The selected K. pneumoniae C3091-derived fosmids confer enhanced GI colonisation to EPI100. The ability of each EPI100 fosmid clone (filled symbols) to outcompete EPI100 carrying the empty pEpiFOS vector (open symbols) was tested by feeding sets of two mice with equal amounts of the control strain and one of the fosmid clones. The presented data is for fosmid clone 2. Three days post-feeding, the bacterial counts of the control strain were below the detection limit of 50 CFU/g faeces (dashed horizontal line). Similar results were obtained for all fosmid clones.