Sept. 17, 2009 -- For millions of women and some men, bladder infections are a painful part of life.
More than half of women will have at least one urinary tract infection in their lifetime and many will have recurrent infections. Men get them too, but much less often than women and usually as a result of another medical problem, such as kidney stones or an enlarged prostate.
Although easily treated in most cases, the infections are not so easily prevented. But early animal research might lead to a nasal spray that protects against bladder and other urinary tract infections.
Researchers from the University of Michigan created the nasal vaccine, which targets specific strains of the Escherichia coli (E. coli) bacterium that causes most urinary tract infections.
Mouse Studies Promising
In animal studies, mice treated with three of six experimental vaccine candidates tested by the researchers developed antibodies against the bacteria and became resistant to infection.
The mice received an initial immunization, delivered via nasal spray, followed by two booster sprays a few weeks later, lead researcher Harry L.T. Mobley, PhD, tells WebMD.
“We screened more than 5,300 possible proteins and ended up with three that were very effective for preventing infection,” Mobley says.
In a separate study, the researchers looked for, and found, these proteins in E. coli strains obtained from women treated for urinary tract infections.
“This suggests we are on the right track and that this might prove to be an effective vaccine in humans,” he says.
The researchers hope to test the vaccine in humans but have no firm plans to do so. Mobley says a commercially available vaccine based on the research is at best years away.
245,000 UTI Hospitalizations Each Year
The University of Michigan researchers are not the first to attempt a vaccine to prevent urinary tract infections, and urologist Tomas Griebling, MD, MPH, tells WebMD that such a vaccine makes a lot of sense.
Griebling is vice chairman of the department of urology at the University of Kansas Medical Center.
By one estimate, urinary tract infections account for 6.8 million visits to doctors, 1.3 million emergency room trips, and 245,000 hospitalizations a year in the United States at a cost of $2.4 billion.
“The costs associated with urinary tract infections far exceed that of any other urologic disorder,” he says.
Although in most cases the infections are not serious, when bacteria move beyond the bladder into the kidney or the blood or when infections involve antibiotic-resistant bacteria, they can become deadly.
The death of a Brazilian model early this year was a reminder of this
Doctors reportedly misdiagnosed 20-year-old Mariana Bridi’s urinary tract infection, which was caused not by E. coli but by another bacterium, called Pseudomonas aeruginosa.
Widespread infection led doctors to amputate Bridi’s hands and feet in an effort to save her life, but the model died within weeks of entering the hospital.
A vaccine targeting the E. coli infection that causes most urinary tract infections would not have saved Bridi, but it could keep millions of people from becoming infected each year and save the health care system billions of dollars a year, Griebling says.
“This is an ideal infection to try and target with a vaccine because it is so common,” he says. “I would say the early research looks promising, even though this certainly isn’t ready for prime time. But if they could produce a nasal vaccine that is safe and cost-effective it could have a dramatic impact.”