title: Spread of Escherichia coli O25b:H4-B2-ST131 producing CTX-M-15 and SHV-12 with high virulence gene content in Barcelona (Spain).
abstract: OBJECTIVE
  The present study was carried out to evaluate the current prevalence of the clonal group O25b:H4-B2-ST131 among extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBLEC) collected in the Hospital Vall d'Hebron in Barcelona (Spain) with regard to other clonal groups and to characterize their genetic background.
  
  
  METHODS
  Ninety-four consecutive non-duplicate ESBLEC isolates collected from May to December 2008 were studied. ESBL enzymes, phylogenetic groups, serotypes, virulence genes, sequence types (STs) and PFGE profiles were determined. Results The most prevalent ESBLs were CTX-M-14 (47%), CTX-M-15 (26%) and SHV-12 (19%). Thirty (32%) of the 94 ESBLEC isolates belonged to the clonal group O25b:H4-B2-ST131 of which 19 (63%) carried the bla(CTX-M-15) gene and eight (27%) the bla(SHV-12) gene. Moreover, five additional clonal groups (O15/O25a:H1/HNM-D-ST393, O78:HNM-A-ST369, ONT:H21,42/HNM-B1-ST101, O9:H4-A-ST410 and O8:H19-B1-ST162) were detected among 16 isolates producing CTX-M-14 and SHV-12. The 30 ST131 isolates exhibited a significantly higher virulence score (mean number of virulence genes 9.60 versus 5.84) compared with the 64 non-ST131 isolates. In particular, the SHV-12-producing ST131 isolates showed the highest virulence score (range 8-13, mean score 11.75).
  
  
  RESULTS
  also revealed that the 30 ST131 isolates were distributed in five different groups according to their virulence, XbaI macrorestriction and resistance patterns.
  
  
  CONCLUSIONS
  We report for the first time the clonal spread of SHV-12-producing O25b:H4-B2-ST131 isolates characterized by high virulence gene content. Moreover, we describe the distribution of the ST131 isolates within different virulence groups.
authors.affiliation: Servei de Microbiología, Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Coelho
authors.forename: Azucena
authors.initials: A
authors.lastname: Mora
authors.forename: Rosalia
authors.initials: R
authors.lastname: Mamani
authors.forename: Cecilia
authors.initials: C
authors.lastname: López
authors.forename: Juan José
authors.initials: JJ
authors.lastname: González-López
authors.forename: María Nieves
authors.initials: MN
authors.lastname: Larrosa
authors.forename: J Natalia
authors.initials: JN
authors.lastname: Quintero-Zarate
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Alexandra
authors.initials: A
authors.lastname: Herrera
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: Guillem
authors.initials: G
authors.lastname: Prats
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
mesh_terms: D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005838:Genotype; D006761:Hospitals; D006801:Humans; D058889:Molecular Typing; D058885:Multilocus Sequence Typing; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D037521:Virulence Factors; C473109:beta-lactamase CTX-M-15; C107198:beta-lactamase SHV-12; D001618:beta-Lactamases