CONTACT: JENNIFER BROWN
Iowa City IA 52242
(319) 335-9917; fax(319) 384-4638
Release: July 3, 2001
UI project surveys rates of antibiotic resistance in Iowa
IOWA CITY, Iowa -- Recent media coverage has highlighted the dangers posed
by rising rates of antibiotic resistance in bacteria that cause human illness.
A long-term study based at the University of Iowa is providing important information
about the scale and nature of this problem in Iowa. The results of this unique
statewide surveillance project may help the health care community come to
grips with this difficult health issue.
The Emerging Infections and the Epidemiology of Iowa Organisms (EIEIO): A
Prospective, Statewide, Longitudinal Surveillance Study of Antimicrobial Resistance
is the only statewide, systematic surveillance program in the nation that
tracks emerging antibiotic resistance. The EIEIO project was started in July
1998 by UI researchers in collaboration with 15 Iowa hospitals. The surveillance
system covers 71 percent of all in-patient hospital beds in the state.
"Despite some cost to these institutions in terms of time and effort,
we have had three years of continuous, high-level commitment to this study,"
said Gary V. Doern, Ph.D., UI professor of pathology and director of the study.
"A tremendous spirit of cooperation that is typical of Iowa has driven
the success of this project."
When a patient with an infection is seen at one of the participating hospitals,
a sample is taken and analyzed to identify the infection-causing bacteria.
The sample is then sent to the UI where it is tested to determine the bacteria's
spectrum of antibiotic resistance.
The study has examined the resistance patterns of two groups of bacteria:
those commonly associated with hospital infections and those that are primarily
the causes of community-acquired infections.
"The most striking findings from this study are that resistance rates
of bacteria associated with hospital-based infections in the state of Iowa
are consistently and substantially lower than national rates," Doern
said. "For example, nationally in 71 percent of bloodstream infections
caused by Staphylococcus aureus (S. aureus), the bacteria are resistant to
oxacillin, an antibiotic considered a first line of defense. In Iowa that
number is 42 percent."
On the downside, rates of resistance for two pathogens that cause respiratory
tract infections in the community are higher in Iowa than in the rest of the
nation. The more important pathogen, S. pneumoniae, was found to be resistant
to penicillin in about a half of all infections in Iowa, compared to about
one third in the rest of the country.
"The implication for Iowa is that we are not doing as well as the rest
of the country when it comes to controlling antibiotic resistance in bacteria
that cause community-acquired infections," Doern said.
According to Doern, the first goal of the EIEIO project was to assess the
scope and size of the antibiotic-resistance problem in Iowa. Step two, which
is the stage the researchers have reached, is to make sense of the data and
try to explain differences in resistance rates. The third step will be to
use the information to devise and implement ways to combat this problem. Finally,
these approaches will be evaluated to see which ones are successful in curbing
and hopefully reversing the trend of rising rates of resistance.
Numerous studies have shown that the single most important factor in both
the emergence of antibiotic resistance and the evolution of even higher rates
of resistance over time is increased antibiotic usage. Specifically, antibiotic
overuse causes bacteria to develop antibiotic resistance. Conversely, Doern
explained that a decrease in usage would restore a more normal balance between
resistance and non-resistance bacteria, thus reducing rates of resistance.
"The machinery the bugs need in order to be resistant is essentially
excess cellular baggage. Resistance is only an evolutionary advantage when
the bacteria are under attack from antibiotics," said Doern. "If
there is no antibiotic pressure, the nonresistant bacteria will be able to
beat out their overloaded cousins."
Doern believes that education is a key to reducing overuse and inappropriate
use of antibiotics and that physicians, the public and managed care organizations
would all benefit from a better understanding of how antibiotic resistance
occurs and how it can be prevented.
In the future, Doern hopes that it will be possible to develop a fast, accurate
and simple diagnostic test that will take the guesswork out of diagnosing
causes of infection and allow physicians to prescribe antibiotics only when
the patient has a treatable bacterial infection. This strategy would reduce
inappropriate antibiotic use but these tests may not be available for years.
Current strategies, which are proving effective in curbing the rise of antibiotic
resistance, include infection control, whereby the spread of resistant strains
of bacteria between people is prevented. It is likely that good infection
control practices play an important role in Iowa's success in restraining
the rates of antibiotic resistance in hospital-associated bacteria. Another
strategy used to defeat antibiotic resistance is prevention of infection.
A vaccine designed to prevent infection specifically by antibiotic-resistant
bacteria has recently been developed and approved for use in children. So
far it has proved to be highly effective.
The final approach that Doern strongly advocates is that it may be time to
change the paradigm of only prescribing the least potent antibiotics and leaving
the most powerful drugs in reserve.
"That approach was reasonable before antibiotic resistance became such
a problem," Doern said. "We no longer have the luxury of using older,
cheaper and invariable less potent drugs. Now that antibiotic resistance is
so prevalent, I think we should consider using more potent drugs as a first
line of defense, not only to provide an effective cure, but also to prevent
further emergence of resistance."
University of Iowa Health Care describes the partnership between
the UI College of Medicine and the UI Hospitals and Clinics and the patient
care, medical education and research programs and services they provide. Visit
UI Health Care online at www.uihealthcare.com.