title: Convergent evolution of TEM-26, a beta-lactamase with extended-spectrum activity.
abstract: TEM-26, an extended-spectrum beta-lactamase has been characterized in clinical isolates of Klebsiella pneumoniae and Escherichia coli derived from patients on the Paediatric Oncology Unit of St James's University Hospital, Leeds. The nucleotide sequence of this beta-lactamase gene (blaTEM26b) was determined, and compared with the nucleotide sequences of other TEM-type beta-lactamases. The blaTEM26b gene was found to differ from blaTEM12b by a single nucleotide. This difference causes the substitution of glutamic acid in blaTEM12b for lysine in blaTEM26b at position 102 in the predicted amino acid sequence. The blaTEM12b gene was first described in an isolate of Klebsiella oxytoca from a patient nursed on the same unit that yielded the strains that carry blaTEM26b. However, the blaTEM26b gene differs at no less than six nucleotides from the nucleotide sequence encoding the TEM-26 beta-lactamase that was first described in isolates from cancer patients nursed in the Children's Hospital, Stanford, California, USA. This indicates that the genes encoding TEM-26 have evolved from different progenitors.
authors.affiliation: Department of Microbiology, University of Leeds, UK.
authors.forename: L C
authors.initials: LC
authors.lastname: Hibbert-Rogers
authors.forename: J
authors.initials: J
authors.lastname: Heritage
authors.forename: N
authors.initials: N
authors.lastname: Todd
authors.forename: P M
authors.initials: PM
authors.lastname: Hawkey
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D005075:Biological Evolution; D002442:Ceftazidime / Q000494:pharmacology; D002648:Child; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D007525:Isoelectric Focusing; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D002442:Ceftazidime; C087312:beta-lactamase TEM-26; D001618:beta-Lactamases