Asymptomatic Bacteriuria and Pyuria in Premenopausal Women

Abstract

Background: Asymptomatic bacteriuria and pyuria in healthy women often trigger inappropriate antimicrobial treatment, but there is a paucity of data on their prevalence and persistence.

Methods: To evaluate the prevalence and persistence of asymptomatic bacteriuria and pyuria in women at high risk of recurrent urinary tract infection, we conducted an observational cohort study in 104 healthy premenopausal women with a history of recurrent urinary tract infection with daily assessments of bacteriuria, pyuria, and urinary symptoms over a 3-month period.

Results: The mean age of participants was 22 years, and 74% were white. Asymptomatic bacteriuria events (urine cultures with colony count ≥105 CFU/mL of a uropathogen on days with no symptomatic urinary tract infection diagnosed) occurred in 45 (45%) women on 159 (2.5%) of 6283 days. Asymptomatic bacteriuria events were most commonly caused by Escherichia coli, which was present on 1.4% of days, with a median duration of 1 day (range, 1-10). Pyuria occurred in 70 (78%) of 90 evaluable participants on at least 1 day and 25% of all days on which no symptomatic urinary tract infection was diagnosed. The positive predictive value of pyuria for E. coli asymptomatic bacteriuria was 4%.

Conclusions: In this population of healthy women at high risk of recurrent urinary tract infection, asymptomatic bacteriuria is uncommon and, when present, rarely lasts more than 2 days. Pyuria, on the other hand, is common but infrequently associated with bacteriuria or symptoms. These data strongly support recommendations not to screen for or treat asymptomatic bacteriuria or pyuria in healthy, nonpregnant women.

Keywords: ASB; UTI; antimicrobial stewardship; asymptomatic bacteriuria; pyuria.

Figure 1.

Daily midstream urine (MSU) Escherichia coli colony count, level of leukocyte esterase, presence of UTI symptoms, and presence of recurrent UTI (rUTI) by day of follow-up. Panels A–F represent 6 study participants whose ID numbers correspond to subject identifiers in Supplementary Figures (data from all study participants are in the Supplement). All study participants had UTI symptoms and pyuria at their enrollment UTI visit (Follow-up day 0) and for 0–6 days afterward. Leukocyte esterase and UTI symptom information were from participants’ diaries. MSU E. coli colony counts and leukocyte esterase levels connected with a straight line with no dots represent days with missing information. Following are brief highlights of the 6 participants’ findings: A) #66 no E. coli rUTI, bacteriuria, pyuria, or UTI symptoms; B) #55 no E. coli rUTI but frequent high-level pyuria with occasional low colony count E. coli bacteriuria, no UTI symptoms; C) #57 no E. coli rUTI but some E. coli ASB episodes and low colony count E. coli bacteriuria and frequent pyuria, no UTI symptoms; D) #9 E. coli rUTI (10⁵) with E. coli ASB events, UTI symptoms, and pyuria before/after rUTI; some low colony count E. coli bacteriuria and UTI symptoms, without pyuria; E) #11 E. coli rUTI (10⁵) with E. coli ASB event and pyuria before rUTI; frequent pyuria without bacteriuria; F) #94 E. coli rUTI (10⁵); 2 clusters of E. coli ASB episodes, frequent pyuria, occasional UTI symptoms (“subclinical UTI” when all 3 factors are present). Abbreviations: neg, negative; UTI, urinary tract infection.