December 12, 1996

Media Contacts: Sarah Goodwin, 404/727-3366 -
Kathi Ovnic, 404/727-9371 -

As bacteria have become increasingly adept at outsmarting antibiotics, scientists at the Rollins School of Public Health of Emory University and the Centers for Disease Control and Prevention (CDC) have stepped up efforts to detect and deflect this problem.

The Project on Intensive Care Antibiotic Resistance Epidemiology, or Project ICARE, is a joint effort to collect, analyze and rapidly report information about national patterns of antibiotic use and resistance in hospital intensive care units. A major goal of the study is to develop and improve mechanisms for the surveillance and control of antibiotic resistance.

During Phase I of the project, investigators evaluated in eight hospitals nationwide the relation between the use of antibiotics and the types of bacteria resistant to the drugs. According to co-principal investigator John McGowan, M.D., professor of epidemiology at the Rollins School of Public Health, the group found a "wide variation in antibiotic use and in levels of resistance...." Investigators now have begun Phase II, which increased the roster of hospitals involved to 41.


"Before we can prevent or even control bacterial resistance to antibiotics, we must first carefully characterize the problem," Dr. McGowan says. "That is why disease surveillance, at both the clinical and molecular levels, is so important."

The team is focusing primarily on two types of bacteria: enterococci resistant to the antimicrobial vancomycin and enterobacteriaceae resistant to the antimicrobials imipenem/cilistatin and ciprofloxacin.

In today's presentation, the researchers discuss the methods for examining the relationship between antibiotic use and anitbiotic resistance at the different institutions.

During Phase II of Project ICARE investigators are continuing to combine epidemiology with laboratory studies. The epidemiologic studies are under the guidance of co-principal investigator Robert Gaynes, M.D. Dr. Gaynes is director of the National Nosocomial Infections Surveillance System at CDC as well as adjunct associate professor of epidemiology at Emory.


Project ICARE researchers first isolate from hospital patients antibiotic-resistant bacteria associated with infections.

Samples then undergo molecular typing in Rollins School of Public Health labs, under the direction of co-principal investigator Fred Tenover, Ph.D., head of CDC's Nosocomial Pathogens Laboratory Branch and adjunct associate professor at the school. Strands of DNA within the samples are "sliced" with an enzyme knife. Using pulsed-field gel electrophoresis, a laboratory technique Dr. Tenover helped refine, the DNA slices are placed on a gel through which an electrical current is passed. They separate according to size, with smaller segments settling to the bottom of the gel. The resulting "genetic fingerprints" provide clinical microbiologists an entire bacterial chromosome portrait useful in determining the relatedness of a group of cultures of bacteria. If several bacterial samples taken from different patients at the same hospital yield identical "fingerprints," investigators know a genuine outbreak of infection with antibiotic-resistant organisms is in progress. Such specific molecular typing has helped Dr. Tenover identify the cause of several mysterious hospital outbreaks.

These techniques now are in use to help explain the pattern of nonepidemic infections in the ICARE hospitals. Once project staff (most of whom are also master's of public health or doctoral students at Emory) have identified the bacteria involved, they can then offer advice to hospitals (to stepup infection control measures, for example) -- and just as important, can add to their valuable collection of antimicrobial surveillance data.

Phase III will focus on specific factors that influence the pattern, and Phase IV on prevention and control.

"We hope to develop an index for hospitals and healthcare systems to use in choosing the best control measures for their individual situation," Dr. McGowan says. "Depending on what we find, we may recommend more emphasis on surveillance of organisms coming into the acute care hospital from the community, more attention to proper antibiotic use, more infection-control efforts or a combination of these measures."

Project ICARE is sponsored by the National Foundation for Infectious Diseases; the American Society for Health-System Pharmacists; Bayer Corporation, Pharmaceutical Division; Zeneca Pharmaceuticals; Rhone-Poulenc-Rorer; Roche Laboratories; and Kimberly Clark Corporation.

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Copyright ©Emory University, 1996. All Rights Reserved.
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