title: The coexistence of Escherichia coli serotype O157:H7 and its specific bacteriophage in continuous culture.
abstract: For the development of phage therapy, systematic understanding mechanisms of bacteriophage resistance will be required. We describe a new strain of Escherichia coli O157:H7, named Mu(L), which stably co-exists with the O157:H7-specific lytic bacteriophage PP01. Chemostat cultures of E. coli O157:H7 infected with PP01 showed unchanging cell concentration, but phage concentrations which increased by approximately 10(8) PFU mL(-1). However, the latent period, burst size, and growth rate of Mu(L) were the same as in a PP01-susceptible strain. The binding rate of PP01 to the cell surface was diminished 8.5-fold in Mu(L). By observation of the binding of fluorescently labeled O157:H7-specific phage to individual Mu(L) cells, we found that clonal Mu(L) cultures were heterogeneous in their ability to bind bacteriophage. 15% of the Mu(L) population was completely resistant to PP01 infection. Mu(L) also co-existed with bacteriophages unrelated to PP01. Broad-range phage resistance by clonal heterogeneity represents a new class of bacteria-phage interactions.
authors.affiliation: Department of Bioengineering, Tokyo Institute of Technology, 4259 B41 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Curt R
authors.initials: CR
authors.lastname: Fischer
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yoichi
authors.forename: Hajime
authors.initials: H
authors.lastname: Unno
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Tanji
mesh_terms: D000818:Animals; D001433:Bacteriolysis; D003090:Coliphages / Q000254:growth & development* / Q000502:physiology*; D015169:Colony Count, Microbial; D003470:Culture Media; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000821:virology*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D011135:Polysaccharides, Bacterial; D012703:Serotyping
chemical_list: D003470:Culture Media; D011135:Polysaccharides, Bacterial