title: Antagonistic activities of some Bifidobacterium sp. strains isolated from resident infant gastrointestinal microbiota on Gram-negative enteric pathogens.
abstract: The gastrointestinal microbiota contributes to the consolidation of the anti-infectious barrier against enteric pathogens. The purpose of this study was to investigate the influence of Bifidobacterium sp. strains, recently isolated from infant gastrointestinal microbiota on the in vitro growth and virulence features expression of enteropathogenic bacterial strains. The antibacterial activity of twelve Bifidobacterium sp. strains isolated from human feces was examined in vitro against a wide range of Gram negative pathogenic strains isolated from 30 infant patients (3 days to 5 years old) with diarrhea. Both potential probiotic strains (Bifidobacterium longum, Bifidobacterium pseudocatenulatum, Bifidobacterium catenulatum, Bifidobacterium breve, Bifidobacterium ruminantium) and enteropathogenic strains (EPEC, EIEC, Klebsiella pneumoniae, Salmonella sp., Yersinia enterocolitica, Pseudomonas aeruginosa) were identified by MALDI-TOF and confirmed serologically when needed. The bactericidal activity, growth curve, adherence to the cellular HEp-2 substratum and production of soluble virulence factors have been assessed in the presence of different Bifidobacterium sp. cultures and fractions (whole culture and free-cell supernatants). Among the twelve Bifidobacterium sp. strains, the largest spectrum of antimicrobial activity against 9 of the 18 enteropathogenic strains was revealed for a B. breve strain recently isolated from infant intestinal feces. The whole culture and free-cell supernatant of B. breve culture decreased the multiplication rate, shortened the log phase and the total duration of the growth curve, with an earlier entrance in the decline phase and inhibited the adherence capacity to a cellular substratum and the swimming/swarming motility too. These results indicate the significant probiotic potential of the B. breve strain.
authors.affiliation: Iancului Private Laboratory, Bucharest, Romania; Faculty of Biology - University of Bucharest, Dept. Microbiology & Immunology and Research Institute of the University of Bucharest -ICUB- University of Bucharest, Aleea Portocalelor 1-3, Sect. 6, Bucharest, 060101, Romania.
authors.forename: Cristina
authors.initials: C
authors.lastname: Delcaru
authors.affiliation: Iancului Private Laboratory, Bucharest, Romania.
authors.forename: Ionela
authors.initials: I
authors.lastname: Alexandru
authors.affiliation: Iancului Private Laboratory, Bucharest, Romania.
authors.forename: Paulina
authors.initials: P
authors.lastname: Podgoreanu
authors.affiliation: Department of Microbiology Reference Laboratory Central Synevo, Bucharest, Romania.
authors.forename: Violeta Corina
authors.initials: VC
authors.lastname: Cristea
authors.affiliation: Faculty of Biology - University of Bucharest, Dept. Microbiology & Immunology and Research Institute of the University of Bucharest -ICUB- University of Bucharest, Aleea Portocalelor 1-3, Sect. 6, Bucharest, 060101, Romania.
authors.forename: Coralia
authors.initials: C
authors.lastname: Bleotu
authors.affiliation: Faculty of Biology - University of Bucharest, Dept. Microbiology & Immunology and Research Institute of the University of Bucharest -ICUB- University of Bucharest, Aleea Portocalelor 1-3, Sect. 6, Bucharest, 060101, Romania. Electronic address: carmen.chifiriuc@gmail.com.
authors.forename: Mariana Carmen
authors.initials: MC
authors.lastname: Chifiriuc
authors.affiliation: Faculty of Agricultural Development, Dept. Food Science & Technology, Democritus University of Thrace, Greece.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Bezirtzoglou
authors.affiliation: Faculty of Biology - University of Bucharest, Dept. Microbiology & Immunology and Research Institute of the University of Bucharest -ICUB- University of Bucharest, Aleea Portocalelor 1-3, Sect. 6, Bucharest, 060101, Romania.
authors.forename: Veronica
authors.initials: V
authors.lastname: Lazar
mesh_terms: D000898:Antibiosis; D001422:Bacterial Adhesion / Q000187:drug effects; D001644:Bifidobacterium / Q000502:physiology*; D002675:Child, Preschool; D003967:Diarrhea / Q000382:microbiology / Q000503:physiopathology; D005243:Feces / Q000382:microbiology; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000254:growth & development; D007778:Lactobacillus / Q000502:physiology*; D008297:Male; D019936:Probiotics / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D012475:Salmonella / Q000187:drug effects / Q000254:growth & development; D037521:Virulence Factors / Q000096:biosynthesis / Q000633:toxicity*; D015008:Yersinia enterocolitica / Q000187:drug effects / Q000254:growth & development
chemical_list: D037521:Virulence Factors
keywords: Antagonistic relationships; Bifidobacterium sp; Disbiosis; Enteric pathogens; Lactobacillus sp; Normal microbiota; Probiotics