title: Cefotaxime and ceftazidime-resistant Escherichia coli isolate producing TEM-15 beta-lactamase from a Tunisian hospital.
abstract: A clinical isolate of Escherichia coli LBT04 was found to have a high-level resistance to broad-spectrum beta-lactams. Analysis of this strain by the disk diffusion test revealed synergies between clavulanic acid and ceftazidime, cefotaxime. Clavulanic acid decreased the MICs of ceftazidime, cefotaxime, and ceftriaxone, which suggested that LBT04 produced an extended-spectrum beta-lactamase. These resistances were carried by a 1080-bp chromosomal gene that encoded a beta-lactamase with a pI of 6.3. Cloning and sequencing experiments showed that this beta-lactamase revealed identity with the bla(TEM-1) gene encoding the TEM-1 beta-lactamase, except for a replacement of the Glu residue at position 104 by Lys, and of the Gly residue at position 238 by Ser. These two mutations were encountered in TEM-15 beta-lactamase, but this is the first description of this enzyme in the E. coli species in Tunisian hospitals.
authors.affiliation: Laboratoire de biochimie et de biotechnologie, faculté des sciences de Tunis, 2092 El-Manar II, Tunisia. chdoula77@yahoo.fr
authors.forename: Chedly
authors.initials: C
authors.lastname: Chouchani
authors.forename: Nahed
authors.initials: N
authors.lastname: Ben-Achour
authors.forename: Arij
authors.initials: A
authors.lastname: M'charek
authors.forename: Omrane
authors.initials: O
authors.lastname: Belhadj
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015139:Blotting, Southern; D002439:Cefotaxime / Q000494:pharmacology*; D002442:Ceftazidime / Q000494:pharmacology*; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology*; D005784:Gene Amplification; D006801:Humans; D007297:Inpatients; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D014416:Tunisia / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D004279:DNA, Viral; D002442:Ceftazidime; C106857:TEM-15 beta-lactamase; D001618:beta-Lactamases; D002439:Cefotaxime