Intravaginal administration of gelatine capsules containing freeze-dried autochthonous lactobacilli: a double-blind, randomised clinical trial of safety.

Vaginal lactobacilli (LAB) in probiotic formulas constitute a promising alternative for microbiome reconstitution and for the prevention and treatment of urogenital infections. A double-blind, randomised clinical trial was conducted to assess the safety of LAB-gelatine capsules vaginally administered to healthy sexually active women. Participants were randomised into three groups: intervention A: Lactobacillus reuteri CRL1324, Lactobacillus gasseri CRL1263 and CRL1307; intervention B: Lactobacillus rhamnosus CRL1332, L. gasseri CRL1256 and CRL1320; and intervention C: placebo. In a survey and clinical evaluation, participants received a blister with 7 capsules to be administered 1 per day. A second sampling and a new survey were conducted 3-10 days after completing application. Colposcopy was performed to assess adverse effects on vaginal-cervical mucosa. Vaginal swabs were taken for Gram staining to determine the Nugent score, and obtainment of viable-cell cultures to quantify cultivable lactic acid bacteria and pathogens. The main outcomes evaluated were overall satisfaction and secondary effects, including discomfort, urogenital infection, inflammatory response or other symptoms. No significant differences were found in Nugent score or in leukocyte numbers in vaginal samples either before or after the three interventions. However, a tendency to decrease in both the Nugent score and in leukocyte numbers was observed after interventions A and B, though not after C. A significant increase in cultivable lactobacilli was determined after LAB interventions. No severe adverse events were detected. LAB-containing capsules were well tolerated by subjects, so they could be proposed as an adequate alternative to restore vaginal lactobacilli in sexually active women.

Pseudomonas protegens CS1 from the lemon phyllosphere as a candidate for citrus canker biocontrol agent.

Citrus canker is a worldwide-distributed disease caused by Xanthomonas citri subsp. citri. One of the most used strategies to control the disease is centred on copper-based compounds that cause environmental problems. Therefore, it is of interest to develop new strategies to manage the disease. Previously, we reported the ability of the siderophore pyochelin, produced by the opportunistic human pathogen Pseudomonas aeruginosa, to inhibit in vitro several bacterial species, including X. citri subsp. citri. The action mechanism, addressed with the model bacterium Escherichia coli, was connected to the generation of reactive oxygen species (ROS). This work aimed to find a non-pathogenic strain from the lemon phyllosphere that would produce pyochelin and therefore serve in canker biocontrol. An isolate that retained its capacity to colonise the lemon phyllosphere and inhibit X. citri subsp. citri was selected and characterised as Pseudomonas protegens CS1. From a liquid culture of this strain, the active compound was purified and identified as the pyochelin enantiomer, enantio-pyochelin. Using the producing strain and the pure compound, both in vitro and in vivo, we determined that the action mechanism of X. citri subsp. citri inhibition also involved the generation of ROS. Finally, the potential application of P. protegens CS1 was evaluated by spraying the bacterium in a model that mimics the natural X. citri subsp. citri infection. The ability of P. protegens CS1 to reduce canker formation makes this strain an interesting candidate as a biocontrol agent.

Preventive effect of Lactobacillus reuteri CRL1324 on Group B Streptococcus vaginal colonization in an experimental mouse model.

AIMS: To assess the preventive effect of different intravaginal (i.va.) doses of Lactobacillus reuteri CRL1324 against vaginal colonization by Group B Streptococcus (GBS) in a murine experimental model. METHODS AND RESULTS: The major virulence factors of four vaginal GBS clinical isolates were determined to select the most virulent strain and set up a murine model of streptococcal vaginal colonization. Later, the effect of four and seven doses of 10(8) viable cells of Lact. reuteri CRL1324 i.va. administered, prior to the GBS challenge was studied. Seven doses of lactobacilli were able to significantly reduce the number of viable GBS cells, while four doses showed no preventive effect. Both doses reduced the leucocyte influx induced by GBS. Seven doses caused a slight increase in the Lact. reuteri CRL1324 vaginal colonization compared with four doses and reduced murine vaginal pH compared to control mice. CONCLUSIONS: Lactobacillus reuteri CRL1324 evidenced a preventive effect on GBS vaginal colonization in an experimental mouse model. SIGNIFICANCE AND IMPACTS OF THE STUDY: Maternal GBS colonization is one of the most important risk factors for developing disease in newborns. Lactobacillus reuteri CRL1324 could be considered as a new biological agent to reduce infections caused by this micro-organism.