As Always, asymptomatic Bacteriuria is best Ignored

A study in healthy young women confirms that treatment leads to trouble.

Many clinicians treat patients who have asymptomatic bacteriuria (AB), but studies have confirmed that AB treatment provides no benefit in many groups, including older people, diabetic patients, and those with spinal cord injuries. Similar evidence now is provided for healthy young women with recurrent urinary tract infections (UTIs).

Almost 700 sexually active premenopausal women with AB who presented to a single Italian clinic were randomized to receive unblinded treatment or to be followed without treatment. All participants had experienced at least one UTI in the previous year. Those who were treated received oral antibiotics, to which their microbial isolates were confirmed to be sensitive.

After 3 months, 3.5% of untreated women and 8.8% of treated women experienced new symptomatic UTIs. The curves continued to diverge: By 1 year of follow-up, UTI recurrence rates were dramatically higher in the treated group (by our calculations from the data provided, cumulative UTI recurrence rates were 24% in the untreated group and 83% in the treated group). Rates of pyelonephritis were similar between groups.

At the beginning of the study, most bacterial isolates were Escherichia coli (39%) or Enterococcus faecalis (33%). One year later, urine samples from most recurrence-free patients in the nontreatment group grew E. faecalis, whereas most samples from the few treated patients who were recurrence free grew E. coli.

Comment: This study adds sexually active young women to the list of those in whom asymptomatic bacteriuria should not be treated — in fact, treatment was harmful in this study. Treatment now is endorsed only during pregnancy and before urinary instrumentation. Editorialists link this insight to the developing understanding of the human microbiome and bacterial interference, in which colonizing nonpathogenic bacteria often defend against local infection far better than antibiotics do. Is E. faecalis a colonizer to be valued? Further studies will tell us.

Published in Journal Watch General Medicine October 11, 2012

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