Fig. 1
Phylogenetic tree based on 147 blaCTX-M sequences (191 bp). The unrooted tree was constructed using the maximum likelihood method in MEGA 6.0. Bootstrap values of 1000 replicates are indicated as numbers out of 100 at the nodes. Scale bar shows the number of nucleotide substitutions per site. ‘SSSIHL E. coli’ refer to the blaCTX-M-15 sequences from the 13 isolates characterized in this study whose accession numbers are given in Table 2. The accession numbers of 134 blaCTX-M sequences (128 of blaCTX-M-15, two of blaCTX-M-27, one each of blaCTX-M-1, blaCTX-M-8, blaCTX-M-9, and blaCTX-M-14) are shown in the figure (and in Additional file 3). Colors used for representing various bacterial genera/species are explained within the figure. The first blaCTX-M-15 sequence with the accession number AAL02127 submitted in July 2001 is highlighted in orange. A representative 191 bp blaCTX-M-15 sequence (from isolate Q76A) is also shown within the figure