Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria.

Urinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by Escherichia coli and other Gram-negative uropathogens. We tested RapidBac, a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC), compared with standard bacterial culture using 966 clean-catch urine specimens submitted to a clinical microbiology laboratory in an urban academic medical center. RapidBac was performed in accordance with instructions, providing a positive or negative result in 20 min. RapidBac identified as positive 245/285 (sensitivity 86%) samples with significant bacteriuria, defined as the presence of a Gram-negative uropathogen or Staphylococcus saprophyticus at ≥10(3) CFU/ml. The sensitivities for Gram-negative bacteriuria at ≥10(4) CFU/ml and ≥10(5) CFU/ml were 96% and 99%, respectively. The specificity of the test, detecting the absence of significant bacteriuria, was 94%. The sensitivity and specificity of RapidBac were similar on samples from inpatient and outpatient settings, from male and female patients, and across age groups from 18 to 89 years old, although specificity was higher in men (100%) compared with that in women (92%). The RapidBac test for bacteriuria may be effective as an aid in the point-of-care diagnosis of UTIs especially in emergency and primary care settings.

Voided midstream urine culture and acute cystitis in premenopausal women.

BACKGROUND: The cause of acute uncomplicated cystitis is determined on the basis of cultures of voided midstream urine, but few data guide the interpretation of such results, especially when gram-positive bacteria grow. METHODS: Women from 18 to 49 years of age with symptoms of cystitis provided specimens of midstream urine, after which we collected urine by means of a urethral catheter for culture (catheter urine). We compared microbial species and colony counts in the paired specimens. The primary outcome was a comparison of positive predictive values and negative predictive values of organisms grown in midstream urine, with the presence or absence of the organism in catheter urine used as the reference. RESULTS: The analysis of 236 episodes of cystitis in 226 women yielded 202 paired specimens of midstream urine and catheter urine that could be evaluated. Cultures were positive for uropathogens in 142 catheter specimens (70%), 4 of which had more than one uropathogen, and in 157 midstream specimens (78%). The presence of Escherichia coli in midstream urine was highly predictive of bladder bacteriuria even at very low counts, with a positive predictive value of 10(2) colony-forming units (CFU) per milliliter of 93% (Spearman's r=0.944). In contrast, in midstream urine, enterococci (in 10% of cultures) and group B streptococci (in 12% of cultures) were not predictive of bladder bacteriuria at any colony count (Spearman's r=0.322 for enterococci and 0.272 for group B streptococci). Among 41 episodes in which enterococcus, group B streptococci, or both were found in midstream urine, E. coli grew from catheter urine cultures in 61%. CONCLUSIONS: Cultures of voided midstream urine in healthy premenopausal women with acute uncomplicated cystitis accurately showed evidence of bladder E. coli but not of enterococci or group B streptococci, which are often isolated with E. coli but appear to rarely cause cystitis by themselves. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.).

Recurrent urinary tract infection and urinary Escherichia coli in women ingesting cranberry juice daily: a randomized controlled trial.

OBJECTIVE: To compare the time to urinary tract infection (UTI) and the rates of asymptomatic bacteriuria and urinary P-fimbriated Escherichia coli during a 6-month period in women ingesting cranberry vs placebo juice daily. PATIENTS AND METHODS: Premenopausal women with a history of recent UTI were enrolled from November 16, 2005, through December 31, 2008, at 2 centers and randomized to 1 of 3 arms: 4 oz of cranberry juice daily, 8 oz of cranberry juice daily, or placebo juice. Time to UTI (symptoms plus pyuria) was the main outcome. Asymptomatic bacteriuria, adherence, and adverse effects were assessed at monthly visits. RESULTS: A total of 176 participants were randomized (120 to cranberry juice and 56 to placebo) and followed up for a median of 168 days. The cumulative rate of UTI was 0.29 in the cranberry juice group and 0.37 in the placebo group (P=.82). The adjusted hazard ratio for UTI in the cranberry juice group vs the placebo group was 0.68 (95% confidence interval, 0.33-1.39; P=.29). The proportion of women with P-fimbriated urinary E coli isolates during the intervention phase was 10 of 23 (43.5%) in the cranberry juice group and 8 of 10 (80.0%) in the placebo group (P=.07). The mean dose adherence was 91.8% and 90.3% in the cranberry juice group vs the placebo group. Minor adverse effects were reported by 24.2% of those in the cranberry juice group and 12.5% in the placebo group (P=.07). CONCLUSION: Cranberry juice did not significantly reduce UTI risk compared with placebo. The potential protective effect we observed is consistent with previous studies and warrants confirmation in larger, well-powered studies of women with recurrent UTI. The concurrent reduction in urinary P-fimbriated E coli strains supports the biological plausibility of cranberry activity. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00128128.