title: Survival in the environment is a possible key factor for the expansion of Escherichia coli strains producing extended-spectrum β-lactamases.
abstract: Acquired resistance to cephalosporins in Enterobacteriaceae is a global problem. After an outbreak at Uppsala University Hospital of extended-spectrum β-lactamase (ESBL)-positive Klebsiella pneumoniae producing CTX-M-15, there was a shift from AmpC to ESBL production among Escherichia coli isolates. To explore the basis for this epidemiological shift, 46 E. coli isolates (ESBLs, n = 23; AmpC, n = 23) were characterized with regard to genetic relatedness, β-lactamase, replicon and integron types, antibiotic resistance profiles, and genes encoding virulence factors. In addition, the survival in the environment and on hospital-associated materials was analysed. CTX-M-15 was the most frequent ESBL (78%). Only three (13%) of the AmpC enzymes were harboured on plasmids (CMY-2, DHA-1). Independent of plasmid-mediated beta-lactamase, IncF plasmids predominated and only class I integrons were detected. The ESBL producers carried more virulence genes (p = 0.04), exhibited a broader resistance phenotype (p = 0.01) and survived significantly longer (p = 0.03) on different materials than the AmpC-producing isolates. In conclusion, ESBL-producing isolates had properties which are likely to augment their competitiveness. Apart from antibiotic resistance and virulence factors, extended survival in the environment could be a selective trait for successful ESBL-producing E. coli strains.
authors.affiliation: Department of Medical Sciences/Section of Clinical Bacteriology, Uppsala University, Uppsala, Sweden.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Starlander
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
authors.forename: Petra
authors.initials: P
authors.lastname: Edquist
authors.forename: Åsa
authors.initials: Å
authors.lastname: Melhus
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002511:Cephalosporins / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004783:Environmental Microbiology; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005798:Genes, Bacterial; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity; D013548:Sweden / Q000453:epidemiology; D014774:Virulence / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002511:Cephalosporins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases
keywords: AmpC; E. coli; ESBL; environment; plasmids; virulence genes