Effects of Cetyltrimethylammonium Naproxenate on the Adherence of Gardnerella Vaginalis, Mobiluncus Curtisii, and Lactobacillus Acidophilus to Vaginal Epithelial Cells

Background and Objectives: A decreased concentration or total disappearance of Lactobacillus acidophilus in the vagina constitutes a frequent observation in bacterial vaginosis. Goal of the Study: Cetyltrimethylammonium naproxenate has been evaluated in vitro to detect antiadhesive properties at subinhibitory concentrations for Gardnerella vaginalis and Mobiluncus curtisii to vaginal epithelial cells (VEC). Study Design: Bacterial strains ¹⁴C- and or ³H-labeled were tested for adherence and competition to binding sites in VECs before and after treatment at sub-MIC with cetyltrimethylammonium naproxenate. Results: In control tests of adherence, G. vaginalis and M. curtisii had their maximal adhesion at pH 5.4, L. acidophilus at pH 4.4. Preincubation of G. vaginalis and M. curtisii with cetyltrimethylammonium naproxenate 2.5 mg/mL (subinhibitory concentration) at pH 5.4 reduced adherence to VECs respectively by 483% and 34.1%. The same treatment of L. acidophilus showed no statistically significant difference. Treatment of VECs alone did not modify adherence. Competition tests between L. acidophilus and G. vaginalis and between L. acidophilus and M. curtisii showed that, in small quantities, L. acidophilus could compete with G. vaginalis and M. curtisii for binding sites in VECs at pH 4.4, when pretreated with cetyltrimethylammonium naproxenate. At a higher pH (4.8 and 5.4), L. acidophilus in higher quantities did not compete for binding sites occupied by G. vaginalis and M. curtisii. Conclusions: Cetyltrimethylammonium naproxenate at subinhibitory concentrations modifies the adhesiveness of G. vaginalis and M. curtisii to VECs, reducing it by 48.3% and 34.1%, respectively. Adhesion of L. acidophilus to VECs is not impaired by pretreatment with cetyltrimethylammonium naproxenate at pH 4.4, even if they are in low number and compete for binding sites against pathogens. At higher pH levels, L. acidophilus did not compete for binding sites occupied by G. vaginalis and M. curtisii.