title: Prevalence of O25b-ST131 clone among Escherichia coli strains producing CTX-M-15, CTX-M-14 and CTX-M-92 β-lactamases.
abstract: BACKGROUND
  Dissemination of multidrug-resistant Escherichia coli is closely associated with the worldwide spread of a single clone ST131, which is the main cause of urinary tract and bloodstream infections in patients from nursing homes and immunocompromised patients. The aim of our study was to determine the prevalence of ST131 clone and the replicons involved in the spread of blaCTX-Mgenes among O25b-ST131 CTX-M-producing E. coli isolates in Lithuania.
  
  
  METHODS
  The strains included in this study were screened for CTX-M β-lactamase-encoding genes, phylogenetic groups and ST131 clone by PCR. Bacterial conjugation was performed to identify plasmid replicon types responsible for blaCTX-Mgenes dissemination.
  
  
  RESULTS
  A total of 158 E. coli clinical non-duplicate ESBL isolates were analyzed. Nearly half (n = 67, 42.4%) of the investigated E. coli isolates belonged to phylogenetic group B2. The isolates producing CTX-M-92 β-lactamases were identified to be the ST131 clone more frequently than the non-ST131 clone (11.5% vs. 3.1%, p = .035). The CTX-M-15 isolates were identified as ST131 isolates less frequently than non-ST131 isolates (50.8% vs. 71.1%; p = .015). The ST131 clone isolates contained type L/M and A/C replicons; a fused FII/FIB replicon was found in four isolates (23.5%). Type HI1 replicon was identified in ST131 E. coli isolates producing CTX-M-15 β-lactamases.
  
  
  CONCLUSIONS
  This study demonstrates the predominance of the ST131 clone among CTX-M β-lactamase-producing E. coli isolates. Dissemination of blaCTX-Mgenes in ST131 strains can be linked not only to highly adapted IncF plasmids such as FII/FIB and FII, but also to plasmid replicon types A/C, L/M and HI1.
authors: a Institute of Microbiology and Virology, Veterinary Academy , Lithuanian University of Health Sciences , Kaunas , Lithuania.
authors: Agnė
authors: A
authors: Giedraitienė
authors: b Department of Laboratory Medicine, Medical Academy , Lithuanian University of Health Sciences , Kaunas , Lithuania.
authors: Astra
authors: A
authors: Vitkauskienė
authors: a Institute of Microbiology and Virology, Veterinary Academy , Lithuanian University of Health Sciences , Kaunas , Lithuania.
authors: Alvydas
authors: A
authors: Pavilonis
authors: c Institute of Cardiology, Medical Academy , Lithuanian University of Health Sciences , Kaunas , Lithuania.
authors: Vaiva
authors: V
authors: Patamsytė
authors: d Laboratoire de Bacteriologie, Faculte de Médecine , Universite Pierre et Marie Curie Paris 6 , Paris , France.
authors: Nathalie
authors: N
authors: Genel
authors: d Laboratoire de Bacteriologie, Faculte de Médecine , Universite Pierre et Marie Curie Paris 6 , Paris , France.|e Service de Microbiologie , Hopital Saint Antoine, APHP , Paris , France.
authors: Dominique
authors: D
authors: Decre
authors: d Laboratoire de Bacteriologie, Faculte de Médecine , Universite Pierre et Marie Curie Paris 6 , Paris , France.|f Service de Bacteriologie , Hopital Tenon, APHP , Paris , France.
authors: Guillaume
authors: G
authors: Arlet
mesh_terms: D003227:Conjugation, Genetic; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D008097:Lithuania / Q000453:epidemiology; D017720:Molecular Epidemiology; D010802:Phylogeny; D010957:Plasmids / Q000032:analysis / Q000145:classification; D016133:Polymerase Chain Reaction; D015995:Prevalence; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases
keywords: CTX-M; Escherichia coli; ST131 clone; plasmids