FIG 1.
Virulence characteristics of K. pneumoniae RJY9645. (A) Serum resistance assay. K. pneumoniae RJY9645 exhibited a grade 4 response, with viable counts of >100% of the inoculum after both 1 and 2 h but <100% after 3 h. The hypervirulence control LA-Kp23 and the low-virulence control HAP-Kp11 exhibited grade 5 and grade 1 responses, respectively. (B) Human neutrophil phagocytosis assay. The data are presented as the means ± standard deviation. The survival of RJY9645 and LA-Kp23 was significantly higher than that of HAP-Kp11 at each time point (*, P < 0.05, one-way ANOVA). (C) Survival curves for K. pneumoniae RJY9645-infected mice. Mice were intraperitoneally infected with 5 × 104 CFU of each strain. Six mice were used as a sample population for each strain. Symptoms and mortality rates were observed for 14 days.