Reduced Bacteriophage T7 Infectivity of Gentamicin Treated Escherichia Coli UB1005 Is Likely Not a Result of Treatment- Induced Release of Cellular Factors Into The Culture Supernatant

Pre-treatment of Escherichia coli UB1005 with sub-lethal concentrations of gentamicin has been shown to reduce the infectivity of Bacteriophage T7. However, levels of infectivity has been shown to increase after a wash following antibiotic treatment. Thus we investigated the cause for the decreased infection of Bacteriophage T7 in Escherichia Coli UB1005 after treatment with a sub-lethal concentration of gentamicin. We hypothesized that treatment with sub inhibitory concentrations of gentamicin releases a cellular factor into the supernatant that serves as a decoy receptor to prevent T7 absorption. To test this hypothesis, we transferred supernatants of gentamicin treated UB1005 to untreated UB1005 and tested T7 infection. We observed that the transfer of supernatants from
gentamicin treated UB1005 to untreated UB1005 did not reduce the infection of T7 in a double agar overlay assay. These data suggest that reduced T7 infectivity of UB1005 following gentamicin treatment is not due to a released, transferrable, cellular factor in the culture supernatant.