Five novel plasmid-determined beta-lactamases

Plasmid-mediated carbencillin hydrolyzing beta-lactamases of Proteus mirabilis.

Since ABRAHAM and CHAIN') reported the production of beta((l)-lactamase by Escherichia coli, penicillinases have been shown to play an important role in the resistance of organisms against (3lactam antibiotics2.3). In many cases, the 46lactamases of Gram-negative bacteria have been shown to be mediated by R plasmids'), in contrast to chromosomally encoded drug resistance'). 46-Lactamases of Pro...

Extended-Spectrum-Beta-Lactamases, AmpC Beta-Lactamases and Plasmid Mediated Quinolone Resistance in Klebsiella spp. from Companion Animals in Italy

We report the genetic characterization of 15 Klebsiella pneumoniae (KP) and 4 isolates of K. oxytoca (KO) from clinical cases in dogs and cats and showing extended-spectrum cephalosporin (ESC) resistance. Extended spectrum beta-lactamase (ESBL) and AmpC genes, plasmid-mediated quinolone resistance (PMQR) and co-resistances were investigated. Among KP isolates, ST101 clone was predominant (8/15,...

Alain Philippon , Guillaume Arlet and George A . Jacoby - Lactamases β Plasmid - Determined AmpC

Extended - spectrum Beta - lactamases

Beta-lactamase enzymes (BLs) have become the most worrisome mediators of antimicrobial resistance expressed by gram-negative bacteria (GNB). The multiple families of BLs have in common the ability to hydrolyze the -lactam rings of one or more members of the penicillins, cephalosporins, cephamycins, carbapenems, and monobactams. Extended-spectrum -lactamases (ESBLs) are a subset of BLs that conf...

Extended-spectrum beta-lactamases.

At least 30 extended-spectrum beta-lactamases (ESB) have emerged responsible for resistance to indigestible beta-lactams (C3G) since their discovery in West Germany in 1983. Most of them are produced by enterobacteria and essentially K. pneumoniae which appeared susceptible to oxyimino-beta-lactams. A double-disk test was useful to detect such nosocomial isolates of enterobacteria (urines, bloo...