Mechanical ventilation has no impact on lung bacterial outgrowth and systemic bacterial dissemination. Pneumococcal pneumonia (S.p.) was induced 24 hours before mechanical ventilation (MV) was performed for 6 hours. Continuous adrenomedullin (AM) infusion (0.05 mg/kg/hour) started with the onset of MV. Nonventilated mice were sacrificed 30 hours after infection. Serial dilutions of bronchoalveolar lavage (BAL) fluid, spleen homogenate and blood were plated on agar, and colony-forming units (CFU) were counted after 24 hours of incubation (n = 5 to 7).