Paediatricsmiddle twist
A 5-month-old girl has had a fever of 39.2 °C for 24 hours with vomiting and irritability, and no cough, runny nose or rash. Examination is otherwise unremarkable. A urine sample collected in an adhesive bag shows leucocytes 3+ and nitrites positive on dipstick. She has not yet received any antibiotics.
Which one of the following is the most appropriate next step?