[Occurrence and mechanisms of resistance to beta-lactam antibiotics in clinically important species of Enterobacter].
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.
Michálková-Papajová
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D
Katedra mikrobiológie a virológie, Prírodovedecká fakulta Univerzity Komenského, Bratislava. michalkova@fns.uniba.sk
Bujdáková
H
H
Klimácková
J
J
Moravcíková
M
M
Kettner
M
M
D004754:Enterobacter / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics
D001618:beta-Lactamases