Acute Cystitis in Premenopausal Women: How Valuable is Midstream Urine Culture?

Thomas M. Hooton M.D. Associate Chief of Staff, Medical Service, Miami VA Healthcare System Professor of Clinical Medicine and Vice Chair for VA Affairs, Department of Medicine, UMSOM Clinical Director, Division of Infectious Diseases, UMSOMMedicalResearch.com Interview with:
Thomas M. Hooton M.D.
Professor of Medicine and Vice Chair for VA Affairs,
University of Miami Miller School of Medicine
Associate Chief of Staff, Medical Service, Miami VA Healthcare System
Clinical Director, Division of Infectious Diseases

MedicalResearch.com: What are the main findings of the study?

Dr. Hooten: The main findings from this study are:

·        Voided urine colony counts of E. coli as low as 101 to 102 cfu/mL are highly sensitive and specific for their presence in bladder urine in symptomatic women (growth of bacteria in bladder urine is the gold standard for the etiology of UTI). Moreover, even when E. coli is found along with other mixed flora in voided urine, it should not be considered a contaminant since it likely represents true bladder infection.

·        On the other hand, enterococci and Group B streptococci, which are frequently isolated from voided urine, are rarely isolated from paired catheter specimens, suggesting that these organisms only rarely cause acute uncomplicated cystitis. In our study, E. coli frequently grew from the urines of these women and is the likely cause for UTI symptoms in such episodes.

·        Organisms usually considered contaminants, such as lactobacilli, occasionally grow from catheter urines, but they are rarely found alone with pyuria, suggesting that these bacteria rarely cause acute uncomplicated cystitis.

·        The etiology of a quarter of acute uncomplicated cystitis episodes is unknown.  It is possible that some of these women have E. coli urethritis, which has been documented in some women with UTI symptoms, but we did not do further studies to evaluate this. It is possible also that enterococci and Group B streptococci may also cause urethritis, but there is no published evidence of this in young women with UTI symptoms.

·        Although voided urine cultures growing mixed flora are common in women with acute cystitis, true polymicrobic cystitis, as determined by sampling bladder urine, appears to be rare in this population.
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