Findings reported in the New England Journal of Medicine ( NEJM ) highlight promising findings from two Seattle-based researchers on the origins of bacterial vaginosis.

In a collaborative effort to identify specific bacterial markers for bacterial vaginosis in vaginal-fluid samples, David Fredricks, of the Program in Infectious Diseases, Fred Hutchinson Cancer Research Center and Jeanne Marrazzo, of the University of Washington and Harborview Medical Center in Seattle report the detection of three newly recognized bacteria that were highly specific for bacterial vaginosis. Subjects for this study were recruited from Marrazzo's Vaginal Health Project and from Public Health-Seattle and King County Sexually Transmitted Disease ( STD ) Clinic.
Although preliminary, the researchers are hopeful that these findings may contribute to identifying the specific cause of and better treatment for the disease.

Bacterial vaginosis is the most common cause of vaginitis, and the most common reason women seek treatment for vaginal symptoms. The cause of bacterial vaginosis is not known.
In recent years, awareness of the adverse effects of bacterial vaginosis has grown markedly.

Among pregnant women, bacterial vaginosis may cause up to 10% of low-birth weight deliveries, and in several studies has been strongly implicated in increasing women's risks of becoming infected with other STD and with HIV.
While it may cause abnormal discharge, odor, and itching, bacterial vaginosis often exists without causing any symptoms, and women may not know they have it.
Bacterial vaginosis can be treated with antibiotics but often comes back. For unknown reasons, lesbians and bisexual women apparently have a higher occurrence of bacterial vaginosis than heterosexual women.

Researchers identified bacteria in samples of vaginal fluid with a combination of broad-range polymerase-chain-reaction ( PCR ) amplification of 16S rDNA with clone analysis, bacterium-specific PCR assay of 16S rDNA, and fluorescence in situ hybridization ( FISH ) performed directly on vaginal fluid from 27 subjects with bacterial vaginosis and 46 without the condition.
Twenty-one subjects were studied with the use of broad-range PCR of 16S rDNA, and 73 subjects were studied with the use of bacterium-specific PCR.

Women without bacterial vaginosis had 1 to 6 vaginal bacterial species ( phylotypes ) in each sample ( mean, 3.3 ), as detected by broad-range PCR of 16S rDNA, and lactobacillus species were the predominant bacteria noted ( 83 to 100 percent of clones ).

Women with bacterial vaginosis had greater bacterial diversity ( P<0.001 ), with 9 to 17 phylotypes ( mean, 12.6 ) detected per sample and newly recognized species present in 32 to 89 percent of clones per sample library ( mean, 58 percent ).

Thirty-five unique bacterial species were detected in the women with bacterial vaginosis, including several species with no close cultivated relatives. Bacterium-specific PCR assays showed that several bacteria that had not been previously described were highly prevalent in subjects with bacterial vaginosis but rare in healthy controls.
FISH confirmed that newly recognized bacteria detected by PCR corresponded to specific bacterial morphotypes visible in vaginal fluid.

Women with bacterial vaginosis have complex vaginal infections with many newly recognized species, including three bacteria in the Clostridiales order that were highly specific for bacterial vaginosis.

Source: University of Washington, 2005


XagenaMedicine2005