Persistent bacteriuria in the rat after reflux challenge with Pseudomonas aeruginosa

An experiment based upon reflux of culture suspensions of Pseudomonas aeruginosa into the rat kidney was set up to examine possible factors of importance in the development of ascending renal infection. We monitored the persistence of challenge bacteria in the rat urinary tract by quantitative culture of urine collected by spontaneous micturition, despite heavy contamination with commensal microflora. In most animals challenged, pseudomonads gave rise to bacteriuria of only limited duration. During bacterial persistence in urine, colony counts fluctuated widely from day to day.