Porin expression in clinical isolates of Klebsiella pneumoniae

Two porins, OmpK36 and OmpK35, have been previously isolated from Klebsiella pneumoniae, and they are homologous to the Escherichia coli porins OmpC and OmpF, respectively. Identification of the two porins revealed that most isolates lacking expression of extended-spectrum beta-lactamases express the two porins, while most isolates producing these beta-lactamases express only porin OmpK36, and the OmpK35 porin is either very low or not expressed.