학술논문
Characterization of a new TEM-derived beta-lactamase produced in a Serratia marcescens strain
Document Type
Article
Author
Source
Antimicrobial Agents and Chemotherapy; November 1997, Vol. 41 Issue: 11 p2374-2382, 9p
Subject
Language
ISSN
00664804; 10986596
Abstract
A natural TEM variant beta-lactamase was isolated from an epidemic strain of Serratia marcescens. Nucleotide gene sequencing revealed multiple point mutations located in the 42-to-44 tripeptide and positions 145 to 146, 178, and 238. In addition, a glutamic acid 212 deletion was also found. The purified enzyme was studied from a kinetic point of view, revealing the highest catalytic efficiency (k[cat]/Km) values for ceftazidime and aztreonam compared with the TEM-1 prototype enzyme. The in vitro resistance correlated with kinetic parameters, and the enzyme also mediated resistance to some penicillins and an ampicillin-clavulanic acid combination. The mutational and kinetic changes are discussed in relation to the three-dimensional crystallographic structure of the wild-type TEM-1 enzyme.