Are Escherichia coli causing recurrent cystitis just ordinary Uropathogenic E. coli (UPEC) strains?

Specific determinants associated with Uropathogenic Escherichia coli (UPEC) causing recurrent cystitis are still poorly characterized. The aims of this study were (i) to describe genomic and phenotypic traits associated with recurrence using a large collection of recurrent and paired sporadic UPEC isolates, and (ii) to explore within-host genomic adaptation associated with recurrence using series of 2 to 5 sequential UPEC isolates. Whole genome comparative analyses between 24 recurrent cystitis isolates (RCIs) and 24 phylogenetically paired sporadic cystitis isolates (SCIs) suggested a lower prevalence of putative mobile genetic elements (MGE) in RCIs, such as plasmids and prophages. The intra-patient evolution of the 24 RCI series over time was characterized by SNP occurrence in genes involved in metabolism or membrane transport, and by plasmid loss in 5 out of the 24 RCI series. Genomic evolution occurred early in the course of recurrence, suggesting rapid adaptation to strong selection pressure in the urinary tract. However, RCIs did not exhibit specific virulence factor determinants and could not be distinguished from SCIs by their fitness, biofilm formation, or ability to invade HTB-9 bladder epithelial cells. Taken together, these results suggest a rapid but not convergent adaptation of RCIs that involves both strain- and host-specific characteristics.

MULTIMODAL IMAGING OF POSTERIOR POLAR ANNULAR CHOROIDAL DYSTROPHY.

BACKGROUND: Posterior polar annular choroidal dystrophy (PPACD) is a rare disease. Patients with PPACD show loss of retinal pigment epithelium and choriocapillaries surrounding the vascular arcades and optic nerve. METHODS: Two patients with PPACD were evaluated with multimodal imaging, including fundus autofluorescence (FAF) and adaptive optics (AO). REPORT OF CASES: One patient (32 year old, one eye) with PPACD was followed up for 3 years. Best-corrected visual acuity (BCVA) was stable at 20/40, whereas a slight enlargement of paravascular atrophy of pigment epithelium was observed at fundus autofluorescence (FAF). Adaptive optics obtained at last examination showed reduced density of foveal cone photoreceptors. The second patient (30 year old, two eyes) with PPACD showed bilateral normal BCVA, associated with reduction in the density of foveal cone photoreceptors. CONCLUSION: At FAF, longitudinal follow-up of PPACD showed progression of the paravascular atrophy of the pigment epithelium. Foveal cone photoreceptors can be reduced even in the presence of preserved visual acuity.