The Isolation of a Staphylococcal Phage Variant Susceptible to an Unusual Host Control

Abstract

A series of phage P1 variants was isolated from plaques developing on S. aureus WF 145. One in particular, phage 14, was studied in detail because its host range appeared to be dependent on the previous host of production; i.e., it was subject to a host control. When this phage was produced on host K1 its lysate assayed equally well on both 145 and K1 cells. When produced on host 145, however, it assayed manyfold higher on 145 than on host K1. All its particles adsorbed on K1 cells, but only a small percentage were able to produce plaques. No differences could be found in adsorption rates, latent periods, or burst sizes of the phage on the two hosts. No extracellular inactivating substances could be detected which could account for such changes, nor could the results be explained readily on a mutational basis, since distinct phage strains could not be isolated. The change in virus properties was found to occur in the first burst of singly infected host 145 cells, regardless of the previous host or its prior lytic abilities. Heat inactivation destroyed activity for K1 cells more rapidly than for 145 cells. This was found to be a property of both the stock phage P1 and phage 14. Phage 14 could be heated until there remained particles which could multiply only on strain 145. When the plaques of such survivors were examined they were found to contain phage which could multiply on both hosts in a ratio characteristic of the original unheated preparation. The data suggest that the observed changes were caused by a host control over the formation of a phage material(s) necessary for successful infection of host K1. Such a substance theoretically could be related to the labile material destroyed by heat and required for plaque formation on host K1.

Phage Typing of Salmonella typhimurium: its Place in Epidemiological and Epizootiological Investigations

“…The different patterns of reaction to the typing phages were often correlated with the presence in the culture of one, two or more different natural phages, in the same way as was shown in earlier work on Salmonella paratyphi-B (Nicolle, Hamon & Edlinger, 1951;Scholtens, 1950Scholtens, , 1952Felix & Callow, 1951). I n other instances differences in the content of the cultures of certain natural phages were observed, but these were not reflected by the pattern of reactions to the typing phages.…”

“…paratyphi-B has provided other examples of the successful application as typing phages of preparations derived from natural phages which had not been subjected to any elaborate process of adaptation (Nicolle, Pavlatou & Diverneau, 1953, 1954Nicolle & Diverneau, 1955;Nicolle, Hamon & Edlinger, 1953;Scholtens, 1950Scholtens, , 1952Scholtens, , 1955a. These findings are in keeping with the view that the multiplicity of phage-systems applicable to any bacterial species is correlated with the multiplicity of enzyme-systems at work in that species (Felix, 1949(Felix, , 1953a.…”

“…The phenomenon of phage adaptability is evidently not restricted to the special typhoid Vi phages in which it was first observed by Craigie & Yen ( 1 9 3 8~) but is one of much wider application (e.g. Luria & Human, 1952;Bertani & Weigle, 1953;Ralston & Krueger, 1954). On the other hand, it is obvious that these findings about adapted phages of S .…”

Variations in a Related Series of Staphylococcal Bacteriophages

“…Rippon (1952) described mutation of antigenic structure from group B to group F in the staphylococcal typing phage 42D. Ralston & Krueger (1954) produced evidence of phenotypic variation in host range of phage K (not a typing phage) dependent on the host used for its propagation.…”

Propagation of Staphylococcal Typing Phages on a Common Host, Staphylococcus aureus K1, and Host-Controlled Changes in Their Lytic Range

“…In previous work we have shown that two forms of the KI strain released the host-induced restriction of the polyvalent Ki4 phage (also designated Pia) which occurs during replication on staphylococci typing with group I1 phages (Ralston & Krueger, 1952,1954; Ralston & Baer, 1 9 6 4~) . Evidence is presented in this paper to indicate that propagation of the typing phages on these cultures of strain KI results in marked host-modified changes in phage host range so as to mask the original high efficiency of plating for their usual propagating host strain, thus altering the lytic group of the phages.…”