1- Infant appears generally well

2- Infant has been previously healthy:

• Born at term (>/=37 weeks of gestation)

• No perinatal antimicrobial therapy

• No treatment for unexplained hyperbilirubinemia

• No previous antimicrobial therapy

• No previous hospitalization

• No chronic or underlying illness

• Not hospitalized longer than mother

3- Infant has no evidence of skin, soft tissue, bone, joint or ear infection

4- Infant has these laboratory values:

• White blood cell count of 5,000 to 15,000 per mm³ (5 to 15 x 10⁹ per L)

• Absolute band cell count of </=1,500 per mm³ (</=1.5 x 10⁹ per L)

• Ten or fewer white blood cells per high-power field on microscopic examination of urine

• Five or fewer white blood cells per high-power field on microscopic examination of stool in infant with diarrhea