Restoration of O-antigen production in E. coli K-12 DFB1655 confers resistance to T2 bacteriophage-mediated lysis

Abstract

Bacteriophage infection of Escherichia coli has long been studied to understand possible applications to bacterial disease, due to the specificity and efficiency of lysis. Commonly used strains such as E. coli K-12 lack expression of the outer membrane structure O-antigen, which is found in many wild-type strains. O-antigen expression impacts replication of bacteriophage reliant on interaction with host lipopolysaccharide. Previous studies using lipopolysaccharide-interacting T4 and T7 bacteriophage found that restored O-antigen expression in E. coli K-12 strain MG1655 did confer resistance to bacteriophage-induced lysis. However, it is unclear if this resistance is specific to T4 and T7 bacteriophage, or if resistance to other similar lipopolysaccharide-interacting bacteriophages is conferred. T2 bacteriophage has been demonstrated to take advantage of the lipopolysaccharide layer for adsorption in E. coli K-12 strains and exploit it for host cell entry through interaction with OmpF and FadL. We demonstrated that E. coli K-12 with restored O-antigen did not lyse when incubated with T2 bacteriophage through spectrophotometric bacterial growth curve assays and stab assays. Our findings provide preliminary results to suggest that O-antigen expression in E. coli provides resistance against lysis induced by lipopolysaccharide-interacting bacteriophage. Further understanding of these interactions may elucidate bacterial adaptations to bacteriophages and provide more context for industrial or therapeutic bacteriophage applications.