Novel genes associated with capsule production in uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) are responsible for the majority of urinary tract infections (UTIs). UPEC strains possess an array of virulence-associated factors that aid in their colonization, survival and persistence in the urinary tract. One such factor is the polysaccharide K capsule, which provides protection against host innate immune factors. Among the different K capsule types, the K1 serotype is strongly associated with UPEC strains that cause UTI, bloodstream infections and meningitis. In this study, we employed a combination of a lytic K1 capsule-specific phage, saturated Tn5 transposon mutagenesis, and high-throughput transposon directed insertion-site sequencing (TraDIS) to identify genes associated with K1 capsule production in the clinical urosepsis isolate PA45B.