28 Jul Study finds that superbugs may develop without antibiotics
Doctors are finding it more and more difficult to treat a common infection because the bacteria
that cause it are becoming increasingly resistant to antibiotics. Now, new research may have
uncovered one reason for the pervasiveness of these superbugs.
Urinary tract infections (UTIs) arise when bacteria enter the urinary tract. It is one of the most
common infections to affect people.
Although any part of the urinary tract can become infected, UTIs most commonly occur in the
bladder. UTIs are more common in girls and women than in boys and men.
The main cause of UTI in women is the bacterium Escherichia coli. Drug-resistant strains of
E.coli is spreading widely, causing doctors to think twice about which antibiotics to prescribe.
In the new Clinical Infectious Diseases study, researchers tested stool samples from more than
1,000 healthy women who were free of UTI symptoms. The women were from the Puget Sound
area of Washington.
The tests revealed that 8.8% of the women were carrying fluoroquinolone-resistant strains of E.
coli in their guts.
Doctors frequently prescribe fluoroquinolones for the treatment of UTIs. The researchers note
that, although there have been efforts to limit the use of these antibiotics, resistant strains of
bacteria are spreading widely.
In addition, the researchers found that most of the fluoroquinolone-resistant E. coli bacteria also
belonged to two widespread, multidrug-resistant strains that are responsible for most hard-to-
treat urinary and blood infections.
The researchers also tested urine samples that the women had given at the same times as the
These tests revealed that more than one-third of the women with fluoroquinolone-resistant E. coli
gut bacteria also had E.coli in their urine. Of these, almost 77% had fluoroquinolone-resistant
strains that matched those of their stool samples.
Of the women, 45 also gave permission for the team to track their medical records. These
showed that 7% of them went on to receive diagnoses of UTI some 3 months later.
The study authors describe the two drug-resistant strains of E.coli that they found as superior
gut colonizers" that tend to persist there."
They can also show up," they note, at an unusually high rate, in the urine of healthy women
who did not have a documented urinary tract infection diagnosis at the time of sample testing.
Both phenomena appear to be interconnected."