Investigation on the mechanisms of porins OmpK35 and OmpK36 impacting antimicrobial susceptibility of hypervirulent Klebsiella pneumoniae

Objective To investigate the gene background of porin OmpK35/36 in Klebsiella pneumoniae type K1 (KP), construct the deletion mutant of OmpK35/36 and analyze the effect of OmpK35/36 on the antimicrobial sensitivity of Klebsiella pneumoniae type K1.Methods The whole KP genome in GenBanrk was collected, then the distribution of porins and the polymorphism of gene and protein sequences in Klebsiella pneumoniae were analyzed through BLAST. Single and double knocking of ompK35/36 was performed on K1 strain NTUH-K2044 by CRISPR-Cas9 knockout method, and the changes of antibiotic sensitivity before and after knockout were measured.Results ompK35/36 was found to be common in KP genome with homology of more than 90%. After OmpK36 deletion, the minimum inhibitory concentration (MIC) of NTUH-K2044 against piperacillin, cefoxitin, cefazolin, cefuroxime and imipenem increased by 4, 4, 4, 8 and 4 times respectively. After OmpK35/36 double deletion, the MIC of piperacillin, cefoxitin, cefazolin, cefuroxime, imipenem and meropenem increased by 8, 32, 32, 16, 8 and 8 times respectively.Conclusions OmpK35/36 is common in Klebsiella pneumoniae with conserved sequence. Loss of OmpK35/36 leads to increased resistance of strains to certain beta-lactam antimicrobials, and when additional OmpK35 is further lost on basis of the loss of OmpK36, MIC will be further increased.