[Are bacteriological and pathomorphological signs of bacterial prostatitis related between? (An experimental study)]

INTRODUCTION

In some cases, there is a dissociation between the severity of complaints, physical examination data, and levels of contamination of the biomaterial in the differential diagnosis of various categories of prostatitis (NIH-NIDDK, 1995). Patients note the presence of pronounced symptoms when verifying the threshold indicators of microbial load (104-105 CFU / ml) of prostate secretion or post-massage urine in a few observations. However, clinical manifestations and deviations in objective indicators are not so significant in some patients with higher titers of contamination.

PURPOSE OF THE STUDY

To evaluate the relationship between the microbial load indices and the degree of pathomorphological changes in the prostate tissue during infection with the "reference" uropathogen E. coli in various titers under experimental conditions MATERIALS AND METHODS: Animal model was carried out using the FELASA protocols. Experimental individuals: 16 "New Zealand" rabbits, weight: 3580 [3480; 3695] (3300-4410), age: 25 [24; 26] (23-28) weeks. Uropathogen used: E. coli. Titers: 103 CFU / ml, 105 CFU / ml, 107 CFU / ml. Infection pathway: inoculation of the uropathogen was performed through urethra according to the modified technique of J.C. Nickel. Randomization: all lab animals were evenly divided into 4 groups of 4 animals, taking into account the initial titer of the uropathogen and the observation period - experimental groups 1 (103 CFU / ml), 2 (105 CFU / ml), 3 (107 CFU / ml); group 4 was control (Sol.NaCl 0.9%). Observation terms: 1, 3, 7 and 14 days, after which the animals were euthanized and dissected. 4 biopsies (1A-1D) for bacteriological (MacConkey agar - "HiMedia", India) and 2 biopsies (P1-P2) for morphological (Hematoxylin-eosin - "BlikMediklProduction", Russia; magn. 10x, 40x, 100x, 400x) studies were formed from various parts of the prostatic complex (prostate + proprostate + paraprostate). A three-point grading system was used for morphometric assessment of destructive changes in the prostate tissue in different groups. Analytical processing of the results was carried out using the software packages Microsoft 365 ("Microsoft", USA) and Statistica 10.2 ("StatSoft Inc.", USA) by methods of descriptive and nonparametric statistics.

RESULTS

The maximum total absolute / median values of the seeding of biopsy specimens of the prostatic complex were revealed ( titer, 1A-1D) in group 1 and amounted to 76 lg CFU / ml / 5.00 [4.00; 5.25] lgCFU / ml, in group 2 defined as intermediate - 57 lgCFU / ml / 3.50 [3.00; 4.00] lgCFU / ml, and in group 3 were minimal - 48 lgCFU / ml / 3.00 [3.00; 3.25] lg CFU / ml according to the indicators of bacteriological research in the period from 1 to 14 days. Nevertheless, it was found that the cumulative maximum degree of histological changes in the prostate was recorded in group 2 ( p. - 84), in group 1 it was defined as intermediate ( p. - 68), and in group 3, it was the smallest ( p. - 64) according to the data of pathomorphological studies. When comparing daily changes in the seeding values and nominal indicators of inflammatory lesions in the prostate tissue, only in group 1, the trend graphs had a synchronous trend - an increase in microbial load led to the formation of more severe pathomorphological transformations on the day 7; in group 2, destructive changes were significant, and the rates of contamination, on the contrary, were minimal on the day 7; in group 3 a pronounced pathomorphological transformations in the tissues were noted on the day 3 and 7, but the microbial load of the tissues gradually decreased from the day 1. Also, differences in the increase in the "reactivity" of changes in the affected tissues were determined: in groups 1 and 3, a torpid reaction was revealed, accompanied by the development of moderate inflammatory changes on the day 1 and an "abrupt" increase in the intensity of destruction by the day 3; in group 2, in turn, a rapid reaction was determined, that characterized by the formation of a more pronounced destructive process already from the day 1.

CONCLUSION

It was found that the parameters of contamination do not fully reflect the nature and severity of pathological changes in the prostate. Low titers of the uropathogen induce the development of an inflammatory process comparable in the severity of changes with that at higher concentrations. On the contrary, inoculation of obligate pathogenic titers does not always lead to a pronounced increase in microbial load but causes significant inflammatory changes in the prostate.

[Experimental evaluation of inflammatory process in the prostate caused by transurethral transmission of uropathogen in low counts]

BACKGROUND

According to the literature, bacterial count of uropathogens isolated from expressed prostate secretion and urine which is sufficient for a diagnosis of bacterial prostatitis I and II categories, remains contradictory. Undoubtedly, the identification of microorganisms from affected organ in high titers indicates the presence of a relevant infectious-inflammatory process. In turn, there is no consensus on the development of bacterial prostatitis at lower titers of uropathogens. Thus, the aim of our study was to identify and compare the potential features of the development and occurrence of an infectious inflammatory process in the prostate during the reproduction of bacterial prostatitis in an animal model using a low titer of causative uropathogens.

MATERIALS AND METHODS

A total of 16 "New Zealand" mature male rabbits aged 24+/-2 weeks old with weight of 3.5+/-0.3 kg were examined. Inoculation was performed via transurethral route, according to the developed experimental technique. E. coli was used as bacterial agent with a count of 1 x 103 CFU/ml, 1 x 105 CFU/ml and 1 x 107 CFU/ml. All animals were randomized into 4 groups of 4 individuals depending on the titer of the inoculated microorganisms (groups 1-3, respectively), group 4 - control (with inoculation by Sol. NaCl 0.9%). Sacrification and vivisection were performed on days 1, 3, 7 and 14 of the control days. Biopsy specimens from the lower urinary tract and internal genital organs of laboratory animals (bladder, urethra, prostatic complex - 6 biopsies #1A-1D, 2A, 2B) were evaluated morphologically and bacteriologically. Analytical evaluation of the experimental data was presented using descriptive statistical methods.

RESULTS

In experimental groups (Groups 1-3), bacteriological examination of prostatic complex biopsies showed growth of microflora in all samples in titers of 101-107 CFU / ml. In group 1, the maximum concentration of uropathogen was observed on day 7, compared to day 1 in both groups 2 and 3. In all observed cases, the highest degree of bacterial contamination was noted in the biopsy specimens from paraprostatic tissues and distal part of the prostate, which was 4.0+/-1.7 lg CFU/ml and 3.5+/-1.9 lg CFU/ml, respectively, and the smallest in proximal prostatic loci (1C) and bladder neck (2B) - 3.0+/-1.2 lg COE / ml and 3.0+/-1.7 lg COE / ml, respectively. According to the morphological study, a relevant progression of the suppurative and destructive inflammation (with foci of colliquation necrosis) was identified in group 1 in the biopsies from the prostate with a maximum degree of changes on day 7 with subsequent formation of loose connective tissue proliferation areas by 14 days. This indicates the conversion of the inflammatory process to the chronic stage. These changes corresponded with the results of histopathological studies in groups 2 and 3 where higher titers of bacterial agent were used. In group 4 (control) the commensal flora was bacteriologically determined in the biopsies, but there were no signs of inflammation, according to the results of the morphological study.

CONCLUSION

In experimental model, we found that E. coli 103 CFU / ml induces the development of a phasic inflammatory process in the structures of the prostatic complex. These processes resulted in the formation of irreversible proliferative changes. As a consequence, it shold be recommended to consider these signs of contamination when evaluating the results of bacteriological examination of expressed prostate secretion/urine samples during planning treatment strategy.

[Bacterial prostatitis: epidemiology and etiology]

Prostatitis is considered as heterogeneous group of the diseases attracting broad interest of researchers worldwide. The acute and chronic stages of the process, as particular categories of bacterial prostatitis, remain in the realities of modern practical and scientific urology with lively discussions. Despite a large number of domestic and international publications, consensus on many topical issues of bacterial prostatitis is currently not achieved. The true incidence and prevalence of bacterial prostatitis in various regions of the world has not been finally determined. The exhaustive data concerning the etiological structure, mechanisms of development and persistence of the inflammatory process in the prostate tissue are not presented. At the same time, new risk factors that can influence the development and progress of these diseases are identified and discussed. Researchers review algorithms for examining patients, obligate spectrum of diagnostic methods, as well as the desirability of using the newest investment means necessary for the successful verification of the diagnosis taking into account the development of modern medical technologies. This review describes in detail the various aspects of the epidemiology and etiology of bacterial prostatitis, based on an analysis of major literature sources in conjunction with its own scientific facts.