Dysbiosis of urine microbiota in obstructive urinary retention patients revealed by next-generation sequencing.

BACKGROUND: Urinary retention (UR) is a common urinary system disease can be caused by urinary tract obstruction with numerous reasons, however, the role of urine microbes in these disorders is still poorly understood. The aim of this study was to identify the urine microbial features of two common types of obstructive UR, caused by urinary stones or urinary tract tumors, with comparison to healthy controls. METHODS: Urine samples were collected from a cohort of 32 individuals with stone UR, 25 subjects with tumor UR and 25 healthy controls. The urine microbiome of all samples was analyzed using high-throughput 16S rRNA (16S ribosomal RNA) gene sequencing. RESULTS: We observed dramatically increased urine microbial richness and diversity in both obstructive UR groups compared to healthy controls. Despite different origins of UR, bacteria such as Pseudomonas, Acinetobacter and Sphingomonas were enriched, while Lactobacillus, Streptococcus, Gardnerella, Prevotella and Atopobium were decreased in both UR groups in comparison with healthy controls, exhibited an approximate urine microbial community and functional characteristics of two types of obstructive UR. Furthermore, disease classifiers were constructed using specific enriched genera in UR, which can distinguish stone UR or tumor UR patients from healthy controls with an accuracy of 92.29% and 97.96%, respectively. CONCLUSION: We presented comprehensive microbial landscapes of two common types of obstructive urinary retention and demonstrated that urine microbial features of these patients are significantly different from that of healthy people. The urine microbial signatures would shed light on the pathogenesis of these types of urinary retention and might be used as potential classification tools in the future.

Multiple drug resistance bacterial isolates and associated factors among urinary stone patients at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia.

BACKGROUND: The urinary stone and urinary tract infection (UTI) are invariably associated and are frequent causes of morbidity. Date on burden of UTI among urinary stone patients is lacking in Ethiopia. This study was aimed to assess bacterial profile, antimicrobial susceptibility and associated factors among urinary stone patients at the University of Gondar Comprehensive Specialized Hospital. METHODS: An institution based cross sectional study was conducted. Basic sociodemographic data were collected using a structured questionnaire. Bacterial identification of uropathogens and drug susceptibility testing were done following standard microbiological techniques. The data were entered and analyzed using SPSS version-23. Bivariate and multivariate logistic regressions were used to identify possible associated risk factors. Results with P value < 0.05 was considered statistically significant. RESULT: A total of 300 urinary stone patients were enrolled. Of these, 153 (51%) were male and 261(87%) were urban residents. The overall prevalence of urinary tract infection was 49 (16.3%) (95% CI 12-21%). A high level of resistance was observed to ampicillin, penicillin and trimethoprim-sulfamethoxazole while majority of isolates were most sensitive to nitrofurantoin and ciprofloxacin. Multi-drug resistant isolates were 16/49 (32.7%), 75% of them being Enterobacteriaceae isolates. More than one-third 9/26 (34.6%) of Gram-negative isolates were Extended Spectrum Beta-Lactamase (ESBL) producing E. coli and K. pneumoniae. Being female, history of urinary tract infection and history of drug use were the independent risk factors. CONCLUSION: Most of the bacterial isolates from urinary stone patients were resistant to ampicillin, penicillin and trimethoprim-sulfamethoxazole. E. coli and K. pneumoniae were the most common extended spectrum beta-lactamase producing isolates. Sex, history of urinary tract infection and previous drug use were found to be risk factors. Routine diagnosis of urinary stone patients for urinary tract infection should be promoted and further researches are encouraged.

Microbiological Features and Clinical Factors Associated with Empirical Antibiotic Resistance in Febrile Patients with Upper Urinary Tract Calculi.

BACKGROUND: To investigate the clinical and microbiological features of febrile patients with upper urinary tract calculi and factors that affect empirical antibiotic resistance. METHODS: A retrospective analysis was performed on 203 febrile patients hospitalized between January 2011 and December 2016 with antibiotic treatment for urinary tract infections and upper urinary tract calculi at three institutions. We collected and analyzed data, including patients' age, sex, body mass index, underlying diseases, stone-related factors, and the results of urine and blood culture examinations and antibiotic sensitivity tests. RESULTS: The male-to-female ratio was 1:2.3. Bacteria were identified in 152 of the 203 patients (74.9%). The most commonly cultured microorganisms included Escherichia coli (44.1%), followed by Enterococci spp. (11.8%), Proteus spp. (8.6%), Streptococcus agalactiae (6.6%), Klebsiella spp. (5.3%), Pseudomonas spp. (4.6%), coagulase-negative Staphylococcus (4.0%), Staphylococcus epidermidis (4.0%), Serratia spp. (2.6%), Enterobacter spp. (0.7%), Acinetobacter spp. (0.7%), and mixed infections (7.2%). Cultured bacterial species showed sex-specific differences. Multivariate analysis revealed that calculi's multiplicity was an independent predictive factor for quinolone resistance (P = 0.008). Recurrent infections were a significant predictor of cefotaxime resistance during multivariable analysis (P = 0.041). CONCLUSION: Based on the present study results, quinolone was not recommended as the empirical treatment in febrile patients with upper urinary tract calculi. Combination antibiotic therapy is recommended in cases of recurrent infections due to the possible occurrence of cefotaxime resistance.

[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.

Inhibition of urinary stone disease by a multi-species bacterial network ensures healthy oxalate homeostasis.

The incidence of urinary stone disease is rapidly increasing, with oxalate being a primary constituent of approximately 80% of all kidney stones. Despite the high dietary exposure to oxalate by many individuals and its potential nephrotoxicity, mammals do not produce enzymes to metabolize this compound, instead relying in part on bacteria within the gut to reduce oxalate absorption and urinary excretion. While considerable research has focused on isolated species of oxalate-degrading bacteria, particularly those with an absolute requirement for oxalate, recent studies have pointed to broader roles for microbiota both in oxalate metabolism and inhibition of urinary stone disease. Here we examined gut microbiota from patients with and live-in individuals without urinary stone disease to determine if healthy individuals harbored a more extensive microbial network associated with oxalate metabolism. We found a gender-specific association between the gut microbiota composition and urinary stone disease. Bacteria enriched in healthy individuals largely overlapped with those that exhibited a significant, positive correlation with Oxalobacter formigenes, a species presumed to be at the center of an oxalate-metabolizing microbial network. Furthermore, differential abundance analyses identified multiple taxa known to also be stimulated by oxalate in rodent models. Interestingly, the presence of these taxa distinguished patients from healthy individuals better than either the relative abundance or colonization of O. formigenes. Thus, our work shows that bacteria stimulated by the presence of oxalate in rodents may, in addition to obligate oxalate users, play a role in the inhibition of urinary stone disease in man.

Understanding the Link Between Gut Microbiome and Urinary Stone Disease.

PURPOSE OF REVIEW: With recent advances in sequencing technologies and increasing research into the gut microbiome (GMB), studies have revealed associations between the GMB and urinary stone disease (USD). We sought to determine whether the evidence pointed towards a few specific gut bacteria or the broader GMB network is seemingly responsible for this relationship. RECENT FINDINGS: Initially, Oxalobacter formigenes (OF) was pursued as the main link between GMB and USD given its ability to degrade oxalate in the gut. However, the latest studies consistently suggest that the entire GMB is much more likely to be involved in handling oxalate absorption and other risk factors for urinary stone formation, rather than just a few microbiota. The GMB has complex networks that are likely involved in the pathophysiology of USD, although the causal mechanisms remain unclear. With increasing interest and research, potential modalities that act on the GMB may help to prevent incidence of USD.

Evaluation of Biofilm Induced Urinary Infection Stone Formation in a Novel Laboratory Model System.

PURPOSE: Infection stones, which comprise approximately 15% of all urinary tract stones, are induced by infection with urease-positive pathogens. The bacteria in the stone matrix present significant treatment impediments compared to metabolic kidney stones. While much is known about how urinary composition regulates metabolic stone formation, there is a general lack of knowledge of which urinary factors regulate the rate of infection stone formation. Unfortunately more in-depth research into infection stones is limited by the lack of suitable models for real-time study of bacterial biofilm formation and stone formation under varying conditions. MATERIALS AND METHODS: We developed an in vitro model to study infection stone formation. The model closely represents the processes that occur in vivo, including the observed migration of ureolytic bacteria (our culture of Proteus mirabilis) from the bladder to the kidneys, followed by biofilm and stone formation in the kidney. We used scanning electron and confocal laser microscopy, x-ray diffraction, biological counts and dissolved chemical analyses to evaluate the model system. RESULTS: Crystals that formed in the system resembled clinically removed struvite stones in structure and composition. Results showed that the degree of ureolysis required to significantly change urine pH was minimal, bacterial communities inhabited the ureter, and upstream colonization and struvite formation required lag time. CONCLUSIONS: These results have implications for the detection and treatment of struvite stones. Currently this model is being used to study specific urinary factors that regulate struvite formation to identify treatment options, which combined with antibiotics would improve treatment of these stones and decrease recurrence.

Comparison between non-septic and septic cases in stone-related obstructive acute pyelonephritis and risk factors for septic shock: A multi-center retrospective study.

PURPOSE: This study assessed risk factors for septic shock in patients with obstructive acute pyelonephritis (APN) associated with upper urinary tract calculi in a multi-center retrospective study. METHODS: We studied 143 patients admitted to 4 hospitals in Japan with obstructive APN associated with upper urinary tract calculi. Data on gender, age, hypertension, diabetes, neurological disease or malignant disease, laboratory data (white blood cell (WBC) and C-reactive protein (CRP)), drainage, and bacterial strains including Escherichia coli in the non-septic and septic groups were collected. Risk factors for septic shock were analyzed by univariate and multivariate statistical analyses. RESULTS: There were a total of 107 non-septic cases (74.8%) and 36 septic cases (25.2%). The commonest strains of urinary tract infection-causative bacteria were E. coli in the non-septic group (23 cases, 21.5%) and septic group (13 cases, 36.1%) (p > 0.05). Emergency drainage was administered in 74.8% of the non-septic group and 97.2% of the septic group (p > 0.05). Meropenem was most often used as the initial treatment in the non-septic group (20 cases, 18.7%) and septic group (22 cases, 61.1%) (p < 0.0001). Risk factors for septic shock in multivariate analyses were diabetic mellitus (odds ratio (OR) = 3.591, p = 0.0098) and CRP ≥ 10 (OR = 1.057, p = 0.0119) as significant independent factors in this multicenter study. CONCLUSIONS: APN is a common infectious disease, especially in the cases with urinary tract obstruction where patients easily acquire bacteremia or sepsis. Stone-associated obstructed APN can cause fatal septic shock in cases with diabetes and CRP ≥ 10. Further prospective studies will be undertaken to draw definitive conclusions.

The analysis of microbial spectrum and antibiotic resistance of uropathogens isolated from patients with urinary stones.

PURPOSE: The characteristics and resistance patterns of urine bacteriology in patients with urinary tract stones have not been extensively studied. This study aims to investigate the microbial spectrum and antibiotic resistance of uropathogens isolated from urinary tract infections in patients with urinary stones and provide a basis for appropriate antimicrobial treatments. METHODS: The results of positive bladder midstream urine cultures and their antimicrobial susceptibility were retrospectively analysed from hospitalised patients with diagnosis of urinary calculi and urinary tract infections between January 2010 and December 2015. RESULTS: A total of 3892 samples were analysed during the study period: 2201 were female patients (56.6%) and 1691 were male patients (43.4%). The 4 most common uropathogens were Escherichia coli (48.7%), Klebsiella pneumoniae (10.4%), Enterococcus faecalis (8.7%) and Proteus mirabilis (5.2%). Both E. coli (60.8%) and Proteus mirabilis (7.5%) were higher in female patients than in male patients (32.8%; 2.3%; P < .05). ESBL-positive E. coli accounted for 59.5% of total number of E. coli, while ESBL-positive K. pneumoniae comprised 42.0% of total K. pneumoniae. The majority of uropathogens in patients with stones had high resistance to fluoroquinolones, ceftriaxone, ceftazidime, cefepime, penicillins, sulfonamides and monobactams (resistance >20%). CONCLUSIONS: The microbial spectrum in patients with urinary stones had a complex pattern. The uropathogens showed marked multidrug resistance and a large proportion of the uropathogens were able to produce ß-lactamase.

In vitro studies of epithelium-associated crystallization caused by uropathogens during urinary calculi development.

Infectious urinary stones account for about 10% of all urinary stones. In 50% of cases urolithiasis is a recurrent illness, which can lead to the loss of a kidney if not properly treated. One of the reasons for recurrence of the disease may be the ability of bacteria to invade urothelial cells, persist in the host cells and serve as potential reservoirs for infection. Various uropathogens are associated with the formation of bacteria-induced urinary stones but Proteus mirabilis is the most commonly isolated (70%). An in vitro model was used in this study to analyze intracellular growth and crystallization in the presence of P. mirabilis, Klebsiella pneumoniae and Escherichia coli. Human ureter (Hu 609) and bladder (HCV 29) epithelial cell lines were infected with bacteria and incubated (3-72 h) in the presence of synthetic urine and amikacin to prevent extracellular bacterial growth. During the incubation the number of bacteria (CFU/ml) inside epithelial cells and the intensity of crystallization were established. Crystallization was determined as an amount of a calcium radioisotope. The chosen strains of uropathogens were able to invade both types of epithelial cells but the Hu 609 cells were invaded to a higher extent. However, crystallization occurred only in the presence of P. mirabilis strains which were invasive and urease-positive. The highest intensity of cell-associated crystallization was observed when the number of bacteria within the urothelium remained stable during the time of incubation. These results show that P. mirabilis has an ability to form crystals inside the host cells. Under these conditions bacteria are protected from antibiotic killing, which leads to persistent and recurrent infections. We also suspect that this phenomenon may be an important stage of kidney stones formation.

[Bacterial culture and drug sensitivity analysis of upper urinary tract calculi complicating with infection].

OBJECTIVE: To investigate the bacteriology and drug sensitivity of upper urinary tract calculi patients, and to provide information for choosing suitable antibiotics. METHODS: In the study, 21 patients who suffered from lithiasis in upper urinary tract and required an emergency drainage for acute obstruction and infection were the "acute group"; 64 patients with calculi in upper urinary tract and accompanied with no infectious symptoms were the "common group". The bacteriology and drug sensitivity of the two groups were investigated. RESULTS: Gram-negative bacteria infected the most common of upper urinary tract calculi patients with infection, accounting for 71.4% in the acute group and 65.7% in the common group, among which Escherichia coli were the predominant ones (35.7% in the acute group and 32.9% in the common group). No difference was found between these two groups in bacterial distribution (P>0.05). Although the average drug resistance rate of Gram-negative bacteria in the acute group was higher than that in the common group, it revealed no significant difference (P>0.05). The drug resistance rate to semisynthetic penicillin, cefuroxime and ceftriaxone were more than 50%, 60%, and 50%, respectively. Quinolones, such as ciprofloxacin and levofloxacin, got a 45% drug resistance. Aminoglycoside, carbapenema were sensitive to Gram-negative bacteria. Cefoperazone/sulbactam and piperacillin/tazobactam were more effective than ceftriaxone and piperacillin, respectively. CONCLUSION: There was no significant difference between upper urinary tract calculi patients with acute infection and common infection in bacteriology and drug sensitivity. Semisynthetic penicillin, the second generation of cephalosporin and quinolone were no longer the good choices of empirical use. Antibiotics combined with ß-lactamase inhibitors would be an ideal empirical therapeutic choice.

Understanding the role of zinc ions on struvite nucleation and growth in the context of infection urinary stones.

Taking into account that in recent decades there has been an increase in the incidence of urinary stones, especially in highly developed countries, from a wide range of potentially harmful substances commonly available in such countries, we chose zinc for the research presented in this article, which is classified by some sources as a heavy metal. In this article, we present the results of research on the influence of Zn2+ ion on the nucleation and growth of struvite crystals-the main component of infection urinary stones. The tests were carried out in an artificial urine environment with and without the presence of Proteus mirabilis bacteria. In the latter case, the activity of bacterial urease was simulated chemically, by systematic addition of an aqueous ammonia solution. The obtained results indicate that Zn2+ ions compete with Mg2+ ions, which leads to the gradual replacement of Mg2+ ions in the struvite crystal lattice with Zn2+ ions to some extent. This means co-precipitation of Mg-struvite (MgNH4PO4·6H2O) and Znx-struvite (Mg1-xZnxNH4PO4·6H2O). Speciation analysis of chemical complexes showed that Znx-struvite precipitates at slightly lower pH values than Mg-struvite. This means that Zn2+ ions shift the nucleation point of crystalline solids towards a lower pH. Additionally, the conducted research shows that Zn2+ ions, in the range of tested concentrations, do not have a toxic effect on bacteria; on the contrary, it has a positive effect on cellular metabolism, enabling bacteria to develop better. It means that Zn2+ ions in artificial urine, in vitro, slightly increase the risk of developing infection urinary stones.

Microbial communities, antibiotic resistance genes, and virulence factors in urinary infectious stone-associated urinary tract infections.

Urinary infectious stones are challenging due to bacterial involvement, necessitating a comprehensive understanding of these conditions. Antibiotic-resistant urease-producing bacteria further complicate clinical management. In this study, analysis of urine and stone samples from urinary tract infection (UTI) patients revealed microbial shifts, gene enrichment in stones, and metabolic pathway disparities; antibiotic resistance gene trends were phylum-specific, urease-producing bacteria are at risk of acquiring AMR carried by Enterobacteriaceae under antibiotic, emphasizing potential AMR dissemination between them; Correlations of key pathogenic species in kidney stone and urine microbial communities highlight the need for targeted therapeutic strategies to manage complexities in UTIs; Stones and urine contain a variety of deleterious genes even before antibiotic use, and piperacillin/tazobactam better reduced the abundance of antibiotic resistance genes in stones and urine. The presence of diverse antibiotic resistance and virulence genes underscores challenges in clinical management and emphasizes the need for effective treatment strategies to mitigate risks associated with UTIs and urinary infectious stone formation. Ongoing research is vital for advancing knowledge and developing innovative approaches to address these urological conditions.

A new era in the treatment of calcium oxalate stones?

Calcium oxalate (CaOx) is the most prevalent type of kidney stone. The amount of oxalate excreted in the urine is a major risk factor for CaOx stone formation. The study by Siener et al. makes a substantial contribution to our understanding of how Oxalobacter formigenes affects oxalate metabolism and excretion in humans and hence influences the risk of developing CaOx kidney stones.

The role of Oxalobacter formigenes colonization in calcium oxalate stone disease.

About 75% of urinary stones contain oxalate. As Oxalobacter formigenes is a Gram-negative anaerobic bacterium that degrades oxalate in the intestinal tract, we assessed the role of O. formigenes in oxalate metabolism by evaluating its intestinal absorption, plasma concentration, and urinary excretion. Of 37 calcium oxalate stone formers, 26 tested negative for O. formigenes and were compared with the 11 patients who tested positive. Patients provided 24-h urine samples on both a self-selected and a standardized diet. Urinary oxalate excretion did not differ significantly on the self-selected diet, but was significantly lower in O. formigenes-positive than in O. formigenes-negative patients under controlled, standardized conditions. Intestinal oxalate absorption, measured using [(13)C2]oxalate, was similar in the patients with or without O. formigenes. Plasma oxalate concentrations were significantly higher in noncolonized (5.79 µmol/l) than in colonized stone formers (1.70 µmol/l). Colonization with O. formigenes was significantly inversely associated with the number of stone episodes. Our findings suggest that O. formigenes lowers the intestinal concentration of oxalate available for absorption at constant rates, resulting in decreased urinary oxalate excretion. Thus, dietary factors have an important role in urinary oxalate excretion. The data indicate that O. formigenes colonization may reduce the risk of stone recurrence.

Extensive characterizations of bacteria isolated from catheterized urine and stone matrices in patients with nephrolithiasis.

BACKGROUND: Urinary tract infections are generally known to be associated with nephrolithiasis, particularly struvite stone, in which the most common microbe found is urea-splitting bacterium, i.e. Proteus mirabilis. However, our observation indicated that it might not be the case of stone formers in Thailand. We therefore extensively characterized microorganisms associated with all types of kidney stones. METHODS: A total of 100 kidney stone formers (59 males and 41 females) admitted for elective percutaneous nephrolithotomy were recruited and microorganisms isolated from catheterized urine and cortex and nidus of their stones were analyzed. RESULTS: From 100 stone formers recruited, 36 cases had a total of 45 bacterial isolates cultivated from their catheterized urine and/or stone matrices. Among these 36 cases, chemical analysis by Fourier-transformed infrared spectroscopy revealed that 8 had the previously classified 'infection-induced stones', whereas the other 28 cases had the previously classified 'metabolic stones'. Calcium oxalate (in either pure or mixed form) was the most common and found in 64 and 75% of the stone formers with and without bacterial isolates, respectively. Escherichia coli was the most common bacterium (approximately one-third of all bacterial isolates) found in urine and stone matrices (both nidus and periphery). Linear regression analysis showed significant correlation (r = 0.860, P < 0.001) between bacterial types in urine and stone matrices. Multidrug resistance was frequently found in these isolated bacteria. Moreover, urea test revealed that only 31% were urea-splitting bacteria, whereas the majority (69%) had negative urea test. CONCLUSIONS: Our data indicate that microorganisms are associated with almost all chemical types of kidney stones and urea-splitting bacteria are not the major causative microorganisms found in urine and stone matrices of the stone formers in Thailand. These data may lead to rethinking and a new roadmap for future research regarding the role of microorganisms in kidney stone formation.

Post-percutaneous nephrolithotomy systemic inflammatory response: a prospective analysis of preoperative urine, renal pelvic urine and stone cultures.

PURPOSE: Prior studies suggest that renal pelvic urine culture is a more accurate predictor of urosepsis. We prospectively determined the correlation between preoperative bladder urine cultures, intraoperative renal pelvis cultures and stone cultures in patients undergoing percutaneous nephrolithotomy. We also examined post-procedure risk factors for systemic inflammatory response syndrome. MATERIALS AND METHODS: From February 2009 to February 2011 urine samples from the bladder and renal pelvis were collected from patients undergoing percutaneous nephrolithotomy. Extracted stones were also sent for culture analysis. Postoperatively patients were closely monitored for any signs of systemic inflammatory response syndrome. The concordance of urine and stone cultures across different sites was examined. Regression analysis was done to identify clinical variables associated with systemic inflammatory response syndrome. RESULTS: A total of 204 percutaneous nephrolithotomies were done in 198 patients, of whom 20 (9.8%) had evidence of systemic inflammatory response syndrome postoperatively, including 6 (30%) requiring intensive care. The concordance among stone, renal pelvic and preoperative cultures was 64% to 75% with the highest concordance between renal pelvic urine and stone cultures. In a multivariate model multiple access tracts and a stone burden of 10 cm(2) or greater were significant predictors of systemic inflammatory response syndrome postoperatively. CONCLUSIONS: Even appropriately treated preoperative urinary infections may not prevent infected urine at percutaneous nephrolithotomy. Renal pelvic urine and stone cultures may be the only way to identify the causative organism and direct antimicrobial therapy. We recommend collecting pelvic urine and stone cultures to identify the offending organism in patients at risk for sepsis, particularly those with a large stone burden requiring multiple access tracts.

Detection and isolation of nanobacteria-like particles from urinary stones: long-withheld data.

OBJECTIVES: To report our experimental results on detection and isolation of nanobacteria-like particles (NLP) from urinary stone samples. METHODS: From March 2001 to August 2003, 47 urinary stone samples from Japanese patients and 18 from Paraguayan patients were collected and used for compositional analysis, direct survey of NLP by scanning electron microscopy (SEM) and their cultural isolation. For the isolation, culturing was carried out using strict aseptic techniques. Dulbecco's modified Eagle medium with 10% gamma-irradiated fetal bovine serum was used based on the original method described by Kajander and Ciftçioglu. RESULTS: Positive NLP detection rates for Japanese and Paraguayan patient samples were 61.7% (29/47) and 66.7% (12/18), respectively. Positive NLP isolation rates for Japanese patient samples were 20.6% (7/34) and 20.0% (2/10) for Paraguayan patient samples. In the initial isolation, markedly different periods of incubation time were needed for each of the nine cases (6-220 days; median 36 days). Positive detection and isolation were obtained in stone samples with or without calcium phosphate. Growth modes and morphogenesis of NLP were divided into two phases; rod-shaped NLP was detected mainly as a floating form growing in culture medium and spherical NLP with a characteristic apatite shell was detected as an attached form growing on the surface of culture dishes. CONCLUSIONS: Lifeless calcifying nanoparticles can be isolated from various human urinary stones, cultured in cell culture mediums and show two characteristic growth phases.

Potentially Probiotic Lactobacillus Strains Derived from Food Intensify Crystallization Caused by Proteus mirabilis in Urine.

Proteus mirabilis is a common cause of infectious urolithiasis. The first stage in the formation of urinary stones is the crystallization of mineral salts in the urine induced by urease activity of this microorganism. Lactobacillus spp. are an important component of the human microbiota and in large quantities occur in foods. Regardless of their origin, those with probiotic properties are proposed as an alternative to antibiotic therapy in the treatment of urinary tract infections. The aim of the study was to check the effect of selected Lactobacillus plantarum and Lactobacillus brevis strains on crystallization caused by P. mirabilis in an in vitro experiment. It has been confirmed that selected Lactobacillus strains have antibacterial properties and colonize the urinary tract epithelium. During 24-h incubation of bacterial cultures, containing P. mirabilis and individual Lactobacillus strains, in synthetic urine, bacterial viability (CFU/mL), pH, and crystallization were determined. Crystallization was assessed quantitatively and qualitatively using AAS and XRD techniques as well as phase-contrast microscopy. It has been shown that in the presence of selected Lactobacillus strains, the culture pH increases faster, especially after 8 h of incubation, compared with the pure P. mirabilis culture. An increase in pH reduces the viability of P. mirabilis; however, in the presence of some lactobacilli, the uropathogen grows more intensively. The presence of Lactobacillus also affected crystallization by increasing its intensity, and the resulting crystals were larger in size. Tested L. plantarum and L. brevis strains could therefore accelerate the formation of urinary stones and development of infection.