Fig. 2. Cladogram for n = 181 blaSHV alleles. The cladogram was inferred from a pairwise genetic distance matrix calculated from nt sequences using BioNJ, rooted on SHV-1. Tips are labelled with the SHV allele name and coloured to indicate the mutation profile (black, WT; red, orange and pink, ESBL profiles; and blue and purple, BLI-resistant profiles). For alleles classed as non-WT, the class-modifying mutation is included in the label (e.g. 238S indicates substitution of serine at Ambler site 238 in the encoded protein; ‘omegaINS’ refers to a 6-aa insertion in the omega-loop between Ambler codons 167 and 168). Shading indicates clusters of alleles referred to in the text, which may share class-modifying mutations via vertical inheritance.
