title: Emergence and outbreaks of CTX-M beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae strains in a Tunisian hospital.
abstract: Sixty-two isolates of Enterobacteriaceae (35 Escherichia coli and 27 Klebsiella pneumoniae isolates) producing CTX-M-type beta-lactamases were collected between March 2000 and June 2003 in different wards of Charles Nicolle Hospital in Tunis (Tunisia). Sequencing identified the bla(CTX-M-15) determinant in 55 isolates and bla(CTX-M-16) in 7 isolates. The CTX-M-15-producing strains were isolated in several wards and consisted mainly of two successive clonal groups of E. coli and a major clonal group of K. pneumoniae. The second clonal group of E. coli belonged to phylogenetic group B2 and harbored more virulence factors than the first clonal group. Among the 22 transconjugants or electroporants obtained with selected E. coli and K. pneumoniae CTX-M-15-producing strains, a predominant plasmid restriction pattern was obtained with 17 isolates. The four CTX-M-16-producing strains of E. coli yielded the same pulsed-field gel electrophoresis (PFGE) pattern, while the three CTX-M-16-producing strains of K. pneumoniae yielded two different PFGE patterns. All of the CTX-M-16-producing isolates were recovered in the pediatric ward and had the same plasmid restriction pattern.
authors.affiliation: Laboratoire Résistance aux Antibiotiques, Département de Microbiologie, Faculté de Medecine, Tunis, Tunisia.
authors.forename: Kelthoum
authors.initials: K
authors.lastname: Mamlouk
authors.forename: Ilhem
authors.initials: I
authors.lastname: Boutiba-Ben Boubaker
authors.forename: Valérie
authors.initials: V
authors.lastname: Gautier
authors.forename: Sophie
authors.initials: S
authors.lastname: Vimont
authors.forename: Bertrand
authors.initials: B
authors.lastname: Picard
authors.forename: Saida
authors.initials: S
authors.lastname: Ben Redjeb
authors.forename: Guillaume
authors.initials: G
authors.lastname: Arlet
mesh_terms: D003428:Cross Infection / Q000382:microbiology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000472:pathogenicity; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000472:pathogenicity; D010802:Phylogeny; D010957:Plasmids; D012189:Retrospective Studies; D014774:Virulence; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: C071167:beta-lactamase CTX-2; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases