FIG. 2.

Shannon entropy of each amino acid position calculated across each library and among all CTX-M group 1 reference sequences from the Lahey Clinic (www.lahey.org/Studies/). Bars greater than zero indicate the presence of two or more alleles, with greater height of the bar generally indicating greater frequency of the rare allele and rarely the presence of more than two alleles in the library. Solid icons indicate amino acid positions with variability shared with the CTX-M group 1 reference sequences. Figure created using R (R Foundation for Statistical Computing, Vienna, Austria [www.R-project.org/]). Amino acid numbering is absolute (i.e., not referenced to S70 and position 239 is included). Color images available online at www.liebertpub.com/mdr