title: Novel GES/IBC extended-spectrum beta-lactamase variants with carbapenemase activity in clinical enterobacteria.
abstract: Two clinical isolates, an Escherichia coli and a Klebsiella pneumoniae, with decreased susceptibility to carbapenems were studied. This phenotype was associated with production of novel GES/IBC variant beta-lactamases, designated GES-3 (from E. coli) and GES-4 (from K. pneumoniae), exhibiting carbapenemase activity. Both enzymes possessed Ser at Ambler's position 170 instead of Gly found in the beta-lactamases GES-1 and IBC-1 that lack carbapenemase activity. Additionally, position 104 in GES-4 was occupied by a Lys as in IBC-1. bla(GES-3) and bla(GES-4) occurred as gene cassettes in the variable regions of class 1 integrons carried by plasmids. The structure of the GES-4-encoding integron was similar to that of previously described IBC-1 integrons. The GES-3-encoding integron was, most likely, truncated at the 3' conserved segment.
authors.affiliation: Laboratory of Bacteriology, Hellenic Pasteur Institute, University of Athens, Athens, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Vourli
authors.forename: Panagiota
authors.initials: P
authors.lastname: Giakkoupi
authors.forename: Vivi
authors.initials: V
authors.lastname: Miriagou
authors.forename: Eva
authors.initials: E
authors.lastname: Tzelepi
authors.forename: Alkiviadis C
authors.initials: AC
authors.lastname: Vatopoulos
authors.forename: Leonidas S
authors.initials: LS
authors.lastname: Tzouvelekis
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D017931:DNA Primers; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D017931:DNA Primers; D001618:beta-Lactamases; C063912:carbapenemase