title: Antimicrobial activity against Shigella sonnei and probiotic properties of wild lactobacilli from fermented food.
abstract: Four lactobacilli strains (Lactobacillus paracasei subp. paracasei M5-L, Lactobacillus rhamnosus J10-L, Lactobacillus casei Q8-L and L. rhamnosus GG (LGG), were systematically assessed for the production of antimicrobial substances active towards Shigella sonnei, Escherichia coli and Salmonella typhimurium. Agar-well assay showed that the four lactobacilli strains displayed strong antibacterial activity towards S. sonnei. The nature of antimicrobial substances was also investigated and shown to be dependent on the production of organic acids, in particular the lactic acid. Time-kill assay showed that the viability of the S. sonnei was decreased by 2.7-3.6logCFU/ml after contact with CFCS (cell-free culture supernatants) of four lactobacilli for 2h, which confirmed the result of the agar-well assay. Further analysis of the organic acid composition in the CFCS revealed that the content of lactic acid range from 227 to 293mM. In addition, the aggregations properties, adherence properties and tolerance to simulated gastrointestinal conditions were also investigated in vitro tests. The result suggested that the M5-L, J10-L and Q8-L strains possess desirable antimicrobial activity towards S. sonnei and probiotic properties as LGG and could be potentially used as novel probiotic strains in the food industry.
authors.affiliation: School of Food Science and Engineering, Harbin Institute of Technology, Harbin, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lanwei
authors.initials: L
authors.lastname: Zhang
authors.forename: Ming
authors.initials: M
authors.lastname: Du
authors.forename: Huaxi
authors.initials: H
authors.lastname: Yi
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Guo
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Tuo
authors.forename: Xue
authors.initials: X
authors.lastname: Han
authors.forename: Jingyan
authors.initials: J
authors.lastname: Li
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001422:Bacterial Adhesion; D005285:Fermentation; D005516:Food Microbiology; D007778:Lactobacillus / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D019936:Probiotics / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D012764:Shigella sonnei / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents