Urinary tract infection by Streptococcus equinus: a pediatric case presentation

Streptococcus equinus is a non-enterococcal group D Streptococcus, Gram positive, non-hemolytic, lactic acid bacterium. The incidence of colonization in humans increases in rural areas, where there is high risk of exposure to animal feces and fermented food products. It is associated with specific diseases, such as osteoarticular infections, meningitis, biliary infections, infective endocarditis and colorectal cancer. A male 10-year-old patient, asymptomatic, without underlying medical conditions, was referred for routine check-up at the Outpatient Pediatric Clinic of the Nikea General Hospital, Piraeus, Greece. According to patient history, he had spent two weeks at a summer camp, where he had direct contact with horses, such as horse riding, horse feeding, watering, horse care, etc. His brother, although he had the same contacts and activities, did not present an infection. Examinations of the eyes, mouth, ears, nose, throat and abdomen were normal. Laboratory tests showed mild leukocytosis (12 000/mm³, with 80% neutrophils) and slightly increased erythrocyte sedimentation rate (30 mm/h). Urinalysis and microscopy revealed bacteriuria by nitrite test and pyuria, so urine cultures were performed (Multistix 10 SG Reagent Strips, Siemens Healthineers). The urine culture grew monomicrobial S. equinus > 10⁵ CFU/ml. The bacterium was identified by the RapID™ REMEL ONE identification system (Thermo Fisher Scientific). Antimicrobial susceptibility testing revealed resistance to Clindamycin, Tetracycline, Cefotaxime and high susceptibility to Erythromycin. The patient received treatment with Erythromycin. Streptococcus equinus has been isolated from the bowel in approximately 7% of the general population. Urinary tract infections are less common. Risk factors for human colonization are considered living in rural areas and having contact with animal feces. The patient, during his stay at the summer camp, had probably contact with horse feces during the relevant activities and therefore infected.