The vagina is home to a range of microbes from a pool of over 50 species. Lactobacilli are the most common, particularly in healthy women. The microbiota can change composition suddenly, for reasons that are still a mystery. This can lead to infection or a situation where organisms with pathogenic potential coexist with other commensals.
As further studies reveal the microbial diversity of the vagina, it seems apparent that the balance between a healthy and problematic situation involves some sort of equilibrium which can swing in either direction.
The microbial mixture depends on a number of factors, such as hormone levels, sexual activity, as well bacterial interactions and host defences.
Antimicrobial treatment of urogenital infections isn’t always successful and issues can persist due to bacterial and yeast resistance, recurrent infections or side effects. It is therefore unsurprising that alternative remedies are popular with patients and their caregivers.
Over one billion doses of probiotics are administered worldwide every year, and those used for urogenital health have been well tolerated. However, safety of probiotic use should be monitored when doing clinical studies.
The potential for transfer of antibiotic resistance is one factor to ponder, though it’s yet to be proven that probiotics have contributed in any way to drug resistance or disease.
In the United States, most probiotics are sold as dietary supplements, which do not undergo the testing and approval process that drugs do. Manufacturers are responsible for making sure they’re safe before they’re marketed and that any claims made on the label are true. But there’s no guarantee that the types of bacteria listed on a label are effective for the condition they are being taken for. Health benefits are strain-specific, and not all strains are necessarily useful.
Thin on evidence
The use of probiotic lactobacilli to prevent infection has a good rationale, and an excellent safety record, but so far only a few strains have been clinically proven to be effective, in particular to prevent BV.
A recent study in the Journal of Applied Microbiology provides new data about antimicrobial resistance and genotypic diversity of vaginal Lactobacillus isolates. Researchers from the Institute of Biomedicine and Translational Medicine at the University of Tartu, Estonia assessed the antibiotic susceptibility of vaginal lactobacilli strains to 13 antibiotics.
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