Vautrin, N. | bioRxiv Science

bioRxiv2024

In vitro activity of hydroxychloroquine in combination with antibiotics against intracellular uropathogenic Escherichia coli

BackgroundTwo pathophysiological concepts may explain recurrent UTI: a reinfection by a bacterial strain from the digestive microbiota or a relapse from Escherichia coli persisting within the superficial urothelial cells as intracellular bacterial communities (IBC). Hydroxychloroquine (HCQ)-antibiotic combination is effective against intracellular adherent-invasive E. coli isolated from patients with Crohns disease. We hypothesized that HCQ may enhanced antibiotic efficacy against E. coli IBC. MethodsUTI89 reference strain and two clinical E. coli strains forming IBCs (VITALE#2157, VITALE#2206) were used in this study. MIC, MBC and time killing curves (4xMIC) were performed for AZYTHROMYCIN (AZT), CIPROFLOXACIN (CIP), DOXYCYCLINE (DC), FOSFMOMYCIN (FF) and HCQ. In vitro activity of antibiotics alone and combined with HCQ was evaluated on intracellular bacterial survival assay using a model of urothelium cells (HTB-9). ResultsTime-killing curves showed that CIP has a bactericidal activity at H6 (-4.6 log10 CFU/mL) with regrowth at H24 against 2157, and a bactericidal activity at H6 without regrowth at H24 against 2206 (-3.3 log10 CFU/mL) and UTI89 (-3.4 log10 CFU/mL); DC, AZT and FF demonstrated bacteriostatic activity at H24 regardless of the strain. We observed a significant decrease in the number of intracellular bacteria at H42 with CIP (-1.83 log10 / 106 cells). DC, FF, and AZT exposure did not reduce IBC formation at H42 (P>0.05). IBC formation after HCQ-antibiotic combination exposure was not significantly different (P>0.05) from antibiotic exposure alone, regardless of the antibiotic or strain studied. ConclusionsIn conclusion, HCQ exposure does not enhance antibiotics activity against intracellular uropathogenic E. coli. HighlightsO_LIUsing an in vitro model of superficial urothelium monolayer, we observed a significant decrease in intracellular uropathogenic Escherichia coli in response to ciprofloxacin exposure. C_LIO_LIHydroxychloroquine exposure does not enhance antibiotics activity against intracellular uropathogenic Escherichia coli. C_LI

microbiology↗

bioRxiv2023

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. Author summaryThe recurrence of cystitis is a frequent but poorly understood phenomenon. There are currently many hypotheses trying to explain recurrence, but data on large collections of well-characterized clinical isolates are lacking. In order to identify specific recurrence-associated markers, we conducted a large genomic and phenotypic study involving 48 well-characterized cystitis isolates: 24 recurrent cystitis isolates (RCIs) and 24 pairs of isolates causing sporadic cystitis (SCIs). Moreover, we were able to explore intra-host overtime RCI evolution, by analyzing up to 5 sequential UPEC isolates per RCI series. Our results suggest that RCI rapidly adapt to their host through mobile genetic elements loss and SNP accumulation in genes involved in metabolism and membrane transport. However, no convergent genomic nor phenotypic evolution was observed between isolates collected from distinct patients. Taken together, these results suggest a host-shaped evolution of RCIs, highlighting a need for future studies focused on the host-pathogen relationships.

microbiology↗