Mouse thigh model of infection.

Mice were rendered neutropenic with cyclophosphamide prior to infection as described above for the acute lung model of infection. They were separated into groups of 5 animals per treatment. Inoculation (confirmed by culture) was with 1.52 × 10⁶ CFU/ml of P. aeruginosa strain LES431 conducted 1 h prior to treatment, which was i.v. for saline vehicle control-, ciprofloxacin-, and CYS-treated mice and subcutaneous for colistin (used as a positive control). The animals were sacrificed 25 h postinfection (24 h posttreatment), and thigh weights and numbers of CFU per gram of tissue were calculated and recorded.