Ampicillin

Ampicillin (C₁₆H₁₈N₃O₄S ; CAS No.: 69-53-4) is an aminopenicillin and, as such, is a broad-spectrum antibiotic and has been used extensively to treat bacterial infections since 1961. It can sometimes result in allergic reactions that range in severity from a rash to potentially lethal anaphylaxis. more...

Belonging to the group of beta-lactam antibiotics, ampicillin is able to penetrate Gram-negative bacteria. It inhibits the third and final stage of bacterial cell wall synthesis, which ultimately leads to cell lysis. Ampicillin is closely related to Amoxicillin, another type of penicillin, and both are used to treat urinary tract infections, otitis media, uncomplicated community acquired pneumonia, Haemophilus influenzae, invasive salmonella and Listeria meningitis. It is used with Flucloxacillin in the combination antibiotic Co-fluampicil for empiric treatment of cellulitis; providing cover against Group A streptococcal infection whilst the Flucloxacillin acts against Staphylococcus aureus.

Ampicillin is often used in molecular biology as a test for the uptake of genes (e.g., by plasmids) by bacteria (e.g., E. coli). A gene that is to be inserted into a bacterium is coupled to a gene coding for an ampicillin resistance (in E. coli, usually the bla gene, coding for β-lactamase). The treated bacteria are then grown on a medium containing ampicillin. Only the bacteria that successfully take up the desired genes become ampicillin resistant, and therefore contain the other desired gene as well.

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