The Journal of Medical Microbiology, Vol 10, Issue 2 171-178, Copyright © 1977 by Society for General Microbiology
Properties of strains of Staphylococcus aureus in the 94, 96 complex
E. H. Asheshov, A. W. Coe and A. Porthouse
Strains of Staphylococcus aureus that are lysed by typing phages 94 or 96,
or by both phages, are usually resistant to lysis by other basic-set typing
phages. They are, however, sensitive to several experimental phages and
show a number of different lytic patterns when tested against these phages.
These differences in susceptibility are due, in part, to immunity imposed
by temperate phages carried by the different strains. Resistance to lysis
by other basic-set phages was not due to prophage immunity, but to at least
one restriction and modification system in such strains. Restrictionless
mutants were isolated from one strain in several experiments. These showed
an increased sensitivity to many basic-set phages. However, all of these
mutants retained the ability to modify the phages to the characteristic
"94, 96" specificity. Strains in the 94, 96 complex showed a remarkable
homogeneity in biological traits. The majority were non-pigmented, and
produced lipase, fibrinolysin, alpha and delta haemolysins and enterotoxin
B. This homogeneity may well be a reflexion of the restriction and
modification systems in these strains, that prevent the acquisition of
genetic material from strains outside the complex. A new lytic group V is
proposed for members of the 94, 96 complex.
