Fig. 5

Test for the independence of the acquisition of carbapenemase alleles in defined genetic backgrounds. a Cladogram obtained from the maximum likelihood tree estimated for the ST167 E. coli isolates (Fig. 4). Four different genetic events, represented by colored circles, have been placed by parsimony on the tree. In blue, mutations affecting the ompF gene (inactivation, by frameshift of premature stop codons, and mutations in the regulatory region); in red, genetic events affecting the ompC gene (gains of new ompC alleles by homologous recombination, inactivation of the gene, and non-synonymous mutations modifying the charge of AA localized in the pore lumen); in green, homologous recombination of ftsI alleles with a four-codon insertion; and in yellow, acquisition of a carbapenemase gene. b Testing for the independence between the acquisition of carbapenemase genes and mutations in porin genes and/or ftsI. *P < 0.05; **P < 0.01; ***P < 0.001