Ampicillin is commonly used as pathogen directed therapy for intravascular, intra-abdominal and urinary infections secondary to certain Enterococcus spp.
Ampicillin is used as empiric therapy for bacterial meningitis if risk factors for Listeria monocytogenes are present.
Patients with infectious mononucleosis secondary to EBV and given amoxicillin or ampicillin may develop a rash and this is not indicative of a true allergy.