Halothane (HAL) minimizes clinical symptoms, lung damage, and bacterial burden of secondary bacterial pneumonia (SBP) postflu. CD-1 mice were inoculated intranasally with 40 plaque-forming units A/PR/8/34 influenza virus (SBP) or mock infected (mock). Mock-HAL and SBP-HAL mice (white bars) were exposed to 2% HAL for 2 h just before infection (day 0) and again for 2 h on day 4 postviral infection (PVI). Mock-cont and SBP-cont mice (black bars) received ketamine sedation. (A) On day 6 PVI, mice were assessed for clinical score on a six-point scale and then inoculated intranasally with 2.5 × 106 colony-forming units (CFUs) Streptococcus pneumoniae (EF3030). (B) Mice with 24-h postbacterial infection (PBI) were again assessed for clinical score. They were killed, bronchoalveolar lavage (BAL) was performed, and lungs were harvested. (C) Cell-free BAL fluid was assessed for albumin concentration, as an indicator of lung injury. (D) Nonclarified recovered BAL fluid and lung homogenates were titered for EF3030 CFU, and a total EF3030 lung burden was determined. Sample sizes are displayed above groups. *P < 0.05, **P < 0.01 SBP-HAL compared with SBP-cont. Data are expressed as mean ± SEM. cont = control.
