High Diagnostic Accuracy of Nitrite Test Paired with Urine Sediment can Reduce Unnecessary Antibiotic Therapy

Abstract

Background:Urinary tract infections (UTIs) are common bacterial infections dominated by lower UTI in women (LUTIW). Symptoms only are insufficient for diagnosis and accordingly, near patient diagnostic tests confidently confirming significant bacteriuria are desirable. The nitrite test (NIT) has low sensitivity, while bacterial and leukocyte counts disjunctively paired in urine sediment microscopy (SED) have high sensitivity. Similar symptomatic cure rates are found post antibiotic vs. placebo therapy in patients with negative cultures. Consequently, prescription on symptoms only implies unnecessary antibiotic therapy.Aims:to evaluate the diagnostic outcomes of NIT, SED and NIT disjunctively paired with SED (NIT+SED) vs. urine culture, with special focus on bladder incubation time (BIT), and to assess if NIT+SED can reduce unnecessary antibiotic therapy.Methods:A diagnostic, primary care, multicentre study including 1070 women with symptoms suggestive of lower UTI.Results: Significant bacteriuria was found in 77%. The BIT highly influenced the diagnostic outcomes and the optimal duration was ≥4h with sensitivity of 66, 90 and 95% for NIT, SED and NIT+SED, respectively. SED performed only in NIT negative specimens could reduce unnecessary antibiotics by 10% vs. prescription on symptoms only. The number needed to test with SED to reduce one unnecessary antibiotic course was five patients at BIT ≥4h and six patients at ≤3h or overall.Conclusion:The BIT highly influences the diagnostic outcomes with the highest accuracy of NIT+SED. Diagnosis of LUTIW with NIT+SED can reduce unnecessary antibiotic therapy and subsequently decrease antimicrobial resistance. Trial registration:The Swedish Medical Product Agency 1995 03 01:151:01783/94.

Clinical accuracy of point-of-care urine culture in general practice

“…Agreement in this study was higher than most studies investigating urine dipstick in symptomatic patients, but comparable to a recent study diagnosing UTI with a combination of dipstick and microscopy [ 11 , 28 ]. The field trial validation study of Flexicult™ SSI-Urinary Kit [ 17 ] does not report overall agreement, but reports discrepancies in quantification between index and reference as 16% before adjustment for various factors.…”

Strategies to reduce antibiotic use in women with uncomplicated urinary tract infection in primary care: protocol of a systematic review and meta-analysis including individual patient data

“…Candidate prognostic factors and moderators will include age, presence, severity and duration of patient-reported symptoms (eg, dysuria, frequency, urgency, lower abdominal pain), physician-reported physical examination findings (eg, fever, loin pain), point-of-care tests (eg, dipstick test results, C reactive protein, urine sediment, other point-of-care tests) and other additional variables like the bladder incubation time, at the initial consultation or inclusion, if available. 20 Although urine culture results are not available at the time of the treatment decisions, we will investigate the results (positive or negative for the presence of uropathogens and antimicrobial resistance) as possible antibiotic effect moderators.…”

Prevalence of urinary tract infection in ambulatory patients and its relationship to nitrite values and leukocytes

“…Uma possível explicação seria a necessidade de mais de quatro horas de retenção urinária para que a bactéria pudesse ser capaz de reduzir o nitrato a nitrito. (22) A análise da contagem de leucócitos nos revelou maior especificidade (89,2%) do que sensibilidade (67,2%). Situação também encontrada por Huysal et al, (12) que observaram uma especificidade de 91,1% e sensibilidade de 47,0%.…”