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Protective Role of Lactobacillus acidophilus against vaginal infection with Trichomonas vaginalis

Zarrintaj Valadkhani, Nayerreh Hassan, Zohre Aghighi, Ehsan Mostafavi


Introduction: Vaginal colonization with lactobacilli species is characteristic of normal vaginal ecology. The absence of vaginal lactobacilli, particularly hydrogen peroxide producing isolates, has been associated with bacterial vaginosis and increased risk for sexually transmitted infection. In order to check the role of Lactobacillus acidophilus in vaginal infection when infected with Trichomonas vaginalis, in this study we mimic the vaginal condition in presence and absence of lactobacilli.

Methods: Forty Trichomonas vaginalis isolates from women referred to gynecology clinic were evaluated in this study. The parasites were isolated from vaginal discharge and urine  in TYI-S-33media. The attachment of parasites, as pathogen, to vaginal epithelial cells was examined in healthy women in presence and absence of lactobacilli as well as their excretory-secretory products specially those of Lactobacillus acidophilus.

Results: Maximum number of vaginal epithelial cells infected by Trichomonas vaginalis was 37% (at 50 min from co-incubation) in experiments with parasites and vaginal epithelial cells (1st group) against 47% (at 40 min) in tube containing parasite along with Lactobacillus acidophilus and vaginal epithelial cells (2nd group). However, parasites in presence of vaginal epithelial cells and excretory-secretory product of Lactobacillus acidophilus (3rd group) showed the least number of infected cells 20% (at 40 min). Difference between 1st and 3rd group as well as 2nd and 3rd group of these experiments were significant (p<0.001). However, no significant difference were found between 1st and 2nd groups (p=0.28).

Conclusion: Modifiable biological and behavioral factors in vaginal ecology are associated to Lactobacillus colonization. This study suggests intervention strategies to improve vaginal health in women with risk of pathogens

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