Ampicillin

Ampicillin
Systematic (IUPAC) name
7-(2-amino-2-phenyl-acetyl)amino-3,3 -dimethyl-6-oxo-2-thia-5-azabicyclo [3.2.0]heptane-4-carboxylic acid
Identifiers
CAS number	69-53-4
ATC code	J01CA01
PubChem	6249
DrugBank	APRD00320
Chemical data
Formula	C16H19N3O4S
Mol. mass	349.406 g/mol
Pharmacokinetic data
Bioavailability	40% (oral)
Protein binding	15 to 25%
Metabolism	12 to 50%
Half life	approx 1 hour
Excretion	75 to 85% renal
Therapeutic considerations
Pregnancy cat.	A (Au), B (U.S.)
Legal status
Routes	Oral, intravenous

Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. It is considered part of the aminopenicillin family and is roughly equivalent to amoxicillin in terms of spectrum and level of activity. (2006) AHFS DRUG INFORMATION® 2006, 2006 ed, American Society of Health-System Pharmacists.  It can sometimes result in allergic reactions that range in severity from a rash (e.g. patients with mononucleosis) to potentially lethal anaphylaxis.

Mechanism of action

Belonging to the penicillin group of beta-lactam antibiotics, ampicillin is able to penetrate Gram-positive and some Gram-negative bacteria. It differs from penicillin only by the presence of an amino group. That amino group helps the drug penetrate the outer membrane of gram-negative bacteria. Ampicillin acts as a competitive inhibitor of the enzyme transpeptidase. Transpeptidase is needed by bacteria to make their cell walls. It inhibits the third and final stage of bacterial cell wall synthesis, which ultimately leads to cell lysis.

Indications

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. Of concern is the number of bacteria that become resistant to Ampicillin necessitating combination therapy or use of other antibiotics.

All Pseudomonas and most strains of Klebsiella and Aerobacter are considered resistant. (2006) Mosby\'s Drug Consult 2006, 16 ed, Mosby, Inc.. 

Use in research

Ampicillin is often used as a selective agent in molecular biology to confirm the uptake of genes (e.g., of 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 (TEM-1) 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. It can be used with Cloaxicillin as well.

External links

References

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