Antibiotic Therapy and Bacterial Challenge

At 1, 14, or 28 dpi with either PBS or 10⁸ cfu of Kan^R, all mice were treated with trimethoprim and sulfamethoxazole in the drinking water daily for 10 days at concentrations of 54 and 270 µg/ml, respectively [46] (link). During this time, longitudinal urinalysis was continued weekly to confirm clearance of bacteriuria. Four weeks after the initiation of antibiotic therapy, mice from each test group (previously infected or naïve) were challenged with either PBS or 10⁷ cfu of UTI89 Spc^R. Longitudinal urinalysis was then performed as for the primary infection (except now triplicate plating on LB, LB/Kan25 and McConkey agar with 50 µg/ml spectinomycin (McC/Spc50) to identify mice with persistent bacteriuria and the responsible strain. Mice were sacrificed 4 weeks after challenge and tissue titers determined as above, triplicate plating on LB, LB/Kan25, and LB/Spc50.