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Release: March 5, 1999

Iowa at or below national averages in antibiotic resistant bacteria, UI research shows

IOWA CITY, Iowa -- After six months of surveillance, University of Iowa investigators have found that in some cases Iowa fares better than other parts of the country when it comes to the effectiveness of antibiotics in fighting bacterial infections.

The first two quarters of data from a UI initiative show that Iowa does not have a major problem with antibiotic resistance against enterococcus and gram-negative bacteria, both of which are associated with gastrointestinal tract problems.

As for the antibiotic resistance of Staphylococcus aureus -- which cause skin infections -- and Streptococcus pneumoniae -- which cause middle ear infections, sinusitis, bronchitis, pneumonia and meningitis -- Iowa mirrors the national averages, said Gary Doern, Ph.D., UI professor of pathology.

On July 1, 1998, Doern, along with UI professors of pathology Ronald Jones, M.D., and Michael Pfaller, M.D., began the first-ever, statewide tracking of the emergence of antibiotic resistance. During the five-year study -- titled "Emerging Infections and the Epidemiology of Iowa Organisms: A Prospective, Statewide, Longitudinal Surveillance Study of Antimicrobial Resistance" -- the UI researchers will develop a database of bacterial samples collected from 15 participating medical centers from across the state. The investigating team wants to determine the magnitude and scope of antibiotic resistance in Iowa, measure the phenomenon's change over the long term, identify appropriate solutions to combat the resistance and then implement those solutions.

While Doern said at this point it is difficult to say why Iowa does not follow the national trend for enterococcus and gram-negative bacteria, he does offer a couple of possible explanations. First, there might be more prudent use of antibiotics in Iowa than elsewhere. Second, the infection-control practices in hospitals -- where these bacteria are most often found -- might prevent infections from occurring in the first place.

"These are over-simplistic explanations, but they are at least two factors that might explain what we've seen up until this point," Doern said.

The statewide surveillance is only one of the UI's investigation into the antibiotic-resistant-bacteria problem. In January, Doern and his colleagues also started a nationwide project looking at the issue in chronic-care facilities.

"We don't have any idea about the scope and the magnitude of the problem in chronic-care facilities," Doern said. "There appears to be a bigger problem of antibiotic resistance with patients in chronic-care facilities than there is in the general population, but there isn't a lot of good, systematic data upon which to even make that case. We have to conduct this surveillance to find out whether that is true and to determine the problem's scope and magnitude."

Once the researchers understand the problem, they can begin to formulate solutions to tackle it, Doern said.

The five-year, roughly $1 million investigation, called the Omega Study, involves nine medical centers from across the country, each representing 20 to 30 affiliated chronic-care facilities. The medical centers collect and send samples from the facilities to the UI lab for analysis.

The issue of antibiotic resistant bacteria is an important one that needs more attention, Doern said. Many bacteria are developing resistance to antibiotics, and the emergence of a "superbug" resistant to all treatments is a real possibility unless health care professionals and the public take corrective steps soon.

It is a process of survival of the fittest, Doern stated when describing why bacteria are becoming more and more resistant. For example, when scientists introduced the widely used antibiotic penicillin in the 1940s, the drug was effective against almost all strains of Staphylococcus aureus. In the United States today, 95 percent of the strains of this important cause of human infections are penicillin resistant.

"If you have two bacteria and one is penicillin susceptible and one is penicillin resistant, the penicillin-resistant organism has a selective advantage," Doern said.

The factors creating antibiotic resistance are multifaceted, in some cases poorly defined and in other cases completely obscure. However, one of the most widely accepted contributors is the use of antibiotics themselves.

"In a very real way, antibiotics are a double-edged sword," Doern said. "Obviously, they are essential medicines in the treatment of infections, but they have a serious downside. The very use of those drugs contributes to resistance that in the end renders the antibiotics less effective."

Limiting antibiotic usage will require physician education, public communication and better diagnostic tests, Doern said.

"When a physician is confronted with an individual patient in whom it is not absolutely clear that an infection is present, where does he or she want to err?" Doern asked. "You want to err on the side of being conservative and that is going to prompt you to use antibiotics. What we need is better, simpler, less expensive, non-invasive diagnostic tests that provide accurate information more rapidly. Then physicians can make more reasonable judgments in terms of antibiotic therapy."

However, the most effective means of dealing with the antibiotic resistance problem is to prevent infections from occurring in the first place, Doern said. That is going to take better infection control practices and the use of vaccines.