title: Characterization of third-generation cephalosporin-resistant Escherichia coli from bloodstream infections in Denmark.
abstract: The aim of the study was to investigate the molecular epidemiology of 87 third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec) from bloodstream infections in Denmark from 2009. Sixty-eight of the 87 isolates were extended-spectrum beta-lactamase (ESBL) producers, whereas 17 isolates featured AmpC mutations only (without a coexpressed ESBL enzyme) and 2 isolates were producing CMY-22. The majority (82%) of the ESBL-producing isolates in our study were CTX-M-15 producers and primarily belonged to phylogroup B2 (54.4%) or D (23.5%). Further, one of the two CMY-22-producing isolates belonged to B2, whereas only few of the other AmpCs isolates belonged to B2 and D. Pulsed-field gel electrophoresis revealed that both clonal and nonclonal spread of 3GC-R Ec occurred. ST131 was detected in 50% of ESBL-producing isolates. The remaining ESBL-producing isolates belonged to 17 other sequence types (STs), including several other internationally spreading STs (e.g., ST10, ST69, and ST405). The majority (93%) of the ESBL-producing isolates and one of the CMY-22-producing isolates were multiresistant. In conclusion, 3GC-R in bacteriaemic E. coli in Denmark was mostly due to ESBL production, overexpression of AmpC, and to a lesser extent to plasmid-mediated AmpC. The worldwide disseminated CTX-M-15-ST131 was strongly represented in this collection of Danish, bacteriaemic E. coli isolates.
authors: 1 Department of Microbiology and Infection Control, Statens Serum Institut , Copenhagen S, Denmark .
authors: Frank
authors: F
authors: Hansen
authors: Stefan S
authors: SS
authors: Olsen
authors: Ole
authors: O
authors: Heltberg
authors: Ulrik S
authors: US
authors: Justesen
authors: David
authors: D
authors: Fuglsang-Damgaard
authors: Jenny D
authors: JD
authors: Knudsen
authors: Anette M
authors: AM
authors: Hammerum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D002511:Cephalosporins / Q000627:therapeutic use; D003718:Denmark / Q000453:epidemiology; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D015870:Gene Expression; D006761:Hospitals; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D010957:Plasmids; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D007527:Isoenzymes; D001618:beta-Lactamases