Role of Klebsiella pneumoniae OmpK35 porin in antimicrobial resistance

OmpK35 from Klebsiella pneumoniae is the homologue of Escherichia coli OmpF porin. Expression of OmpK35 in K. pneumoniae strain CSUB10R (lacking both OmpK35 and OmpK36) decreased the MICs of cephalosporins and meropenem greater than or equal to128-fold and decreased the MICs of imipenem, ciprofloxacin, and chloramphenicol greater than or equal to8-fold. MIC reductions by OmpK35 were 4 times (cefepime), 8 times (cefotetan, cefotaxime, and cefpirome), or 128 times (ceftazidime) higher than those caused by OmpK36, but the MICs were similar or 1 dilution lower for other evaluated agents.