Characterization and selection of vaginal Lactobacillus strains for the preparation of vaginal tablets

Abstract

Aims: To characterize and select Lactobacillus strains for properties that would make them a good alternative to the use of antibiotics to treat human vaginal infections. Methods and Results: Ten Lactobacillus strains belonging to four different Lactobacillus species were analysed for properties relating to mucosal colonization or microbial antagonism (adhesion to human epithelial cells, hydrogen peroxide production, antimicrobial activity towards Gardnerella vaginalis and Candida albicans and coaggregation with pathogens). The involvement of electrostatic interactions and the influence of bacterial metabolic state in the binding of lactobacilli to the cell surface were also studied. Adherence to epithelial cells varied greatly among the Lactobacillus species and among different strains belonging to the same Lactobacillus species. The reduction in surface negative electric charge promoted the binding of several Lactobacillus strains to the cell membrane whereas lyophilization reduced the adhesion capacity of many isolates. The antimicrobial activity of lactobacilli culture supernatant fluids was not directly related to the production of H 2 O 2 . Conclusions: Three strains (Lactobacillus brevis CD2, Lact. salivarius FV2 and Lact. gasseri MB335) showed optimal properties and were, therefore, selected for the preparation of vaginal tablets. The selected strains adhered to epithelial cells displacing vaginal pathogens; they produced high levels of H 2 O 2 , coaggregated with pathogens and inhibited the growth of G. vaginalis. Significance and Impact of the Study: The dosage formulation developed in this study appears to be a good candidate for the probiotic prophylaxis and treatment of human vaginal infections.

Lactobacillus rhamnosus L60, a potential probiotic isolated from the human vagina

“…Mean numbers of human urogenital lactobacilli adhering to uroepithelial cells ranged from 8 67 in studies by Boris et al (1998), and 23 48 in studies by Mastromarino et al (2002). Numbers of adhering lactobacilli in the present study were comparable.…”

Identification and in vitro production of Lactobacillus antagonists from women with or without bacterial vaginosis

“…During an 8-month study, Vallor et al (2) showed that, in contrast to L. crispatus and L. jensenii H 2 O 2 -producing isolates, strains that did not produce the antimicrobial substance were rapidly lost, a fact that supports the role of this production in sustained colonization. However, as demonstrated by diffusion assays, there is not always a direct correlation between the ability for H 2 O 2 production and the antagonistic activity of lactobacilli (24). In fact, the potential of H 2 O 2 production by Lactobacillus described here and in the literature has been demonstrated by in vitro assays and one must be cautious when extrapolating it to the in vivo environment.…”

Binding of Aflatoxin B1 to Lactic Acid Bacteria and Saccharomyces cerevisiae in vitro: A Useful Model to Determine the Most Efficient Microorganism

“…Suspensions were observed by optic microscopy after Gram staining. 1 The score is based upon a scale described by Mastromarino et al (2002), from 0 for no aggregation to 3 for maximum aggregation. Table 12.…”