Use of genetically modified lactic acid bacteria and bifidobacteria as live delivery vectors for human and animal health

There is now strong evidence to support the interest in using lactic acid bacteria (LAB)in particular, strains of lactococci and lactobacilli, as well as bifidobacteria, for the development of new live vectors for human and animal health purposes. LAB are Gram-positive bacteria that have been used for millennia in the production of fermented foods. In addition, numerous studies have shown that genetically modified LAB and bifodobacteria can induce a systemic and mucosal immune response against certain antigens when administered mucosally. They are therefore good candidates for the development of new mucosal delivery strategies and are attractive alternatives to vaccines based on attenuated pathogenic bacteria whose use presents health risks. This article reviews the most recent research and advances in the use of LAB and bifidobacteria as live delivery vectors for human and animal health.

Effect of Probiotic Supplementation on Intestinal Permeability in Overweight and Obesity: A Systematic Review of Randomized Controlled Trials and Animal Studies

Overweight and obesity are associated with increased intestinal permeability, characterized by loss of gut epithelial integrity, resulting in unregulated passage of lipopolysaccharide (LPS) and other inflammatory triggers into circulation, i.e., metabolic endotoxemia. In obesity, shifts in the gut microbiome negatively impact intestinal permeability. Probiotics are an intervention that can target the gut microbiome by introducing beneficial microbial species, potentially restoring gut barrier integrity. Currently, the role of probiotic supplementation in ameliorating obesity- and overweight-associated increases in gut permeability has not been reviewed. This systematic review aimed to summarize findings from both animal and clinical studies that evaluated the effect of probiotic supplementation on obesity-induced impairment in intestinal permeability (International Prospective Register of Systematic Reviews, CRD42022363538). A literature search was conducted using PubMed (Medline), Web of Science, and CAB Direct from origin until August 2023 using keywords of intestinal permeability, overweight or obesity, and probiotic supplementation. Of 920 records, 26 eligible records were included, comprising 12 animal and 14 clinical studies. Clinical trials ranged from 3 to 26 wk and were mostly parallel-arm (n = 13) or crossover (n = 1) design. In both animal and clinical studies, plasma/serum LPS was the most common measure of intestinal permeability. Eleven of 12 animal studies reported a positive effect of probiotic supplementation in reducing intestinal permeability. However, results from clinical trials were inconsistent, with half reporting reductions in serum LPS and half reporting no differences after probiotic supplementation. Bifidobacterium, Lactobacillus, and Akkermansia emerged as the most common genera in probiotic formulations among the animal and clinical studies that yielded positive results, suggesting that specific bacteria may be more effective at reducing intestinal permeability and improving gut barrier function. However, better standardization of strain use, dosage, duration, and the delivery matrix is needed to fully understand the probiotic impact on intestinal permeability in individuals with overweight and obesity.

Evaluation of Antibacterial Effects of an Oral Rinse Containing Ocimum tenuiflorum and Ocimum gratissimum on Streptococcus mutans and Lactobacillus Species

BACKGROUND AND AIM

Dental caries, primarily caused by Streptococcus mutans and Lactobacillus spp., is a major global health issue. There is a growing need for effective, natural antimicrobial treatments. Ocimum tenuiflorum and Ocimum gratissimum are known for their medicinal properties, including antimicrobial activity. This study investigates the antibacterial efficacy of a herbal oral rinse derived from these plants. This study aimed to evaluate the antibacterial activity of an herbal formulation-based oral rinse prepared from Ocimum tenuiflorum and Ocimum gratissimum against Streptococcus mutans and Lactobacillus spp.

METHODS

Fresh leaves of Ocimum tenuiflorum and Ocimum gratissimum were shade-dried, powdered, and extracted in distilled water. The extract was incorporated into an oral rinse formulation. The antibacterial activity was assessed using the agar well diffusion method, protein leakage and cytoplasmic leakage assays, and time-kill curve analysis. A commercial oral rinse was used as a standard.

RESULTS

The herbal oral rinse exhibited significant antibacterial activity against both Streptococcus mutans and Lactobacillus spp. The zones of inhibition for Streptococcus mutans were 10 mm, 13 mm, and 15 mm at concentrations of 25 µg/mL, 50 µg/mL, and 100 µg/mL, respectively. For Lactobacillus spp., the inhibition zones were 10 mm, 12 mm, and 14 mm at the same concentrations. The protein leakage and cytoplasmic leakage analysis supported these findings, demonstrating the formulation's efficacy at low concentrations. Time-kill curve assays showed rapid bactericidal action, particularly at higher concentrations.

CONCLUSION

The Ocimum tenuiflorum and Ocimum gratissimum-based herbal oral rinse demonstrates strong antibacterial activity against key oral pathogens, suggesting that it could be a natural alternative to conventional oral rinses.