The vaginal microbiota comprises a variety of microorganisms, predominantly vaginal lactobacilli, such as: Lactobacillus jensenii, Lactobacillus crispatus, Lactobacillus gasseri and Lactobacillus iners. Vaginal lactobacilli play a crucial role in maintaining a healthy vaginal environment by protecting it from bacterial and fungal infections. They accomplish this by secreting various antimicrobial substances, with lactic acid being the most important, and by competing with pathogens for adherence to the vaginal mucosa. In addition, they secrete various antimicrobial substances, such as hydrogen peroxide and bacteriocins, which destroy pathogenic microorganisms such as Gardnerella vaginalis, Candida albicans, and Trichomonas vaginalis. A decrease in the number of lactobacilli, for various reasons, disrupts the balance between normal vaginal flora and pathogenic microorganisms, leading to the development of vaginal infections. The use of lactobacilli as probiotics can facilitate the restoration of normal vaginal microbiota and consequently the treatment of infections; however, the lack of an appropriate delivery system is the main reason for their limited use. In the context of the master's thesis, we evaluated 77 strains of vaginal lactobacilli from the species L. gasseri, L. jensenii, and L. crispatus. During the evaluation, we monitored bacterial growth, bacterial survival in a phosphate buffer, change of pH of the medium, aggregation, and surface hydrophobicity. Out of 77 analyzed strains, only 48 strains (20 strains of L. crispatus, 20 strains of L. jensenii, and 8 strains of L. gasseri) have grown 24 hours after inoculation in liquid culture at 37°C. We evaluated these strains in more detail. We determined the viability of bacterial strains using the drop plate method. pH changes in the medium were determined using a pH meter. Changes in aggregation over time were determined by measuring optical density spectrophotometrically at 600 nm. Surface hydrophobicity was evaluated by measuring optical density spectrophotometrically at 560 nm in the aqueous phase after extraction with hexadecane. To obtain information about bacterial growth and to prepare a growth curve, we cultured the strains in microtiter plates and monitored growth using an absorbance reader. Based on their properties, we categorized the analyzed strains into groups. Our goal was to incorporate strains with the best characteristics (good growth, high survival, low pH, high aggregation, and high hydrophobicity) into nanofibers using the electrospinning method and to evaluate their survival. From the 48 analyzed strains, we identified 3 strains (L. crispatus 6, L. jensenii 6 in L. gasseri 35) with the best properties for incorporation into nanofibers. Using the electrospinning method, we successfully incorporated bacteria into nanofibers and then evaluated their survival. The smallest difference in viability before and after incorporation into nanofibers was 0.1 log CFU/g (L. gasseri 35). The difference for the other two strains (L. crispatus 6 and L. jensenii 6) was 1.8 and 2.2 log CFU/g, respectively.
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