In order to define the contributions of the mechanisms for carbapenem resistance in clinical strains of Pseudomonas aeruginosa, we investigated the presence of OprD, the expressions of the MexAB-OprM and MexEF-OprN systems, and the production of the beta-lactamases for 44 clinical strains. All of the carbapenem-resistant isolates showed the loss of or decreased levels of OprD. Three strains ove...

The genus Yersinia includes species with a wide range of eukaryotic hosts (from fish, insects, and plants to mammals and humans). One of the major outer membrane proteins, the porin OmpC, is preferentially expressed in the host gut, where osmotic pressure, temperature, and the concentrations of nutrients and toxic products are relatively high. We consider here the molecular evolution and phylog...

Vibrio anguillarum serotype O2 strains express a 40-kDa outer membrane porin protein. Immunoblot analysis revealed that antigenic determinants of the V. anguillarum O2 40-kDa porin were conserved within bacterial species of the genus Vibrio. The relative amounts of the V. anguillarum O2 40-kDa porin were enhanced by growth of V. anguillarum O2 in CM9 medium containing 5 to 10% sucrose or 0.1 to...

Mitochondrial porin, the outer membrane pore-forming protein, was isolated in the presence of detergents and converted into a water-soluble form. This water-soluble porin existed under nondenaturing conditions as a mixture of dimers and oligomers. The proportion of dimers increased with decreasing porin concentration during conversion. Water-soluble porin inserted spontaneously into artificial ...

OBJECTIVES To characterize at the genomic level the evolution of multiresistance during an outbreak of Klebsiella pneumoniae in a burns intensive care unit. The outbreak involved a DHA-1 β-lactamase-producing strain that later acquired carbapenem and fosfomycin resistance, and in one case colistin resistance. METHODS The genomes of two isolates were sequenced and compared with a previously se...

BACKGROUND Bordetella pertussis infections continue to be a major public health challenge in Canada. Polymerase chain reaction (PCR) assays to detect B pertussis are typically based on the multicopy insertion sequence IS481, which offers high sensitivity but lacks species specificity. METHODS A novel B pertussis real-time PCR assay based on the porin gene was tested in parallel with several p...

Aims: The general aims of the present studies were to assess the levels of antibiotic resistance, in relation to antibiotic consumption at the Karolinska University Hospital, Solna (KS) and at 11 other Swedish hospitals, furthermore to assess the role of the membrane protein OprD and penicillin-binding proteins in Pseudomonas aeruginosa resistance to imipenem. Methods: Resistance figures were r...

Investigations were undertaken to characterize the protective immunity induced by porin-lipopolysaccharide (LPS) against Salmonella typhimurium infection in mice. Mice immunized with porin-LPS showed higher levels of antiporin immunoglobulin G than mice which received porin alone. Further, T cells from porin-LPS-immunized mice showed an augmented proliferative response to porin in vitro compare...

Carbenicillin-resistant mutants of Escherichia coli K-12 and B/r were found to produce greatly diminished levels of the porin coded by the ompF gene. Physiological and ecological implications of these findings are discussed.

Osmotic shock fluid of Escherichia coli exhibited pore-forming activity. This activity could be followed by an in vitro assay based on the conductivity increase for ions due to the presence of pores in black lipid membranes. The histogram (the distribution of conductivity increments in a single pore experiment) obtained with osmotic shock fluid from E. coli was identical to the histogram obtain...