Porin expression in clinical isolates of Klebsiella pneumoniae

Abstract

Two porins, OmpK36 and OmpK35, have been described previously in Klebsiella pneumoniae, and they are homologous to the Escherichia coli porins OmpC and OmpF, respectively, at both the DNA and amino acid levels. Optimal resolution of the two K. pneumoniae porins by electrophoresis on polyacrylamide gels is not achieved using gel systems already described for E. coli and requires modifications of the bisacrylamide content of the resolving gels. Once resolved, identification of porins OmpK36 and OmpK35 cannot be based solely on their apparent molecular masses since in some strains the OmpK36 porin migrates faster than the OmpK35 porin, whilst in other strains OmpK35 is the faster-migrating porin. Expression of OmpK35 porin is increased in low-osmolarity medium and, combined with Western blot analysis, this allows for the identification of both porins. Application of this identification system showed that most isolates lacking expression of extended-spectrum /?-lactamases express the two porins, whereas most isolates producing these /?-lactamases express only porin OmpK36, and the OmpK35 porin is either very low or not expressed.

Risk factors for KPC-producing Klebsiella pneumoniae: watch out for surgery

“…Those patients had several co-morbidities and were subjected to aggressive medical interventions, including broad-spectrum antibiotics. These results are in agreement with previously reported findings that showed that prior antimicrobial exposure in hospitalised patients, especially severely ill patients, is the main force driving the spread of carbapenem-resistant organisms (Hernandez-Alles et al, 1999;Hoenigl et al, 2012;Patel et al, 2008;Souli et al, 2012).…”

TheKlebsiella pneumoniaeYfgL (BamB) lipoprotein contributes to outer membrane protein biogenesis, type-1 fimbriae expression, anti-phagocytosis, andin vivovirulence

“…OM proteins were extracted from each strain grown in 20-mL LB medium or nutrient broth (NB) broth with sodium lauroyl sarcosinate (Sigma-Aldrich) and recovered by ultracentrifugation, as described previously. 44 Samples were separated by 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and stained with Coomassie brilliant blue R250 (Gibco-BRL). For protein gel blots, proteins were separated using 12% SDS-PAGE and blotted to a Hybond-C membrane (Amersham), probed with polyclonal antibodies raised against YfgL, and revealed with peroxidase-labeled goat anti-rabbit antibody and the enhanced chemiluminescent substrate.…”

Outer membrane proteins and morphological alterations of Shigella spp. under starvation in seawater

“…OmpF is highly expressed at low osmolarity and suppressed at high osmolarity, while OmpC is totally the opposite (Cai and Inouye, 2002). More and more similar regulations have been found in other bacteria, such as major outer membrane protein and Omp50 in Campylobacter jejuni (Dedieu et al, 2002), and OmpK35 and OmpK36 in Klebsiella pneumoniae (Hernandez-Alles et al, 1999). Furthermore, Wu et al (2006) indicated that OmpW and OmpV are required for environmental salt regulation in Photobacterium damsela, in which OmpW and OmpV, respectively, elevate and reduce the ability in salinity tolerance.…”