Figure 2: MLST phylogenetic tree and serotyping analyses of Colombian ETEC clinical isolates. Phylogenetic tree constructed after assembly and alignment of MLST DNA sequences using the ClustalW program. MLST and serotyping experiments are described in Materials and Method. E. coli strains from ancestral groups A, B1, B2, and D were used as control for phylogenetic analyses. EAEC: enteroaggregative E. coli; EPEC: enteropathogenic E. coli; ETEC: enterotoxigenic E. coli; STEC: shiga toxin-producing E. coli. (−) refers to negative reaction with standard antisera and/or PCR amplification. (+) refers to positive reaction; the group is novel and does not match known reference standards. (M) Multiple positives. (X) Unclassified O types. (ND) Not done. Numbers 1 to 6 correspond to clonal groups based on identical MLST DNA sequences.