Molecular epidemiology of ESBL-producing E. coli and K. pneumoniae : establishing virulence clusters

To genetically characterize clusters of virulence factors (VFs) among extended spectrum β-lactamase (ESBL)-producing and and assess whether these clusters are associated with genetic determinants or clinical outcomes. One hundred forty-eight and 82 . clinical isolates were obtained from 213 patients in Paris, France. Isolates underwent ESBL characterization, MultiLocus Sequence Typing (MLST) typing and phylogenetic group identification. Detection of ten and seven . VF-encoding genes were assessed, from which a -medians partition algorithm with Jaccard similarity measure was used to construct clusters. CTX-M was the predominant ESBL and susceptibility to trimethoprim-sulfamethoxazole (32%), ciprofloxacin (22%) and aminoglycosides (32%) was low. In , there were five identified clusters, with significantly different distributions of ESBL-sequence type (