A Study of Screening Tests for the Presumptive Diagnosis of Significant Bacteriuria in Urinary Tract Infections (original) (raw)
Related papers
Comparison of various screening methods for presumptive diagnosis of significant bacteriuria
International Journal of Medical Science and Public Health, 2016
Background: Urinary tract infection is a common source of bacterial infection among people of any age. Urinalysis is one of the important and useful urological tests for diagnosis of the infection. Microscopic examination of urine, catalase test, and the dipstick urinalyses (leukocyte esterase test and nitrite test) are common tests used for detecting bacteriuria and pyuria. Although culture is the gold standard method for diagnosis of urinary tract infection, the culture is an expensive and time-consuming method. Objective: (1) To compare dipstick urinalysis with microscopic urinalysis, (2) to compare dipstick and microscopic urinalyses results with urine culture results, by calculating performance characteristics of dipstick tests, and (3) to compare catalase test with urine culture results. Materials and Methods: The 1,000 urine specimens were processed by using dipstick and microscopic urinalyses and cultured. Reagent strips reading and microscopic examination were included in laboratory urinalysis in this study. Result: Of 1,000 urine samples of patients, 186 (18.6%) patients revealed urine cultures with significant bacteriuria (10 5 colonies/mL or greater). Sensitivity and specificity of microscopic urinalysis bacteriuria were 96.77% and 98.52%, respectively. Whereas, in dipstick urinalysis, sensitivity and specificity of nitrite test were 90% and 97% and, in leukocyte esterase test, they were 87% and 95%, respectively. Sensitivity and specificity of catalase test for bacteriuria were 88.63% and 75.86%, respectively. Conclusion: Dipstick test could be used more effectively as office procedure in rural areas where laboratory facility for microscopy and culture is not available for diagnosis of urinary tract infection.
Evaluation of rapid screening methods in the diagnosis of urinary tract infection
IP Innovative Publication Pvt. Ltd., 2018
Introduction: Urinary Tract Infection (UTI) is one of the most common bacterial infection encountered in clinical practice. Even though urine culture is considered as the gold standard in detection of bacteriuria, many alternative screening methods like urine microscopy, chemical analysis using dipstick method and Gram’s staining have been evaluated which are more economical and rapid. Hence, this study was undertaken to evaluate various screening methods in the rapid diagnosis of Urinary Tract Infections. Objectives: To evaluate Gram staining of urine, leucocyte esterase and nitrite dipstick test methods in the rapid diagnosis of Urinary Tract Infections. Materials and Methods: All urine samples received at Microbiology laboratory, McGann hospital, attached to Shimoga Institute of Medical Sciences, during study period was subjected to Gram staining, leucocyte esterase and nitrite dip stick test along with culture. Results of these tests were compared to culture results. Sensitivity and specificity of the tests was determined taking culture as standard. Results: A total of 560 urine samples were processed. Culture showed significant bacteriuria in 210 cases. The sensitivity of urine microscopy was 70.9%, leucocyte esterase test was 98% and nitrite test was 74.8%. Whereas the specificity of urine microscopy was 70%, leucocyte esterase test was 79.1% and nitrite test was 98.8%. Similarly, the sensitivity of combined leucocyte esterase and nitrite tests was 90.9% and specifity was 97.4%. Sensitivity and specificity of all the three screening tests combined were 95.7% and 94.8% respectively. Conclusion: Screening tests such as, Urine microscopy by Gram’s staining, Leucocyte esterase and nitrite dipstick test in combination can be used routinely to exclude bacteriuria. Urine culture can be employed only in the screening tests positive cases and in symptomatic cases irrespective of test results, thereby making diagnosis of UTI cost effective and rapid. Keywords: Bacteriuria, Leukocyte esterase, Nitrite test, UTI, Urine microscopy.
Evaluation of Rapid Methods for the Detection of Bacteriuria (Screening) in Primary Health Care
Acta pathologica, microbiologica et immunologica Scandinavica, 2009
Evaluation of rapid methods for the detection of bacteriuria (screening) in primary health care. Acta path. microbiol. immunol. scand. Sect. B, 94: The diagnostic performance of six methods for bacteriuria testing has been studied in 781 urine specimens obtained in primary health care, using conventional culture as reference method. The cutoff limits for classification of test results into positive and negative have been optimized with respect to diagnostic performance in primary health care. With optimized tests the following diagnostic efficiencies were obtained: 1) Bacterial ATP, 0.94; 2) Bacterial count in sediment, 0.93; 3) Nitrite test, 0,92; 4) Dipslide test, 0,92; 5) White cell count in sediment; 0,87; 6) Granulocyte esterase test; 0.83. The diagnostic performance was also studied for all combinations of two tests. The highest diagnostic efficiency (0.96) was obtained by combining the ATP and dipslide tests. High diagnostic efficiencies can be obtained by a rapid primary test, using other tests for follow-up testing of specimens with intermediate or uninterpretable primary results. The most promising results were obtained by using ATP as the primary test, with follow-up testing of specimens with 3-25 nmol/l of ATP (12 per cent of the specimens). Follow-up testing by conventional culture resulted in overall diagnostic efficiency of 0.98. By performing the nitrite test on specimens with intermediary ATP-results, 81 per cent of the patients with UTI can be classified without culture. Only patients with intermediary ATP and negative nitrite results (10 per cent of the total number) will have to wait for final diagnosis based on conventional culture. Some alternative strategies to combine available methods are discussed in detail. Major advantages of the ATP test are that the test can be performed while the patients are waiting; it provides a numerical and objective result, and, in contrast to culture, it is not influenced by adhesion of bacteria to somatic cells.
Asymptomatic Bacteriuria or Urinary Tract Infection? New and Old Biomarkers
International Journal of Translational Medicine, 2022
Urinary tract infections (UTIs) are among the most common infective disease in the adult population. UTI diagnosis is based essentially on the presence of lower urinary tract symptoms (e.g., dysuria, urgency, and frequency) and the evidence of bacteriuria (by dipstick testing and/or urine culture). UTI diagnosis is not always easy because symptoms can be vague, or patient basal conditions can interfere negatively with the diagnostic process, whereas urine culture is still ongoing. In those cases, the differential diagnosis among UTIs and asymptomatic bacteriuria (ABU) may be challenging, while the clinician has to decide whether to start an antibiotic treatment shortly. The purpose of the present review is to analyze the biomarkers that could help in UTI diagnosis. Some biomarkers, such as procalcitonin, interleukin-6, neutrophil gelatinase-associated lipocalin, chemokines, lactoferrin, and bone morphogenetic protein-2, seem promising in UTI diagnosis, while other biomarkers failed ...
Asymptomatic bacteriuria, to screen or not to screen – and when to treat?
Current Opinion in Urology, 2017
Purpose of review Asymptomatic bacteriuria (ABU) is a common clinical condition that often leads to unnecessary treatment. The purpose of this review is to outline and evaluate the most recent literature on the management of ABU. Recent findings The role of ABU management has been evaluated in several patient subgroups: healthy patients without identified risk factors, pregnant women, postmenopausal women, women with recurrent UTI, patients with diabetes, elderly institutionalized patients, patients with renal transplants, patients with indwelling catheters and prior to surgery. Available evidence only supports the need for screening and treatment of ABU in pregnant women and prior to urological procedures breaching the mucosa. In all the other conditions the treatment of ABU is not only useless but also harmful. A short course treatment in pregnant women is recommended; in patients with ABU prior to urological procedures breaching the mucosa the treatment should be given in line with antibiogram and in line with the recommendations of European Association of Urology guidelines.
Asymptomatic Bacteriuria: Significance for Different Patient Population
Urinary Tract Infections, 2011
The use of quantitative urine cultures for the microbiological diagnosis of UTI was suggested and validated more than 50 years ago (Kass, 1957, 1962). If bacteria were isolated in quantitative counts of ≥10 5 colony-forming units (CFU)/mL in a voided urine specimen from asymptomatic patients, the condition was described as asymptomatic bacteriuria. Interestingly, in this patient population the isolated organisms were always the same in paired specimens obtained by urinary catheterization. Quantitative counts of ≤10 5 colonyforming units (CFU)/mL in a voided urine specimen usually resulted in a negative paired catheterized specimens. Therefore, ≤10 5 colony-forming units (CFU)/mL in voided specimens were considered as contamination. The general acceptance and widespread use of this technique identified several clinically asymptomatic patient populations with an increased prevalence of positive urine cultures (Kunin, 1966). Specifically, pregnant women, patients with urogenital abnormalities, and patients with indwelling urethral catheters demonstrated a higher incidence of asymptomatic bacteriuria (Kunin, 1966). Antibiotic treatment of asymptomatic bacteriuria in pregnant women resulted in a significantly reduced incidence of pyelonephritis (Kass, 1962), which is considered an important concern in pregnancy. The obvious benefits of eradicating bacteriuria in asymptomatic pregnant women were interpreted to be generally applicable. Therefore, other patient populations with asymptomatic bacteriuria were also treated ordinarily (Kass, 1962). This treatment strategy was not based on clinical studies or facts, rather on the assumption that asymptomatic bacteriuria was consistently harmful in all populations and necessitated antibiotic treatment (Nicolle, 2006). Both basic and clinical research conducted over the last few decades, including long-term cohort studies and prospective randomized comparative trials in defined populations with asymptomatic bacteriuria, have improved the understanding of this clinical condition and addressed appropriate management (Nicolle, 2006). 2. Material and methods To identify all relevant materials, comprehensive literature searches were performed via the data sources: MEDLINE, EMBASE, CINAHL and OVID using the key words: asymptomatic bacteriuria, pyuria, urinary tract infection, urine culture, UTI, antibiotic treatment. Relevant articles and references between 1962 and 2010 were reviewed and analyzed for data on the association between asymptomatic bacteriuria and antibiotic treatment. Reference lists from relevant review articles were also searched. Only articles published as formal papers in peer-reviewed journals were selected for inclusion if they reported outcomes of interest including potential benefits of antibiotic treatment for asymptomatic bacteriuria. The data base searches resulted in 1400 articles, of which 356 of 1400 pertained directly to asymptomatic bacteriuria and antibiotic treatment. The entirety of these articles was reviewed, forming the basis for the current review. 3. Results 3.1 Causes and pathogenesis of asymptomatic bacteriuria The normal upper and lower urinary tract is considered sterile, except for the distal end of the urethra. Colonization with bacteria or development of an asymptomatic bacteriuria occurs due to ascension of bacteria into the urinary bladder or into the upper urinary tract,
2019
RESULTS Nineteen studies (N = 8443) meeting inclusion criteria were identified. Two cohort studies (n = 5289) found fewer cases of pyelonephritis in the cohorts of screened pregnant women (0.5%) than within retrospective comparisons of unscreened cohorts (2.2% and 1.8%); the larger study estimated a statistically significant relative risk of 0.30 (95% CI, 0.15-0.60). No studies examined screening in nonpregnant populations. Among 12 trials of asymptomatic bacteriuria screening and treatment during pregnancy (n = 2377; 1 conducted within past 30 years), there were reduced rates of pyelonephritis (range, 0%-16.5% for the intervention group and 2.2%-36.4% for the control group; pooled risk ratio [RR], 0.24 [95% CI, 0.14-0.40]; 12 trials) and low birth weight (range, 2.5%-14.8% for the intervention group and 6.7%-21.4% for the control group; pooled RR, 0.64 [95% CI, 0.46-0.90]; 7 trials). There was no significant difference in infant mortality (pooled RR, 0.98 [95% CI, 0.29-3.26]; 6 tri...
Research, Society and Development
Bacterial urinary tract infections (UTI) are among the most frequent infectious diseases of small animals. Although antimicrobial therapy is recommended for treating bacterial UTIs, the current consensus is that treatment may not be necessary for asymptomatic animals. The aim of this study was to evaluate the diagnostic ability of urinalysis to detect bacteriuria and to compare it with urine culture (gold standard method) to assess the risk of false-positive results. A retrospective study was conducted from January 2016 to July 2019 and urine samples of 119 dogs were analyzed. Diagnostic validation was performed for urinalysis, based on the morphological classification and intensity of bacteriuria. Agreement between the results was assessed using the kappa (k) index. When the presence of cocci was used as a diagnostic criterion to suggest bacteriuria, it was observed that the agreement (k = -0.006) was lower than that expected by chance. However, a poor agreement (k = 0.22) was also...
FEMS Microbiology Letters, 2013
Bacteriuria, or the presence of bacteria in urine, is associated with both asymptomatic and symptomatic urinary tract infection and underpins much of the dynamic of microbial colonization of the urinary tract. The prevalence of bacteriuria in dissimilar patient groups such as healthy adults, institutionalized elderly, pregnant women, and immune-compromised patients varies widely. In addition, assessing the importance of 'significant bacteriuria' in infected individuals represents a diagnostic challenge, partly due to various causal microorganisms, and requires careful consideration of the distinct etiologies of bacteriuria in different populations and circumstances. Recent molecular discoveries have revealed how some bacterial traits can enable organisms to grow in human urine, which, as a fitness adaptation, is likely to influence the progression of bacteriuria in some individuals. In this review, we comprehensively analyze currently available data on the prevalence of causal organisms with a focus on asymptomatic bacteriuria in dissimilar populations. We evaluate recent advances in the molecular detection of bacteriuria from a diagnostic viewpoint and briefly discuss the potential benefits and some of the challenges of these approaches. Overall, this review provides an update on the comparative prevalence and etiology of bacteriuria from both microbiological and clinical perspectives.