Pulmonary bacterial clearance expressed as the median (IQR) ratio between the amounts of bacteria recovered from the lung culture and the initial Staphylococcus aureus inoculum 24 hours after bacterial challenge in either spontaneously breathing or mechanically ventilated animals. Pulmonary-to-systemic bacterial translocation expressed as the spleen positive cultures rate 24 hours after bacteria instillation according to the experimental group in either spontaneously breathing or mechanically ventilated animals with Staphylococcus aureus pneumonia. Values are presented as percentages (right). Kruskall-Wallis test with Dunn correction for multiple comparisons or Fisher exact test was used as appropriate for intergroup comparisons. CFU: colony forming unit; MRSA: methicillin-resistant S. aureus; LNZ: linezolid; SB: spontaneously breathing; MV: mechanical ventilation; IQR: interquartile range.