a danger to only the sickest patients, whose immune systems are already weakened.
Far more dangerous is an extremely common hospital-spread bug called Staphylococcus aureus. This germ is the leading cause of wound infections after surgery and often causes pneumonia and bloodstream infections.
Unlike enterococcal infections, which often get better without treatment, this staph germ can be fatal unless killed with drugs. And often, the only medicine that will control it is vancomycin, which has been on the market since the 1960s.
The enterococci carry their vancomycin-thwarting ability on tiny loops of genetic material called plasmids. Experts fear that one of these bugs will pass its plasmid to Staphylococcus aureus, making it impervious to the last weapon against it.
“The worst fear we have has not happened yet, but there is no guarantee it won’t,” said Dr. Clyde Thornsberry, director of MRL Pharmaceutical Services in Franklin, Tenn., which monitors antibiotic resistance worldwide.
Resistant bugs are most likely to afflict the sickest patients, such as those in intensive care units and cancer wards. Several reports on efforts to stop the spread of vancomycin-resistant enterococci to these patients were presented Monday.
Typically, hospitals are attempting to identify patients who already carry resistant enterococci when they are admitted so they can be put in private rooms or otherwise separated from other patients.
Some hospitals are requiring stricter use of gloves and gowns when seeing patients. Some separate their staffs, so nurses exclusively see only patients with or without the resistant bacteria.
At a hospital affiliated with New York Medical College, where several controls were started in the cancer unit, the number of new exposures to vancoymycin-resistant enterococci was cut in half. Dr. Marisa Montecalvo, who presented the findings, said infection control specialists worked with cancer doctors to get them to reduce the use of vancomycin.