|
NPR (National Public Radio) Broadcast
Eight million Americans will suffer a urinary tract infection this year, nearly all of them women; many
women will have several infections. Now in tomorrow's New England Journal of Medicine, researchers
report that a new strain of bacteria is causing urinary infections around the country. And as NPR's
Richard Knox reports, that new strain is proving difficult to treat.
RICHARD KNOX reporting:
Urinary tract infections are common, but doctors consider them to be sporadic; that is, they almost
never occur in epidemics. The reason is that one organism doesn't usually spring forth and infect many
people as in an epidemic. Urinary infections are caused by a wide range of bacterial types. So when
Berkeley grad student Aimee Mangus(ph) began studying an outbreak of urinary infections related to
the bacterium E. coli, she found something unexpected. Ms. AIMEE MANGUS (Berkeley Grad
Student): We, to our surprise, discovered that a lot of women in the area were being infected by a
nearly identical strain of E. coli, a specific type of E. coli. And then once we discovered that, we
thought, 'Well, maybe this is something that's happening just locally.'
KNOX: It wasn't just local. Mangus and her colleagues found that college women in Minnesota and
Michigan also suffered from infections caused by genetically identical E. coli strain; not only that, it's a
strain that's resistant to drugs usually used to treat urinary infections. How did this new bug crop up in
such disparate locations? Mangus doesn't know yet, but she and other researchers think it probably
traveled in a food product of some kind.
Ms. MANGUS: One of the only logical explanations that we're thinking about now is that it may have
been disseminated through some contaminated product around different parts of the United States, and
now that's why we're seeing it in Berkeley and now in cities in Michigan and Minnesota.
KNOX: If their hunch is right, that would be highly unusual. Disease-causing organisms that travel in
food normally cause intestinal disease, not something else. In this case, the new E. coli strain can live
in the intestines of healthy people without causing disease, but in some women, it migrates to the
urinary tract where it does cause trouble. Already the newly discovered strain is causing many
infections that don't respond to standard antibiotics.
Ms. MANGUS: It did seem to contribute a lot to the level of resistance that we observed in the women
that we looked at. So almost 10 percent of the resistant urinary tract infection were maybe due to
this specific type of E. coli.
KNOX: The new bug is resistant to four or five of the most commonly prescribed antibiotics. Dr. Walter
Stamm of the University of Washington finds it particular troubling that the new strain can't be treated
with a drug called trimethoprim-sulfa. Resistance to this antibiotic is already a widespread problem,
Stamm says.
Dr. WALTER STAMM (University of Washington): And that means that many clinicians are moving
away from trimethoprim-sulfa, which was the workhorse treatment for these kinds of infections to other
drugs.
KNOX: These other drugs are often far more expensive, they can be toxic, and the newly emerging E.
coli strain shows, once again, that bacteria are rapidly outpacing the pharmaceutical industry's ability to
invent new, more effective antibiotics.
Dr. STAMM: We are not doing a very effective job at being able to use
these antimicrobials on a
long-term basis, and we need to somehow revise our approaches to be able to utilize them without
emergence of resistance over longer periods of time or we'll reach the point where we don't have many
of them left.
KNOX: There is a class of drugs that can vanquish the new E. coli strain and other bacteria resistant to
trimethoprim. They're called floraquinalones(ph). But Stamm says scientists are finding urinary tract
infections in other countries that are already resistant to these drugs. Richard Knox, NPR News,
Boston.
HEADLINE: Researchers find single strain of bacteria caused infections in three states
BYLINE: By STEPHANIE NANO, Associated Press Writer
BODY:
Food contaminated with a strain of drug-resistant E. coli has emerged as a possible new source of
urinary tract infections.
E. coli is a normal inhabitant of the digestive tract that can cause both intestinal upsets and urinary
infections. But while E. coli from bad food is a frequent cause of diarrhea and other digestive miseries,
urinary tract infections were thought until now to result mostly from inadvertent contact with the
victim's own feces. The new research found that a single, genetically identical strain was responsible for
outbreaks of urinary tract infections among women in California, Michigan and Minnesota. Because
the germs are exactly the same, investigators assume they came from the same source, and the most
likely such source is food.
The research, conducted at the University of California at Berkeley, was based on analysis of 302
cases. It was published in Thursday's New England Journal of Medicine.
"We were really, really surprised," said researcher Amee R. Manges at Berkeley. "When we looked at
these organisms from these various different women, many of them turned out to be the same. We
weren't anticipating that."
Urinary tract infections are common, especially among women, and cause painful and frequent
urination. An estimated 90 percent of them are caused by E. coli, which is becoming increasingly
immune to the antibiotics used to clear up the infection.
Manges and her colleagues collected urine samples from women treated for infections at Berkeley's
health center over a four-month period. They were compared with samples from health centers at the
University of Minnesota and the University of Michigan.
The researchers looked specifically at infections caused by E. coli strains resistant to a common
antibiotic, trimethoprim-sulfamethoxazole, sold as Bactrim or Septra.
They found the same strain caused 51 percent of the drug-resistant infections at Berkeley, 38 percent
in Michigan and 39 percent in Minnesota.
Manges said they also tested healthy people in California and found the strain in both men and women.
"It's an initial step," said Dr. Walter E. Stamm of the University of Washington School of Medicine, who
wrote an accompanying editorial. "It will take further studies to look at this clone, see if it's more
widespread."
If the strain is eventually traced to one source or a few sources, then steps could be taken to prevent its
spread, he said.
The only other known outbreak of urinary infections from a drug-resistant E. coli strain happened in
London in the 1980s. The source of that outbreak wasn't found, and Manges said it would be hard to go
back and trace the source of the U.S. cases.
She said the next steps include a large study that closely follows lifestyles and eating habits and other
tests to try to determine whether the strain is actually spread through food.
"We have the most logical explanation for it, but we need to get more evidence," she said.
|
