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Sunday, November 06, 2005Despite being one of the most common infections among women, scientists and doctors know little about the causes of bacterial vaginosis (BV), a usually benign disease that is also linked to serious health problems including pelvic inflammatory disease, an increase in the viral load of HIV from infected women and a two-fold increase in risk for pre-term labor and delivery. Now researchers at the Fred Hutchinson Cancer Research Center have shed new light on BV by using genetic-sequencing technology to detect several new bacterial species -- enough to almost double the number of known strains associated with the infection. ....."Numerous bacterial genera identified in this study have not, to our knowledge, been previously detected in the vaginal milieu with the use of cultivation methods," researchers said. Bacterial vaginosis, also known more colorfully as Gardnerella (after a man named Gardner who identified a bacteria in the 1950's that was thought to be the cause of the infection), is common and can at times be difficult to eradicate. It isn't so much an infection that is "caught" from someone else as it is a bacterial coup de'tat. Events conspire within the vaginal environment to allow bacteria normally in the minority to overwhelm the vaginal flora. So much so, that one of the ways we diagnose the infection is by identifying vaginal cells under the microscope that are covered with bacteria clinging to their surfaces.The events that make the coup possible are often things that change the alkalinity of the vagina - things like hormonal changes, the presence of semen, diet, douching, and other factors yet unrealized. It's odd that such a common infection in such a small pocket of the body is yet so little understood. But a paper in this week's New England Journal of Medicine sheds some more light in its dark corners. Researchers found the new species of bacteria by finding their DNA in the vaginal fluids of afflicted women. Using polymerase chain reactions and fluorescence in situ hybridization, they were able to identify bacteria that would be difficult to identify by traditional methods, such as coaxing them to grow in a petri dish and identifying them by sight under a microscope. And what a variety they identified. And what exotic names. In addition to the expected lactobacilli and Gardnerella vaginalis, there were Atopobium vaginae, Leptotrichia amnionii, Sneathia sanguinegens, Porphyromonas asaccharolytica, and a "bacterium distantly related to Eggerthella hongkongensis." The vaginal tract must be a microbiologist's dream. Most interestingly, however, was the identification of three as yet never known members of the Clostridium family (technically it's a phylum, not a family, but you get the idea. They're related.) The Clostridia have already have a reputation as an opportunistic clan. It's a Clostridium that's responsible for C. diff colitis, a Clostridium that's responsible for gas gangrene, a Clostridium that's responsible for botulism, and a Clostridium that's responsible for tetanus. They can be nasty brutes. Luckily, the members of the family that dwell in the reproductive tract are tame by comparison. So what does it mean for patients? Probably not much. We already use Flagyl for bacterial vaginosis, a drug which is effective against clostridium. But it may help us understand the role bacterial vaginosis can play in pelvic inflammatory disease and uterine infections. posted by Sydney on 11/06/2005 07:48:00 AM 0 comments 0 Comments: |
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