title: Diversity of extended-spectrum beta-lactamase-producing Escherichia coli rods.
abstract: BACKGROUND
  The aim of the study was to evaluate genetic relatedness and antimicrobial susceptibility of extended-spectrum beta-lactamase-producing E. coli strains isolated from patients hospitalized in the University Hospital in Bydgoszcz (Poland).
  
  
  METHODS
  The study included 33 extended-spectrum beta-lactamase-producing E. coli strains isolated from 31 patients. The chromosomal DNA was extracted from the strains and separated by pulsed-field gel electrophoresis. Antimicrobial susceptibility testing was performed by the agar dilution method and carried out according to the European Committee on Antimicrobial Susceptibility Testing recommendations.
  
  
  RESULTS
  According to the pulsed-field gel electrophoresis results, 32 distinct pulsotypes were revealed. Based on Molecular Analyst Fingerprinting software analysis, the studied isolates were divided into four subgroups: 6 (18.2%) isolates showing similarity greater than 90% (group A); 19 (57.6%) showing 80-90% similarity (group B); 7 (21.2%) showing 70-79% similarity (group C); and one isolate with less than 70% similarity (group D). Among E. coli isolates showing similarity greater than 90%, four antimicrobial patterns were noted. Among the isolates showing 80-90% similarity, 18 antimicrobial patterns were observed. E. coli isolates showing 70-79% similarity presented 6 antimicrobial patterns.
  
  
  CONCLUSIONS
  Our results show a high degree of genetic diversity of extended-spectrum beta-lactamase-producing E. coli isolates. However, based on a similarity of ≥80%, almost 75% of E. coli isolates were clonally related. Although it is difficult to identify definitive transmission events based on the recovery of indistinguishable pulsed-field gel electrophoresis types alone, we speculate that extended-spectrum beta-lactamase-producing E. coli strains may have disseminated throughout the hospital.
authors.affiliation: Department of Microbiology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Zalas-Więcek
authors.affiliation: Department of Microbiology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Bogiel
authors.affiliation: Department of Microbiology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Wiśniewski
authors.affiliation: Department of Microbiology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Gospodarek-Komkowska
mesh_terms: D016470:Bacteremia / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000235:genetics / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011044:Poland; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D001618:beta-Lactamases