title: Effect of plasmids harbouring blaCTX-M on the virulence and fitness of Escherichia coli ST131 isolates.
abstract: The effect of plasmids harbouring blaCTX-M on the virulence and fitness on Escherichia coli sequence type 131 (ST131) isolates was investigated. Plasmids harbouring blaCTX-M-14 or blaCTX-M-15 were transferred by transconjugation into five non-extended-spectrum β-lactamase (ESBL)-producing ST131 isolates. Clinical non-ESBL-producing ST131 isolates demonstrated a higher degree of biofilm formation and serum resistance compared with CTX-M-producing ST131 isolates. In addition, non-ESBL-producing isolates were more competitive than CTX-M-producing isolates. Transconjugants showed no significant defect in growth rate and competitiveness compared with their hosts. However, serum resistance and biofilm formation were diminished in the transconjugants. In conclusion, non-ESBL-producing E. coli ST131 isolates were more competitive and virulent than CTX-M-producing E. coli ST131 isolates. However, transconjugants harbouring blaCTX-M were no less competitive than their susceptible hosts, which may partially explain the global dissemination of CTX-M-14- and CTX-M-15-producing E. coli ST131 isolates, in addition to their increased antimicrobial resistance.
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea.
authors.forename: Juyoun
authors.initials: J
authors.lastname: Shin
authors.affiliation: Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, South Korea. Electronic address: ksko@skku.edu.
authors.forename: Kwan Soo
authors.initials: KS
authors.lastname: Ko
mesh_terms: D018441:Biofilms / Q000254:growth & development; D001770:Blood Bactericidal Activity; D003227:Conjugation, Genetic; D004926:Escherichia coli / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D010957:Plasmids; D014169:Transformation, Bacterial; D014774:Virulence; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: C456080:beta-lactamase CTX-M-14; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases
keywords: CTX-M-14; CTX-M-15; Plasmid; ST131; Sequence type 131