Open AccessLXA‐1: a new plasmid‐mediated β‐lactamase giving low‐level resistance
Author(s) -
Yang Youjun,
Jacoby G.A.,
Livermore D.M.
Publication year - 1988
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1988.tb02578.x
Subject(s) - citrobacter freundii , enterobacter cloacae , microbiology and biotechnology , klebsiella pneumoniae , cefotaxime , cloxacillin , plasmid , amp resistance , carbenicillin , penicillin , ampicillin , enterobacteriaceae , klebsiella oxytoca , cephalosporin , chemistry , biology , antibiotics , biochemistry , escherichia coli , dna , gene
LXA‐1, a novel plasmid‐mediated β‐lactamase, was observed in clinical isolates of Klebsiella oxytoca, Klebsiella pneumoniae, Citrobacter freundii and Enterobacter cloacae . All the strains additionally produced TEM‐1 β‐lactamase. LXA‐1 had an M r of 24 000 and a pI of 6.7. It hydrolysed benzyl‐penicillin, ampicillin, carbenicillin and first generation cephalosporins, but not methicillin, oxacillin or cefotaxime. Clavulanate and cloxacillin were inhibitors. Studies of one of the E. cloacae isolates showed that LXA‐1 was encoded by a 41‐MDa IncFII plasmid distinct from that encoding TEM‐1 enzyme in the strain. Transconjugants which acquired LXA‐1 production, but not TEM‐1, exhibited only low‐level resistance to substrate β‐lactams.