title: Coaggregation between probiotic bacteria and caries-associated strains: an in vitro study.
abstract: OBJECTIVE
  To evaluate the in vitro abilities of probiotic bacteria derived from consumer products to coaggregate with caries-associated mutans streptococci.
  
  
  METHODS
  Six lactobacillus strains (L. acidophilus (CCUG 5917), L. plantarum 299v, L. rhamnosus GG and LB21, L. paracasei F19, L. reuteri PTA5289) were cultivated under anaerobic conditions at 37°C in Man Rogosa Sharpe (MSB) broth for 24 h. Four strains of human streptococci (S. mutans Ingbritt, S. mutans (ATCC 25175), S. mutans GS-5, S. sobrinus (ATCC 33478) were similarly grown in Brain Heart Infusion (BHI) broth. A gastrointestinal pathogen (Escherichia coli) was aerobically cultivated on BHI broth as a positive control. After incubation, the bacteria were aerobically harvested, washed, and suspended in 10 mmol/l phosphate-buffered saline (pH 7.2). The probiotic strains were characterized with the API 50 CH system to confirm their identity. Coaggregation was determined by spectrophotometry in mixtures and bacterial suspensions alone after 1, 2, 4, and 24 h and expressed as the aggregation ratio (%).
  
  
  RESULTS
  All probiotic strains showed coaggregation abilities with the oral pathogens and the results were strain specific and dependent on time. S. mutans GS-5 exhibited a significantly higher ability to coaggregate with all the probiotic strains than the other mutans streptococci and E. coli. The differences among the probiotic strains were modest with L. acidophilus being the most prone and L. rhamnosus LB21 the least prone to coaggregate with the oral streptococci.
  
  
  CONCLUSIONS
  The results demonstrated different abilities of lactobacilli-derived probiotic bacteria to coaggregate with selected oral streptococci. Aggregation assays may be a useful complement for screening of probiotic candidates with possible anti-caries properties.
authors.affiliation: Department of Cariology and Endodontics, School of Dentistry, University of Copenhagen, Denmark.
authors.forename: Lisa
authors.initials: L
authors.lastname: Twetman
authors.forename: Ulla
authors.initials: U
authors.lastname: Larsen
authors.forename: Nils-Erik
authors.initials: NE
authors.lastname: Fiehn
authors.forename: Christina
authors.initials: C
authors.lastname: Stecksén-Blicks
authors.forename: Svante
authors.initials: S
authors.lastname: Twetman
mesh_terms: D000693:Anaerobiosis; D001422:Bacterial Adhesion / Q000502:physiology*; D001431:Bacteriological Techniques; D018920:Coculture Techniques; D003731:Dental Caries / Q000382:microbiology; D004926:Escherichia coli / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000502:physiology*; D007779:Lactobacillus acidophilus / Q000502:physiology; D048191:Lactiplantibacillus plantarum / Q000502:physiology; D052200:Limosilactobacillus reuteri / Q000502:physiology; D052201:Lacticaseibacillus rhamnosus / Q000502:physiology; D019936:Probiotics; D013053:Spectrophotometry; D013295:Streptococcus mutans / Q000502:physiology*; D016986:Streptococcus sobrinus / Q000502:physiology*; D013997:Time Factors