Urinary tract infections (UTI) caused by uropathogenic Escherichia coli (UPEC) result in 8 million outpatientvisits (mostly by women) and over $1 billion in health care costs annually in the U.S. Recurrent UTI (rUTI) isa significant problem: >25% of women who suffer from an acute UTI experience a rUTI within 6 months. Toaddress this problem, Project 2 is enrolling a cohort of women presenting with acute cystitis but no recenthistory of UTI. Bacterial isolates from the urine of these patients will be characterized in our mouse model inProject 1. We have detailed a pathogenic cycle within mice in which UPEC invade superficial umbrella cellsthat line the bladder and rapidly replicate to form a densely packed, biofilm-like intracellular bacterialcommunity (IBC). Bacteria within an IBC are protected from both host innate immune defenses and manyantibiotics, thus allowing one bacterium to clonally replicate to 10,000 or more bacteria within hours afterinfection. IBCs eventually disperse, with bacteria fluxing out of the cells and going on to repeat the IBC cyclewithin another epithelial cell or going on to form a quiescent intracellular reservoir (QIR). QIRs can persistfor months and then later seed a rUTI. We will determine whether IBC and QIR formation is a generalproperty of UPEC and whether prominent features of these cycles differ between bacteria causing differentclinical UTI syndromes (asymptomatic bacteriuria, acute infection, or recurrent infection) and betweendifferent host genetic backgrounds. We have completed the genome sequence of cystitis strain UTI89 inProject 3 and will use this with additional sequence information to computationally search for candidategenetic determinants of pathogenesis and recurrence. These candidate genes will be analyzed in ourmurine model, in part by investigating the effects of mutations using advanced imaging methods, lasercapture microdissection, functional genomics, and gfp fusions. Host responses will be characterized byimmunohistology, flow cytometry, and cytology. Mass spectrometry will be used to profile qualitative andquantitative changes in both host and pathogen factors to identify those with pathophysiologic andprognostic significance. The combined expertise of the three projects in this SCOR will allow a coordinatedeffort to understand the epidemiology and basic pathogenic mechanisms of UTIs in women, allowing us tobegin addressing clinical questions in the management of UTI.
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