Recurring Bladder Infections
Can Result From One
Lingering Infection
By Michael Kahn
WASHINGTON (Reuters) - A new study suggests a painful, recurring bladder condition might be caused by a single lingering infection rather than by a series of new ones as scientists had thought, researchers said Thursday.
Urinary tract infections affect seven million people annually in the United States, mostly women. Symptoms include frequent and painful urination as well as fever and can usually be treated with antibiotics. But a team of researchers at Washington University in St. Louis showed these antibiotics may be less effective in some cases because of bacteria able to burrow deep into cell tissue and hide out in the bladder.
``What's important here is we've discovered a mechanism by which bacteria are able to gain a foothold in the bladder, colonize and cause disease,'' said Scott Hultgren, a molecular microbiologist, who led the study. Using high-resolution microscopic techniques, the team was able to view the interaction between the bacteria and the bladder. Images from the study on mice showed how E. coli bacteria invade the cells and use hair-like extensions to bind to the surface of the bladder. The team said this provided the first high-resolution direct visual evidence showing the crucial step that triggers urinary tract infections.
``That attachment is absolutely necessary for colonization,'' Hultgren said. ``You can see with your own eyes what is happening.'' But the study, published in the journal Science, also showed how the cells fight back. After the bacteria attach, the cells kill themselves and fall off into the bladder where urine washes them out of the body, Hultgren explained in a telephone interview. While this is a good defense mechanism for reducing the number of bacteria in the body, some E. coli may escape and burrow deep into cell tissue, he explained. This could mean later infections for people unable to completely clear the bacteria from their bladders. ``The bacteria may be able to escape the defense system and make its way into the cell tissue, and this could be how they are able to cause recurrent infections at a later time and point,'' said Matt Mulvey, a microbiologist who also worked on the study. However, because antibiotics are often an effective treatment, the problem of urinary tract infections is often ignored, he added in a telephone interview.
But better understanding how these E. coli cause bladder infections could help create vaccine and treatments, especially for those suffering from chronic infections, he said. ``The more you know about the infection, the more targets for treatment will become noticeable,'' Mulvey said.