Biochemical-genetic analysis and distribution of FAR-1, a class A beta-lactamase from Nocardia farcinica

Citation
F. Laurent et al., Biochemical-genetic analysis and distribution of FAR-1, a class A beta-lactamase from Nocardia farcinica, ANTIM AG CH, 43(7), 1999, pp. 1644-1650
Citations number
58
Categorie Soggetti
Microbiology
Journal title
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
ISSN journal
00664804 → ACNP
Volume
43
Issue
7
Year of publication
1999
Pages
1644 - 1650
Database
ISI
SICI code
0066-4804(199907)43:7<1644:BAADOF>2.0.ZU;2-M
Abstract
From genomic DNA of the clinical isolate Nocardia farcinica VIC, a 1.6-kb S au3AI fragment was cloned and expressed in Escherichia coli JM109. The reco mbinant strain expressed a beta-lactamase (pI, 4.6), FAR-1, which conferred high levels of resistance to amoxicillin, piperacillin, ticarcillin, and c ephalothin. The hydrolysis constants (k(cat), K-m, K-i, and 50% inhibitory concentration) confirmed the MIC results and showed that FAR-1 activity is inhibited by clavulanic acid and at a low level by tazobactam and sulbactam , Moreover, FAR-1 beta-lactamase hydrolyzes aztreonam (at a low level) with out significant activity against ceftazidime, cefotaxime and imipenem. FAR- 1 mature protein of molecular mass ca 32 kDa, has less than 60% amino acid identity with any other class A beta-lactamases, being most closely related to PEN-A from Burkholderia cepacia (52%). A bla(FAR-1)-like gene was found in all studied N. farcinica strains, underlining the constitutive origin o f this gene.