Urine pH Research Articles

Analysis of components and related risk factors of urinary stones: a retrospective study of 1055 patients in southern China.

We conducted a retrospective study of 1055 patients with urinary stones who attended our single center from September 2017 to June 2024. Clinical data and laboratory indicators of patients were evaluated and compared with stone components. The most common type in our study was calcium oxalate (CaOx) stones (76.6%), followed by infection stones (13.2%) and uric acid (UA) stones (7.8%). Among the 1055 specimens, 899 (85.2%) cases were mixed component stones, of which calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) mixture were the most frequent (34.8%). There were only 156 cases (14.8%) of pure-component stones, of which anhydrous UA was the most frequent (7.0%). There were 738 males and 317 females, with a male-to-female ratio of 2.33:1. Male dominance was evident in CaOx stones (79.0 vs. 71.0%, P = 0.005). Female dominance was noted in infection stones (21.1 vs. 9.8%, P < 0.001). The multivariate analysis showed that higher serum albumin level was a risk factor for CaOx stone formation (OR = 2.959; 95% CI 1.470-5.953, P = 0.002). Women were more likely to develop infection stones than men (OR = 1.796; 95% CI 1.150-2.803, P = 0.010). As the urine pH increased, the risk of infection stones formation increased (OR = 2.521; 95% CI 1.809-3.513, P < 0.001). Moreover, a history of hypertension (OR = 2.339; 95% CI 1.409-3.881, P = 0.001), low urine pH (OR = 0.242; 95% CI 0.147-0.399, P < 0.001), and low serum albumin level (OR = 0.351; 95% CI 0.125-0.988, P = 0.047) were risk factors for the formation of UA stones.

Characteristics of urinary stone composition among patients with urolithiasis: a retrospective study in China

ObjectiveTo present the most recent data on urinary calculi characteristics in the southern region of China and explore the effects of sociodemographic, clinical and laboratory characteristics on stone composition to...

The role of vegetarian diet in Nephrolithiasis

Nephrolithiasis, commonly known as kidney stone disease, is a prevalent condition with significant morbidity worldwide. Notably, this medical condition is strongly influenced by nutritional habits. Dietary choices play a critical role in both the formation and prevention of kidney stones, highlighting the importance of proper nutrition in managing this disease. This review explores the impact of a vegetarian diet on nephrolithiasis. Evidence suggest that plant-based diets, which excludes animal protein, may contribute to a reduced risk of kidney stone formation. Vegetarian diet could be also considered as higher in fruits and vegetables, so in conclusion, people on plant-based diet have a water-rich food intake. Not only the fluid intake, but also the balance of calcium and oxalates is very important in managing risk of forming kidney stones. This diet typically result in lower acid load, higher urinary pH and increased urinary citrate levels. Everything mentioned is a key preventive strategy against kidney calculi. Nephrolithiasis has undenyable colligation with diet. Patients dietary choices and their lifestyle could strongly influence the course of this disease. Overall, well-planned vegetarian diet may offer protective benefits against nephrolithiasis. It should be individualized and preferably prepared by a professional dietitian. In this case, it is important to remember that our diet plays role similarly in genesis as in recurrence of kidney stone disease. Changing eating habits aims to reduce lithogenic risk factors.

Fat Distribution and Urolithiasis Risk Parameters in Uric Acid Stone Formers and Patients with Type 2 Diabetes Mellitus.

Key Points Under a controlled diet, uric acid stone formers (UASFs) and diabetic patients have higher endogenous net acid production.Under a controlled diet, UASFs have lower ammonium-to-net acid excretion ratio.Body fat inversely correlates with urine buffer capacity in normal individuals, but this relationship is lost in diabetic patients and UASFs. Background Uric acid (UA) nephrolithiasis affects approximately 10% of kidney stones, with a greater preponderance among patients with obesity and diabetes mellitus (DM). UA lithogenicity is driven by abnormally acidic urine pH. Distinguishing the contribution of intrinsic (e.g., body adiposity) versus external (e.g., dietary) factors to UA stone propensity is challenging because of uncontrolled diets in outpatients in previously published studies. Methods This compilation of metabolic studies with body composition examined by dual-energy x-ray absorptiometry scan and blood and urine biochemistry collected under a controlled metabolic diet was conducted across three distinct populations: 74 UA stone formers (UASF group), 13 patients with type 2 DM without kidney stones (DM group), and 51 healthy volunteers (HV group). Results Compared with HVs, both UASFs and patients with DM exhibited higher levels of net acid excretion (NAE) and significantly lower urine pH and lower proportion of NAE excreted as ammonium (NH4 +/NAE), all under controlled diets. UASFs exhibited significantly lower NH4 +/NAE compared with patients with DM. UASFs also showed higher total body and truncal fat compared with HVs. Among the HVs, lower NH4 +/NAE ratio correlated with higher truncal and total fat. However, this association was abolished in the UASF and DM groups who exhibit a fixed low NH4 +/NAE ratio across a range of body and truncal fat. Conclusions The findings suggest a dual defect of diet-independent increase in acid production and impaired kidney NH4 + excretion as major contributors to the risk of UA stone formation. There is an inverse physiologic association between body fat content and NH4 +/NAE in HVs, whereas NH4 +/NAE is persistently low in UASFs and patients with DM, regardless of body fat, representing pathophysiology.

Physiological Response and Sports Injury Risk Relevant Biomechanics in Endurance Obstacle Course Races

Obstacle course races (OCR) have experienced significant growth in recent years, with millions of participants worldwide. However, there is limited research on the specific physiological demands and injury prevention strategies required for these events. This study aimed to analyze the physiological responses and injury risks in participants of a 5 km (Sprint) and 13 km (Super) OCR. Sixty-eight participants were assessed for cortical arousal, leg strength, isometric handgrip strength, blood lactate, heart rate, blood oxygen saturation, body temperature, urine composition, spirometry values, hamstring flexibility, lower limb stability, foot biomechanics, and scapular kinematics, one hour before and immediately after the races. The results showed a significant decrease in leg strength (Sprint: r = −0.56, p &lt; 0.01; Super: r = −0.54, p = 0.01) and urine pH (Sprint: r = −0.70, p = 0.03; Super: r = −0.67, p = 0.01) in both distances, with increases in urine colour, protein, and glucose (Sprint: p &lt; 0.04). In the 13 km race, lower limb stability decreased significantly post-race (r = −0.53, p = 0.01). Positive correlations were found between performance and pre-race handgrip strength (Sprint: r = 0.71, p = 0.001; Super: r = 0.72, p = 0.01) and spirometry values (FVC, FEF 25–75%, FEV1) (Sprint: r = 0.52, p = 0.031; Super: r = 0.48, p = 0.035). Thermoregulation capacity, reflected in a higher pre-race body temperature and lower post-race body temperature, also correlated with improved performance (r = 0.49, p = 0.046). Injury risk increased post-race, with a significant decline in lower limb stability (p &lt; 0.05). These findings highlight the importance of targeted training programs, focusing on grip strength, leg strength, respiratory muscle training, and hydration strategies to optimize performance and reduce injury risk in OCR athletes.

Kidney Stones of Type I vs. Type II Diabetic Patients: Are There Any Differences?

Background: This study highlighted the differences between the biochemical compositions of urinary stones from patients with type 1 diabetes versus those with type 2 diabetes. Materials and Methods: This study included patients diagnosed with kidney stones and diabetes who were referred to the Urological Clinic of the Dr. C. I. Parhon Hospital in Iasi from April 2017 to April 2024. We analyzed the spectroscopic stone composition from 128 lithiasis patients treated in our Clinic. In the current study, the distribution of the biochemical composition of stones varied significantly between diabetic patients with type 2 diabetes, who formed primarily mixed uric acid stones, and diabetic patients with type 1 diabetes, who mainly developed pure uric acid stones (p &lt; 0.001). Patients with uric acid stones had significantly higher mean creatinine values than the other stone types (p &lt; 0.001). Urinary pH levels were abnormal for all biochemical subtypes of stones, indicating acidic urine. However, patients with uric acid stones had lower pH values than the group average. From the Kaplan–Mayer analysis, patients with pure uric acid stones had a shorter time to stone recurrence compared to patients with other biochemical types identified. Conclusions: These findings, which highlight the prevalence of pure uric acid stones in patients with type 1 diabetes and the impact of this on the strategy for dissolving pure stones, represent a significant advancement in understanding urinary lithiasis in diabetic patients.

Evaluating the role of urine chemistry in shock wave lithotripsy outcomes.

Extracorporeal Shock Wave Lithotripsy (ESWL) is a commonly used method for the noninvasive treatment of kidney stones. However, achieving optimal treatment outcomes and minimizing potential damage to the kidney necessitates careful consideration for the total amount of energy utilized. This study aims to investigate whether urine pH and urine specific gravity have an impact on the total amount of energy applied during SWL. Between January 2023 and December 2023, 129 patients with renal stones underwent SWL in our department using the Storz Medical Modulith Inline lithotripter. Stone-free rates, complications, and the impact of patient, urine, and stone characteristics on energy use were analyzed. Urine samples were analyzed for pH and specific gravity. Stone characteristics, including size, HU, and skin-to-stone distance, were recorded. The obtained data were evaluated regarding the possible relationship between the total energy amount (determined as a risk factor) and the age, BMI, urine pH, urine specific gravity, stone size, HU, and skin-to-stone distance by using the Pearson correlation coefficient. p-value of < 0.05 was considered statistically significant. Evaluation of our findings revealed a negative linear relationship between total amount of energy used and the urine pH, indicating a decrease in the total energy amount as urine pH shifts towards alkaline values (p = 0.038; p < 0.05). However, no statistically significant relationship was observed between age, BMI, urine specific gravity, stone size, HU, and skin-to-stone distance and the total energy amount. Our findings demonstrated a significant relationship between urine pH and the total amount of energy applied during SWL sessions, suggesting the need for further prospective research to better understand the possible association between these two parameters. Such investigations could contribute to the development of more reasonable and effective strategies for kidney stone treatment in an attempt to minimize the potential kidney damage.

Medical dissolution of presumptive upper urinary tract struvite uroliths in 6 dogs (2012-2018).

Minimally invasive approaches are the standard for treatment of upper urinary tract uroliths in humans. To describe the medical dissolution of upper urinary tract uroliths in a series of dogs and report clinical outcomes. 6 female dogs (9 kidneys). Retrospective case series. A review of medical records in dogs that underwent medical dissolution of upper urinary tract uroliths utilizing diet, administration of antibiotics, and double-pigtail ureteral stent(s) placement, when indicated, was performed. Medical management was generally continued for 4 weeks beyond urolith dissolution. Information on biochemical, microbiological, imaging, and clinical outcomes before and after dissolution were recorded. Six dogs (9 kidneys) were included with bilateral (3) or unilateral (3) nephrolithiasis, ureterolithiasis, or a combination. A ureteral stent(s) was placed endoscopically in 5/6 dogs (6/9 kidneys) for obstructive ureterolithiasis (n = 5) or a nonobstructive massive nephrolith (n = 1). All dogs had a positive urine culture of Staphylococcus pseudintermedius with a median urine pH of 7.25 (range, 6.5-8) and 4/5 had pyonephrosis. All dogs had initial evidence of urolith dissolution at a median of 1.1 months (range, 0.42-5.9), with complete dissolution of ureteroliths at a median of 3.9 months (range, 1.5-7.6), nephroliths at 5.3 months (range, 1.5-7.6), and lower urinary tract uroliths at 0.87 months (range, 0.42-5.9). Stents were removed in 3/6 once dissolution was documented. The median follow-up time was 519 days (range, 177-2492 days). Medical dissolution and decompression of upper urinary tract struvite uroliths should be considered a minimally invasive treatment for dogs before more invasive options.

A Multi-Channel Urine Sensing Detection System Based on Creatinine, Uric Acid, and pH.

Urine analysis represents a crucial diagnostic technique employed in clinical laboratories. Creatinine and uric acid in urine are essential biomarkers in the human body and are widely utilized in clinical analysis. Research has demonstrated a correlation between the normal physiological concentrations of creatinine and uric acid in urine and an increased risk of hypertension, cardiovascular diseases, and kidney disease. Furthermore, the pH of urine indicates the body's metabolic processes and homeostatic balance. In this study, an integrated multi-channel electrochemical sensing system was developed, combining electrochemical analysis techniques, microelectronic design, and nanomaterials. The architecture of an intelligent medical detection system and the production of an interactive interface for smartphones were accomplished. Initially, multi-channel selective electrodes were designed for creatinine, uric acid, and pH detection. The detection range was 10 nM to 100 μM for creatinine, 100 μM to 500 μM for uric acid, and 4 to 9 for pH. Furthermore, interference experiments were also conducted to verify the specificity of the sensors. Subsequently, multi-channel double-sided sensing electrodes and function-integrated hardware were designed, with the standard equations of target analytes stored in the system's read-only memory. Moreover, a WeChat mini-program platform was developed for smartphone interaction, enabling off-body detection and real-time display of target analytes through smartphones. Finally, the aforementioned electrochemical detection electrodes were integrated with the smart sensing system and wirelessly interfaced with smartphones, allowing for intelligent real-time detection in primary healthcare and individual household settings.

Association between Urine Volume, Urine pH, and Urine H+ Excretion

Association between Urine Volume, Urine pH, and Urine H+ Excretion

Cystine and urate cystoliths in dogs are frequently visible on radiographs prior to surgical or nonsurgical removal.

To investigate the frequency at which cystine and urate cystoliths (stones) are visible on radiographs prior to surgical or nonsurgical retrieval. Records of client-owned dogs (n = 331) were analyzed between January 2019 and December 2023 for cystoliths submitted for stone analysis after surgical removal or nonsurgical retrieval. Records were analyzed for cystolith type; when cystine or urate stones were identified, records were analyzed for signalment, procedure, presence of mineral opaque cystoliths on pre-procedural radiographs, urine pH and crystalluria, history of previous cystoliths, prior prescription diet attempt, recurrence, and genetic, congenital and acquired comorbidities. Descriptive statistics were generated after data collection. 31 of 331 (9%) were cystine stones, 49 of 331 (15%) were urate, and 1 of 331 (0.3%) was a mix of urate and cystine. When radiographs were taken prior to stone removal, 24 of 28 (85%) of urate, 24 of 26 (92%) of cystine, and 1 of 1 (100%) of urate/cystine were visible on radiographs. Cystine and urate stones are visible on survey radiography at a high frequency in dogs. While cystine and urate stones have been historically designated as radiolucent, they are frequently radiopaque on radiographs. Radiopacity is commonly used as one of the criterion to determine whether a dissolution or prevention diet is an appropriate management technique, particularly when determination of the stone type has yet to be performed. As a result, these findings may prompt clinicians to investigate other patient-specific factors before a specific dietary recommendation is made.

Comparison of Thiazide vs. Alkali Citrate for Kidney Stone Recurrence among Individuals with Hypocitraturia and High Urine pH

Comparison of Thiazide vs. Alkali Citrate for Kidney Stone Recurrence among Individuals with Hypocitraturia and High Urine pH

Metabolic profile of prepartum dairy cows and its influence on the immediate postpartum period, colostrum quality and passive immunity transference

The objective of this study was to evaluate which biochemical markers in the prepartum period of dairy cows influence the immediate postpartum period, the quality of colostrum, and the passive immunity transference in the calves. The experiment was performed on a commercial dairy farm with 52 pregnant multiparous Holstein cows. Animals that gave birth to twins or males were discarded from the experiment. On days -20 of the expected calving date and 24hours after calving, blood collections, body condition score assessments, and animals weighing were performed. Blood samples from calves were performed 24hours after colostrum intake. Calf plasma was used to estimate the passive immunity transfer by % brix and total plasma proteins (TPP). In the principal component analysis, it was shown that postpartum NEFA and BHBA was higher in cows with higher prepartum urinary pH and Ca lower prepartum. The cows with the highest NEFA and BHBA in pre and postpartum were the ones that had the lowest % brix in the colostrum. The % brix of the cow’s colostrum directly influenced the % brix and TPP of the calves. The NEFA in the cows prepartum negatively influenced the markers of immunity, the higher the NEFA, the lower the % brix of the cows’ colostrum, % brix of the calves, and TPP. In multivariate regression analyses it was shown that pre-calving NEFA was the marker that most influenced post-calving cow markers and calf % brix, along with colostrum time and % brix of the colostrum (P= 0.0092; r2= 0.83). Cows with higher values NEFA in the prepartum had lower calcemic in the immediate postpartum period. Prepartum NEFA was the marker that most influenced the cows’ immediate postpartum period, being directly related to Ca serum, and also to the passive immunity transference.

Changes in 24-hour Urine Chemistry in Patients with Nephrolithiasis during Weight Loss with Glucagon-Like Peptide-1 Based Therapies

Background: Obesity is an independent risk factor for incident and recurrent nephrolithiasis. The impact of weight loss through glucagon-like peptide 1 (GLP-1) receptor agonists and dual GLP-1/ gastric inhibitory polypeptide receptor agonists (GLP-based therapies) on nephrolithiasis is not well-understood. This study examined the changes in 24-hour urine chemistry assessing for stone risk during weight loss through GLP-based therapies. Methods: This retrospective analysis identified adult stone formers followed at our academic institution’s weight wellness clinic between September 2015 and August 2023 and included patients with at least two 24-hour urine collections for stone risk assessment. 24-hour urine parameters before and during weight loss in patients on GLP-based therapies were compared. Results: Forty-four obese patients with nephrolithiasis experienced significant weight reduction (-6.6±7.3 kg, p&lt;0.001) over a median 1.1 years of follow-up with GLP-based therapies. During this period, there was a significant decrease in 24-hour urine oxalate (40±16 to 32±11 mg/day, p=0.002), sulfate (21±10 to 17±9 mmol/day, p=0005), and ammonium (35±22 to 29±15 mEq/day, p=0.01). There were non-significant changes in urine calcium, citrate, uric acid, pH, phosphorus, sodium, potassium, magnesium, chloride, creatinine or total volume. Additionally, there was no statistical difference in urine supersaturation indices with respect to calcium oxalate, calcium phosphate and uric acid. Conclusion: Our results indicate that weight loss through GLP-based therapies is not associated with pro-lithogenic changes in 24-hour urine chemistry in patients with nephrolithiasis, unlike what happens with other weight loss modalities.

Assessment of Sodium Butyrate’s Pharmacological Effects on Gentamicin-induced Nephrotic Disorders in a Rat Model

Background Sodium butyrate (SB) used to increase oxidative stress was reduced and the glutathione redox pathway was boosted. It inhibits proliferation, induction of differentiation, and induction or repression of gene expression and it has also anti-inflammatory action. This is endorsed for suppression of nephrotic symptoms. Objectives The present study was carried out to evaluate the nephroprotective activity of SB on gentamicin-induced nephrotoxicity in rats. Materials and Methods Present research work was designed to estimate pharmacological potential of SB in gentamicin-induced nephrotic disorder. The pharmacological prospective was estimated in gentamicin-induced rats through the oral administration of SB formulation 200 mg/kg and 300 mg/kg BW. Results The study observed that the SB significantly protects the kidneys from gentamicin-induced nephrotic disorders. Gentamicin 100 mg/kg for 7 days was used for induction of nephrotoxicity in Wistar rats by intraperitoneal administration. The administration of SB was observed to decrease the occurrence of glomerular congestion, vascular congestion, epithelial desquamation, inflammatory cell build-up, and kidney cell necrosis induced by gentamicin. The dose of SB maintained the gentamicin-induced increased creatinine (0.62±0.05), serum urea (18.10±0.79), uric acid (2.10±0.28), and blood urea nitrogen (BUN) (17.56±0.55) levels. This fact is further sustained by the histopathological examinations. Conclusion Sodium butyrate formulation with antinephrotic activity in maintaining uremic solutes such as urea, uric acid, creatinine, BUN, ketone, urobilinogen, glucose, specific gravity, and urine pH in Wistar rats with gentamicin-induced glomerulonephritis (GN). The SB was administered to the animals at doses of 200 and 300 mg/kg body weight. Pretreatment with the drug showed promising results in maintaining elevated parameters in nephritic rats within a short duration.

Optimizing Antibiotic Treatment for Urinary Tract Infections Secondary to Escherichia coli in Elderly Diabetic Patients: Considering Age and Blood Glucose Control

Introduction: This study aimed to examine the susceptibility profile of Escherichia coli in urinary tract infections (UTIs) among elderly diabetic patients to support judicious and evidence-based antibiotic use. Methods: From January 2021 to December 2022, urine culture results were analyzed to determine the distribution of pathogens, especially E. coli, and their drug susceptibility. Results: E. coli infection was the most prevalent infection in elderly diabetic patients with UTIs, accounting for 32.6% of cases. Moreover, this bacterium’s multiple resistance rate (38.3%) was significantly higher than other bacteria’s multiple resistance rate (χ2 = 81.644, p < 0.05). Compared to older diabetic patients with optimal glucose control (HbA1c ≤7.0%), patients with poor glycemic control (HbA1c >7.0%) had lower resistance rates to lactams, and urine pH values were higher (p < 0.05). Conclusion: The most common cause of UTIs is E. coli, with advanced age and diabetes being the main risk factors. To optimize UTI treatment safety and efficacy, antibiotics should be administered based on the patient’s age and blood glucose control.

Effect of D,L methionine and ammonium chloride on urine acidification, urinary fractional excretion of calcium, and blood bicarbonate in clinically healthy goats.

Urinary acidification with ammonium chloride (AC) for urolith dissolution is a common treatment for goats with urolithiasis. Studies have reported increased fractional excretion of calcium (FECa) following AC administration, which could increase calcium-based urolithiasis. D,L methionine (MET) may result in similar acidification with less calcium excretion. To compare the effects of orally administered MET and AC on urine and blood pH, FECa, and blood HCO3- concentrations in male goats. Prospective, randomized, crossover study. 12 healthy, 5-to-6-month-old Boer-cross wethers were administered 200 mg/kg of AC or MET orally for 14 days with a 7-day washout period between trials. Venous blood and urine samples were collected every 2 days. The effects of treatment and treatment day on urine and blood pH, HCO3-, and FECa were assessed using linear mixed models. Ammonium chloride and MET lowered least squares means (LSM) urine pH on day 6 (LSM, 7.49; 95% CI, 6.44 to 8.54), 8 (LSM, 7.78; 95% CI, 6.73 to 8.83), and 10 (LSM, 7.53; 95% CI, 6.49 to 8.58) when compared to day 0 (LSM, 8.23; 95% CI, 7.18 to 9.28). Some goats' urine indicated acidification (pH < 7.0) in the first phase of the trial; however, for the entire trial, a significant treatment effect was not detected on urine pH, blood pH, blood HCO3- or log10 FECa. Ammonium chloride and MET acidified urine of some goats. Dietary cation-anion difference should be considered when treating healthy goats to acidify their urine.

Urinary metabolic profile and its predictive indexes after MSG consumption in rat.

Monosodium glutamate (MSG) is a widely used food additive with conflicting evidence regarding its potential effects on human health, with proposed relevance for obesity and metabolic syndrome (MetS) or chronic kidney disease. As being able to accurately quantify the MSG dietary intake would help clarify the open issues, we constructed a predictive formula to estimate the daily intake of MSG in a rat model based on the urinary metabolic profile. Adult male Wistar rats were divided into groups receiving different daily amounts of MSG in drinking water (0.5, 1.5, and 3.0 g%), no MSG, and MSG withdrawal after 3.0% MSG treatment for 4 weeks. We then analyzed 24-hour urine samples for chemistries and metabolites using 1H NMR spectrometry and observed a strong correlation between urine pH, sodium, bicarbonate, alpha-ketoglutarate, citrate, fumarate, glutamate, methylamine, N-methyl-4-pyridone-3-carboxamide, succinate, and taurine and the daily MSG intake. Following the multiple linear regression analysis a simple formula model based on urinary Na+, citrate, and glutamate was most accurate and could be validated for estimating daily MSG intake. In conclusion, we propose that the daily MSG intake correlates with urinary metabolites in a rat model and that this new tool for monitoring the impact of MSG on health measures.

Assessing the Influence of Urine pH on the Efficacy of Ciprofloxacin and Fosfomycin in Immunocompetent and Immunocompromised Murine Models of Escherichia coli and Klebsiella pneumoniae Infection in the Lower Urinary Tract.

In vitro studies have suggested that acidic pH may reduce and increase the efficacy of ciprofloxacin and fosfomycin, respectively, when used to treat Escherichia coli and Klebsiella pneumoniae infections. We assessed the effects of acidic, neutral, and alkaline urine pH on the efficacy of optimized ciprofloxacin and fosfomycin dosages in UTI murine model of E. coli and K. pneumoniae. Immunocompetent and immunocompromised mice with adjusted urine pH were inoculated with E. coli and K. pneumoniae strains, and the efficacy was assessed based on the bacterial concentrations in tissues and fluids at 72 h, with respect to untreated controls. At acidic urine pH, both antimicrobials were effective, achieving similar reductions in E. coli concentrations in the kidneys in immunocompetent and immunocompromised mice and in K. pneumoniae in immunocompetent mice. At a neutral urine pH, both therapies reduced the presence of E. coli in the kidneys of immunocompetent mice. However, in immunocompromised mice, antimicrobials were ineffective at treating E. coli infection in the kidneys at a neutral urine pH and showed reduced efficacy against K. pneumoniae at both acidic and neutral urine pH. The results showed no correlation between urine pH and antimicrobial efficacy, suggesting that the reduced effectiveness is associated with the animals' immunocompetence status.

Daily and Weekly Urine Variations in Bacterial Growth Susceptibility in Postmenopausal Women With no History of Urinary Tract Infection: A Pilot Study

ObjectivesTo evaluate bacterial growth in the bladder as a major virulence factor during urinary tract infections (UTIs), we assessed the variability of uropathogenic bacterial growth in urine samples over multiple timepoints from three postmenopausal women with no history of UTI. MethodsFollowing IRB approval, postmenopausal women who never had a UTI provided mid-stream urine samples three times daily (8 a.m., 12 p.m. and 4 p.m.), twice a week over two weeks, as well as dietary intake logs. Each sample was studied for pH and bacterial growth using three uropathogenic Escherichia coli (E.coli) strains (LRPF007, KE40, UTI89), one uropathogenic Enterococcus faecalis strain (HRH40), and one non-pathogenic E. coli strain (W3110). ResultsSimilar mean growth yields were observed for the uropathogenic strains (mean ∆OD600 = 0.1 – 0.13) with high variability (standard deviation (SD) = 0.13 – 0.28) and lower mean growth for the non-pathogenic strain (mean ∆OD600 = 0.05). Urine from each individual at different collection times never had the same bacterial growth potential for any bacterial strain. There were significant associations between urine pH decrease with higher fat (p=0.017), vitamin D (p=0.02), magnesium (p=0.049), fluid (p=0.013), and ash (p=0.01) intake. ConclusionsMajor variations were observed in the bacterial growth response in the urine of the same individuals. These variations imply a requirement for a normalization procedure, e.g., growth in synthetic urine, for analysis of bacterial growth in urine. There were significant associations between decreased urine pH and several nutrients found in foods that are classified as highly acidic.