FIG 4.
Enhanced lethality and increased capsule expression in M23ND/CovS− compared to M23ND/CovS+ isolates. (A) Kaplan-Meier survival curves of mice (n = 9) after subcutaneous infection with 1.2 × 107 to 1.8 × 107 CFU of strains M23ND/CovS+ and M23ND/CovS−. The mice were monitored for 10 days. The differences between the curves were evaluated by the log-rank test. M23ND/CovS− showed significantly higher lethality than M23ND/CovS+ (P = 0.0003). (B) Measurement of hyaluronic acid capsule levels at LP and SP growth. M23ND/CovS+ showed capsule deficiency during the growth. The error bars indicate the SEM with three repeats.