title: Sensitivity of capsular-producing Streptococcus thermophilus strains to bacteriophage adsorption.
abstract: OBJECTIVE
  To determine whether the presence and type of exopolysaccharides (EPS), slime-EPS or capsular, and the structural characteristics of the polymers produced by Streptococcus thermophilus strains could interfere with or be involved in phage adsorption.
  
  
  RESULTS
  Phage-host interactions between eight EPS-producing Strep. thermophilus strains (CRL419, 638, 804, 810, 815, 817, 821, 1190) and five streptococcus specific phages (phiYsca, phi3, phi5, phi6, phi8) isolated from Argentinean faulty fermentation failed yoghurts were evaluated. No relationship was found between the EPS chemical composition and the phage sensitivity/resistance phenotype. In general, the capsular-producing strains were more sensitive to phage attacks than the noncapsular-producing strains. Streptococcus thermophilus CRL1190 (capsular-producing) was the only strain sensitive to all bacteriophages and showed the highest efficiency of plating. Phage adsorption to a capsular-negative, EPS low-producing mutant of strain CRL1190 was reduced, especially for phiYcsa and phi8.
  
  
  CONCLUSIONS
  The presence of capsular polysaccharide surrounding the cells of Strep. thermophilus strains could play a role in the adsorption of specific phages to the cells.
  
  
  CONCLUSIONS
  Capsular-producing Strep. thermophilus strains should be evaluated for their bacteriophage sensitivity if they are included in starter cultures for the fermented food industry.
authors.affiliation: Centro de Referencia para Lactobacilos (CERELA)-CONICET, San Miguel de Tucumán, Argentina.
authors.forename: C
authors.initials: C
authors.lastname: Rodríguez
authors.forename: R
authors.initials: R
authors.lastname: Van der Meulen
authors.forename: F
authors.initials: F
authors.lastname: Vaningelgem
authors.forename: G
authors.initials: G
authors.lastname: Font de Valdez
authors.forename: R
authors.initials: R
authors.lastname: Raya
authors.forename: L
authors.initials: L
authors.lastname: De Vuyst
authors.forename: F
authors.initials: F
authors.lastname: Mozzi
mesh_terms: D001118:Argentina; D016667:Bacterial Capsules / Q000096:biosynthesis* / Q000737:chemistry; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005516:Food Microbiology; D011135:Polysaccharides, Bacterial / Q000032:analysis; D019105:Random Amplified Polymorphic DNA Technique; D017108:Streptococcus Phages / Q000502:physiology*; D048249:Streptococcus thermophilus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000821:virology*; D053585:Virus Attachment
chemical_list: D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial