title: Outer membrane protein profiles of clonally related Klebsiella pneumoniae isolates that differ in cefoxitin resistance.
abstract: Eleven genotypically related Klebsiella pneumoniae isolates were obtained from 11 patients. All isolates were resistant to third-generation cephalosporins due to the production of SHV-2a extended-spectrum beta-lactamase. Comparison of the outer membrane protein profiles revealed one isolate that lacked porins. This porin-deficient isolate was also resistant to cefoxitin (MIC 128 microg ml(-1)) and moxalactam (MIC 64 microg ml(-1)) and had elevated MIC of meropenem (2 microg ml(-1)) when compared to porin-expressing isolates (2-8, 4 and <0.06-0.125 microg ml(-1), respectively). Higher MICs, associated with loss of porins in outer membrane, were also observed for cefotaxime (4-8-fold), cefepime (>2-16-fold), ciprofloxacin (4-16-fold), imipenem and aztreonam (2-16-fold), but there was no significant difference among MICs of ceftazidime. The porin-deficient mutant was probably selected in vivo during ofloxacin therapy.
authors.affiliation: Department of Microbiology and Virology, Comenius University, Mlynska dolina B-2, 845 15 Bratislava, Slovakia. martina.skopkova@savba.sk
authors.forename: Martina
authors.initials: M
authors.lastname: Skopková-Zarnayová
authors.forename: Eliane
authors.initials: E
authors.lastname: Siebor
authors.forename: Daniela
authors.initials: D
authors.lastname: Rovná
authors.forename: Helena
authors.initials: H
authors.lastname: Bujdáková
authors.forename: Catherine
authors.initials: C
authors.lastname: Neuwirth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D002440:Cefoxitin / Q000494:pharmacology*; D018550:Cephalosporin Resistance; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005838:Genotype; D006801:Humans; D007525:Isoelectric Focusing; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D002440:Cefoxitin; D001618:beta-Lactamases