The wells in the second plate were carefully washed three times with PBS and then

used to determine the total number of adherent bacteria. All assays were performed in duplicate and repeated independently four times. Murine models of infection Six- to eight-week-old female CFW1 mice (Harlan) selleck chemicals were used for intestinal colonization experiments as described previously [64]. Briefly, mice were provided with drinking water containing 5 g/l streptomycin sulphate for 24 h and fed a 100 μl suspension containing ~109 CFU of each strain in 20% sucrose. On indicated days, faecal pellets were collected, weighed and homogenised in 0.9% NaCl and dilutions plated onto MacConkey agar supplemented Geneticin with appropriate antibiotics for faecal CFU counts.

A previously described intranasal infection model was used in a co-infection format [23]. Six- to eight-week-old female NMRi mice (Harlan) were anaesthetized and hooked on a string by their front teeth. 50 μl of bacterial suspension containing ~5 × 107 CFU of each strain was dropped onto the nares to allow for aspiration. Mice were left hooked on the string for 10 min before being returned to their cages. At sacrifice lungs, spleen and liver were collected in 0.9% NaCl and homogenised. Serial dilutions were plated on selective media for CFU counts. The ascending urinary tract infection model in which C3H mice (Harlan) were inoculated transurethrally

PDK4 with 50 μl of bacterial suspension containing ~5 × 108 CFU bacteria has been described in detail previously [22, 65]. All animal experiments were conducted under the auspices of the Animal Experiments Inspectorate, the Danish Ministry of Justice. Data analysis, statistics and nucleotide accession number Nucleotide sequences were annotated and analysed using the Integrative Services for Genomic Analysis software and manually curated [66]. The competitive index (CI) was calculated by dividing the ratio of fim2-positive to fim2-negative bacteria recovered from infected organs by the ratio of the corresponding bacteria in the initial inoculum. The non-parametric Mann–Whitney U test was used to analyse infection data. Biofilm and cell-adhesion data were analysed using the non-parametric Kruskal-Wallis test and Dunn’s posthoc analysis. The nucleotide sequence of KpGI-5 has been deposited online [GenBank: JN181158]. Acknowledgements We thank Jean-Marc Ghigo, Unité de Génétique des Biofilms, Institut Pasteur, France, for providing pKOBEG-Apra and Stefan Hyman, Centre for Core Biotechnology Services, University of Leicester, for electron microscopy analysis. This study was supported by a Medisearch research grant. JJvA was supported by a University of Leicester, 50th Anniversary PhD Scholarship. SGS was partially supported by the Danish Research Agency grant 2101-06-0009.