Fig. 1.
Dynamics and phylogenetic relationships of extended-spectrum cephalosporin resistant E. coli isolated from pigs over a period of four years from an Australian pig farm following the voluntary removal of ceftiofur. Transmission of IncI1-blaCTXM-1 plasmid (pCTXM1-MU2) in the pig farm among multiple E. coli lineages isolated from pigs of different age groups was demonstrated and a maximum parsimony tree using single nucleotide polymorphisms (SNPs) of extended-spectrum cephalosporin-resistant E. coli was generated. Year of isolation is marked with the colours green (2013), blue (2014), pink (2015) and brown (2016). MLST groupings for each cluster are also included. Isolates carrying the eae, ehx and paa gene are marked with an asterisk and written gene name