Background and purpose: The role of opportunistic microorganisms in urethritis in men is controversial. The aim of this study was to determine the changes in urethral microflora in the presence of persistent nonspecific urethritis (PNU) in men by in vitro detection of decomplementary activity (DCA) phenotypes of urethral isolates and comparison of the isolates with those from patients with or without PNU.
Methods: The study included 18 healthy men and 24 men with PNU. Culture specimens were spread on various selective media. Bacterial DCA was tested by measuring the decrease in complement activity (CH(50)) under the influence of culture supernatants.
Results: The most common isolates in both groups were coryneforms, coagulase-negative staphylococci, and streptococci. Enterobacteriaceae, enterococci, micrococci, and Staphylococcus aureus were isolated only from the PNU group. Simpson's diversity index (D) was significantly lower in the PNU group as compared to that in healthy men (D = 1.37 +/- 0.4 versus 3.5 +/- 0.9, p<0.05). DCA of staphylococci from the PNU group was significantly higher than that of the control group (7.3 +/- 1.4 versus 1.56 +/- 1.05 anti-CH(50), p<0.05). DCAs of Enterobacteriaceae and enterococci were 16.7 +/- 0.5 and 7.2 +/- 2.9 anti-CH(50), respectively, while that of micrococci was 7.4 +/- 3.2 anti-CH(50).
Conclusions: PNU is associated with a decrease in bacterial diversity and the occurrence of opportunistic microorganisms with pronounced pathogenic properties in the urethral microflora. These data suggest that PNU may be associated with microecological disorders.