Preoperative urine culture with contaminants is not associated with increased risk for urinary tract infection after ureteroscopic stone treatment.

PURPOSE: We aimed to assess whether the presence of contaminants in the pre-operative urine culture (preop-UC) predicts postoperative urinary tract infection (postop-UTI) in patients undergoing elective ureteroscopy with laser lithotripsy. METHODS: A retrospective chart review was performed from 01/2019 to 12/2021 examining patients with unilateral stone burden ≤ 2 cm who underwent ureteroscopy with laser lithotripsy and had a preop-UC within 3 months. Positive, negative, contaminated, and polymicrobial definitions for UCs were established in accordance with current guidelines. Patients with positive and polymicrobial cultures were excluded. Postop-UTI was defined as the presence of urinary symptoms and a positive UC within 30 days of the procedure. Multivariable logistic regression models were utilized to evaluate risk factors for contamination in the preop-UC and the risk of postop-UTI. RESULTS: A total of 201 patients met the inclusion-exclusion criteria. Preop-UC was negative in 153 patients and contaminated in 48 patients. Significant contaminant-related factors included female gender and increased BMI. Postop-UTI was diagnosed in 3.2% of patients with negative preop-UCs and 4.2% of patients with contaminants, with no difference between groups (p = 0.67). The regression model determined that the presence of contaminants in preop-UC failed to predict postop-UTI (OR 0.69, p = 0.64). CONCLUSION: The presence of contaminants in preop-UCs is not associated with an increased risk of postop-UTIs after ureteroscopy. Our study supports that contaminants in the preop-UC can be interpreted as a negative UC in terms of postop-UTI risk stratification. Preoperative antibiotics should not be prescribed for patients undergoing uncomplicated ureteroscopy for stone surgery in the setting of a contaminated preop-UC.

Asymptomatic bacteriuria prior to partial and radical nephrectomy: To screen or not to screen? Results from the national and multicenter TOCUS database.

INTRODUCTION: In the era of increased bacterial resistance, the main strategy is to reduce the prescription of antibiotics when possible. Nowadays, it is highly recommended to screen for asymptomatic bacteriuria (ABU), prior to urological surgery with potential mucosal breach or urine exposure. Screening and treating urinary colonization is a strategy widely adopted before radical and partial nephrectomy but without any evidence. Our main end point in this study is to analyze the relationship between preoperative urine culture and the risk of postoperative febrile urinary tract infection (UTI) or surgical-site infection (SSI) in partial or radical nephrectomy patients. METHODS: We conducted a multicenter retrospective cohort study between January 2016 and January 2023 in 11 French tertiary referral hospitals (TOCUS database). We collected the data for 269 patients including several pre-, intra-, and post-operative variables that could potentially increase the risk of postoperative UTI and SSI including preoperative urinary culture results. RESULTS: The incidence rate of postoperative UTI and SSI was 8.9% in our study. After conducting a logistic multivariate analysis, a propensity score matching analysis, and a subgroup analysis, we found no significant correlation between the urine culture and the postoperative UTI risk [OR = 1.2 (0.5-2.7) (p = 0.7)]. Only the postoperative non-infectious complications were related to a higher risk of postoperative UTI [OR = 12 (4-37), p < 0.001)]. CONCLUSION: Our research shows that screening and treating for ABU prior to radical or partial nephrectomy seems to be unnecessary to prevent postoperative UTI and SSI.

Preliminary reading of antibiogram by microdilution for clinical isolates in urine culture.

PURPOSE: We evaluated a modification of automated antibiograms in urine cultures designed to facilitate the early interpretation of minimum inhibitory concentrations (MICs) and accelerate the targeted treatment of urinary tract infections (UTIs), METHODS: A prospective study was conducted of 309 isolates (219 Enterobacteriaceae, 75 Enterococcus spp., and 15 non-fermenting Gram-negative bacilli (NFGNB), and a retrospective study of 9 carbapenemase-producing clinical isolates from urine cultures. Colonies grown on conventional isolation plates were inoculated in MicroScan Walkaway system panels and incubated for 7 h, using a MicroScan AutoScan-4 plate reader for preliminary MIC determination by turbidimetry. Resulting antibiograms were compared with definitive antibiograms obtained after incubation for 17 h. RESULTS: Preliminary and definitive readings were concordant for 86.7% of Gram-positive cocci isolates (65/75), 61.6% of Enterobacteriaceae (135/219), and 53.3% of NFGNB. The agreement rate was greater than 90% for most antimicrobials against Gram-positive cocci (94.7% or more) and Enterobacteriaceae, (97.2% or more for 10 of 17 antibiotics) except with nitrofurantoin (89%). The agreement rate was 86.7% or more for most antibiotics against NFGNB apart from piperacillin/tazobactam, aztreonam, amikacin, and ciprofloxacin. Gram-negative bacilli showed the highest differences in MIC values between preliminary and definitive readings. CONCLUSIONS: A preliminary antibiogram reading may be useful in urine cultures to reduce the delay before targeted antibiotherapy, especially against Enterobacteriaceae and Gram-positive cocci, but not in cases of carbapenemase-producing NFGNB. Further local studies are warranted to evaluate the usefulness of this approach in relation to resistance rates.

Urinalysis is predictive for absence of urinary tract infection in men with and without catheters.

OBJECTIVES: To determine accuracy of negative urinalysis (UA) for predicting negative urine culture and the absence of urinary tract infection (UTI), and optimal urine culture growth cutoff for UTI diagnosis in men with and without urinary catheters. SUBJECTS AND METHODS: UAs with urine cultures within 1 week from adult men were identified and evaluated. Predictive values for the absence of UTI (absence of ≥1 of the following criteria: documentation of UTI diagnosis, antibiotic prescription, uropathogen presence on culture) were calculated. RESULTS: In total, 22 883 UAs were included. Negative UA had a high predictive value for negative urine culture (0.95, 95% confidence interval [CI]: 0.94-0.95) and absence of UTI (0.99, CI: 0.99-0.995) in the overall cohort. Negative UA also had a high predictive value for negative urine culture (0.93, CI: 0.90-0.95) and absence of UTI (0.99, CI: 0.98-0.999) in those with indwelling urinary catheters. The traditional threshold of culture growth of 100 000 colony-forming units (CFU)/mL did not capture 22% of UTIs. CONCLUSION: UA exhibits high predictive value for negative urine culture and absence of UTI in men, supporting a protocol wherein culture is only performed in the context of abnormal UA. The traditional 100 000 CFU/mL cut-off may have not captured a subset of UTI in the male population, and warrants further investigation.

Impact of Preoperative Urinary Tract Infection Screening in Asymptomatic Women Undergoing Midurethral Sling.

INTRODUCTION: There is limited information regarding the utility of preoperative urine culture (Ucx) screening to decrease postoperative UTI rates following midurethral sling (MUS). HYPOTHESIS: The primary objective of this study was to determine if the rate of postoperative UTI within the first 6 weeks after surgery is lower in women undergoing MUS when preoperative Ucx is obtained compared to when it is not. Secondary objectives were to determine clinical factors associated with postoperative UTI risk. METHODS: This is a retrospective cohort study of women who did not have symptoms of or a diagnosis of cystitis at the time of their preoperative evaluation and are undergoing MUS. Patients were grouped into those who had preoperative Ucx screening within 6 weeks preceding surgery and those who did not. UTI rates 6 weeks following surgery were compared between groups. Additionally, factors impacting the risk of developing a UTI within 6 weeks of surgery were assessed. RESULTS: Among 661 patients, 13.2% had a UTI within the first 6 weeks. There was no significant difference in UTI rates between those who did and did not have preoperative Ucx, respectively (14.9% vs 10.2%, p = 0.09). On multivariable analysis, current smoker status (OR 3.02, 95% CI 1.10-8.26), history of recurrent UTI (OR 3.00, 95% CI 1.14-7.86), and requiring postoperative SIC (OR 8.75, 95% CI 1.83-41.74) were independently associated with a UTI within 6 weeks of MUS. CONCLUSION: Obtaining preoperative Ucx in asymptomatic women prior to MUS does not appear to be associated with lower postoperative UTIs rates within 6 weeks of surgery.

Bacteriology and clinical outcomes of urine mixed bacterial growth in pregnancy.

INTRODUCTION AND HYPOTHESIS: The objective was to analyse the risk of significant bacteriuria in repeat urine cultures from pregnant women, following initial mixed bacterial results. METHODS: This retrospective study examined maternal characteristics and clinical features of women who repeated urine cultures due to previous mixed cultures results. RESULTS: Of 262 women included, 80 (30.5%) had negative cultures and 125 (47.7%) had mixed bacterial growth in their repeat cultures. Positive results (≥104 CFU/ml of a urinary pathogen) were obtained for 57 women (21.8% [95% CI 17.1-27.0]). For 37 (14.1%), the repeat specimen grew 104-105 CFU/ml of microorganisms; whereas for 20 women (7.6% [95% CI 4.9-11.3]), it grew ≥105 CFU/ml. Among women with positive (>104 CFU/ml) compared with those with negative or mixed growth, rates of urinary symptoms were higher (38.6% vs 23.4%, p=0.028), abnormal dipstick results (49.1% vs 21.0%, p<0.001) and hydronephrosis, as demonstrated by renal ultrasound (12.3% vs 2.0, p=0.003). In a multivariate logistic regression analysis, hydronephrosis was associated with the occurrence of a positive repeat culture (aOR = 10.65, 95% CI 2.07-54.90). The sensitivity and specificity for predicting a repeat urine culture with ≥105 CFU/ml were 12.9% and 94.3% respectively, for urinary symptoms; and 19.7% and 97.4% respectively, for abnormal dipstick results. CONCLUSIONS: Mixed bacterial growth might represent a true urinary tract infection in a considerable proportion of women who are symptomatic and have an abnormal dipstick urinalysis.

Urogenital cultures and preterm birth in women with cervical cerclage: a single center retrospective cohort study.

BACKGROUND: The leading hypothesis of the pathogenesis of cervical insufficiency suggests a role of cervical inflammation. Urogenital tract infections could play a causative role in this process. To test this hypothesis in women with a cervical cerclage, we aimed to retrospectively examine the relationship between gestational age (GA) at delivery and positive urogenital cultures. METHODS: This single center retrospective study reviewed the records of all women with a singleton pregnancy that underwent cervical cerclage (n = 203) between 2010 and 2020 at the University Hospital of Leuven, Belgium. Transvaginal cerclages were categorized as history indicated (TVC I, n = 94), ultrasound indicated (TVC II, n = 79) and clinically indicated (TVC III, n = 20). Additionally, ten women received transabdominal cerclage (TAC). Urogenital cultures (vaginal and urine) were taken before and after cerclage with 4-week intervals. Urogenital cultures were reported 'positive' if urine and/or vaginal cultures showed significant growth of a microorganism. Treatment decision depended on culture growth and clinical presentation. The primary aim was to evaluate the association between the urogenital culture results and the GA at delivery, for each of the cerclage groups. Secondarily, to investigate the effect of antibiotic treatment of positive cultures on GA at delivery. RESULTS: Positive pre-cerclage urogenital cultures were associated with lower GA at delivery in TVC III (positive culture 26w4d ± 40d vs. negative 29w6d ± 54d, p = 0.036). For TVC I, GA at delivery was longer when pre-cerclage urogenital cultures were positive (positive culture 38w0d ± 26d vs. negative 35w4d ± 42d, p = 0.035). Overall post-cerclage urogenital cultures status was not associated with a different GA at delivery. Treating patients with pre- or post-cerclage positive urogenital cultures did also not change GA at delivery. CONCLUSION: Positive urogenital cultures taken before clinically indicated cerclage intervention may be associated with lower GA at delivery. However, there seems to be no benefit of antibiotic treatment or routine urogenital cultures during follow-up of asymptomatic women after cerclage placement.

Distribution and antimicrobial resistance patterns of urinary pathogens in preoperative midstream urine cultures from Chinese patients with urinary calculi: a meta-analysis.

BACKGROUND AND OBJECTIVE: This study comprehensively evaluates the distribution patterns and antimicrobial resistance profiles of urinary pathogens in Preoperative midstream urine cultures collected from patients with urinary calculi in China over the last two decades. METHODS: A cross-sectional analysis of 41 studies was conducted. A systematic search across various databases, including Wanfang Data, CNKI, SinoMed, Embase, PubMed, and Web of Science, was carried out, covering the time period from 2002 to 2022. Using R 4.2.1 software, a meta-analysis was performed to assess heterogeneity using Cochran's Q test and the I2 statistic. RESULTS: In the analysis of preoperative midstream urine cultures from Chinese patients with urinary calculi, gram-negative bacteria dominated at 69%, with Escherichia coli (43%), Klebsiella pneumoniae (8%), Proteus mirabilis (6%), Pseudomonas aeruginosa (5%), Acinetobacter baumannii (3%), and Enterobacter cloacae (4%) being prominent. Gram-positive organisms included Enterococcus faecalis (9%), Enterococcus faecium (5%), and Staphylococcus aureus (4%). Over time, proportions of Proteus mirabilis, Enterococcus faecalis, and Staphylococcus aureus decreased, while Klebsiella pneumoniae and Pseudomonas aeruginosa increased. Notably, Escherichia coli proportion reduced from 37 to 33% within the last two decades. Antimicrobial resistance analysis indicated declining resistance in E. coli (e.g., co-trimoxazole from 73 to 55%, gentamicin from 64 to 40%), but rising resistance in piperacillin and cefotaxime (34-60%). Enterococcus faecalis exhibited increasing resistance to ampicillin (5-69%), gentamicin (59-94%), and tetracycline (77-89%) over time, while resistance to levofloxacin and ciprofloxacin notably decreased (72-16% and 49-8%, respectively). CONCLUSION: Over the past two decades, the proportion of gram-negative bacteria was declined, while the proportion of gram-positive bacteria increased. Escherichia coli remained the most common pathogen in the urine culture of patients with urinary calculi in China and the resistance of Escherichia coli to commonly used antibiotics increased. Clinicians should select appropriate antibiotics according to the results of urine culture and drug sensitivity test to reduce the occurrence of antibiotic resistance.

The Impact of Polymerase Chain Reaction Urine Testing on Clinical Decision-Making in the Management of Complex Urinary Tract Infections.

While urinary polymerase chain reaction (PCR) testing is effective in organism identification in patients with complex urinary tract infections (cUTI), limited data exists on the clinical usefulness of this test. We serially surveyed physicians treating symptomatic patients with cUTI both at presentation and after PCR, and urine culture (UC) results were available to ascertain how the test results modified the therapy. A total of 96 unique surveys completed by 21 providers were included in the data analysis. The mean age for female and male patients was 69.4 ± 15.5 and 71.6 ± 12.7 years, respectively. The test positivity and line-item concordance for UC and PCR were consistent with prior reports. The PCR results modified or confirmed treatment in 59/96 (61.5%) and 25/96 (26.0%) of the cases, respectively, with 12/29 (41.4%) and 47/67 (70.1%) having negative and positive PCR results, respectively, resulting in treatment change (difference 28.7%, p < 0.01). Of these, 55/59 (57.3%) were alterations in the antibiotic regimen. PCR use to modify treatment was similar across providers and not statistically different when stratified by patient age, gender, or prior empiric therapy. In 31/59 (52.5%) of the cases, the PCR results modified the treatment where UC would not; conversely, UC would have modified the treatment in 3/37 (8.1%) of the cases where PCR did not (difference 44.4%, p < 0.01). We find that PCR test results are used by clinicians in managing cUTI, and use of this test provides an opportunity to improve antibiotic stewardship in this difficult-to-treat subset of patients.

Development, Evaluation, and Multisite Deployment of a Machine Learning Decision Tree Algorithm To Optimize Urinalysis Parameters for Predicting Urine Culture Positivity.

PittUDT, a recursive partitioning decision tree algorithm for predicting urine culture (UC) positivity based on macroscopic and microscopic urinalysis (UA) parameters, was developed in support of a broader system-wide diagnostic stewardship initiative to increase appropriateness of UC testing. Reflex algorithm training utilized results from 19,511 paired UA and UC cases (26.8% UC positive); the average patient age was 57.4 years, and 70% of samples were from female patients. Receiver operating characteristic (ROC) analysis identified urine white blood cells (WBCs), leukocyte esterase, and bacteria as the best predictors of UC positivity, with areas under the ROC curve of 0.79, 0.78, and 0.77, respectively. Using the held-out test data set (9,773 cases; 26.3% UC positive), the PittUDT algorithm met the prespecified target of a negative predictive value above 90% and resulted in a 30 to 60% total negative proportion (true-negative plus false-negative predictions). These data show that a supervised rule-based machine learning algorithm trained on paired UA and UC data has adequate predictive ability for triaging urine specimens by identifying low-risk urine specimens, which are unlikely to grow pathogenic organisms, with a false-negative proportion under 5%. The decision tree approach also generates human-readable rules that can be easily implemented across multiple hospital sites and settings. Our work demonstrates how a data-driven approach can be used to optimize UA parameters for predicting UC positivity in a reflex protocol, with the intent of improving antimicrobial stewardship and UC utilization, a potential avenue for cost savings.

The role of microbiome: a novel insight into urolithiasis.

Urolithiasis, referred to as the formation of stones in the urinary tract, is a common disease with growing prevalence and high recurrence rate worldwide. Although researchers have endeavoured to explore the mechanism of urinary stone formation for novel effective therapeutic and preventative measures, the exact aetiology and pathogenesis remain unclear. Propelled by sequencing technologies and culturomics, great advances have been made in understanding the pivotal contribution of the human microbiome to urolithiasis. Indeed, there are diverse and abundant microbes interacting with the host in the urinary tract, overturning the dogma that urinary system, and urine are sterile. The urinary microbiome of stone formers was clearly distinct from healthy individuals. Besides, dysbiosis of the intestinal microbiome appears to be involved in stone formation through the gut-kidney axis. Thus, the human microbiome has potential significant implications for the aetiology of urolithiasis, providing a novel insight into diagnostic, therapeutic, and prognostic strategies. Herein, we review and summarize the landmark microbiome studies in urolithiasis and identify therapeutic implications, challenges, and future perspectives in this rapidly evolving field. To conclude, a new front has opened with the evidence for a microbial role in stone formation, offering potential applications in the prevention, and treatment of urolithiasis.

A randomised controlled trial comparing two protocols of preoperative antibiotics in patients with positive urine culture undergoing percutaneous nephrolithotomy.

AIM: To compare the outcomes of two different protocols of antibiotic prophylaxis in patients with positive urine culture undergoing percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: Patients were prospectively enrolled for the randomised study to either group A which included patients where an attempt to sterilise the urine was made with a 1 week course of sensitive antibiotics or group B that included patients who received a shorter duration of prophylaxis using sensitive antibiotics for 48 h prior to procedure which was continued for 48 h postoperatively. Enrolled patients had stones requiring percutaneous nephrolithotomy and had a positive preoperative urine culture. Primary outcome was difference in sepsis rates between the groups. RESULTS: A total of 80 patients randomised into two groups of 40 each based on the antibiotic protocol used were analysed in the study. There was no difference in infectious complication rates between groups on univariate analysis. The rate of SIRS in Group A and Group B was found to be 20% (N = 8) and 22.5% (N = 9) respectively. The rate of septic shock in Group A and Group B was 7.5% and 5% respectively. On multivariate analysis, longer duration of antibiotics did not decrease the risk of sepsis compared to shorter antibiotic course (p = 0.79). CONCLUSION: Attempts to sterilise urine before PCNL may not decrease the risk of sepsis in patients with positive urine culture undergoing PCNL and may only result in unnecessary prolonging of antibiotic usage thereby increasing the chances of antibiotic resistance.

Nomogram for predicting risk factors of fever in patients with negative preoperative urine culture after retrograde intrarenal surgery.

PURPOSE: To determine the risk factors for postoperative fever after retrograde intrarenal surgery (RIRS) in patients with negative preoperative urine culture (UC), and to establish a nomogram for predicting postoperative fever based on these risk factors. METHODS: This study collected 322 patients with negative UC who received RIRS at the First Affiliated Hospital of Anhui Medical University from March 2019 to May 2022. The study population was divided into a fever group and a non-fever group. The risk factors of postoperative fever were determined by univariate and multivariate logistic regression analyses, and a nomogram was established. The nomogram was evaluated in terms of differentiation, calibration, and clinical practicability. RESULTS: In this study, 47 (14.6%) patients developed a fever after surgery. Multivariate logistic regression analysis showed that for patients with negative preoperative urine culture, urinary leucocyte esterase (P = 0.005), operative time (P = 0.019), and intraoperative hypotension (P = 0.028) were independent risk factors of postoperative fever, and a nomogram was constructed according to the above variables. The area under the curve (AUC) calculated by receiver operating characteristic (ROC) analysis was 0.807 (95% CI 0.739-0.876), indicating good discrimination. The calibration curves showed good consistency, and the clinical decision curve analysis (DCA) showed the clinical applicability of the model. CONCLUSIONS: For patients with negative preoperative urine culture, urine leukocyte esterase, operative time, and intraoperative hypotension are independent risk factors of postoperative fever. The new nomogram can better assess the risk of infection in patients with negative UC after RIRS.

Analysis of factors with low positive predictive value in the diagnosis of urinary tract infection by flow cytometry.

PURPOSE: Culture-negative urine specimens can be rapidly screened by urine flow cytometry (UFC), while low positive predictive value (PPV) limits the clinical application. We explored the factors associated with a low PPV. METHODS: A total of 5095 urine specimens were analyzed with UFC and culture. Diagnostic performance of leukocytes, bacteria, and BACT-info flags was evaluated by sensitivity, specificity, PPV, and negative predictive value (NPV). The association of contaminated culture and squamous epithelial cell count and BACT-info flag was performed by logistic regression analysis. RESULTS: The NPVs of parallel combination of bacteria and leucocytes were 98.9% in males and 97.9% in females, and PPVs of serial combination were 86.6% and 77.8% in men and women, respectively. The PPV of Gram-negative flag was higher than that of Gram-positive flag. The proportions of contamination in the urine culture results of false positive specimens were 86.9% in males and 98.5% in females at the cutoff points of the serial combination, and these parameters were 53.2% in males and 85.6% in females for the Gram-positive flag. There was a statistically significant association between contaminated cultures and squamous epithelial cells count in females, but not in males. Associations between contaminated cultures and Gram-positive flags or Gram-pos/-neg flags were statistically significant, but there was no association between contaminated cultures and Gram-negative flags. CONCLUSIONS: A serial combination of leukocytes and bacteria may maximize PPV in the diagnosis of bacterial urinary tract infection by urine flow cytometry, and contamination is the main reason for a low PPV.

Urobiome changes differ based on OAB treatment in adult females.

INTRODUCTION AND HYPOTHESIS: Representatives of two classes of oral medication are often used to treat urgency urinary incontinence (UUI): solifenacin, an M3-receptor-selective antimuscarinic, and mirabegron, a beta-3 agonist. Two previous asynchronous drug-specific studies suggested different interactions between these medications and the urobiome despite identical methodologies, including recruitment, sample procurement, medication dose escalation strategy, determination of 12-week responders versus nonresponders, and data collection. This analysis compares data from these two studies using a uniform analytic approach. METHODS: Urine was collected aseptically via transurethral catheter from consenting participants for subsequent processing by the Expanded Quantitative Urine Culture (EQUC) protocol in two cohorts (n=50 and n=47) that were demographically similar. Species accumulation curves were generated to compare the total number of unique species detected. Indices that measure richness, evenness, and/or abundance were used to compare alpha (within sample) diversity. The Bray-Curtis Dissimilarity Index was used to determine between sample (beta) diversity. RESULTS: The majority of the 40 species detected in the pre-treatment urobiomes were detected in both cohorts. Both pre-treatment urobiomes were substantially similar in species richness, evenness, and diversity. Differences in pre-treatment urobiomes were associated with treatment response for solifenacin-treated participants only. In contrast, the pre-treatment urobiomes of mirabegron-treated participants were not associated with treatment response. Changes in the post-treatment urobiomes were detected in both cohorts with an increase in richness for both solifenacin (5-mg dose only) and mirabegron. CONCLUSIONS: Pre-treatment urobiome characteristics were associated with treatment response in participants treated with solifenacin, but not mirabegron. Differences exist in urobiome response after treatment with two medications that have known differences in mechanism of action.

Is it meaningful to apply midstream urine culture to urine specimens with negative Gram stain results?

INTRODUCTION: Gram staining is a convenient method for bacterial estimation. Urine culture is typically used to diagnose urinary tract infections. Therefore, urine culture is also performed on Gram stain-negative urine specimens. However, the frequency of uropathogen identification in these samples remains unclear. METHODS: From 2016 to 2019, we retrospectively compared the results of Gram staining and urine culture tests on midstream urine specimens submitted for the diagnosis of urinary tract infections to confirm the significance of urine culture on Gram stain-negative specimens. Analysis was performed according to the patients' sex and age, and the frequency of uropathogen identification in the culture was examined. RESULTS: A total of 1763 urine specimens (women, 931; men, 832) were collected. Of these, 448 (25.4%) were not positive on Gram staining but were positive on culture. In specimens without bacteria on Gram staining, the frequencies of specimens with uropathogens detected on culture were 20.8% (22/106) in women aged <50 years, 21.4% (71/332) in women aged ≥50 years, 2.0% (2/99) in men aged <50 years, and 7.8% (39/499) in men aged ≥50 years. CONCLUSIONS: In men aged <50 years, the frequency of uropathogenic bacteria identification by urine culture was low in Gram stain-negative specimens. Therefore, urine cultures may be excluded from this group. In contrast, in women, a small number of Gram stain-negative specimens showed significant culture results for the diagnosis of urinary tract infection. Therefore, urine culture should not be omitted in women without careful consideration.

Urine culture practices for complicated urinary tract infections in an academic emergency department.

OBJECTIVE: Complicated UTIs (cUTIs) are defined by a heterogenous group of risk factors that place the patient at increased risk of treatment failure in whom urine cultures are recommended. We evaluated the ordering practices for urine cultures for cUTI patients and patient outcomes in an academic hospital setting. METHODS: Retrospective chart review of adults of 18 years and older with cUTIs diagnosed in a single academic emergency department (ED). We reviewed 398 patient encounters based on a range of ICD-10 diagnosis codes consistent with cUTI between 1/1/2019 and 6/30/2019. The definition of cUTI consisted of thirteen subgroups composited from existing literature and guidelines. The primary outcome was ordering a urine culture for cUTI. We also assessed impact of the urine culture results and compared clinical course severity and readmission rates between cultured and not cultured patients. RESULTS: During this period, the ED had 398 potential cUTI visits based on ICD-10 code, of which 330 (82.9%) met the study inclusion criteria for cUTI. Of these cUTI encounters, clinicians failed to obtain urine cultures in 92 (29.8%). Of the 217 cUTI with cultures, 121 (55.8%) demonstrated sensitivity to original treatment, 10 (4.6%) demonstrated the need to change antimicrobial coverage, 49 (22.6%) demonstrated the presence of contamination, and 29 (13.4%) demonstrated insignificant growth. Patients with cUTI who received cultures experienced higher rates of admission to both ED observation (33.2% vs 16.3%, p = 0.003) and the hospital (41.9% vs 23.8%, p = 0.003) compared to those with missed cultures. Admitted cUTI patients experienced greater length of hospital stay when cultures were obtained (3.23 vs 1.53 days, p < 0.001). Readmission rates for patients with cUTI discharged from the ED within 30 days were 4.0% for patients with urine cultures and 7.3% for patients without urine cultures (p = 0.155). CONCLUSION: Over a quarter of cUTI patients in this study did not receive a urine culture. Further studies are needed to assess if improving adherence to urine culturing practices for cUTIs will impact clinical outcomes.

Quantitative multiplex polymerase chain reaction in copies ml-1 linearly correlates with standard urine culture in colonies ml-1 for urinary tract infection (UTI) pathogens.

Standard urine culture (SUC) is the current standard method for confirmation of a urinary tract infection (UTI). SUC identifies microorganisms in urine samples and semi-quantifies these as colony-forming units (CFUs) ml-1. In contrast, quantitative multiplex polymerase chain reaction (q-MPCR) is a culture-independent assay in which the microbes are quantified by targeting genomic sequences and reported as cells ml-1, calculated from copies ml-1. Using serial dilutions within the 104-105 cells ml-1 range, the usual reporting range of SUC, this study compared the quantification results based on SUC and q-MPCR for four uropathogens with the control hemocytometer counts. The results revealed a linear relationship and a 1:1 correlation between the q-MPCR and SUC results. Additional q-MPCR quantification of 36 uropathogenic non-fastidious and fastidious bacteria and yeast indicated a reproducible linear correlation in a 1:1 manner with the control counts over a range of cell densities (103-106 cells ml-1). The results confirm that the quantifications by q-MPCR in cells ml-1 and by SUC in CFUs ml-1 are comparable and answer to the lingering question of how the results of these two methods correlate. Moreover, q-MPCR provided accurate quantification of various microorganisms over wider cell density ranges without the time required for microbial growth.

Mixed Bacterial Growth in Prenatal Urine Cultures; An Investigation into Prevalence, Contributory Factors and the Impact of education-based Interventions.

PURPOSE: Undiagnosed urinary tract infections (UTIs) in pregnancy are associated with adverse perinatal outcome. Urine microbiology cultures reported as 'mixed bacterial growth' (MBG) frequently present a diagnostic dilemma for healthcare providers. We investigated external factors contributing to elevated rates of (MBG) within a large tertiary maternity centre in London, UK, and assessed the efficacy of health service interventions to mitigate these. DESCRIPTION: This prospective, observational study of asymptomatic pregnant women attending their first prenatal clinic appointment aimed to establish (i) the prevalence of MBG in routine prenatal urine microbiology cultures, (ii) the association between urine cultures and the duration to laboratory processing and (iii) ways in which MBG may be reduced in pregnancy. Specifically we assessed the impact of patient-clinician interaction and that of an education package on optimal urine sampling technique. ASSESSMENT: Among 212 women observed over 6 weeks, the negative, positive and MBG urine culture rates were 66%, 10% and 2% respectively. Shorter duration from urine sample collection to laboratory arrival correlated with higher rates of negative cultures. Urine samples arriving in the laboratory within 3 hours of collection were most likely to be reported as culture negative (74%), and were least likely to be reported as MBG (21%) or culture positive (6%), compared to samples arriving > 6 hours (71%, 14% and 14% respectively; P < 0.001). A midwifery education package effectively reduced rates of MBG (37% pre-intervention vs 19% post-intervention, RR 0.70, 95% CI 0.55 to 0.89). Women who did not receive verbal instructions prior to providing their sample had 5-fold higher rates of MBG (P < 0.001). CONCLUSION: As many as 24% of prenatal urine screening cultures are reported as MBG. Patient-midwife interaction before urine sample collection and rapid transfer of urine samples to the laboratory within 3 hours reduces the rate of MBG in prenatal urine cultures. Reinforcing this message through education may improve accuracy of test results.

Increased demand of urine cultures from Danish general practice: a five-year register-based study.

OBJECTIVE: To characterise and explore the development in the number and content of urine samples sent from general practice in the North Denmark Region to the Department of Clinical Microbiology (DCM) at Aalborg University Hospital during a five-year period. DESIGN: A register-based study. SETTING: General practice. SUBJECTS: Urine samples received at DCM, Aalborg University Hospital from general practice between 2017 and 2022. MAIN OUTCOME MEASURES: Number and content of urine samples. RESULTS: A total of 255,271 urine samples from general practice were received at DCM, with 76.1% being from female patients. Uropathogens were identified in 43.0% of the samples. During the five-year period, a 23.0% increase in the number of urine samples per person (incidence rate ratio (IRR) 1.23, 95% CI 1.21-1.25) was observed. A slight increase in the proportion of positive cultures (risk ratio (RR) 1.03, 95% CI 1.01-1.05) was seen. No notable change in the patient population (age, gender) was observed. Overall, Escherichia coli was the most identified uropathogen (60.4%) followed by Klebsiella spp. (8.7%) and Enterococcus spp. (7.7%). Distribution of the various uropathogens differed slightly depending on patient gender and age, importantly E. coli was less frequently observed in males aged >65 years. CONCLUSION: During the past five years an increasing amount of urine cultures have been requested at DCM from general practice. Importantly, the cause(s) of this increasing demand needs to be explored further in future studies.

Appropriate diagnostics of urinary tract infections can reduce the use of antibiotics in general practice.From 2017 to 2022 a 23% increase per person in requested urine cultures from general practice was observed.A slight increase in positive cultures was found, but no notable change in the patient population (age, gender) was seen.E. coli was the most identified uropathogen independent of gender and age, however, the proportion differed within the various groups.