Molecular ecology of Streptococcus thermophilus bacteriophage infections in a cheese factory
| Autor: | B Huni, Nicola D'amico, Anne Bruttin, J P Guérin, Josette Sidoti, Sacha Lucchini, Frank Desiere, Harald Brüssow |
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| Rok vydání: | 1997 |
| Předmět: |
Streptococcus thermophilus
Streptococcus Phages viruses Molecular Sequence Data Population Biology Polymerase Chain Reaction Applied Microbiology and Biotechnology Microbiology Bacteriophage Cheese Environmental Microbiology Animals Point Mutation Longitudinal Studies education Phage typing Genetic diversity education.field_of_study Base Sequence Ecology Genetic Variation Nucleic Acid Hybridization Streptococcus Sequence Analysis DNA biology.organism_classification Temperateness Milk Lytic cycle Mutagenesis Food Microbiology Restriction fragment length polymorphism Sequence Alignment Polymorphism Restriction Fragment Length Research Article Food Science Biotechnology |
| Zdroj: | Applied and Environmental Microbiology. 63:3144-3150 |
| ISSN: | 1098-5336 0099-2240 |
| DOI: | 10.1128/aem.63.8.3144-3150.1997 |
| Popis: | A mozzarella cheese factory using an undefined, milk-derived Streptococcus thermophilus starter system was monitored longitudinally for 2 years to determine whether the diversity of the resident bacteriophage population arose from environmental sources or from genetic changes in the resident phage in the factory. The two hypotheses led to different predictions about the genetic diversity of the phages. With respect to host range, 12 distinct phage types were observed. With two exceptions, phages belonging to different lytic groups showed clearly distinct restriction patterns and multiple isolates of phages showing the same host range exhibited identical or highly related restriction patterns. Sequencing studies in a conserved region of the phage genome revealed no point mutations in multiple isolates of the same phage type, while up to 12% nucleotide sequence diversity was observed between the different phage types. This diversity is as large as that between the most different sequences from phages in our collection. These observations make unlikely a model that postulates a single phage invasion event and diversification of the phage during its residence in the factory. In the second stage of our factory study, a defined starter system was introduced that could not propagate the resident factory phage population. Within a week, three new phage types were observed in the factory while the resident phage population was decreased but not eliminated. Raw milk was the most likely source of these new phages, as phages with identical host ranges and restriction patterns were isolated from raw milk delivered to the factory during the intervention trial. Apparently, all of the genetic diversity observed in the S. thermophilus phages isolated during our survey was already created in their natural environment. A better understanding of the raw-milk ecology of S. thermophilus phages is thus essential for successful practical phage control. |
| Databáze: | OpenAIRE |
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