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Artículo
Activities of imipenem and cephalosporins against clonally related strains of Escherichia coli hyperproducing chromosomal β-lactamase and showing altered porin profiles
(American Society for Microbiology, 2000-09-06)
Forty clonally related clinical isolates of Escherichia coli from hospitalized patients were resistant to cefoxitin (MICs, >256 μg/ml) and ceftazidime (MICs, 32 to 256 μg/ml) and were intermediate or resistant to cefotaxime ...
Artículo
Roles of β-Lactamases and Porins in Activities of Carbapenems and Cephalosporins against Klebsiella pneumoniae
(American Society for Microbiology, 1999-07-01)
Two clinical isolates of extended-spectrum β-lactamase (ESBL)- producing Klebsiella pneumoniae were noted to be less susceptible than expected to imipenem. Both were missing outer membrane proteins that serve as channels ...
Artículo
Energy-dependent accumulation of norfloxacin and porin expression in clinical isolates of Klebsiella pneumoniae and relationship to extended-spectrum β-lactamase production
(American Society for Microbiology, 2002-12-01)
The relationships between porin deficiency, active efflux of fluoroquinolones, and extended-spectrum β-lactamase (ESBL) production were determined for 53 clinical isolates of Klebsiella pneumoniae. Thirty-two ESBL-positive ...
Artículo
Identification and characterization of a new porin gene of Klebsiella pneumoniae: Its role in β-lactam antibiotic resistance
(American Society for Microbiology, 1999)
Klebsiella pneumoniae porin genes were analyzed to detect mutations accounting for the porin deficiency observed in many β-lactam-resistant strains. PCR and Southern blot analysis revealed the existence of a third porin ...
Artículo
In vivo selection of porin-deficient mutants of Klebsiella pneumoniae with increased resistance to cefoxitin and expanded-spectrum cephalosporins
(American Society for Microbiology, 1996-02-01)
Four Klebsiella pneumoniae isolates (LB1, LB2, LB3, and LB4) with increased antimicrobial resistance were obtained from the same patient. The four isolates were indistinguishable in biotype, plasmid content, lipopolysaccharide, ...
Artículo
Development of resistance during antimicrobial therapy caused by insertion sequence interruption of porin genes
(American Society for Microbiology, 1999-01-01)
We have demonstrated by using an in vitro approach that interruption of the OmpK36 porin gene by insertion sequences (ISs) is a common type of mutation that causes loss of porin expression and increased resistance to ...
Artículo
Energy-dependent accumulation of fluoroquinolones in quinolone- resistant Klebsiella pneumoniae strains
(American Society for Microbiology, 1998-07-01)
The intracellular accumulation of norfloxacin and perloxacin in Klebsiella pneumoniae was evaluated. The roles of lipopolysaccharide, capsule, and outer membrane proteins were not important for the intrabacterial accumulation ...
Artículo
Role of Klebsiella pneumoniae LamB porin in antimicrobial resistance
(American Society for Microbiology, 2003-10-01)
To investigate the contribution of LamB in Klebsiella pneumoniae antimicrobial resistance, we determined the MICs of various antibiotics and the frequency of mutation to increased cefoxitin or meropenem resistance of the ...
Artículo
Outer membrane profiles of clonally related Klebsiella pneumoniae isolates from clinical samples and activities of cephalosporins and carbapenems
(American Society for Microbiology, 1998-07-01)
Fifteen isolates of Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) isolated during a nosocomial outbreak were studied. The strains belonged to the same clonal type, as shown by pulsed-field gel ...