Association Between Sexually Transmitted Infections and the Urine Culture.

Introduction: Bacterial urinary tract infections (UTI) and some sexually transmitted infections (STI) can have overlapping signs and symptoms or nonspecific findings, such as pyuria on urinalysis. Furthermore, results from the urine culture and the nucleic acid amplification test for an STI may not be available during the clinical encounter. We sought to determine whether gonorrhea, chlamydia, and trichomoniasis are associated with bacteriuria, information that might aid in the differentiation of STIs and UTIs. Methods: We used multinomial logistic regression to analyze 9,650 encounters of female patients who were aged ≥18 years and who underwent testing for STIs. The ED encounters took place from April 18, 2014-March 7, 2017. We used a multivariable regression analysis to account for patient demographics, urinalysis findings, vaginal wet-mount results, and positive or negative (or no) findings from the urine culture and testing for Neisseria gonorrhoeae, Chlamydia trachomatis, or Trichomonas vaginalis. Results: In multivariable analysis, infection with T vaginalis, N gonorrhoeae, or C trachomatis was not associated with having a urine culture yielding 10,000 or more colony-forming units per mililiter (CFU/mL) of bacteria compared with a urine culture yielding less than 10,000 CFU/mL or no urine culture obtained. The diagnosis of a UTI in the ED was not associated with having a urine culture yielding 10,000 or more CFU/mL compared with a urine culture yielding less than 10,000 CFU/mL. Conclusion: After adjusting for covariates, no association was observed between urine culture results and testing positive for trichomoniasis, gonorrhea, or chlamydia. Our results suggest that having a concurrent STI and bacterial UTI is unlikely.

Urinary calprotectin as a diagnostic tool for detecting significant bacteriuria.

Pyuria in dipstick examination serves as the most widespread screening tool for urinary tract infections (UTI). The absence of pyuria, however, does not exclude UTI. We investigated the diagnostic value of urinary calprotectin, a mediator protein of the innate immune system, which is released by leukocytes, for the detection of UTI and compared it with dipstick pyuria. Since even low numbers of leukocytes in the urine significantly increase urinary calprotectin concentrations, calprotectin might be a more sensitive marker than pyuria detected by dipstick. All 162 patients were prospectively included and underwent a urine dipstick, urine culture, quantification of proteinuria and determination of calprotectin in the urine. Urinary calprotectin was determined using an enzyme-linked immunosorbent assay (ELISA). UTI was defined as urine cultures with detection of one or a maximum of two uropathogenic bacteria with ≥ 105 colony-forming units per millilitre (CFU/ml). Exclusion criteria were acute kidney injury, chronic renal insufficiency and tumors of the urinary tract. 71 (43.8%) patients had a UTI. Of the 91 patients without UTI, 23 had a contamination and 19 had evidence of ≥ 105 CFU/ml considered to be asymptomatic bacteriuria. The median calprotectin concentration in patients with UTI and pyuria was significantly higher than in patients with UTI and without pyuria (5510.4 vs. 544.7 ng/ml). In ROC analyses, calprotectin revealed an area under the curve (AUC) of 0.70 for the detection of significant bacteriuria. Pyuria in dipstick examinations provided an AUC of 0.71. There was no significant difference between these AUCs in the DeLong test (p = 0.9). In patients with evidence of significant bacteriuria but without pyuria, a significantly higher calprotectin concentration was measured in the urine than in patients with neither pyuria nor UTI (544.7 ng/ml vs 95.6 ng/ml, p = 0.029). Urinary calprotectin is non-inferior to dipstick pyuria in the detection of UTI.

Reviving Sternheimer stain: A single-center retrospective study to detect the diagnostic utility of urinary tract infections in the emergency department.

INTRODUCTION: Qualitative urinalysis using the Sternheimer stain is a common method in Japan for identifying bacteriuria, but there is a lack of studies examining its test characteristics. In this study, we aimed to investigate the sensitivity and specificity of the Sternheimer stain for urine culture results and compare it with the sensitivity and specificity of the Gram stain. Our goal was to determine the usefulness of the Sternheimer stain in identifying bacteriuria. PATIENTS AND METHODS: Among 986 patients aged 16 years or older from whom samples for both urinalysis and urine culture were obtained at the emergency room of Tenri Hospital from January 2019 to December 2019, 342 patients with pyuria, defined as the presence of 10 or more white cells per cubic millimeter in a urine specimen, who had not received prior antimicrobial therapy were included. Urine cultures were used for comparison to determine the sensitivity and specificity of Sternheimer and Gram stain in this patient group. A positive Sternheimer stain result was defined as bacteriuria ≥ (1+), and that of Gram stain was defined as ≥ 1/1 field of high-power ( × 1000) oil immersion. RESULTS: Using urine culture results for comparison, the sensitivity of Sternheimer stain was 92.2%, the specificity was 48.5%, the positive likelihood ratio was 1.79, and the negative likelihood ratio was 0.16. DISCUSSION: Sternheimer stain is a rapid and useful method to exclude bacteriuria in a group of patients with pyuria in the emergency department.

The diagnostic performances of the Atellica® 1500 automated urinalysis system for ruling out bacterial urinary tract infection.

Urinary tract infection (UTI) is one of the most common diseases occurring in both hospitalized and community subjects. Urine culture is the gold standard test for the diagnosis of UTI, but approximately 80% are negative. The aim of this study was to evaluate the performance of the automated urinalysis system Atellica® 1500 (Siemens Healthineers, Erlangen, Germany) as screening tool for ruling out UTI. A total of 5,490 urine specimens from outpatients, that had simultaneous requests for urinalysis and urine culture, were evaluated. Of the 5,490 samples, 833 (15.2 %) resulted positive for urine culture. Among UTI-related parameters, bacterial count was considered the most apt to be diagnostic of subjects affected by UTI. Using a cutoff value for bacteria count equal to 180 elements/µL, Atellica® 1500 detected bacteriuria with diagnostic sensitivity (Se) of 88.1 %, diagnostic specificity (Sp) of 82.1 %, and negative predictive value (NPV) of 95.2 %. Comparing our results with the literature's data, we observed that our Se and NPV were lower, while our Sp was higher. Our data showed that the Atellica® 1500 system detected bacteria with satisfactory analytical performance, but the results obtained do not make it a reliable tool for excluding UTI with urinalysis.

Rapid Screening of Urinary Tract Infection Using Microfluidic Inertial-Impedance Cytometry.

Urinary tract infection (UTI) diagnosis based on urine culture for bacteriuria analysis is time-consuming and often leads to wastage of hospital resources due to false-positive UTI cases. Direct cellular phenotyping (e.g., RBCs, neutrophils, epithelial cells) of urine samples remains a technical challenge as low cell concentrations, and urine characteristics (conductivities, pH, microbes) can affect the accuracy of cell measurements. In this work, we report a microfluidic inertial-impedance cytometry technique for label-free rapid (<5 min) neutrophil sorting and impedance profiling from urine directly. Based on size-based inertial focusing effects, neutrophils are isolated, concentrated, and resuspended in saline (buffer exchange) to improve consistency in impedance-based single-cell analysis. We first observed that both urine pH and the presence of bacteria can affect neutrophil high-frequency impedance measurements possibly due to changes in nucleus morphology as neutrophils undergo NETosis and phagocytosis, respectively. As a proof-of-concept for clinical testing, we report for the first time, rapid UTI testing based on multiparametric impedance profiling of putative neutrophils (electrical size, membrane properties, and distribution) in urine samples from non-UTI (n = 20) and UTI patients (n = 20). A significant increase in cell count was observed in UTI samples, and biophysical parameters were used to develop a UTI classifier with an area under the receiver operating characteristic curve of 0.84. Overall, the developed platform facilitates rapid culture-free urine screening which can be further developed to assess disease severity in UTI and other urologic diseases based on neutrophil electrical signatures.

Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment.

OBJECTIVES: Evaluation of haem dipstick pad, urine protein, urine pH and urine protein:creatinine ratio results as a marker of bacteriuria in dogs and cats with inactive urine sediment. MATERIALS AND METHODS: Cats and dogs with contemporaneous urine dipstick, microscopic sediment analysis and microbiological culture and sensitivity results over a four-year period (2016 to 2020) were retrospectively identified. Dogs and cats with active urine sediments (at least five erythrocytes and/or five leukocytes per high-power field) and/or spermaturia were excluded. Association between urine pH, haem dipstick result, protein dipstick result and urine protein:creatinine ratio with bacteriuria were evaluated using binary logistic regression analysis. Likelihood ratios for bacteriuria were calculated at different diagnostic thresholds. RESULTS: A total of 668 and 169 dog and cat urine samples were included. Of these, 166 dogs (25%) had a positive urine culture, whilst only 29 cats (17%) had a positive urine culture. In dogs and cats, any positive haem dipstick result was significantly associated with bacteriuria, although only a ≥4+ haem positive result in dogs was associated with a small increase in the likelihood of a positive urine culture, and positive likelihood ratios did not support the use of haem dipstick results as a screening test for bacteriuria in cats. pH, urine protein:creatinine ratio and protein dipstick results were not associated with bacteriuria. CLINICAL SIGNIFICANCE: Our findings provide proof of concept that haem dipstick pad results in dogs with inactive sediment and without spermaturia might be useful as a screening test for bacteriuria, although further studies are required to confirm these findings.

Leukocyte Esterase and Nitrite Urine Reagent Strip Utility Under Altered Assay Conditions in Dogs.

The study evaluated leukocyte esterase (LE) and nitrite reagent pad usefulness in canine urine using multiple time endpoints and decision thresholds. Whole and sedimented urine samples from 116 client-owned dogs were analyzed with reagent strips from four manufacturers. Results for LE and nitrite were recorded every 30 s up to 150 s using "trace" and "+" positive thresholds and compared to microscopic urine sediment analysis and culture results. Sedimented urine assessed at 150 s with a "trace" positive threshold for LE had significantly or trending higher sensitivity (brand dependent) for pyuria detection compared with manufacturer recommendations. Using these parameters, LE sensitivity and negative likelihood ratio were 66.67-89.47%, and 0.13-0.37, respectively. Following manufacturer recommendations, LE specificity and positive likelihood ratio were 96.91-100% and 17.02-30.63, respectively. Nitrite performance for pyuria and bacteriuria detection was poor for all conditions. LE reagent pads are a useful screening test for pyuria detection using sedimented urine and a "trace" positive threshold at 150 s, whereas LE use with traditional manufacturer recommendations is a good confirmatory test for pyuria detection. Nitrite reagent pads are not useful for pyuria or bacteriuria detection.

Bacteriuria in Pregnant Adolescents and Behavioral Risk Factors: A Cross-Sectional Study at a Brazilian Teaching Hospital.

INTRODUCTION: Bacteriuria during pregnancy is a frequent and important cause of morbidity and complications. Data on its occurrence in pregnant adolescents are still scarce. METHODS: A cross-sectional study was conducted at a tertiary teaching hospital in São Paulo, Brazil. All adolescents (≤18 years) who came for prenatal care between January 2010 and January 2016 were included. Sociodemographic characteristics, medical history, obstetric history, and the results of laboratory tests were selected. A urine sample was aseptically collected from each patient to undergo microscopic and culture analysis. RESULTS: A total of 388 pregnant adolescents averaging 15.30 ± 1.24 years of age were included. The frequency of bacteriuria in this group was 17.01% (66/388). The lack of sports practice (OR = 8.65; 95% CI, 1.09-68.39), the fact that pregnancy was desired (OR = 2.17; 95% CI, 1.08-4.34), and the use of hormonal methods of contraception (OR = 2.46; 95% CI, 1.04-5.84) turned out to be independent risk factors for bacteriuria. Protective factors were identified as late coitarche (OR = 0.75; 95% CI, 0.57-0.98) and a urine culture analysis at a later gestational age (OR = 0.94; 95% CI, 0.90-0.98). The most often isolated pathogens were Escherichia coli (49%) and Streptococcus agalactiae (18%). CONCLUSION: Bacteriuria among pregnant adolescents is a relatively common condition. The infection risk of the urinary tract was increased by physical inactivity and seemingly by the influence of behavioral and sexual factors. Such results can help to identify patients at risk, favoring the early diagnosis of urinary tract infections and optimizing prenatal care.

Asymptomatic Bacteriuria, antimicrobial susceptibility pattern and associated risk factors among pregnant women attending antenatal care in Assosa General Hospital, Western Ethiopia.

BACKGROUND: Asymptomatic bacteriuria is a common problem in pregnant women and about 40% of women with untreated asymptomatic bacteriuria during pregnancy develop pyelonephritis, which might lead to low birth weight, premature rupture of membranes, and preterm labour. Therefore, this study aimed to assess the prevalence of asymptomatic bacteriuria, antimicrobial susceptibility pattern of the isolates among pregnant women attending the antenatal care of Assosa general hospital, western Ethiopia. METHODS: A facility-based cross-sectional study was conducted from January to February 2019. Two hundred and eighty-three pregnant women with no symptoms of urinary tract infections participated in the study. Bacterial isolates were identified as per the standard bacteriological procedure using colony characteristics, Gram-staining, and series of biochemical tests. Antimicrobial susceptibility test was carried out by Kirby- Bauer disk diffusion technique on Muller-Hinton agar medium and the diameter of zone of inhibition was interpreted according to Clinical Laboratory Standard Institute guidelines. RESULTS: The overall prevalence of asymptomatic bacteriuria among pregnant women in this study was 13.78% (i.e. 39 out of 283 urine samples were positive for bacterial isolates). E. coli was the most predominant isolate (53.8%) followed by K. pneumoniae (17.95%), S. aureus (15.4%), and coagulase-negative staphylococci (12.8%). Gram-negative bacteria were highly resistant to tetracycline (96.4%), and ampicillin (90.5%). CONCLUSION: Significant bacteriuria was observed in asymptomatic pregnant women. A large number of the bacterial isolates were resistant to the commonly used antimicrobial drugs.

Maternal Complications and Adverse Pregnancy Outcomes among Pregnant Women who Acquired Asymptomatic Bacteriuria in Addis Ababa, Ethiopia.

In this study, we aimed to document adverse pregnancy outcomes and maternal complications among pregnant women who acquired asymptomatic bacteriuria in Addis Ababa, Ethiopia. We used hospital-based prospective cohort study design in which we followed 44 pregnant women with asymptomatic bacteriuria confirmed by urine culture result of ≥105cfu/ml of urine. We documented adverse pregnancy outcomes and maternal complications in terms of frequency, percentage, mean, and standard deviation. Additionally, we used Pearson's correlation coefficient to investigate associations of selected variables with perinatal death as one of adverse pregnancy outcomes. Of the 44 pregnant women enrolled in the study, complete data was collected from 43 participants with one lost to follow-up. Six (14%) of women developed fever and were treated with antibiotic during pregnancy, 26 (60.5%) delivered with cesarean section, two (4.3%) perinatal deaths within seven days of delivery, one miscarriage, and 4 (9.3%) newborns were found underweight. The mean birth weight of the newborns was 3.1 kg ± 0.60. Almost half 21(48.8%) were born before 37 weeks of gestational age. Fourteen (32.6%) of newborns were born asphyxiated. Twenty-two (51.2%) of newborns developed early neonatal fever within 48 hours of delivery and treated with antibiotic. Correlation coefficient analysis revealed that weight and gestational age of newborns at birth, Apgar score at 1st and 5th minutes of birth and miscarriage were positively correlated and significantly associated with perinatal death. The occurrence of unsought pregnancy outcomes were frequent, and substantial number of pregnant women developed maternal complications. Therefore, screening pregnant women for asymptomatic bacteriuria and treating may reduce the possible maternal complications and adverse pregnancy outcomes.

A Randomized Clinical Trial of Standard versus Expanded Cultures to Diagnose Urinary Tract Infections in Women.

PURPOSE: We compared urinary tract infection (UTI) symptom resolution rates at 7-10 days in symptomatic women randomized to treatment based on standard urine culture (SUC) versus expanded quantitative urine culture (EQUC) results. MATERIALS AND METHODS: Women ≥18 years old who responded "yes" to "do you feel you have a UTI?" agreed to urethral catheterization and followup. Symptoms were assessed using the validated UTI Symptom Assessment (UTISA) questionnaire. Culture method was randomized 2:1 (SUC:EQUC); antibiotics were prescribed to women with positive cultures. The primary outcome, UTI symptom resolution, was determined 7-10 days following enrollment on all participants regardless of treatment. RESULTS: Demographic data were similar between groups. Of the SUC and EQUC groups 63% and 74% had positive cultures (p=0.10), respectively. Of participants with positive cultures 97% received antibiotics. Primary outcome data were provided by 215 of 225 participants (SUC 143 [95%], EQUC 72 [97%]). At the primary outcome assessment, 64% and 69% in the SUC and EQUC groups, respectively, reported UTI symptom resolution (p=0.46); UTISA scores improved from baseline in the EQUC arm compared to the SUC arm (p=0.04). In the subset of women predominated by non-Escherichia coli (76), there was a trend toward more symptom resolution in the EQUC arm (21%, p=0.08). CONCLUSIONS: Symptom resolution was similar for the overall population (E. coli and non-E. coli) of women treated for UTI symptoms based on SUC or EQUC. Although the sample size limits conclusions regarding the utility of EQUC in women with non-E. coli uropathogens, the detected trend indicates that this understudied clinical subset warrants further study.

Does the duration between urine culture and percutaneous nephrolithotomy affect the rate of systemic inflammatory response syndrome postoperatively?

This study aimed to evaluate the preoperative and intraoperative factors that may cause systemic inflammatory response syndrome (SIRS) after percutaneous nephrolithotomy (PCNL) and to investigate the effect of the duration between urine culture (UC) and operation on postoperative SIRS. Three hundred and fifty-six patients who had PCNL between January 2015 and June 2019 were retrospectively included in the study. UC was obtained from all patients before the operation and during the puncture at the beginning of the operation. Postoperatively, patients were closely monitored for fever and other signs of SIRS. The post-PCNL SIRS incidence was 7%. In univariable and multivariable analyses, the rate of ipsilateral PCNL history, recurrent urinary tract infection (UTI) history, operation time and the length of hospital stay were significant predictive factors for SIRS. The duration between UC and PCNL was not a statistically significant variable in both univariable and multivariable analysis. Our study concluded that the duration between UC and PCNL is not an influential factor for post-PCNL SIRS. Clarifying this issue may be possible with prospective studies in which the effects of factors such as ipsilateral PCNL history and recurrent urinary tract infection history which has been proven to be risk factors for post-PCNL SIRS are restricted.

Urinary cytokines in women with refractory detrusor overactivity: A longitudinal study of rotating antibiotic versus placebo treatment.

Over 50% of women with detrusor overactivity (DO), who do not respond to therapy have been shown to have bacteriuria, which may stimulate the release of inflammatory cytokines than can enhance nerve signalling, leading to symptoms of urgency. This study made use of a consecutive series of urine samples collected from women with refractory DO, who participated in a clinical trial of rotating antibiotic therapy. The aim was to determine the effect of bacteriuria and antibiotic treatment on the levels of urinary cytokines, and to correlate the cytokine concentration with patient outcome measures relating to urgency or urge incontinence. The urinary cytokines chosen were IL-1α, IL-1 receptor antagonist, IL-4, IL-6, IL-8, IL-10, CXCL10 (IP-10), MCP-1 and TNF-α. The presence of bacteriuria stimulated a significant increase in the concentrations of IL-1α (P 0.0216), IL-1 receptor antagonist (P 0.0264), IL-6 (P 0.0003), IL-8 (P 0.0043) and CXCL-10 (P 0.009). Antibiotic treatment significantly attenuated the release of IL-1α (P 0.005), IL-6 (P 0.0027), IL-8 (P 0.0001), IL-10 (P 0.049), and CXCL-10 (P 0.042), i.e. the response to the presence of bacteria was less in the antibiotic treated patients. Across the 26 weeks of the trial, antibiotic treatment reduced the concentration of five of the nine cytokines measured (IL-1α, IL-6, IL-8, IL-10 and CXCL-10); this did not reach significance at every time point. In antibiotic treated patients, the urinary concentration of CXCL-10 correlated positively with four of the six measures of urgency. This study has shown that cytokines associated with activation of the innate immune system (e.g. cytokines chemotactic for or activators of macrophages and neutrophils) are reduced by antibiotic therapy in women with refractory DO. Antibiotic therapy is also associated with symptom improvement in these women, therefore the inflammatory response may have a role in the aetiology of refractory DO.

Prediction of urine culture results by automated urinalysis with digital flow morphology analysis.

To investigate the association between the results of urinalysis and those of concurrent urine cultures, and to construct a prediction model for the results of urine culture. A total of 42,713 patients were included in this study. Patients were divided into two independent groups including training and test datasets. A novel prediction algorithm, designated the UTOPIA value, was constructed with the training dataset, based on an association between the results of urinalysis and those of concurrent urine culture. The diagnostic performance of the UTOPIA value was validated with the test dataset. Six variables were selected for the equation of the UTOPIA value: age of higher UTI risk [odds ratio (OR), 2.069125], female (OR, 1.400648), nitrite (per 1 grade; OR, 3.765457), leukocyte esterase (per 1 grade; OR, 1.701586), the number of WBCs (per 1 × 106/L; OR, 1.000121), and the number of bacteria (per 1 × 106/L; OR, 1.004195). The UTOPIA value exhibited an area under the curve value of 0.837 when validated with the independent test dataset. The UTOPIA value displayed good diagnostic performance for predicting urine culture results, which would help to reduce unnecessary culture. Different cutoffs can be used according to the clinical indication.

Accuracy of urine flow cytometry and urine test strip in predicting relevant bacteriuria in different patient populations.

BACKGROUND: Urinary tract infection (UTI) is diagnosed combining urinary symptoms with demonstration of urine culture growth above a given threshold. Our aim was to compare the diagnostic accuracy of Urine Flow Cytometry (UFC) with urine test strip in predicting bacterial growth and in identifying contaminated urine samples, and to derive an algorithm to identify relevant bacterial growth for clinical use. METHODS: Species identification and colony-forming unit (CFU/ml) quantification from bacterial cultures were matched to corresponding cellular (leucocytes/epithelial cells) and bacteria counts per µl. Results comprise samples analysed between 2013 and 2015 for which urine culture (reference standard) and UFC and urine test strip data (index tests, Sysmex UX-2000) were available. RESULTS: 47,572 urine samples of 26,256 patients were analysed. Bacteria counts used to predict bacterial growth of ≥105 CFU/ml showed an accuracy with an area under the receiver operating characteristic curve of > 93% compared to 82% using leukocyte counts. The relevant bacteriuria rule-out cut-off of 50 bacteria/µl reached a negative predictive value of 98, 91 and 89% and the rule-in cut-off of 250 bacteria/µl identified relevant bacteriuria with an overall positive predictive value of 67, 72 and 73% for microbiologically defined bacteriuria thresholds of 105, 104 or 103 CFU/ml, respectively. Measured epithelial cell counts by UFC could not identify contaminated urine. CONCLUSIONS: Prediction of a relevant bacterial growth by bacteria counts was most accurate and was a better predictor than leucocyte counts independently of the source of the urine and the medical specialty ordering the test (medical, surgical or others).

Characteristics of Asymptomatic Bacteriuria in Patients with Chronic Kidney Disease: A Tertiary Care Hospital Experience from a Developing Country.

Asymptomatic bacteriuria (ASB) is the isolation of bacteria in a urine sample from individuals who do not have any symptoms of a urinary tract infection (UTI). The outcomes of ASB in chronic kidney disease (CKD) patients are poorly understood in Pakistan. This study aimed to determine the characteristics of ASB and antibiotic susceptibility pattern among patients with CKD. A cross-sectional retrospective survey was administered to perform this study in a tertiary care hospital, to include all CKD patients. The study included all those patients with a diagnosis of CKD with no signs and symptoms of UTI present, and showing the growth of an organism in urine culture. A total of 175 urine cultures were observed retrospectively meeting the inclusion criteria through nonprobability consecutive sampling. Out of 175 urine cultures observed, mean age of 58.56 ± 16.81, 71% of them were females, 55% were diabetic, and 22% had a family history of CKD. Escherichia coli, Enterococcus, Klebsiella, Pseudomonas, Enterobacter, and streptococcal species were the most often isolated microbes. A total of 17 subjects got dual bacterial growth in their cultures which were having Enterococcus species as the most common organism. Twenty-three cultures were identified as pandrug resistant (13.14%), only sensitive to colomycin/polymyxin B. The susceptibilities of these organisms were contrasting to traditional antibiotics known to treat UTIs empirically, hence demanding further screening and treatment protocols to be defined for minimizing the irrational choice of antibiotics.

Reevaluating the true diagnostic accuracy of dipstick tests to diagnose urinary tract infection using Bayesian latent class analysis.

OBJECTIVE: Previous studies on diagnostic accuracy of dipstick testing for leukocyte esterase (LE) and nitrite to diagnose urinary tract infection (UTI) had used urine culture, which is an imperfect gold standard. Estimates of diagnostic accuracy obtained using the classical gold standard framework might not reflect the true diagnostic accuracy of dipstick tests. METHODS: We used the dataset from a prospective, observational study conducted in the emergency department of a teaching hospital in southern India. Patients with a clinical suspicion of UTI underwent dipstick testing for LE and nitrite, urine microscopy, and urine culture. Based on the results of urine microscopy and culture, UTI was classified into definite, probable, and possible. Patients with microscopic pyuria and a positive urine culture were adjudicated as definite UTI. Unequivocal imaging evidence of emphysematous pyelonephritis or perinephric collections was also considered definite UTI. We estimated the diagnostic accuracy of LE and nitrite tests using the classical analysis (assuming definite UTI as gold standard) and two different Bayesian latent class models (LCMs; 3-tests in 1-population and 2-tests in 2-populations models). RESULTS: We studied 149 patients. Overall, 64 (43%) patients had definite, 76 (51%) had probable, and 2 (1.3%) had possible UTI; 7 (4.6%) had alternate diagnoses. In classical analysis, LE was more sensitive than nitrite (87.5% versus 70.5%), while nitrite was more specific (24% versus 58%). The 3-tests in 1-population Bayesian LCM indicated a substantially better sensitivity and specificity for LE (98.1% and 47.6%) and nitrite (88.2% and 97.7%). True sensitivity and specificity of urine culture as estimated by the model was 48.7% and 73.0%. Estimates of the 2-tests in 2-populations model were in agreement with the 3-tests in 1-population model. CONCLUSIONS: Bayesian LCMs indicate a clinically important improvement in the true diagnostic accuracy of urine dipstick testing for LE and nitrite. Given this, a negative dipstick LE would rule-out UTI, while a positive dipstick nitrite would rule-in UTI in our study setting. True diagnostic accuracy of urine dipstick testing for UTI in various practice settings needs reevaluation using Bayesian LCMs.

Evaluation of matrix assisted laser desorption ionisation-time of flight mass spectrometry in direct identification of bacteriuria from urine samples.

Objective: The use of matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI) directly on urine can significantly improve turnaround time for diagnosing urinary tract infection (UTI). The present study was planned to compare the performance of MALDI directly on urine samples with conventional urine culture and evaluate an algorithm using a combination of significant pyuria and MALDI directly on urine samples as a screening method for diagnosing UTI. Materials and Methods: A total of 1000 urine samples from patients with symptoms suggestive of UTIs were analysed. Urine microscopy, urine culture and MALDI were performed simultaneously on all the samples. Results: MALDI correctly identified the microorganisms in 73.83% monomicrobial samples. In culture showing a mixed growth of two and more than three organisms, MALDI was able to identify one microorganism in 27.58% and 15.78% of samples, respectively. There were no peaks by MALDI in 93.53% of 464 sterile samples. The sequential algorithm using urine microscopy and MALDI could correctly identify UTI in 66.23% cases. Conclusion: MALDI can be utilised to rule out bacteriuria in >93% of sterile urine samples. The combination of significant pyuria and direct MALDI as screening method to diagnose UTI (whether monomicrobial or polymicrobial) was not found to be superior than using direct MALDI on urine samples alone.

Clinical Utilization of Blood and Urine Cultures and Incidences of Bacteremia and Bacteriuria in a Hospital in Thailand.

BACKGROUND To effectively treat sepsis and urinary tract infection (UTI), blood and urine cultures should be used appropriately and relative to incidences of bacteremia and bacteriuria. This study aimed to investigate the use of blood and urine cultures and incidences of bacteremia and bacteriuria in a hospital in Thailand. MATERIAL AND METHODS Medical records of patients admitted from 2016 to 2018 were randomly selected and data in the records were anonymously extracted for investigation. RESULTS From 12 000 records, data on blood and urine cultures were extracted from 9% and 4% of them, respectively. The negative rate of blood culture was 87.48%. Bacteremia was detected in 10.22%. The positive rate of urine culture was 27.38% and the contamination rate was 31.26%. Escherichia coli was the most common cause of community-onset bacteremia and bacteriuria. Methicillin-resistant coagulase-negative staphylococci and Acinetobacter baumannii were the most common cause of hospital-acquired bacteremia while yeasts were the most common cause of hospital-acquired UTI. CONCLUSIONS A high negative rate of blood culture may result not only from its low sensitivity but also from liberal test use to identify sepsis in some conditions. Improper urine collection is the main problem with use of urine culture.

Diagnosis of bacterial urinary tract infection: Utility of urine myeloperoxidase concentration to predict urine culture results in dogs.

Suspected bacterial urinary tract infections (UTI) are a common cause of overuse and misuse of antimicrobials. A bedside diagnostic test that could accurately predict urine culture results would prevent antimicrobial overuse, but accurate biomarkers have not yet been identified in veterinary medicine. The objective of this study was to evaluate urine myeloperoxidase (uMPO) as a rapidly available, accurate marker to predict urine culture results. We hypothesized that uMPO would be higher in dogs with a positive urine culture than in dogs with a negative urine culture, and that uMPO could be used to aid in the accurate diagnosis of significant bacteriuria. Urine samples were collected from a veterinary university clinical pathology lab. uMPO concentration was measured using a commercially available canine myeloperoxidase (MPO) enzyme-linked immunosorbent assay (ELISA). Following validation, samples from 98 dogs that had a urinalysis and urine culture performed as part of their diagnostic investigation were included. Forty-seven dogs had a negative urine culture and fifty-one dogs had a positive urine culture. uMPO levels were significantly higher in samples that had a positive culture (median 2.13 ng/ml; IQR 0.98-7.07) versus samples that had a negative culture (median 1.07 ng/ml; IQR 0.52-1.84)(p < 0.005). Based on receiver-operator characteristic, a cutoff of 0.55 ng/ml was chosen to maximize sensitivity and specificity. Using a cutoff of 0.55 ng/ml, uMPO had a sensitivity of 70% and specificity of 69% to determine the presence of a positive culture. However, the degree of overlap between groups may preclude the use of this test as a surrogate for urine culture in a clinical setting.