title: [Occurrence and mechanisms of resistance to beta-lactam antibiotics in clinically important species of Enterobacter].
abstract: Extended-spectrum beta-lactam antibiotics have found great medical importance, but their wide use in clinical practice leads to increasing resistance to them. The more frequent occurrence of infections caused by Bush group 1 beta-lactamase producing organisms, including species of the genus Enterobacter, is a serious problem in this field. Resistance to beta-lactams in this important nosocomial pathogens can be due to 1) reduction in outer membrane permeability to antibiotics caused by alterations in outer membrane lipopolysacharides or proteins (porins); 2) production of beta-lactamases, which inactivate beta-lactams and can also lead to resistance by non-hydrolytic mechanism called trapping. Production of plasmid-mediated extended-spectrum beta-lactamases, but especially chromosomally-mediated inducible cephalosporinase AmpC, which can be synthesized constitutively in large amounts as consequence of spontaneous chromosomal mutations, are of great clinical importance. Fourth-generation cephalosporins and carbapenems are the most effective in the treatment of infections caused by species belonging to the genus Enterobacter, but combination of high level beta-lactamase production and decreased outer membrane permeability, which is not rare in Enterobacter spp., leads to resistance even to these drugs.
authors.affiliation: Katedra mikrobiológie a virológie, Prírodovedecká fakulta Univerzity Komenského, Bratislava. michalkova@fns.uniba.sk
authors.forename: D
authors.initials: D
authors.lastname: Michálková-Papajová
authors.forename: H
authors.initials: H
authors.lastname: Bujdáková
authors.forename: J
authors.initials: J
authors.lastname: Klimácková
authors.forename: M
authors.initials: M
authors.lastname: Moravcíková
authors.forename: M
authors.initials: M
authors.lastname: Kettner
mesh_terms: D004754:Enterobacter / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001618:beta-Lactamases