FIG 4.

MRSA exposed to CSE has increased virulence in a mouse model of pneumonia. (A) Lungs harvested at 8 and 20 h postinfection had higher numbers of CSE-MRSA (**, P < 0.01). (B) In a mortality model of pneumonia, 40% of mice infected with CSE-MRSA died, whereas 10% of controls survived (P = 0.021; n = 20 mice per group). (C) Histology of lungs from mice with MRSA pneumonia demonstrated more bacteria and inflammation in CSE-MRSA-infected mice at both the 8- and 20-h time points (n = 5 per group at each time point) (inflammation scores shown in white).