Fig. 4From: Reduced virulence in tigecycline-resistant Klebsiella pneumoniae caused by overexpression of ompR and down-regulation of ompK35Results of serum resistance assay. The survival rates of K. pneumoniae strains were measured after 3 h of incubation with 75% normal human serum. Heat-inactivated serum was used as a negative control. *P < 0.05; **P < 0.01Back to article page