Does targeting Arg98 of FimH lead to high affinity antagonists?

Bacterial resistance has become an important challenge in the treatment of urinary tract infections. The underlying resistance mechanisms can most likely be circumvented with an antiadhesive approach, antagonizing the lectin FimH located at the tip of fimbriae of uropathogenic E. coli.

Dynamic Model of a Catheterized Bladder and Biofilm Assay.

Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI) which represent the most frequent nosocomial infections. Understanding of factors relevant for CAUTI pathogenesis and evaluation of new therapeutics or interference strategies requires a model system that mirrors the physico-chemical conditions prevailing in a catheterized human bladder. The described dynamic model of a catheterized bladder enables to emulate many of the characteristics of a catheterized human bladder albeit in the absence of a bladder epithelium.

Common requirement for the relaxosome of plasmid R1 in multiple activities of the conjugative type IV secretion system.

Macromolecular transport by bacterial type IV secretion systems involves regulated uptake of (nucleo)protein complexes by the cell envelope-spanning transport channel. A coupling protein receptor is believed to recognize the specific proteins destined for transfer, but the steps initiating their translocation remain unknown. Here, we investigate the contribution of a complex of transfer initiation proteins, the relaxosome, of plasmid R1 to translocation of competing transferable substrates from mobilizable plasmids ColE1 and CloDF13 or the bacteriophage R17.

Type 1 fimbriae contribute to catheter-associated urinary tract infections caused by Escherichia coli.

Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli.

Biofilm formation of Klebsiella pneumoniae on urethral catheters requires either type 1 or type 3 fimbriae.

Urinary catheters are standard medical devices utilized in both hospital and nursing home settings, but are associated with a high frequency of catheter-associated urinary tract infections (CAUTI). In particular, biofilm formation on the catheter surface by uropathogens such as Klebsiella pneumoniae causes severe problems. Here we demonstrate that type 1 and type 3 fimbriae expressed by K.

In situ monitoring of IncF plasmid transfer on semi-solid agar surfaces reveals a limited invasion of plasmids in recipient colonies.

Most natural conjugative IncF plasmids encode a fertility inhibition system that represses transfer gene expression in the majority of plasmid-carrying cells. The successful spread of these plasmids in clinically relevant bacteria has been suggested to be supported by a transitory derepression of transfer gene expression in newly formed transconjugants. In this study, we aimed to monitor the extent of transitory derepression during agar surface matings in situ by comparing plasmid spread of the IncF plasmid R1 and its derepressed mutant R1drd19 at low initial cell densities.

Characteristics of Escherichia coli causing persistence or relapse of urinary tract infections: phylogenetic groups, virulence factors and biofilm formation.

Recurrent urinary tract infections (RUTIs) pose a major problem but little is known about characteristics of Escherichia coli associated with RUTI. This study includes E. coli from 155 women with community-acquired lower urinary tract infections (UTIs) randomized to one of three dosing regiments of pivmecillinam and aimed to identify associations between the presence of 29 virulence factor genes (VFGs), phylogenetic groups and biofilm formation and the course of infection during follow-up visits at 8-10 and 35-49 days post-inclusion, respectively.

The transfer operon of plasmid R1 extends beyond finO into the downstream replication genes.

finO is the final gene in the 35.4 kb transfer operon of IncFI plasmid F that is known to be involved in self-conjugative transfer. The genetic region distal to finO separates the conjugation and replication control modules of IncFII plasmid R100 and carries uncharacterized genes not found in plasmid F.

Functional analysis of the finO distal region of plasmid R1.

The intergenic region linking conjugative transfer and replication copy control modules of IncF plasmids shows conservation of gene homology and organization. Genes distal to finO are coordinately expressed with the upstream transfer operon encoding the majority of conjugation genes in related plasmids. Here we investigate potential functions for these genes in copy number control and in processes related to conjugation: gene transfer, pilus specific phage infection and plasmid-promoted biofilm formation by an Escherichia coli host.

Synergistic effects in mixed Escherichia coli biofilms: conjugative plasmid transfer drives biofilm expansion.

Bacterial biofilms, often composed of multiple species and genetically distinct strains, develop under complex influences of cell-cell interactions. Although detailed knowledge about the mechanisms underlying formation of single-species laboratory biofilms has emerged, little is known about the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored.

In vitro biofilm formation of commensal and pathogenic Escherichia coli strains: impact of environmental and genetic factors.

Our understanding of Escherichia coli biofilm formation in vitro is based on studies of laboratory K-12 strains grown in standard media. However, pathogenic E. coli isolates differ substantially in their genetic repertoire from E.

Novel roles for the AIDA adhesin from diarrheagenic Escherichia coli: cell aggregation and biofilm formation.

Diarrhea-causing Escherichia coli strains are responsible for numerous cases of gastrointestinal disease and constitute a serious health problem throughout the world. The ability to recognize and attach to host intestinal surfaces is an essential step in the pathogenesis of such strains. AIDA is a potent bacterial adhesin associated with some diarrheagenic E.

Development and maturation of Escherichia coli K-12 biofilms.

The development and maturation of E. coli biofilms in flow-chambers was investigated. We found that the presence of transfer constitutive IncF plasmids induced biofilm development forming structures resembling those reported for Pseudomonas aeruginosa.

Recombinogenic engineering of conjugative plasmids with fluorescent marker cassettes.

An efficient approach for the insertion of fluorescent marker genes with sequence specificity into conjugative plasmids in Escherichia coli is described. For this purpose, homologous recombination of linear double-stranded targeting DNA was mediated by the bacteriophage lambda recombination functions using very short regions of homology. Initial manipulation of the IncFII target plasmids R1 and R1drd19 indicated that the linear targeting DNA should be devoid of all extraneous homologies to the target molecule for optimal insertion specificity.