Laboratory Diagnosis of Urinary Tract Infection

Pryles, Charles V.; Lustik, Boris

doi:10.1016/s0031-3955(16)32536-6

Cited by 47 publications

(14 citation statements)

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“…75 This was based on studies of adult women with acute pyelonephritis and asymptomatic women. Some have questioned if this threshold is appropriate for children, 76,77 with most suggesting a lower threshold [76][77][78][79] but one advocating an increase. 80 UTI is typically thought to be caused by a single organism present in a high concentration, usually ≥ 10 5 CFU/ml.…”

Section: Bacteriuria Thresholdmentioning

confidence: 99%

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

Hay

Birnie²,

Busby³

et al. 2016

Health Technol Assess

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BackgroundIt is not clear which young children presenting acutely unwell to primary care should be investigated for urinary tract infection (UTI) and whether or not dipstick testing should be used to inform antibiotic treatment.ObjectivesTo develop algorithms to accurately identify pre-school children in whom urine should be obtained; assess whether or not dipstick urinalysis provides additional diagnostic information; and model algorithm cost-effectiveness.DesignMulticentre, prospective diagnostic cohort study.Setting and participantsChildren < 5 years old presenting to primary care with an acute illness and/or new urinary symptoms.MethodsOne hundred and seven clinical characteristics (index tests) were recorded from the child’s past medical history, symptoms, physical examination signs and urine dipstick test. Prior to dipstick results clinician opinion of UTI likelihood (‘clinical diagnosis’) and urine sampling and treatment intentions (‘clinical judgement’) were recorded. All index tests were measured blind to the reference standard, defined as a pure or predominant uropathogen cultured at ≥ 105colony-forming units (CFU)/ml in a single research laboratory. Urine was collected by clean catch (preferred) or nappy pad. Index tests were sequentially evaluated in two groups, stratified by urine collection method: parent-reported symptoms with clinician-reported signs, and urine dipstick results. Diagnostic accuracy was quantified using area under receiver operating characteristic curve (AUROC) with 95% confidence interval (CI) and bootstrap-validated AUROC, and compared with the ‘clinician diagnosis’ AUROC. Decision-analytic models were used to identify optimal urine sampling strategy compared with ‘clinical judgement’.ResultsA total of 7163 children were recruited, of whom 50% were female and 49% were < 2 years old. Culture results were available for 5017 (70%); 2740 children provided clean-catch samples, 94% of whom were ≥ 2 years old, with 2.2% meeting the UTI definition. Among these, ‘clinical diagnosis’ correctly identified 46.6% of positive cultures, with 94.7% specificity and an AUROC of 0.77 (95% CI 0.71 to 0.83). Four symptoms, three signs and three dipstick results were independently associated with UTI with an AUROC (95% CI; bootstrap-validated AUROC) of 0.89 (0.85 to 0.95; validated 0.88) for symptoms and signs, increasing to 0.93 (0.90 to 0.97; validated 0.90) with dipstick results. Nappy pad samples were provided from the other 2277 children, of whom 82% were < 2 years old and 1.3% met the UTI definition. ‘Clinical diagnosis’ correctly identified 13.3% positive cultures, with 98.5% specificity and an AUROC of 0.63 (95% CI 0.53 to 0.72). Four symptoms and two dipstick results were independently associated with UTI, with an AUROC of 0.81 (0.72 to 0.90; validated 0.78) for symptoms, increasing to 0.87 (0.80 to 0.94; validated 0.82) with the dipstick findings. A high specificity threshold for the clean-catch model was more accurate and less costly than, and as effective as, clinical judgement. The additional diagnostic utility of dipstick testing was offset by its costs. The cost-effectiveness of the nappy pad model was not clear-cut.ConclusionsClinicians should prioritise the use of clean-catch sampling as symptoms and signs can cost-effectively improve the identification of UTI in young children where clean catch is possible. Dipstick testing can improve targeting of antibiotic treatment, but at a higher cost than waiting for a laboratory result. Future research is needed to distinguish pathogens from contaminants, assess the impact of the clean-catch algorithm on patient outcomes, and the cost-effectiveness of presumptive versus dipstick versus laboratory-guided antibiotic treatment.FundingThe National Institute for Health Research Health Technology Assessment programme.

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Section: Bacteriuria Thresholdmentioning

confidence: 99%

The Diagnosis of Urinary Tract infection in Young children (DUTY): a diagnostic prospective observational study to derive and validate a clinical algorithm for the diagnosis of urinary tract infection in children presenting to primary care with an acute illness

Hay

Birnie²,

Busby³

et al. 2016

Health Technol Assess

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“…Pryles reviewed the existing pediatric data in 1960 defined UTI in children [22]. This definition is still valid today.…”

Section: Clinical Presentationmentioning

confidence: 99%

Highlights for Management of a Child with a Urinary Tract Infection

Habib

2012

International Journal of Pediatrics

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Urinary tract infections remain the most common bacterial infection in childhood. Escherichia coli is responsible for over 80% of Pediatric UTIs. Other common gram negative organisms include Kleibsiella, Proteus, Enterobacter and occasionally Pseudomonas. Signs and symptoms vary greatly by age of the patient becoming more specific as the child grows older. Even in the absence of specific signs a UTI should be included in the differential diagnosis of high grade fever. In younger children, presence of upper respiratory infections, otitis media or gastroenteritis does not eliminate the possibility of a UTI. Culture of the urine remains the gold standard for diagnosing UTIs. All males and females with well documented UTIs should be imaged for the presence of urological anomalies associated with UTI. Depending on patient's clinical symptoms and tolerance, therapy can be oral or parenteral as they have both been found equally efficacious. Healthcare professionals should ensure that when a child or young person has been identified as having a suspected UTI, they and their parents are given information about the need for treatment, the importance of completing any course of treatment and advice about prevention and possible long-term management.

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“…Similarly, Pryles demonstrated the effect of hydration on colony count by subjecting several untreated children with UTI diagnosed by ≥10 7 CFU/mL on a first morning urine to serial catheterization during a 24-hour period and showed that the colony count during the day decreased by several orders of magnitude to as low as 10 3 to 10 4 CFU/mL. 11 Koskimies reported that 19% of his patients with bacterial growth on SPA had less than 10 5 CFU/ml 12 . Lubell et al in a multicenter emergency department study of 1870 infants 29–60 days of age diagnosed with UTI based on symptoms and either pyuria or a positive urine gram stain found that 6% had colony counts of 10,000–49,000 CFU/mL, 3% reported as 10,000 to 100,000 CFU/ml, and 20% reported as 50,000 to 100,000 CFU/ml.…”

Section: Discussionmentioning

confidence: 94%