title: Inhibition of Clostridium difficile strains by intestinal Lactobacillus species.
abstract: Indigenous intestinal microflora (including lactobacilli) has an important role in protection against Clostridium difficile infection. To assess in vitro interaction between lactobacilli and C. difficile, antagonistic activity of 50 intestinal Lactobacillus spp. strains against 23 pathogenic C. difficile strains was determined. Phenotypic properties of C. difficile strains [production of short-chain fatty acids (SCFAs) and toxin A, and antimicrobial susceptibility] and lactobacilli (production of SCFAs and H(2)O(2)) were investigated. Five lactobacilli (Lactobacillus paracasei and Lactobacillus plantarum species) were antagonistic to all C. difficile strains, 18 were antagonistic to some C. difficile strains and 27 showed no antagonistic activity. This antagonistic activity was strain-specific and seemed to correlate with H(2)O(2) and lactic acid production. C. difficile strains that were more sensitive to lactobacilli (n = 9) usually produced higher toxin levels and more SCFAs, and were more resistant to antibiotics, than strains that were resistant to lactobacilli (n = 14). Compatibility of C. difficile strain properties (resistance to lactobacilli or antibiotics) with intestinal microecological conditions (e.g. presence of antagonistic lactobacilli, concentration of antibiotics) may determine expression of disease.
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Paul
authors.initials: P
authors.lastname: Naaber
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Imbi
authors.initials: I
authors.lastname: Smidt
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Štšepetova
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Brilene
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Heidi
authors.initials: H
authors.lastname: Annuk
authors.affiliation: Department of Microbiology, University of Tartu, Ravila 19, 40411, Tartu, Estonia.
authors.forename: Marika
authors.initials: M
authors.lastname: Mikelsaar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000898:Antibiosis; D001427:Bacterial Toxins / Q000378:metabolism; D016360:Clostridioides difficile / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D024881:Drug Resistance, Bacterial; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007422:Intestines / Q000382:microbiology; D019344:Lactic Acid / Q000378:metabolism; D007778:Lactobacillus / Q000378:metabolism / Q000502:physiology*; D013045:Species Specificity
chemical_list: D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D005232:Fatty Acids, Volatile; D019344:Lactic Acid; D006861:Hydrogen Peroxide