title: Extended-spectrum cephalosporin-resistant Escherichia coli in community, specialized outpatient clinic and hospital settings in Switzerland.
abstract: OBJECTIVE
  Resistance to extended-spectrum cephalosporins (ESCs) in Escherichia coli can be due to the production of ESBLs, plasmid-mediated AmpCs (pAmpCs) or chromosomal AmpCs (cAmpCs). Information regarding type and prevalence of β-lactamases, clonal relations and plasmids associated with the bla genes for ESC-R E. coli (ESC-R-Ec) detected in Switzerland is lacking. Moreover, data focusing on patients referred to the specialized outpatient clinics (SOCs) are needed.
  
  
  METHODS
  We analysed 611 unique E. coli isolated during September-December 2011. ESC-R-Ec were studied with microarrays, PCR/DNA sequencing for blaESBLs, blapAmpCs, promoter region of blacAmpC, IS elements, plasmid incompatibility group, and also implementing transformation, aIEF, rep-PCR and MLST.
  
  
  RESULTS
  The highest resistance rates were observed in the SOCs, whereas those in the hospital and community were lower (e.g. quinolone resistance of 22.6%, 17.2% and 9.0%, respectively; P = 0.003 for SOCs versus community). The prevalence of ESC-R-Ec in the three settings was 5.3% (n = 11), 7.8% (n = 22) and 5.7% (n = 7), respectively. Thirty isolates produced CTX-M ESBLs (14 were CTX-M-15), 5 produced CMY-2 pAmpC and 5 hyper-expressed cAmpCs due to promoter mutations. Fourteen isolates were of sequence type 131 (ST131; 10 with CTX-M-15). blaCTX-M and blaCMY-2 were associated with an intact or truncated ISEcp1 and were mainly carried by IncF, IncFII and IncI1plasmids.
  
  
  CONCLUSIONS
  ST131 producing CTX-M-15 is the predominant clone. The prevalence of ESC-R-Ec (overall 6.5%) is low, but an unusual relatively high frequency of AmpC producers (25%) was noted. The presence of ESC-R-Ec in the SOCs and their potential ability to be exchanged between hospital and community should be taken into serious consideration.
authors.affiliation: Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
authors.forename: Salome N
authors.initials: SN
authors.lastname: Seiffert
authors.forename: Markus
authors.initials: M
authors.lastname: Hilty
authors.forename: Andreas
authors.initials: A
authors.lastname: Kronenberg
authors.forename: Sara
authors.initials: S
authors.lastname: Droz
authors.forename: Vincent
authors.initials: V
authors.lastname: Perreten
authors.forename: Andrea
authors.initials: A
authors.lastname: Endimiani
mesh_terms: D000554:Ambulatory Care Facilities; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D002875:Chromosomes; D016000:Cluster Analysis; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005838:Genotype; D006761:Hospitals; D006801:Humans; D046228:Microarray Analysis; D010957:Plasmids; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013557:Switzerland / Q000453:epidemiology; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D004269:DNA, Bacterial; D001618:beta-Lactamases
keywords: AmpC; CMY; CTX-M; ESBL; ST131