title: Characterization and molecular epidemiology of extended-spectrum beta-lactamases in clinical isolates of Enterobacteriaceae in a Tunisian University Hospital.
abstract: One hundred extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae were recovered from the intensive care unit and the urology ward of the University Hospital of Sahloul in Tunisia between May 2005 and May 2006. The majority of strains showed a high level of resistance to cefotaxime and ceftazidime. Double-disk synergy test and E-test strips were used to confirm production of ESBLs. The molecular analysis revealed that the majority of strains (91%) carried genes encoding CTX-M-15. SHV-12 and SHV-2a were produced, respectively, by 9% and 3% of the strains. Pulsed-field gel electrophoresis of ESBL-producing Klebsiella pneumoniae isolates revealed four different clonal groups and three for Escherichia coli, showing the absence of spread of any epidemic clone. The CTX-M-15 ESBL-producing E. coli of the major clonal group belong to the B2 phylogenetic group, to the sequence type 131, and has a high virulence potential. In conclusion, CTX-M-15 ESBLs accounted for the overwhelming majority of ESBL types among Enterobacteriaceae from our hospital. This study confirms the high rate of ESBLs in Tunisia and further demonstrates the worldwide spread of genes coding for CTX-M-15 enzymes in clinical isolates.
authors.affiliation: Infections with Multiresistant Bacteria to Antibiotics (UR/29/04), Department of Microbiology, University Hospital of Sahloul, Sousse, Tunisia. safia_dah@yahoo.fr
authors.forename: Safia
authors.initials: S
authors.lastname: Dahmen
authors.forename: Dalia
authors.initials: D
authors.lastname: Bettaieb
authors.forename: Wejden
authors.initials: W
authors.lastname: Mansour
authors.forename: Noureddine
authors.initials: N
authors.lastname: Boujaafar
authors.forename: Olfa
authors.initials: O
authors.lastname: Bouallègue
authors.forename: Guillaume
authors.initials: G
authors.lastname: Arlet
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D006785:Hospitals, University / Q000706:statistics & numerical data*; D006801:Humans; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D014416:Tunisia / Q000453:epidemiology; D001618:beta-Lactamases / Q000145:classification* / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases