Background. Chronic bacterial prostatitis (CBP) and chronic prostatitis/chronic pelvic pain syndrome IIIa (CP/CPPS IIIa) are separate nosologies defined diagnostic verification criteria according to the NIH-NIDDK classification (1995). The identification of enterobacteria in the prostatic secretion (PS) has long been a criterion for the diagnosis of CBP, while PS in patients suffering CP/CPPS IIIa was considered as “sterile”. However, the introduction of various methods of PS`s in-depth analysis and UPOINTS classification (2010) development with the allocation of site I (infection) allows us to consider the infectious factor as an etiological predictor of the initiation of inflammation in the prostate with CP/CPPS IIIa. Thus, the determination of the features of the taxonomic composition of microbiota in СBP and CP/CPPS IIIa can act as a differentiating factor of these conditions.
Aims/Objective: performing a comparative analysis of the PS microbiota in patients suffering from CBP and CP/CPPS IIIa.
Materials and methods. Feature: full-scale, prospective, comparative, uncontrolled study. During the study, a staged PS`s bacteriological study was performed in 101 patients (aged 20–60 years) with prostatitis-like symptoms lasting more than 3 months and identified leukocytosis in PS (> 10x`). Stage I of the PS`s study: a standard nutrient medium and culturing conditions were used. Two comparison groups were formed according to the results of the initial bacteriological study: 49 patients were included in group 1 (CBP), in which E. coli, Klebsiella spp., Proteus spp. were identified in PS (causative uropathogens in CBP), in group 2 (CP/CPPS IIIa) included 52 patients, with no growth of the above microorganisms` taxa in the biomaterial and/or primary negative results of the study. Stage II of the PS`s study: an extended set of selective media and special cultivation conditions were used for accessory verification of bacteria in biomaterial. Biochemical identification of bacteria was carried out using test systems. Statistical processing of seeding rates was carried out using Statistica 10.2 package (StatSoft Inc., USA). In both groups, we used descriptive statistics methods and the Mann-Whitney U test to process the results of bacteriological studies. The significance of differences between the studied parameters was considered at the level of p<0.05
and p<0.01.
Results. Usage of an expanded set of selective media and special cultivation conditions (as compared with the results of the primary bacteriological culture of the exprimate) made it possible to collectively verify in PS to 28 species / genera of microorganisms in both groups (25 in group 1 and 24 in group 2). The taxonomic composition of the PS`s microbiota was almost identical in both groups and presented mainly in the form of multicomponent microbial associations. According to the results of analysis of the bacteria`s identification frequency in PS, it was found that in group 2 (CP/CPPS IIIa) significantly more often than in group 1 (CBP) discovered some representatives of the non-clostridial anaerobic flora (NAB: Peptococcus sp., Propionibacterium spp. and others), coagulase-negative staphylococci (CNS: S.haemolyticus, S.warneri) and certain taxa of gram-positive microorganisms (Corynebacterium spp. and Str. agalacticae). In turn, when analyzing the PS contamination, it was found that integrally in group 1 (CBP) in the samples of the biomaterial a higher titer of microorganisms was determined with a wide range of quantitative values, in relation to group 2 (CP/CPPS IIIa), where the titer indices were somewhat lower and had a smaller variation relative to the average.
Conclusion. Identification in patients of both groups in PS of different mixed microbial associations, similar in the taxonomic spectral composition of microbiota, suggests that CP/CPPS IIIa in some cases is unverified CBP, which in turn necessitates a review of diagnostic and therapeutic strategies to achieve positive clinical result.

Keywords: comparison, prostate secretion, chronic prostatitis/chronic pelvic pain syndrome IIIa, bacterial prostatitis, microbiota