Descriptive Epidemiology of Aerococcus urinae Isolated From Urine Cultures in a Pediatric Hospital: A Case Series

Aerococcus urinae is a potential causative pathogen of urinary tract infections in pediatric patients with underlying nephrological or urinary tract disorders. However, the need for targeted antimicrobial therapy remains controversial. Herein, we evaluated pediatric patients in whom A. urinae was identified in urine cultures and compared the clinical outcomes between those who received antimicrobial therapy and those managed with observation alone.

Urine cultures submitted from 2018 to 2023 were retrospectively reviewed. Cases were included if A. urinae was cultured at ≥ 10⁴ colony-forming units (CFU)/mL in the presence of pyuria.

Twenty-six patients met the inclusion criteria; all had preexisting nephrological or urinary tract disorders. A. urinae was isolated as a monoclonal species in only two cases. Thirteen patients (50%) received antimicrobial therapy, most commonly for cystitis, while 13 (50%) were managed conservatively without antimicrobials, achieving spontaneous resolution without relapse. Comparative analysis revealed that myelomeningocele and nitrite positivity were significantly more frequent in the observation group (p = 0.021 and p = 0.009, respectively). Co-infection with other bacterial species was frequently observed in cases where A. urinae was isolated; however, whether these co-isolated organisms were the primary pathogens remains unclear, along with guidance on treatment decisions.

Given that approximately half of the cases involving multiple organisms, including A. urinae, were resolved without antimicrobial intervention, it is crucial to reassess the clinical significance of A. urinae and its potential for contaminating such cultures. Treatment decisions should be individualized by considering anatomical risk factors and the overall clinical context.