Variations in a Related Series of Staphylococcal Bacteriophages

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SUMMARY: Staphylococcal strains which showed a range of reactions with the phages 47C, 52, 52A, 80 and 81 were examined for changes in phage sensitivity following artificial lysogenization. The lysogenic phages used were isolated from strains of three different phage-typing patterns and differed in serology. The changes in phage reactions thus produced included: (1) immunity to the B phages, 52, 52A and 80 produced by a B phage ; (2) immunity to the A phage 81 produced by a serologically unrelated F phage ; (3) immunity to phage 47 C and sensitivity to phages 52 and 52A produced by a number of A phages. The mechanisms whereby a variety of typing patterns may be obtained within a related group of staphylococci are discussed.

Section: P M Rountreementioning

confidence: 99%

mentioning

confidence: 99%

Changes in the Phage-Typing Patterns of Staphylococci Following Lysogenization

Rountree

1959

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“…It has long been recognized that staphylococcal phages are subject to hostcontrolled modifications (Rountree, 1956), but, in general, the changes reported heretofore have been confined to hosts within a given broad lytic phage group. Results of our tests with these phages indicate that by propagation on cultures of Staphylococcus aureus KI many phages can be modified so that their original group lytic specificity is abolished.…”

Section: Discussionmentioning

confidence: 99%

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

Ralston

Baer

1964

SUMMARYA broad range of typing phages belonging to lytic groups I, 11, 111, IV and those classified as miscellaneous produced plaques on Staphylococcus aureus strain KI. Two variant forms of this strain were compared, KIN and KIHI. Phages belonging to lytic group 11, of both A and B serology, had low efficiencies of plating (EOP) for the KiN variant but had high EOP values for the KIHI variant. In general, of phages from other lytic groups, those of B serology tended to plate with low EOP values on both variants, whereas those of A serology plated with high EOP values. Propagation of several of the phages on both KI hosts resulted in host-modifications of the phage progeny. Similar host-induced modifications were produced by propagation of the phages on ps 73. The host-modified phages showed striking losses in plating efficiency for their usual propagating hosts. The significance of these findings with respect to genetic classification of the phages and hosts is discussed.

“…Data from host-control experiments with staphylococcal phage Col of B serology, phage 47C of A serology (Rountree, 1956), and phage Kia of D serology show that phages of widely different serology may be subject to host control.…”

Section: Stock Phagementioning

confidence: 99%

A New Property of Phage Group II Staphylococcus aureus Strains: Host Restriction of Phage K14

Ralston

Baer

1964

SUMMARYVarious strains of Staphylococcus aureus which type exclusively with phages of lytic group I1 were found to modify phage Kia so that its ability to form plaques on host KIN was lessened. The restricted phage formed plaques with high efficiency on all strains of lytic group 11. In general, it plated at lower titres on strains of lytic groups I, 111, IVY and on some strains of miscellaneous typing characteristics ; however, there were some variations among separate cultures of the same strains. For example, the restricted phage plated at high titre on strains 52~/79", 73, and PA, but formed significantly fewer numbers of plaques on strain 5 2~/ 7 9~ and on a second culture of 4 4~. Strain KIN was found to dissociate into apt (KIHI) and non-apt (mm) forms. The probability of plaque development by restricted phage on strain KIN was dependent upon the nutritional state of the cocci and also upon the proportion of apt and non-apt cells. The restriction of phage Kia was eliminated during its propagation on all strains other than lytic group 11. The unrestricted progeny particles tended to assay at equal titre on all the indicator strains. In all cases the genotype of the phage-susceptibility to host-control-remained unchanged. The observations add to existing data which indicate that strains of phage group I1 form a genetically distinct group. The suggestion is made that this phenomenon might help in taxonomic classification of strains of S . aureus.