Comparative study of the bacterial distribution and antimicrobial susceptibility of uropathogens in older and younger patients with urinary stones.

BACKGROUND: This study compared the bacterial spectrum and antibiotic susceptibility of uropathogens in older and younger patients with urinary stones to provide appropriate antibiotic management. METHODS: We retrospectively reviewed urinary tract infection patients with urolithiasis, presented to Xiangya Hospital from March 2014 to April 2021. Patients were divided into older and younger groups according to 60 years of age. The bacterial spectrum and drug sensitivity of uropathogens were compared. RESULTS: A total of 542 strains of uropathogens (177 in older and 365 in younger groups) were isolated from 507 patients. E. coli (41.8% vs 43.6%) remains the most common pathogen, followed by E. faecalis (6.2% vs 9.6%) in older and younger groups, respectively. Particularly, K. pneumoniae was significantly more frequent in older (9.6%) than in younger group (4.7%, P < .05). E. faecium was substantially more prevalent in older group (6.2%) than in younger group (2.7%, P < .05). The proportion of males increased in older patients (47.3%) than in younger patients (34.9%, P = 0.007). In both groups, major Gram-negative bacteria (E. coli and K. pneumoniae) revealed a high sensitivity over 70% to piperacillin/tazobactam, imipenem and amikacin, whereas the resistance level was high to penicillin, tetracycline and vancomycin. Major Gram-positive (E. faecalis and E. faecium) isolates demonstrated high sensitivity of over 50% to gentamicin and vancomycin in both groups. Furthermore, uropathogens isolated from younger urolithiasis patients were more susceptible to antimicrobials than those isolated from older patients. CONCLUSIONS: The male increased in the older urolithiasis patients with UTI and uropathogens microbial spectrum in older urolithiasis patients are different from younger. High susceptibility and age should be utilized in empirical antibiotic selection to avoid increased multidrug-resistant bacteria.

Gender differences in the microbial spectrum and antibiotic sensitivity of uropathogens isolated from patients with urinary stones.

PURPOSE: The characteristics and resistance patterns of urine bacteriology urolithiasis patients between male and female have not been extensively studied. This study aims to investigate the gender differences in microbial spectrum and antibiotic susceptibility of uropathogens isolated from urolithiasis patients and provide insights for appropriate antimicrobial therapies. MATERIALS AND METHODS: We retrospectively collected clinical microbiology data from urine culture in urolithiasis patients between March 2014 and December 2018 in Xiangya Hospital. Then the patients were divided into male and female groups. The microbial spectrum and frequency of susceptibility to antibiotics were compared. RESULTS: A total of 359 uropathogen isolates were collected from 335 patients, including 144 males (43.0%) and 191 females (57.0%). E. coli dominated in both groups, indicating higher frequency in females (53.2%) than in males (26.6%, p < 0.001), followed by E. faecalis, with higher frequency in males (15.6%) than in females (2.9%, p < 0.001). Major Gram-negative (E. coli and K. pneumoniae) bacteria showed high sensitivity to cefoperazone/sulbactam, cefotetan, piperacillin/ tazobactam, and amikacin. In contrast, the resistance level was high to penicillin, tetracycline, and vancomycin in both groups. Gram-positive (E. faecalis and E. faecium) isolates demonstrated high sensitivity to gentamicin and vancomycin in both groups. Furthermore, uropathogens isolated from female urolithiasis patients were more susceptible to antimicrobials than males. CONCLUSIONS: Uropathogen microbial spectrum in female urolithiasis patients is different from males. High susceptibility antibiotics should be used empirically according to gender to avoid multidrug-resistant bacteria increase.

[Bacteriological correlation of urinary stones and preoperative urine culture: Is there a significant impact on postoperative infectious risk? (Moroccan experience)]. / Corrélation bactériologique entre les calculs urinaires et l'ECBU préopératoire : a-t-il un impact sur le risque infectieux postopératoire ? (expérience marocaine).

AIM: The objectives of this study were to evaluate the impact of preoperative urine culture and the infected nature of stones on the occurrence of postoperative urinary sepsis. MATERIAL AND METHODS: A prospective monocentric study included 29 patients operated on for urolithiasis between January and June 2018. RESULTS: Postoperative urinary sepsis was observed in 4 patients (14%). Urinary colonization rate on preoperative CBU exam was 27.6% (8 of 29) while the rate of colonized stones was 31% (9 of 29). The occurrence of urinary sepsis was observed in 37.5% (3 of 8) of patients with urinary colonization, compared to 44.4% of patients with colonized stones (4 of 9). By comparing the bacteriological results observed during sepsis, the germs isolated in postoperative urine were the same found in the culture of stones. The chemical nature of the colonized stones was mainly calcium oxalate (monohydrate, dihydrate) P=0.02. There was a statistically significant correlation between the preoperative urine culture, the bacteriological culture of stones and the postoperative urinary sepsis (P=0.05, P=0.005) respectively. CONCLUSION: Our study demonstrated a strong association between the bacteriological culture of stones and postoperative urinary sepsis superior to preoperative urine culture. It makes it possible to anticipate the occurrence of sepsis in patients requiring many endoscopic treatments. However, several multicentric prospective series may prove necessary to validate these results. LEVEL OF EVIDENCE: 3.

Bacterial spectrum and antibiotic resistance of urinary tract infections in patients treated for upper urinary tract calculi: a multicenter analysis.

The purpose of this study is to collect information on the bacterial resistance to antibiotics of bacteria isolated from urine cultures of patients treated for upper urinary tract calculi. Data of patients with urinary tract infection and urolithiasis were retrospectively reviewed to collect information on age, gender, stone size, location, hydronephrosis, procedure of stone removal and antibiotic treatment, identification and susceptibility of pathogens, symptoms, and infectious complications. A total of 912 patients from 11 centers in 7 countries (Bulgaria, Greece, Italy, North Macedonia, Spain, and Turkey) were studied. Mean age was 54 ± 16 years and M/F ratio 322/590. Out of 946 microbial isolates, the most common were E. coli, Gram-positive, KES group (Klebsiella, Enterobacter, Serratia), Proteus spp., and P. aeruginosa. Carbapenems, piperacillin/tazobactam and amikacin showed low resistance rates to E. coli (2.5%, 7%, and 3.6%) and Proteus spp. (7.7%, 16%, and 7.4%), but higher rates were observed with Klebsiella spp., P. aeruginosa, and Gram-positive. Fosfomycin had resistance rates less than 10% to E. coli, 23% to KES group, and 19% to Gram-positive. Amoxicillin/clavulanate, cephalosporins, quinolones, and TMP/SMX showed high resistance rates to most bacterial strains. High rates of antibiotic resistance were observed in patients candidate to stone treatment from South-Eastern Europe. The empirical use of antibiotics with low resistance rates should be reserved to the most serious cases to avoid the increase of multidrug resistant bacteria. Basing on our results, carbapenems, piperacillin/tazobactam, and amikacin may be a possible option for empiric treatment of urinary stone patients showing systemic symptoms.

[Gut microbiome: from the reference of the norm to pathology].

А systemic assessment of the state of the human intestinal microbiome was carried out in relation to its function in the macroorganism, aimed at providing the nutriome, and the factors that determine the adequate nutritional status. A new concept of "reference gut microbiome of a healthy person" was postulated and the requirements to it were formulated: interaction with the host according to the principle of mutualism, provision of immune balance with the macroorganism due to the correct formation of mucosal immunity, implementation of metabolic and regulatory functions without losses for the nutriome. A set of characteristics and biomarkers reflecting the taxonomic composition and population properties of the microbial community, as well as the state of its essential immune and metabolic functions, was proposed as a criterion for its assessment in healthy adults who consume a diet balanced in nutritive and energy value, appropriate for age and energy spending. The influence of alimentary factors on the formation of the human intestinal microbiome in early ontogenesis, the nature of dysbiotic shifts, including those under common non-infectious alimentary-dependent diseases (obesity, food allergy, urolithiasis), in Russians were studied, the ways of their correction and maintenance of the intestinal microbiota in the process of life were substantiated taking into account modern knowledge.

[Structure of microorganism species cultured from urine of urolithiasis patients].

AIM: To investigate the incidence of microorganisms of different taxonomic groups and their associations in the pelvic and bladder urine of adult urolithiasis patients. MATERIALS AND METHODS: A bacteriological method and metagenomic sequencing were used to investigate the bacterial spectrum of microflora cultured from pelvic and bladder urine sampled during surgical interventions in urolithiasis patients. RESULTS: The both microbiotas had approximately the same spectrum, but in 26.1% of patients it was inconsistent. Metagenomic analysis detected DNA of microorganisms in urine samples which were found free of microflora by the bacteriological method. CONCLUSION: The study findings showed species diversity of microorganisms cultured from pelvic and bladder urine sampled during surgical interventions in urolithiasis patients.

Pyonephrosis Caused by Salmonella Typhi: A Case Report.

INTRODUCTION: Salmonella is a rare cause of urinary tract infections. We report here a unique case of pyonephrosis due to Salmonella Typhi (S. Typhi) complication, a stone-related obstructive pyelonephritis. CASE REPORT: A 47-year-old man, without any history of typhoid fever or gastrointestinal symptoms, presented with a pyonephrosis and life-threatening bacteremia following an acute obstructive right pyelonephritis caused by S. Typhi. The patient was treated by urinary drainage (ureteral stent), antibiotics, and delayed right nephrectomy. We postulated that urolithiasis could explain asymptomatic chronic urinary carriage of S. Typhi. CONCLUSION: S. Typhi is one possible cause of life-threatening urinary tract infection, especially in the context of urolithiasis.

Increased incidence of urolithiasis and bacteremia during Proteus mirabilis and Providencia stuartii coinfection due to synergistic induction of urease activity.

BACKGROUND: Catheter-associated urinary tract infections (CaUTIs) are the most common hospital-acquired infections worldwide and are frequently polymicrobial. The urease-positive species Proteus mirabilis and Providencia stuartii are two of the leading causes of CaUTIs and commonly co-colonize catheters. These species can also cause urolithiasis and bacteremia. However, the impact of coinfection on these complications has never been addressed experimentally. METHODS: A mouse model of ascending UTI was utilized to determine the impact of coinfection on colonization, urolithiasis, and bacteremia. Mice were infected with P. mirabilis or a urease mutant, P. stuartii, or a combination of these organisms. In vitro experiments were conducted to assess growth dynamics and impact of co-culture on urease activity. RESULTS: Coinfection resulted in a bacterial load similar to monospecies infection but with increased incidence of urolithiasis and bacteremia. These complications were urease-dependent as they were not observed during coinfection with a P. mirabilis urease mutant. Furthermore, total urease activity was increased during co-culture. CONCLUSIONS: We conclude that P. mirabilis and P. stuartii coinfection promotes urolithiasis and bacteremia in a urease-dependent manner, at least in part through synergistic induction of urease activity. These data provide a possible explanation for the high incidence of bacteremia resulting from polymicrobial CaUTI.

[PERSISTENCE OF MYCOPLASMA DURING UROLITHIASIS].

AIM: Study the frequency of detection of mycoplasma and ureaplasma in clinical material from urolithiasis patients. MATERIALS AND METHODS: Clinical material samples (blood sera, urine, uroliths) from 31 urolithiasis patients were obtained during operations of urolith-removal. Cultural method, LAR and PCR were used in the study. RESULTS: The study of clinical material from 31 patients by PCR has shown, that in 25 individuals. (80.6%) DNA of mycoplasma and ureaplasma was detected, and mycoplasma DNA was more frequently detected in uroliths and less--in-blood sera. Mycoplasma hominis DNA was detected in clinical material of a significantly largerninmber of patients. 23 cultures were isolated from 8 patients by a cultural method, that were identified by PCR as M. hominis. All the isolates have grown as "mini colonies". Even after multiple passages in agar medium, reversion of "mini-colonies" into colonies with a classic morphology was not obtained. CONCLUSION: A high frequency of detection of mycoplasma and ureaplasma in clinical material of patients with urolithiasis was established. The isolated M. hominis cultures have only grown as "mini-colonies". The phenomenon discovered could give evidence on high variability of mycoplasma and a possibility of existence of previously unknown form of their persistence in human organism.

[Formation of microbial biofilms in causative agents of acute and chronic pyelonephritis].

AIM: Study the intensity of formation of microbial biofilms by Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus strains isolated during various forms of pyelonephritis. MATERIALS AND METHODS: 150 clinical isolates of microorganisms isolated from urine ofpatientswith acute and chronic pyelonephritiswere included into the study. Determination of intensity of film-formation was carried out by staining of the formed biofilms by crystal violet with consequent extraction of the dye and measurement of its concentration in washout solution. RESULTS: Among causative agents ofpyelonephritis P. aeruginosa isolates had the maximum film-forming ability. The intensity of biofilm formation of these isolates was 2-3 time higher than staphylococcus and enterobacteria strains. Strains isolated from patients with chronic pyelonephritis by ability to form biofilms significantly surpassed strains isolated from acute pyelonephritis patients. A higher ability to form microbial biofilms for microorganisms--causative agents of pyelonephritis progressing against the background ofurolithiasis was noted. CONCLUSION: The ability to form biofilms is determined by both causative agent species and character of the infectious process in which this microorganism participates. Intensive formation of biofilms by E. coli, P. aeruginosa, K. pneumoniae, S. aureus clinical isolates may be an important factor of chronization of urinary tract infections.

Insights into the physical and chemical properties of struvite crystal surfaces in terms of the effectiveness of bacterial adhesion.

In this paper, we present the results of research on the physicochemical properties of two selected faces of the struvite crystal, which is the main component of infectious urinary stones. Two main faces, (001) and ([Formula: see text]), ending the c-axis, were selected for the study. These faces are not related by symmetry relations, which means, among other things, that they should have a different atomic structure, which was confirmed experimentally. In addition, the studies show that the tested surfaces have hydrophilic properties, however, the ([Formula: see text]) face is more hydrophilic compared to the (001) face. The physicochemical properties of the crystal as a whole, as well as the physicochemical properties of these faces influence the magnitude of adhesion. The adhesive force in both water and artificial urine is greater for face ([Formula: see text]) compared to face (001). The assessment of the adhesion of Proteus mirabilis bacteria in artificial urine also shows that the adhesion is greater for face ([Formula: see text]) than for face (001). The adhesion of bacteria to the examined faces of the struvite crystal, and in particular the increased adhesion of bacteria to the face ([Formula: see text]), may be the first stage of biofilm formation, which may result in a high rate of recurrence of infectious urinary stones after treatment.

Quantitative analysis of colonization with real-time PCR to identify the role of Oxalobacter formigenes in calcium oxalate urolithiasis.

The objective of the study was to quantitatively measure the number of Oxalobacter formigenes (O. formigenes) colonizations in the gastrointestinal tract in calcium oxalate-forming patients with real-time polymerase chain reaction (PCR). Calcium oxalate-forming patients (n: 27) were included in the study. Serum calcium, sodium, potassium, urea and creatinine levels, as well as 24 h urine levels of calcium and oxalate were measured. The numbers of O. formigenes colonies in stool samples were detected by real-time PCR. One or two metabolic abnormalities were detected in 15 of 27 patients. The O. formigenes levels in patients with metabolic disturbance were significantly decreased when compared to the patients with no metabolic abnormalities (p: 0.038). The undetectable levels of O. formigenes were encountered in one of five patients with hypercalciuria, in three of four patients with hyperoxaluria and in four of six patients with both hypercalciuria and hyperoxaluria. In nine patients with a history of stone recurrence, O. formigenes colonization was significantly lower than the patients with the first stone attack (p: 0.001). O. formigenes formation ceased or significantly diminished in patients with calcium oxalate stones with a coexistence of both hyperoxaluria and hypercalciuria. The measurement of O. formigenes colonies by real-time PCR seemed to be an inconvenient and expensive method. For this reason, the real-time PCR measurements can be spared for the patients with stone recurrences and with metabolic abnormalities like hypercalciuria and hyperoxaluria. The exact measurement of O. formigenes may also help more accurate programming of O. formigenes-based treatments.

Comparative faecal microbiota of dogs with and without calcium oxalate stones.

AIMS: The absence of enteric oxalate-metabolizing bacterial species (OMBS) increases the likelihood of calcium oxalate (CaOx) urolithiasis in humans and dogs. The goal of this study was to compare the gut microbiota of healthy dogs and CaOx stone formed dogs (CaOx-dogs), especially with respect to OMBS. METHODS AND RESULTS: Faecal samples from healthy and CaOx-dogs were obtained to analyse the hindgut microbiota by sequencing the V3 region of bacterial 16S rDNA. In total, 1223 operational taxonomic units (OTUs) were identified at 97% identity. Only 38% of these OTUs were shared by both groups. Significant differences in the relative abundance of 152 OTUs and 36 genera were observed between the two groups of dogs. CONCLUSIONS: The faecal microbiota of healthy dogs is distinct from that of CaOx-dogs, indicating that the microbiota is altered in CaOx-dogs. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study that has compared the gut microbial diversity in healthy and CaOx-dogs. Results of this study indicate the future need for functional and comparative analyses of the total array of oxalate-metabolizing genes between healthy and CaOx stone formers, rather than focusing on specific bacterial species, to understand the critical role of OMBS in CaOx urolithiasis.

Diversity of faecal oxalate-degrading bacteria in black and white South African study groups: insights into understanding the rarity of urolithiasis in the black group.

AIM: To examine whether enhanced diversity or numbers of oxalate-degrading bacteria in the gastrointestinal tracts of black South Africans play a role in determining the rarity of urolithiasis in this group. METHODS AND RESULTS: Fresh faecal samples collected from healthy black and white South African male volunteers were analysed in terms of bacterial oxalate-degrading activity, bacterial diversity and relative species abundance. Varied bacterial populations prepared from samples from the low-risk black group showed a significantly higher level of oxalate degradation. Denaturing gradient gel electrophoresis analyses of Lactobacillus and related spp. and Bifidobacterium spp. 16S rRNA PCR products revealed a significantly higher faecal Lactobacillus diversity for the low-risk black group relative to the higher-risk white group. Quantitative real-time PCR experiments did not show any significant differences between the study groups for Lactobacillus and related spp.. However, Bifidobacterium spp. were present at a significantly higher relative abundance in the black group. Oxalobacter formigenes was present only at very low levels in either group. CONCLUSIONS: The low abundance of O. formigenes and increased diversity and abundance of oxalate-degrading Lactobacillus and Bifidobacterium spp. in the black South African population suggest that these strains rather than O. formigenes may protect this group against calcium oxalate kidney stone disease. SIGNIFICANCE AND IMPACT OF THE STUDY: The South African black population harbours a pool of potential oxalate-degrading lactic acid bacteria, which is more abundant and diverse than that of white South Africans. This may be useful in developing probiotics for calcium oxalate kidney stone prophylaxis.

[Use of furamag to prevent inflammatory complications during endoscopic operations in patients with benign prostatic hyperplasia and urolithiasis].

AIM: To improve surgical results in patients with benign prostatic hyperplasia (BPH) and urolithiasis (UL) and to evaluate the efficacy of Furamag used as an agent to prevent infectious and inflammatory complications. SUBJECTS AND METHODS: Seventy-two patients with BPH (n = 36; Group 1) and UL (n = 36; Group 2) were examined. Within each group, the patients were divided into two subgroups: A) those in whom no preventive measures were taken during endoscopic operations; B) those who received Furamag as a preventive agent. The preventive efficacy was evaluated from the urine microbial spectrum and renal microcirculatory values. RESULTS: The preventive use of Furamag could achieve better urine sanitation, normalize renal microcirculatory values, and reduce the incidence of postoperative complications. CONCLUSION: The use of Furamag to prevent intravesical obstruction (IVO) during transurethral prostatic resection and UL reduces the incidence of IVO, results in less noticeable renal microcirculatory disorders, and accordingly assists in lowering the incidence of postoperative complications.

Consumption of soft drinks rich in phosphoric acid versus struvite crystallization from artificial urine.

In recent years, there has been a continuous increase in the incidence of urolithiasis, especially in highly developed countries. Therefore, the question arises which factors specific to these countries may be responsible for the increase in the incidence of this disease. In this article, we try to assess the effect of phosphoric acid, a component of various carbonated drinks, including Coca-Cola, on the nucleation and growth of struvite crystals, which are the main component of infectious urinary stones. The research was carried out in the environment of artificial urine with and without the presence of Proteus mirabilis bacteria. In the latter case, the activity of bacterial urease was simulated by adding an aqueous ammonia solution. The obtained results indicate that phosphoric acid present in artificial urine causes the nucleation of struvite to shift towards a lower pH, which means that struvite nucleates earlier in artificial urine compared to the control test. The amount of struvite formed is the greater the higher the concentration of phosphoric acid. At the same time, as the concentration of phosphoric acid increases, the growing struvite crystals are larger, which is disadvantageous because they are more difficult to remove from the urinary tract along with the urine. For the highest levels of phosphoric acid tested, large dendrites are formed, which are particularly undesirable as they can damage the epithelium of the urinary tract. The effect of phosphoric acid on the nucleation and growth of struvite is explained in base of chemical speciation analysis. This analysis indicates that the MgHCit and MgCit- complexes have the main influence on the nucleation and growth of struvite in artificial urine in the presence of phosphoric acid. It should be keep in mind that all these effects of phosphoric acid are possible when the urinary tract is infected with urease-positive bacteria. In the absence of infection, phosphoric acid will not cause struvite to crystallize.

Standardization of microbiome studies for urolithiasis: an international consensus agreement.

Numerous metagenome-wide association studies (MWAS) for urolithiasis have been published, leading to the discovery of potential interactions between the microbiome and urolithiasis. However, questions remain about the reproducibility, applicability and physiological relevance of these data owing to discrepancies in experimental technique and a lack of standardization in the field. One barrier to interpreting MWAS is that experimental biases can be introduced at every step of the experimental pipeline, including sample collection, preservation, storage, processing, sequencing, data analysis and validation. Thus, the introduction of standardized protocols that maintain the flexibility to achieve study-specific objectives is urgently required. To address this need, the first international consortium for microbiome in urinary stone disease - MICROCOSM - was created and consensus panel members were asked to participate in a consensus meeting to develop standardized protocols for microbiome studies if they had published an MWAS on urolithiasis. Study-specific protocols were revised until a consensus was reached. This consensus group generated standardized protocols, which are publicly available via a secure online server, for each step in the typical clinical microbiome-urolithiasis study pipeline. This standardization creates the benchmark for future studies to facilitate consistent interpretation of results and, collectively, to lead to effective interventions to prevent the onset of urolithiasis, and will also be useful for investigators interested in microbiome research in other urological diseases.

Meta-analysis of Clinical Microbiome Studies in Urolithiasis Reveal Age, Stone Composition, and Study Location as the Predominant Factors in Urolithiasis-Associated Microbiome Composition.

To determine whether functionally relevant questions associated with the urinary or gut microbiome and urinary stone disease (USD) can be answered from metagenome-wide association studies (MWAS), we performed the most comprehensive meta-analysis of published clinical MWAS in USD to date, using publicly available data published prior to April 2021. Six relevant studies met inclusion criteria. For alpha-diversity, significant differences were noted between USD status, stone composition, sample type, study location, age, diet, and sex. For beta-diversity, significant differences were noted by USD status, stone composition, sample type, study location, antibiotic use (30 days and 12 months before sampling), sex, hypertension, water intake, body habitus, and age. Prevotella and Lactobacillus in the gut and urinary tract, respectively, were associated with healthy individuals, while Enterobacteriaceae was associated with USD in the urine and stones. Paradoxically, other Prevotella strains were also strongly associated with USD in the gut microbiome. When data were analyzed together, USD status, stone composition, age group, and study location were the predominant factors associated with microbiome composition. Meta-analysis showed significant microbiome differences based on USD status, stone composition, age group or study location. However, analyses were limited by a lack of public data from published studies, metadata collected, and differing study protocols. Results highlight the need for field-specific standardization of experimental protocols in terms of sample collection procedures and the anatomical niches to assess, as well as in defining clinically relevant metadata and subphenotypes such as stone composition. IMPORTANCE Studies focused on the microbiome broadly support the hypothesis that the microbiome influences the onset of chronic diseases such as urinary stone disease. However, it is unclear what environmental factors shape the microbiome in ways that increase the risk for chronic disease. In addition, it is unclear how differences in study methodology can impact the results of clinical metagenome-wide association studies. In the current meta-analysis, we show that age, stone composition, and study location are the predominant factors that associate with the microbiome and USD status. Furthermore, we reveal differences in results based on specific analytical protocols, which impacts the interpretation of any microbiome study.

Recent advances on the mechanisms of kidney stone formation (Review).

Kidney stone disease is one of the oldest diseases known to medicine; however, the mechanisms of stone formation and development remain largely unclear. Over the past decades, a variety of theories and strategies have been developed and utilized in the surgical management of kidney stones, as a result of recent technological advances. Observations from the authors and other research groups suggest that there are five entirely different main mechanisms for kidney stone formation. Urinary supersaturation and crystallization are the driving force for intrarenal crystal precipitation. Randall's plaques are recognized as the origin of calcium oxalate stone formation. Sex hormones may be key players in the development of nephrolithiasis and may thus be potential targets for new drugs to suppress kidney stone formation. The microbiome, including urease­producing bacteria, nanobacteria and intestinal microbiota, is likely to have a profound effect on urological health, both positive and negative, owing to its metabolic output and other contributions. Lastly, the immune response, and particularly macrophage differentiation, play crucial roles in renal calcium oxalate crystal formation. In the present study, the current knowledge for each of these five aspects of kidney stone formation is reviewed. This knowledge may be used to explore novel research opportunities and improve the understanding of the initiation and development of kidney stones for urologists, nephrologists and primary care.

[Role of an infectious factor in the pathogenesis of urolithiasis].

The paper gives the data of complex clinical and biochemical examination in 122 urolithiasis (ULT) inpatients treated at the Urology Unit, Moscow City Clinical Hospital Seven, in February 2004 to January 2008. The levels of lithogenic substances and compounds, inhibitors and activators of lithogenesis have been determined. The authors show it possible to use the level of hydrolytic enzymes and activators of cooperative microbial sensitivity as diagnostic and prognostic criteria in diferent forms of ULT, which is in turn of no small importance in developing the science-based methods for the treatment and prevention of recurrent lithogenesis.