The Inhibition by Streptomycin of Certain Streptococcus Bacteriophages, using Host Bacteria Resistant to the Antibiotic

Abstract

SUMMARYStreptomycin is a specific antiviral agent for a variety of bacteriophages active against Streptococcus faecium, S . faecalis, S . liguefaciens and S . xymogenes since it inhibits bacteriophage growth even when the host is resistant to the antibiotic. An analysis of the mode of action of the antibiotic in this system reveals that it probably has two effects. If the antibiotic is present before adsorption, it inhibits injection of the phage DNA. This effect is readily reversible. If the antibiotic is added after adsorption, it appears that injection is not inhibited, but that the phage genome is inactivated. The antibiotic has no effect on replication of the phage once the genome has become established in the host cell. This is consistent with the hypothesis that the phage DNA exists transiently a t a streptomycin-accessible site, and then moves to a site of replication which is inaccessible to the antibiotic. Streptomycin-resistant phages probably have a different injection mechanism from streptomycin-sensitive phages.The senior author has reported similar findings for an RNA bacteriophage of Escherichia coli. The implications of this work for virus chemotherapy and for analysing the mode of penetration into the cell of virus nucleic acid are discussed.

Sublethal streptomycin concentrations and lytic bacteriophage together promote resistance evolution

“…Previous studies suggest that Sm might inhibit certain phages, providing a potential explanation for phage extinction in the presence of Sm [69][70][71]. However, under the Sm concentrations used in this study, the phage initially increased to a high density and did not begin to decline until the host evolved resistance against the phage (figure 1).…”

Host Range of Certain Virulent and Temperate Bacteriophages Attacking Group D Streptococci

“…This was done by plating on agar containing 1,000 jg/ml of streptomycin with a streptomycin-resistant mutant as indicator. As opposed to many of the virulent phages of enterococci (Brock et al, 1963b), the temperate phages were unaffected by streptomycin.…”

“…Without genetic analysis, it is impossible to choose among a variety of alternate hypotheses. Some of the phages discussed here have proven of interest because they are sensitive to streptomycin and provide a model system for antiviral chemotherapy (Brock and Wooley, 1963;Brock et al, 1963b). Other of these phages have been of interest as a source of cell-wall lytic enzyme (Bleiweis and Zimmerman, 1961).…”

“…Todd-Hewitt (Difco) broth and agar were used exclusively. Production of lysates and plaque assay procedures were described by Brock, Mosser, and Peacher (1963b).…”

Productive Infection of Bacillus Subtilis 168, With Bacteriophage Sp-10, Dependent Upon Inducing Treatments

“…Because it was found that cellular receptors for Bi virus remained blocked by B3 virus for long periods of time at low temperatures, ACS was absorbed as described above, except that the cell-serum mixture was incubated at 4 C for 24 hr. The amount of infectious B3 virus found in the absorbed ACS (from 4 X 106 to 7 X 106 P1FU per ml) was not sufficient to account for the specific inhibitory activity associated with the ACS (8), and was either inactivated by ultraviolet irradiation prior to assay of homologous challenge virus, or was neutralized by homotypic antiviral serum prior to assay of heterologous virus.…”