(3) Ampicillin Explanation: Ampicillin is the large spectrum anti-biotic most commonly used. Ampicillin is a beta-lactam antibiotic that is part of the aminopenicillin family and is roughly equivalent to its successor, amoxicillin in terms of spectrum and level of activity. It can sometimes result in reactions that range in severity from a rash (in the case of patients that may unwittingly have mononucleosis) to potentially lethal allergic reactions such as anaphylaxis.