Temperate coliphages: classification and correlation with habitats.

Temperate coliphages were recovered from sewage, mammalian feces, and lysogenic strains of Escherichia coli. A total of 32 phages of independent origin were divided into six groups by applying the criteria of host range, antigenic homology, and the ultraviolet inducibility of the prophage. The demonstration of genetic interactions in some cases has confirmed the classification scheme. Nine phages were assigned to the P2 family and 19 to the lambda family. The remaining four isolates may represent some novel phylogenetic types. Phages recovered from the lysogenic strains of E. coli were all found to be P2 related, whereas a majority of the phages recovered as cell-free plaque-forming units were assignable to the lambda family. It is proposed that the biological attributes of the phages belonging to the two principal families are reflected in the distribution patterns observed. The virions of phage HK256 show multiple tail fibers and may thus represent a "new" virion form among the temperate coliphages.