Diagnosis requires clinical, and laboratory and culture criteria:
Clinical criteria: fever, irritability, decreased feeding, crying with micturition and if verbal, dysuria, urinary frequency, new incontinence, back or flank pain, malaise.
Laboratory criteria: positive nitrites and/or leukocyte esterase (LE) on urinalysis and/or pyuria (>5-10) on microscopy. If both LE and nitrites are negative, do not send a urine culture as low probability of a UTI. Blood culture should be done.
Culture criteria: ≥50 X 106 CFU/L of a single uropathogen such as E. coli, Klebsiella. Amounts less that this or mixed growth are most likely due to contamination.
If above criteria are not met, consider other diagnoses/explanations (e.g., sterile pyuria in other inflammatory conditions).
Routine Practices
If renal dysfunction, use alternative agent such cefotaxime or ceftriaxone
OR
Usually 7 days including oral antibiotics if rapid response to therapy.
Can step down to oral when afebrile for 24-48 hours and susceptibilities available.
Duration should be longer than 7 days (e.g.,10 days) if patient is slow to respond OR has structural abnormality of the urinary tract OR has a relatively resistant pathogen.
Complicated infections such as abscess will require individualized durations.