Antimicrobial and Antibiofilm Activities of Weissella cibaria against Pathogens of Upper Respiratory Tract Infections.

Recently discovered preventive effects of probiotics on oral health have attracted interest to their use for the prevention and treatment of various diseases. This study aimed to evaluate the antimicrobial and antibiofilm properties of Weissella cibaria against Streptococcus pyogenes, Staphylococcus aureus, S. pneumoniae, and Moraxella catarrhalis, the major pathogens of upper respiratory tract infections (URTIs). The antimicrobial activities of W. cibaria were compared with those of other oral probiotics using a competitive inhibition assay and the determination of the minimum inhibitory concentrations (MICs). In addition, a time-kill assay, spectrophotometry, and confocal laser scanning microscopy were used to confirm the antimicrobial and antibiofilm abilities of W. cibaria CMU (oraCMU) and CMS1 (oraCMS1). Both live cells and cell-free supernatants of all tested probiotics, except Streptococcus salivarius, showed excellent antimicrobial activities. All target pathogens were killed within 4 to 24 h at twice the MIC of oraCMU and oraCMS1, which showed the highest antimicrobial activities against M. catarrhalis. The antimicrobial substances that affected different target pathogens were different. Both oraCMU and oraCMS1 showed excellent abilities to inhibit biofilm formation and remove preformed biofilms. Our results suggest that the W. cibaria probiotics offer new possibilities for the prevention and treatment of bacterial URTIs.

Effects of Weissella cibaria CMU on Halitosis and Calculus, Plaque, and Gingivitis Indices in Beagles.

Weissella (W.) cibaria strain Chonnam Medical University (CMU) has shown oral colonizing ability and inhibitory effects on the formation of volatile sulfur compounds (VSCs) in vitro studies. The present study was conducted to analyze the effects of the W. cibaria CMU on canine oral health. Halitosis, calculus, plaque, gingivitis, and intraoral microbiota were assessed in 3 groups: control (maltodextrin), W. cibaria CMU low concentration (CMU-L, 2 × 107 colony forming unit [CFU]), and high-concentration (CMU-H, 2 × 109 CFU). Halitosis was analyzed using both organoleptic evaluation and measurement of VSCs. Intraoral microbiota were analyzed by real-time polymerase chain reaction. From week 4, the total VSC level in the CMU-H group (4.0 ± 1.30 ng/10 mL) was significantly lower than in the control group (6.3 ± 2.28 ng/10 mL). Significant reduction in methyl mercaptan in the CMU-treated groups was also observed. In addition, the plaque index in the CMU-treated groups was significantly decreased. The CMU-treated groups showed significant decreases in Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia and demonstrated the colonizing ability of W. cibaria CMU in the oral cavity. We demonstrated that W. cibaria CMU suppresses halitosis, colonizes the oral cavity, and inhibits the proliferation of malodor-causing oral bacteria in beagles. According to these results, we expect that W. cibaria CMU could be a new oral hygiene solution by reducing VSC production and inhibiting the growth of oral harmful bacteria in companion animals.

Safety Evaluation of Oral Care Probiotics Weissella cibaria CMU and CMS1 by Phenotypic |and Genotypic Analysis.

Weissella cibaria CMU and CMS1 are known to exert beneficial effects on the oral cavity but have not yet been determined to be generally recognized as safe (GRAS), although they are used as commercial strains in Korea. We aimed to verify the safety of W. cibaria CMU and CMS1 strains through phenotypic and genotypic analyses. Their safety was evaluated by a minimum inhibitory concentration assay for 14 antibiotics, DNA analysis for 28 antibiotic resistance genes (ARGs) and one conjugative element, antibiotic resistance gene transferability, virulence gene analysis, hemolysis, mucin degradation, toxic metabolite production, and platelet aggregation reaction. W. cibaria CMU showed higher kanamycin resistance than the European Food Safety Authority (EFSA) cut-off, but this resistance was not transferred to the recipient strain. W. cibaria CMU and CMS1 lacked ARGs in chromosomes and plasmids, and genetic analysis confirmed that antibiotic resistance of kanamycin was an intrinsic characteristic of W. cibaria. Additionally, these strains did not harbor virulence genes associated with pathogenic bacteria and lacked toxic metabolite production, ß-hemolysis, mucin degradation, bile salt deconjugation, ß-glucuronidase, nitroreductase activity, gelatin liquefaction, phenylalanine degradation, and platelet aggregation. Our findings demonstrate that W. cibaria CMU and CMS1 can achieve the GRAS status in future.

Characterization of Antibacterial Cell-Free Supernatant from Oral Care Probiotic Weissella cibaria, CMU.

Recently, studies have explored the use of probiotics like the Weissella cibaria strain, CMU (oraCMU), for use as preventive dental medicine instead of chemical oral care methods. The present study was conducted to investigate the antibacterial properties of the cell-free supernatant (CFS) from this bacterium. Cell morphology using the scanning electron microscope, and the antibacterial effect of CFS under various growth conditions were evaluated. The production of hydrogen peroxide, organic acids, fatty acids, and secretory proteins was also studied. Most of the antibacterial effects of oraCMU against periodontal pathogens were found to be acid- and hydrogen peroxide-dose-dependent effects. Lactic acid, acetic acid, and citric acid were the most common organic acids. Among the 37 fatty acids, only 0.02% of oleic acid (C18:1n-9, cis) was detected. Proteomic analysis of the oraCMU secretome identified a total of 19 secreted proteins, including N-acetylmuramidase. This protein may be a potential anti-microbial agent effective against Porphyromonas gingivalis.

Complete Genome Sequences of Weissella cibaria Strains CMU, CMS1, CMS2, and CMS3 Isolated from Infant Saliva in South Korea.

Weissella cibaria strain CMU is used as a commercial oral care probiotic in South Korea. Here, we present the complete genome sequences of four W. cibaria strains (CMU, CMS1, CMS2, and CMS3) isolated from the saliva of an infant living in Gwangju, South Korea.