title: Characterization of intestinal lactobacilli as putative probiotic candidates.
abstract: OBJECTIVE
  To use antioxidative activity and antagonistic properties of lactobacilli against selected pathogens and members of the normal microflora as a basis for screening probiotic candidates.
  
  
  RESULTS
  Antagonistic activity of lactobacilli against target bacteria in both microaerobic and anaerobic environments was tested. Production of antagonistic metabolites (ethanol, hydrogen peroxide (H2O2), acetic, lactic and succinic acid) by lactobacilli as well as their total antioxidative activity were assessed. In general, the lactobacilli tested were most effective against Gram-negative bacteria and their antagonistic activity was strain-specific. However, obligately heterofermentative lactobacilli had the strongest activity when tested in a microaerobic environment. Additionally, facultatively heterofermentative lactobacilli were equally effective in either milieu and produced significant levels of acetic and lactic acid. Moreover, obligately homofermentative lactobacilli had high H2O2 production and total antioxidative activity but weak antagonistic activity.
  
  
  CONCLUSIONS
  Antioxidative and antagonistic activity of intestinal lactobacilli is strain-specific but typically can be related to their fermentation type which may be used for rapidly screening large numbers of lactobacilli for probiotic candidates.
  
  
  CONCLUSIONS
  This study represents the first report on the utilization of group characteristics to screen lactobacilli intended for specific probiotic use. Such uses include the targeting of particular gut niches and pathogens as well as allowing for long-term benefits to the host.
authors.affiliation: Department of Microbiology, Medical Faculty, University of Tartu, Tartu, Estonia. heidiannuk@yahoo.com
authors.forename: H
authors.initials: H
authors.lastname: Annuk
authors.forename: J
authors.initials: J
authors.lastname: Shchepetova
authors.forename: T
authors.initials: T
authors.lastname: Kullisaar
authors.forename: E
authors.initials: E
authors.lastname: Songisepp
authors.forename: M
authors.initials: M
authors.lastname: Zilmer
authors.forename: M
authors.initials: M
authors.lastname: Mikelsaar
mesh_terms: D000693:Anaerobiosis; D000975:Antioxidants / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism; D002675:Child, Preschool; D003470:Culture Media; D000431:Ethanol / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000502:physiology; D006094:Gram-Positive Bacteria / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007422:Intestines / Q000382:microbiology; D007778:Lactobacillus / Q000302:isolation & purification / Q000378:metabolism*; D019936:Probiotics
chemical_list: D000975:Antioxidants; D002264:Carboxylic Acids; D003470:Culture Media; D000431:Ethanol; D006861:Hydrogen Peroxide