Diagnosis of bacteriuria in men: specimen collection and culture interpretation.

Bacteriologic criteria for diagnosing urinary tract infections in men have not been well defined. For determination of the bacterial colony count in voided specimens that most accurately reflects bladder bacteriuria, culture results were compared for voided urine and bladder urine (obtained by suprapubic aspiration and urethral catheterization) from men with various genitourinary problems. Bladder bacteriuria was found in 36 (47.3%) of 76 sets of specimens from 66 individuals. Culture results of bladder specimens showed excellent agreement with those of clean-catch midstream-void and uncleansed first-void specimens (weighted kappa = 0.924 and 0.906, respectively). The criterion for clean-catch midstream-void specimens that best differentiated sterile from infected bladder urine was growth of greater than or equal to 10(3) cfu of one predominant species/ml; this definition had a sensitivity of 0.97 and a specificity of 0.97. Uncleansed first-void specimens were equally sensitive (0.97) but less specific (0.91-0.92) in detection of bacteriuria. Pyuria (greater than or equal to leukocytes/mm3) and irritative genitourinary symptoms showed modest correlations with bladder bacteriuria.