Ampicillin is a beta-lactam antibiotic that 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.

Mechanism of action

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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.

Indications

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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, salmonellosis 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 the Staphylococcus aureus bacterium.

Use in research

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.

Beta-lactam antibiotics

Ampicillin | Ampicilline | Ampicillin | Ampicilín | แอมพิซิลลิน