title: Occurrence of extended-spectrum beta-lactamases in human and bovine isolates of Escherichia coli from Oyo state, Nigeria.
abstract: BACKGROUND
  The main objective of the study was the molecular characterization of extended spectrum β-lactamases (ESBL) in Escherichia coli isolates collected from human and bovine samples in Oyo state, Nigeria.
  
  
  METHODS
  Between August 2010-2011, 114 E. coli isolates were collected from hospitals (n = 57) and bovine (n = 57). PCR and sequencing were used for identification of ESBLs, upstream sequences, plasmid-mediated quinolone resistance (PMQR) genes and class 1 integrons. Plasmid incompatibility groups were identified among ESBL-positive isolates by PCR. Genetic relatdness was assessed by rep-PCR and MLST. Transfer of ESBL determinants to the recipient strain E. coli J53 was performed by broth mating assays.
  
  
  RESULTS
  CTX-M15 was the unique ESBL found in eight human isolates. Six CTX-M-15 producers also carry the aac(6')-lb-cr gene and/or qnrB gene, and class 1 integrons. FIA, FIB, H11, H12, F, Y and K were the plasmid replicon types found. CTX-M-15 and PMQR determinants were transferred by conjugation in two E. coli assigned by MLST to ST131 and ST2695, a new allele.
  
  
  CONCLUSIONS
  The study highlights the dissemination hability of CTX-M-15 associated with PMQR, and the presence of class 1 integrons, able to capture additional genes, justifying the urgent need of antimicrobial resistance surveillance in Nigeria.
authors.affiliation: University of Ibadan, Oyo state, Nigeria. christyinwezerua@gmail.com.
authors.forename: Christiana
authors.initials: C
authors.lastname: Inwezerua
authors.forename: Nuno
authors.initials: N
authors.lastname: Mendonça
authors.forename: Vera
authors.initials: V
authors.lastname: Calhau
authors.forename: Sara
authors.initials: S
authors.lastname: Domingues
authors.forename: Olufemi Ezekiel
authors.initials: OE
authors.lastname: Adeleke
authors.forename: Gabriela Jorge
authors.initials: GJ
authors.lastname: Da Silva
mesh_terms: D000818:Animals; D002417:Cattle / Q000382:microbiology; D003906:Developing Countries; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D006801:Humans; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009549:Nigeria; D010957:Plasmids / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1