title: Detection of quinolone-resistant Escherichia coli isolates belonging to clonal groups O25b:H4-B2-ST131 and O25b:H4-D-ST69 in raw sewage and river water in Barcelona, Spain.
abstract: OBJECTIVE
  The present study was carried out to evaluate the prevalence of clonal group O25b:H4-B2-ST131 in water environments with faecal pollution (urban sewage and river water) in the north-east of Spain and to study the virulence gene content of environmental isolates and to compare them with isolates causing human extraintestinal infections in Spain.
  
  
  METHODS
  This study was performed with 10 sewage samples (collected in Catalonia, north-eastern Spain, in autumn 2009 from the influent raw urban sewage of a wastewater treatment plant that serves a large urban area) and 6 river water samples (collected monthly from February to April 2010 in the Llobregat river catchment area, near Barcelona, a watercourse subjected to heavy anthropogenic pressure). Escherichia coli colonies were screened by PCR for the rfbO25b gene associated with the clonal group O25b:H4-B2-ST131. Sequence types (STs), serotypes, virulence genes, PFGE profiles, antimicrobial resistance and extended-spectrum β-lactamase (ESBL) enzymes were determined in 75 E. coli isolates positive for the O25b molecular subtype.
  
  
  RESULTS
  Of the 75 O25b-positive isolates, 51 belonged to the O25b:H4-B2-ST131 clonal group and the remaining 24 belonged to clonal group O25b:H4-D-ST69. The majority of ST69 isolates (23 of 24) were isolated from urban sewage, whereas ST131 isolates were isolated from urban sewage (25 isolates) as well as from river water (26 isolates). ST131 and ST69 isolates carried 4-13 virulence genes, the majority (82%) being quinolone resistant.
  
  
  CONCLUSIONS
  We showed the presence of E. coli isolates belonging to clonal groups O25b:H4-B2-ST131 and O25b:H4-D-ST69 in raw sewage and river water in Barcelona. Furthermore, we observed that the environmental O25b:H4-B2-ST131 isolates showed similar virulence and macrorestriction profiles to clinical human isolates. To our knowledge, this is the first study describing the O25b:H4-D-ST69 clonal group.
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Colomer-Lluch
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.forename: Cecilia
authors.initials: C
authors.lastname: López
authors.forename: Rosalia
authors.initials: R
authors.lastname: Mamani
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Juan
authors.initials: J
authors.lastname: Marzoa
authors.forename: Alexandra
authors.initials: A
authors.lastname: Herrera
authors.forename: Susana
authors.initials: S
authors.lastname: Viso
authors.forename: Jesús E
authors.initials: JE
authors.lastname: Blanco
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Alonso
authors.forename: Joan
authors.initials: J
authors.lastname: Jofre
authors.forename: Maite
authors.initials: M
authors.lastname: Muniesa
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
mesh_terms: D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology*; D045483:Rivers / Q000382:microbiology*; D012703:Serotyping; D012722:Sewage / Q000382:microbiology*; D013030:Spain; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000032:analysis
chemical_list: D029968:Escherichia coli Proteins; D015363:Quinolones; D012722:Sewage; D037521:Virulence Factors; D001618:beta-Lactamases