Different methodologies have been proposed to interpret the microbiological
findings associated with contaminating, indigenous microbiota of the anter
ior urethra. In order to solve the controversy related to the diagnosis of
chronic seminal infections in asymptomatic young adults, the results applyi
ng Stamey and Meares' criteria were compared with those obtained when semen
cultures were studied for significant bacteriospermia. A total of 218 cons
ecutive asymptomatic male partners of infertile couples were evaluated by t
he four-specimen technique described by Stamey and Meares' with the additio
n of semen (SM). infection was detected in 46% by SM, while semen cultures
(SC) showed a prevalence of infection of 41%; 73 patients were positive by
both criteria and 102 negative; 27 patients were positive by SM technique i
n prostate fluid while their semen cultures were negative; 16 patients had
positive semen cultures and were considered negative by SM. The kappa stati
stic indicated a good degree of agreement between both methodologies (kappa
= 0.61, z = 8.68, p < 0.001). The estimated risk of being considered negat
ive attributable to the semen culture (27 patients) was 25% (attributable r
isk = y(SC). = 0.2550), and of being considered positive attributable to th
e semen culture (16 patients) was 26% (y(SC+) = 0.2579). The 95% confidence
limits were estimated in 12 to 39%, and in 13 to 31%, respectively. In vie
w of these results, to establish the diagnosis of chronic prostatitis, the
addition of prostatic fluid or voided urine cultures after prostatic massag
e, must be performed. Semen culture confronted with first-voided urine avoi
d overestimating seminal infection.