Characterisation of a refined rat model of respiratory infection with Pseudomonas aeruginosa and the effect of ciprofloxacin

BackgroundWe sought to characterise a refined rat model of respiratory infection with P. aeruginosa over an acute time course and test the antibiotic ciprofloxacin.MethodsAgar beads were prepared ± SPAN®80. Rats were inoculated with sterile agar beads or those containing 105 colony forming units (cfu) P. aeruginosa via intra-tracheal dosing. Bacterial load and inflammatory parameters were measured.ResultsDiffering concentrations of SPAN® 80 modified median agar bead diameter and reduced particle size distribution. Beads prepared with 0.01% v/v SPAN®80 were evaluated in vivo. A stable lung infection up to 7 days post infection was achieved and induced BALF neutrophilia 2 and 5 days post infection. Ciprofloxacin (50 mg/kg) significantly attenuated infection without affecting the inflammatory parameters measured.ConclusionSPAN® 80 can control the particle size and lung distribution of agar beads and P. aeruginosa-embedded beads prepared with 0.01%v/v SPAN®80 can induce infection and inflammation over 7 days.