Novel Potential Probiotic Lactobacilli for Prevention and Treatment of Vulvovaginal Infections.

Lactobacilli in the vaginal tract are essential to protect against microbial infections. We therefore focused on isolating vaginal lactobacilli from pregnant women and testing their functional properties. Lactobacilli were isolated from 50 vaginal swabs and the purified isolates were identified by MALDI-TOF MS. Functional properties (antimicrobial activity, organic acids and hydrogen peroxide production, antibiotic susceptibility, auto-aggregation, and hydrophobicity) of selected isolates were tested. Lactobacilli (41 strains) were identified in 58% of swabs with a predominance of Lactobacillus crispatus (48%) followed by L. jensenii (21%), L. rhamnosus (14%), L. fermentum (10%), and L. gasseri (7%). The highest antibacterial activity was determined for L. fermentum and L. rhamnosus. Strong anti-Candida activity was observed for strains L. crispatus, L. fermentum, and L. rhamnosus. Strain L. jensenii 58C possessed the highest production of hydrogen peroxide (6.32 ± 0.60 mg/l). The best lactic acid producer was strain L. rhamnosus 72A (11.6 ± 0.2 g/l). All strains were resistant to fluconazole and metronidazole. The highest auto-aggregation was observed for strain L. crispatus 51A (98.8 ± 0.1% after 24 h). Strain L. rhamnosus 68A showed the highest hydrophobicity (69.1 ± 1.4%). Strains L. fermentum and L. rhamnosus showed high antibacterial activity and hydrophobicity, and strains L. crispatus possessed high auto-aggregation and anti-Candida activity. Thus, these strains alone or in a mix could be used for the preparation of probiotic products for treatment and prevention of vulvovaginal infections of pregnant and non-pregnant women.

A qualitative method for testing the antimicrobial ability of osteosynthetic fixation material by simulating in vitro contamination by Staphylococcus aureus.

External fixators of serious fractures could be an attractive substrate on which microorganisms can accumulate. Therefore, this study aimed to develop a suitable method for enabling the simulation of a real situation when osteosynthetic fixation material is open for the potential threat of bacterial attack. Agar-based media represented human tissue, and the metallic pin characterized the screw in the fixation. Various types of agar, supplements, and contamination strategy by Staphylococcus aureus were tested. The influence of the initial bacterial concentration was also examined. Surfaces were observed by scanning electron microscopy (SEM), and all results were compared. Brain Heart Infusion Agar with the Egg Yolk Tellurite Emulsion was established in a transparent test tube as a suitable system for enabling the good interpretability of bacterial contamination in the pin's surroundings. Pin contamination has been found to be an appropriate approach for testing microbial growth, rather than agar surface contamination, which distorted obtained results. A lower initial colony forming units (CFU) provided better clarity of the test. SEM observation of the pin surface was comparable with the visual evaluations in the test tubes. Results were assembled for positive and negative control samples as well. Screening method for the most common bacteria S. aureus has been standardized and developed. This experimental setup could also be a useful tool for surface modification with antibacterial properties testing.