(A) Bacterial and (B) viral burdens in the lungs 24 h after inoculation of naïve (MRSA) or day 7 postinfluenza infected (Flu+MRSA) C57BL/6 mice with 107 CFU MRSA BAA-1695 (Flu+MRSA) or PBS (Flu). ***P< 0.001, compared to mice not infected with influenza virus, unpaired t test. (C) Survival of C57BL/6 mice after infection with 2×108 CFU of MRSA BAA-1695 alone (MRSA) or on day 7 after PR8 infection (Flu + MRSA). Also shown, survival of mice infected with 50 PFU PR8 and inoculated with PBS control, instead of MRSA, 7 days later (Flu).