Sub-Lethal Gentamicin Treatment of Escherichia coli UB1005 Induces the Release of Soluble Factors that Reduce Susceptibility to T7 Bacteriophage Infection

07/13/2017

Blair Hardman, David Jure Hunt, Danial Mojaab, Aaron Naor​

Volume 21
Fall 2016 / Winter 2017

Escherichia coli have evolved numerous mechanisms to resist infection by bacteriophages. Here, we investigate if resistance to phage T7 infection involves the gentamicin-induced release of soluble factors, such as lipopolysaccharide (LPS). We show that treatment with sub-lethal levels of gentamicin results in a decreased susceptibility to T7 phage infection in E. coli UB1005. Our data suggest that the mechanism of resistance is not explained by the release of soluble LPS since the addition of soluble LPS from E. coli UB1005 does not increase resistance to T7 infection. Surprisingly, washing cells by performing buffer changes with repeated centrifugation after gentamicin treatment heavily sensitized UB1005 to infection. This data suggests that a factor may be released upon gentamicin treatment that is responsible for resistance to T7 bacteriophage. Our results may be useful in industrial and biotechnological applications where bacteriophage contamination of bacterial cultures has proven to be a persistent and pertinent challenge.