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Asymptomatic Bacteriuria Often Inappropriately Treated With Antibiotics

August 29, 2019

By Megan Brooks

NEW YORK (Reuters Health) - Hospitalized patients with asymptomatic bacteriuria (ASB) are often inappropriately given antibiotics, which is unlikely to improve outcomes and may prolong hospital stay, new research suggests.

"These data show the potential harm of using antibiotics to treat hospitalized patients with bacteriuria in the absence of urinary symptoms," Dr. Lindsay Petty of Michigan Medicine in Ann Arbor told Reuters Health by email. The findings were published online August 26 in JAMA Internal Medicine.

The researchers evaluated risk factors and outcomes associated with treatment of ASB in a retrospective study of 2,733 hospitalized adults with ASB.

They defined ASB as no documentation of signs or symptoms meeting diagnostic criteria for UTI per Infectious Disease Society of America guidelines and National Healthcare Safety Network definitions.

Specifically, patients could not have one of the following documented signs or symptoms: dysuria, urinary frequency/urgency, suprapubic pain, fever (temperature ≥38 degrees Celsius), costovertebral pain/tenderness, hematuria, and autonomic dysreflexia or increased spasticity in patients with spinal cord injury.

Patients with acute alterations in mental status, who often can't communicate symptoms, were categorized as having ASB if they had none of the aforementioned signs or symptoms and no systemic signs of possible infection (peripheral white blood cell count >10 000 cells/μL), systolic blood pressure <90 mm Hg, or ≥2 criteria for systemic inflammatory response syndrome).

Altogether 2,259 (83%) participants received antibiotics for a median of seven days.

Factors significantly associated with antibiotic therapy for ASB included older age (odds ratio, 1.10 per 10-year increase), dementia (OR, 1.57), acutely altered mental status (OR, 1.93), urinary incontinence (OR, 1.81), leukocytosis (white blood cell count >10,000/uL, OR, 1.55), positive urinalysis (presence of leukocyte esterase or nitrite, or >5 white blood cells per high-power field, OR, 2.83) and urine culture with a bacterial colony count >100,000 CFUs per high-power field, OR, 2.30).

"The strongest factor associated with treatment of ASB was an abnormal urinalysis, which likely represents a misinterpretation of the urinary-tract infection (UTI) diagnostic criteria," Dr. Petty commented. "Clinicians should not presume that pyuria or nitrites in the absence of urinary symptoms is diagnostic of a UTI."

"We did not identify benefits to treatment, but did find an association with 37% longer duration of hospitalization. Especially in the elderly altered patient, clinicians may treat ASB despite no other signs of systemic infection out of fear of missing something," she noted.

"To possibly reduce inappropriate antibiotic use, stewardship efforts should focus on improving urine testing practices and management strategies for elderly patients with altered mental status," Dr. Petty and colleagues conclude in their report.


JAMA Intern Med 2019.

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