title: Lack of correlation between in vitro antibiosis and in vivo protection against enteropathogenic bacteria by probiotic lactobacilli.
abstract: Increased resistance to infection is one of the beneficial effects attributed to probiotic microorganisms. This effect may be due to several mechanisms: production of inhibitory substances, blocking of adhesion sites on the intestinal surface, competition for nutrients and stimulation of mucosal and systemic immunity. The present study aimed to investigate the correlation between in vitro and in vivo antimicrobial activity of probiotic lactobacilli. The agar spot test was used to show that twenty Lactobacillus strains were able to inhibit the enteropathogenic bacterium Yersinia enterocolitica. This inhibition was mainly attributable to a decrease in pH resulting from dextrose fermentation by lactobacilli. The inhibition of Y. enterocolitica, Salmonella enterica serovar Typhimurium and Listeria monocytogenes by two probiotic strains, Lactobacillus casei C1 and Lactobacillus plantarum C4, was also associated with the pH decrease. However, both strains lacked protective effects in mouse experimental infection models, with the exception of long-lasting pre-treatment with L. plantarum C4, which exerted a partial protective effect against S. Typhimurium that was attributable to an immunostimulatory mechanism. Our results show that in vitro antibiosis tests do not provide useful information on the probiotic potential of Lactobacillus strains.
authors.affiliation: Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain. Electronic address: ratoncillos@yahoo.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: Bujalance
authors.affiliation: Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain. Electronic address: mjvalera@ugr.es.
authors.forename: María
authors.initials: M
authors.lastname: Jiménez-Valera
authors.affiliation: Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain. Electronic address: morenoc@ugr.es.
authors.forename: Encarnación
authors.initials: E
authors.lastname: Moreno
authors.affiliation: Department of Nutrition and Bromatology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain. Electronic address: mdruiz@ugr.es.
authors.forename: María-Dolores
authors.initials: MD
authors.lastname: Ruiz-López
authors.affiliation: Biotmicrogren S. L., Parque tecnológico de Ciencias de la Salud, BIC nave 6, 18100 Armilla, Granada, Spain. Electronic address: direccion@biot.es.
authors.forename: Agustín
authors.initials: A
authors.lastname: Lasserrot
authors.affiliation: Department of Microbiology, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain. Electronic address: aruizbr@ugr.es.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Ruiz-Bravo
mesh_terms: D000818:Animals; D000898:Antibiosis; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D007778:Lactobacillus / Q000502:physiology*; D008089:Listeria monocytogenes / Q000502:physiology; D051379:Mice; D019936:Probiotics; D012486:Salmonella typhimurium / Q000502:physiology; D015008:Yersinia enterocolitica / Q000502:physiology
keywords: Antibiosis; Infection; Lactobacillus; Probiotics