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Background: Phylogenetic group D Escherichia coli clones (ST69, ST393, ST405) are increasingly reported as multidrug resistant strains causing extra-intestinal infections. We aim to characterize inter- and intraclonal diversity of a broad sample (isolates from different geographic locations and origins with variable antibiotic resistance profiles, 1980-2010) and their ability to adhere and form biofilm by both a modified quantitative biofilm producing assay and Field Emission Scanning Electron Microscopy (FESEM)., Results: High virulence scores were observed among ST69 (median 14/range 9-15) and ST393 (median 14/range 8-15) clones, particularly enriched in pap alleles, iha, kpsMTII-K5 and ompT, in contrast with ST405 (median 6/range 2-14) isolates, exhibiting frequently fyuA, malX and traT. All ST69 and ST393 and only two ST405 isolates were classified as ExPEC. Biofilm production was detected in two non-clinical ST69 and three ST393 isolates from different origins showing variable virulence profiles. Within each clonal group, and despite the high diversity of PFGE-types observed, isolates from different countries and recovered over large periods of time were clustered in a few groups sharing common virulence gene profiles among ST69 (n = 10 isolates) and ST393 (n = 9 isolates) (fimH-iha-iutA-kpsMTII-K5-(traT)-sat-(ompT)-papA-papEF-papGII-papC) or ST405 (n = 6 isolates) (fimH-traT-fyuA-malX)., Conclusions: This study highlights the circulation of highly transmissible ST69, ST393 and ST405 variants among different settings. Biofilm production seems not to be directly correlated with their epidemiological success.

The characterization of a broad representative sample of ST131 Escherichia coli isolates from different origins and settings (1991 to 2010) revealed that this clonal group has likely diversified recently and that the expansion of particular variants has probably been favored by the capture of diverse, multidrug-resistant IncFII plasmids (pC15-1a, pEK499, pKF3-140-like). The low ability to adhere and to grow as biofilm that was detected in this study suggests unknown mechanisms for the persistence of this clonal group which need to be further explored.

Poloxamers are nontoxic, amphiphilic copolymers used in different formulations. Due to its surfactant properties, Poloxamer 338 (P388) is herein proposed as a strategy to avoid biofilm formation often causing recalcitrant catheter-associated urinary tract infections (CAUTI). The aim is to evaluate the ability of P388 coatings to affect the adhesion of Ec5FSL and Ec9FSL Escherichia coli strains on silicone urinary catheters. Attenuated total reflection infrared spectroscopy, atomic force microscopy, and static water contact angle measurement were employed to characterize the P388-coated silicone catheter in terms of amount of P388 layered, coating thickness, homogeneity, and hydrophilicity. In static conditions, the antifouling power of P388 was defined by comparing the E. coli cells adherent on a hydrophilic P388-adsorbed catheter segment with those on an uncoated one. A P388-coated catheter, having a homogeneous coverage of 35 nm in thickness, reduced of 0.83 log10 and 0.51 log10 the biofilm of Ec5FSL and Ec9FSL, respectively. In dynamic conditions, the percentage of cell adhesion on P388-adsorbed silicone channels was investigated by a microfluidic system, simulating the in vivo conditions of catheterized patients. As a result, both E. coli isolates were undetected. The strong and stable antifouling property against E. coli biofilm lead us to consider P388 as a promising anti-biofilm agent for CAUTIs control. [ABSTRACT FROM AUTHOR]