title: A combination of direct viable count and fluorescence in situ hybridization for specific enumeration of viable Lactobacillus delbrueckii subsp.bulgaricus and Streptococcus thermophilus.
abstract: OBJECTIVE
  We have developed a direct viable count (DVC)-FISH procedure for quickly and easily discriminating between viable and nonviable cells of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains, the traditional yogurt bacteria.
  
  
  RESULTS
  direct viable count method has been modified and adapted for Lact. delbrueckii subsp. bulgaricus and Strep. thermophilus analysis by testing different times of incubation and concentrations of DNA-gyrase inhibitors. DVC procedure has been combined with fluorescent in situ hybridization (FISH) for the specific detection of viable cells of both bacteria with specific rRNA oligonucleotide probes (DVC-FISH). Of the four antibiotics tested (novobiocin, nalidixic acid, pipemidic acid and ciprofloxacin), novobiocin was the most effective for DVC method and the optimum incubation time was 7 h for both bacteria. The number of viable cells was obtained by the enumeration of specific hybridized cells that were elongated at least twice their original length for Lactobacillus and twice their original size for Streptococcus.
  
  
  CONCLUSIONS
  This technique was successfully applied to detect viable cells in inoculated faeces.
  
  
  CONCLUSIONS
  Results showed that this DVC-FISH procedure is a quick and culture-independent useful method to specifically detect viable Lact. delbrueckii subsp. bulgaricus and Strep. thermophilus in different samples, being applied for the first time to lactic acid bacteria.
authors.affiliation: Departamento de Biotecnología, Universitat Politècnica de València, Valencia, Spain. jorgarhe@btc.upv.es
authors.forename: J
authors.initials: J
authors.lastname: García-Hernández
authors.forename: Y
authors.initials: Y
authors.lastname: Moreno
authors.forename: C M
authors.initials: CM
authors.lastname: Amorocho
authors.forename: M
authors.initials: M
authors.lastname: Hernández
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015169:Colony Count, Microbial / Q000379:methods*; D005243:Feces / Q000382:microbiology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D048668:Lactobacillus delbrueckii / Q000187:drug effects / Q000302:isolation & purification*; D050296:Microbial Viability; D009675:Novobiocin / Q000494:pharmacology; D048249:Streptococcus thermophilus / Q000302:isolation & purification*; D059005:Topoisomerase II Inhibitors; D015014:Yogurt / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D059005:Topoisomerase II Inhibitors; D009675:Novobiocin