Laboratory diagnosis of urinary tract infections in men

Abstract

In order to understand the epidemiology and pathogenesis of urinary tract infections in men, as well as to most effectively treat them, it is important to determine the best collection procedures and the most appropriate diagnostic criteria for bacteriuria. Studies by our group and others have begun to define the ways in which the laboratory diagnosis of bacteriuria in men differs from that in women. Future efforts should be aimed at discovering how men develop bacteriuria, how the prostate gland becomes infected, how to more accurately localize bacteriuria in men, and how such infections are best treated. Meanwhile, we offer the following recommendations: o 1. Recognize that guidelines for the laboratory diagnosis of urinary tract infections are derived almost entirely from studies on women, and that these are not always applicable to men. 2. In obtaining voided specimens for culture, meatal cleansing is not necessary, regardless of the man's circumcision status; midstream sampling is preferable, but not mandatory. 3. Culture of voided urine is extremely sensitive and specific for detecting true bacteriuria; bladder specimens are unnecessary unless the patient is unable to void or the voided urine results are difficult to interpret. 4. When bladder specimens are necessary, suprapubic aspiration is preferable to urethral catheterization. 5. The best definition of bacteriuria for voided urine is growth of ≥10 3 cfu/mL of one or two microbial species. 6. The role of the prostatic localization study is unclear, and therefore it should not be performed routinely on men with bacteriuria. 7. In terms of cost, speed, and sensitivity, the Gram-stained smear remains the primary screening procedure for detecting bacteriuria for most microbiology laboratories. 8. In patients with irritative genitourinary symptoms or a positive Gramstained smear, a specimen should be plated on chocolate agar when standard urine cultures are negative.