Ligilactobacillus murinus Strains Isolated from Mice Intestinal Tract: Molecular Characterization and Antagonistic Activity against Food-Borne Pathogens

Abstract

Considering the objectives of “One Health” and the Sustainable development Goals “Good health and well-being” for the development of effective strategies to apply against bacterial resistance, food safety dangers, and zoonosis risks, this project explored the isolation and identification of Lactobacillus strains from the intestinal tract of recently weaned mice; as well as the assessment of antibacterial activity against clinical and zoonotic pathogens. For molecular identification, 16S rRNA gene-specific primers were used and, via BLAST-NCBI, 16 Ligilactobacillus murinus, one Ligilactobacillus animalis, and one Streptococcus salivarius strains were identified and registered in GenBank after the confirmation of their identity percentage and the phylogenetic analysis of the 16 Ligilactobacillus murinus strains and their association with Ligilactobacillus animalis. The 18 isolated strains showed antibacterial activity during agar diffusion tests against Listeria monocytogenes ATCC 15313, enteropathogenic Escherichia coli O103, and Campylobacter jejuni ATCC 49943. Electrophoretic and zymographic techniques confirmed the presence of bacteriolytic bands with a relative molecular mass of 107 kDa and another of 24 kDa in Ligilactobacillus murinus strains. UPLC-MS analysis allowed the identification of a 107 kDa lytic protein as an N-acetylmuramoyl-L-amidase involved in cytolysis and considered a bacteriolytic enzyme with antimicrobial activity. The 24 kDa band displayed similarity with a portion of protein with aminopeptidase function. It is expected that these findings will impact the search for new strains and their metabolites with antibacterial activity as an alternative strategy to inhibit pathogens associated with major health risks that help your solution.

Vaginal microbial dynamics and pathogen colonization in a humanized microbiota mouse model

“…Additionally, HMb mice frequently colonized by Ligilactobacillus-dominant communities ( h mCST II) had OTUs mapping to L. murinus. While only a rarely reported human-associated species 49 , L. murinus is a homofermentative lactic acid bacterium 92 isolated from the vaginal tract of wild mice 78 and gut of conventional C57BL/6J mice 93 , having the genetic capacity for glycogen metabolism 94 and pathogen inhibition 95 . It is also important to note that, despite identification of HMb mice sequences mapping to L. crispatus, L. gasseri, and L. jensenii, it is not possible to ascribe the same functionality between the taxa identified in this study and human gut (the Fig.…”

Spatial recovery of the murine gut microbiota after antibiotics perturbation

“…We also identified O. valericigenes 2 , L. murinus , A. muris , and D. freteri 2 as potential foundational species. O. valericigenes and A. muris are capable of high levels of short-chain fatty acid production ( 28 ), L. murinus is an abundant lactic acid-producing bacterium ( 29 ), and D. freteri is a known mucus degrader ( 30 ). These are all important metabolic processes in the gut; however, the presence of Firmicutes rather than mostly Bacteroidetes in this group is unexpected.…”

Shaping the Future of Probiotics: Novel Methodologies, Applications, and Mechanisms of Action

“…Mechanistic studies show that at the basis of their action lies their ability to induce immunomodulatory, immunostimulatory, antioxidant, antimicrobial and antibiofilm action [ 3 ]. In this Special Issue of Microorganisms , four research articles deal with different aspects of probiotic activity, including their antagonistic activity against food-borne pathogens [ 4 ], and the application of omics technologies, such as transcriptomics and metabolomics, to study the metabolic and physiological properties of probiotic strains in different food matrices [ 5 ]. Moreover, three review articles in this Special Issue summarize recent experimental findings in probiotic research, focusing on the main mechanisms of action, and critically discuss the potential beneficial effects of probiotics in human [ 6 , 7 ], as well as in animal, plant, soil, and environmental health, in the context of the ‘’One Health’’ approach [ 8 ].…”