A Case Report of Aerococcus urinae Urinary Tract Infection in an Elderly Male with Multimorbidity.

Aerococcus urinae is a rare cause of urinary tract infection (UTI) seen in elderly males with multimorbidity. Incidence is estimated between 0.15 and 0.8%. This organism is frequently misidentified for other gram-positive species. Missed or delayed diagnosis of A. urinae UTI can lead to systemic infection with high morbidity and potential mortality. We present a classic case of A. urinae UTI in a 91-year-old male with multiple comorbidities, including heart failure, diabetes mellitus, and metastatic prostate carcinoma. Empiric therapy with nitrofurantoin was unsuccessful, but intravenous ceftriaxone and bladder catheterization resulted in rapid symptomatic improvement. Variable antimicrobial sensitivities and resistance have been reported for A. urinae. Therefore, antimicrobial resistance testing should be performed for all patients with A. urinae infections.