title: Beta-lactamases and outer membrane investigations in beta-lactam-resistant Comamonas acidovorans strains.
abstract: Imipenem-induced beta-lactamase (level of expression, specific activity and kinetic parameters (Vmax and Km) in response to nitrocefin) and outer membrane proteins (OMPs) (hydrophobicity, permeability and electrophoretic pattern) were characterized in, one beta-lactam sensitive (PAC-9), one resistant (PAC-1) and two resistant laboratory mutants (PAC-9M, PAC-9M2) of Comamonas acidovorans strains. Beta-lactamases from both mutant strains showed different Vmax values compared to the parental strains. Beta-lactam resistance was found to be associated in PAC-1 with inducible beta-lactamase production and OMP alteration by the appearance of a 102-KDa protein. Moreover, PAC-1 was less permeable to nitrocefin than PAC-9. These data indicate that C. acidovorans resistance to beta-lactam resulted from synergy between beta-lactamase and OMP alterations.
authors.affiliation: Department of Microbiology and Infectious Diseases, Hôtel-Dieu Pavilion, University of Montreal Hospital Center, Québec, Canada. madeleine.ravaoarinoro@umontreal.ca
authors.forename: M
authors.initials: M
authors.lastname: Ravaoarinoro
authors.forename: C
authors.initials: C
authors.lastname: Therrien
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002511:Cephalosporins / Q000378:metabolism; D016946:Gram-Negative Aerobic Rods and Cocci / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D002511:Cephalosporins; D001618:beta-Lactamases; C021720:nitrocefin