Open AccessNew extended-spectrum TEM-type beta-lactamase from Salmonella enterica subsp. enterica isolated in a nosocomial outbreak
Author(s) -
María Isabel Morosini,
Rafael Cantón,
J Martı́nez-Beltrán,
Marı́a-Cristiegri,
J C Pérez-Díaz,
Fernando Baquero,
Jesús Blázquez
Publication year - 1995
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.39.2.458
Subject(s) - aztreonam , cefotaxime , ceftazidime , salmonella enterica , microbiology and biotechnology , beta lactamase , biology , isoelectric point , plasmid , ceftriaxone , salmonella , enzyme , bacteria , gene , escherichia coli , antibiotics , biochemistry , genetics , pseudomonas aeruginosa
A new extended-spectrum beta-lactamase was detected in a lactose-positive Salmonella enterica subsp. enterica strain that caused a nosocomial outbreak involving eight patients in a pediatric cardiology unit. This strain showed high levels of resistance to ceftazidime and aztreonam and relatively low levels of resistance to cefotaxime and ceftriaxone. Resistance was associated with a conjugative plasmid of 59 kb, which encoded a new beta-lactamase with an isoelectric point of 5.9 that strongly hydrolyzed ceftazidime and to a much lesser extent hydrolyzed cefotaxime. The enzyme activity was inhibited by clavulanate. The corresponding bla gene was cloned and sequenced. The deduced amino acid sequence showed three significant amino acid replacements with respect to the TEM-1 sequence: Arg-164-->His, Glu-240-->Lys, and Thr-265-->Met. This combination is unique among extended-spectrum beta-lactamases and served to characterize the new enzyme, TEM-27.