Ampicillin

Ampicillin

Clinical data
Pregnancy category	A (Au), B (U.S.)
Routes of administration	Oral, intravenous
ATC code	J01CA01 (WHO) S01AA19 (WHO) QJ51CA01 (WHO)
Legal status
Legal status	US: WARNING
Pharmacokinetic data
Bioavailability	40% (oral)
Protein binding	15 to 25%
Metabolism	12 to 50%
Elimination half-life	approx 1 hour
Excretion	75 to 85% renal
Identifiers
IUPAC name (2S,5R,6R)-6-([(2R)-2-amino-2-phenylacetyl]amino) -3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2- carboxylic acid
CAS Number	69-53-4
PubChem CID	6249
DrugBank	DB00415
ChemSpider	6013
CompTox Dashboard (EPA)	DTXSID4022602
ECHA InfoCard	100.000.645
Chemical and physical data
Formula	C16H19N3O4S
Molar mass	349.41 g·mol−1 g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C(O)[C@@H]2N3C(=O)[C@@H](NC(=O)[C@@H](c1ccccc1)N)[C@H]3SC2(C)C
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Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. Until the introduction of ampicillin by the British company, Beecham, penicillin therapies had only been effective against Gram-positive organisms such as staphylococci and streptococci. Ampicillin (originally branded as 'Penbritin') also demonstrated activity against Gram-negative organisms such as H. influenzae, coliforms and Proteus spp. Ampicillin was the first of a number of so-called broad spectrum penicillins subsequently introduced by Beecham. Ampicillin 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. However, as with other penicillin drugs, it is relatively non-toxic and adverse effects of a serious nature are encountered only infrequently.

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, which is needed by bacteria to make their cell walls. It inhibits the third and final stage of bacterial cell wall synthesis in binary fission, which ultimately leads to cell lysis.The holes that appear in the cell walls allow the body’s immune system to take over and fight off the bacteria. Ampicillin has received FDA approval for its action of mechanism.

Effects on chloroplasts division

Ampicillin, like other β-lactam antibiotics, not only blocks the division of bacteria, but also the division of chloroplasts of the Glaucophytes (called cyanelles) and chloroplasts of the moss Physcomitrella patens, a bryophyte. In contrast, it has no effect on the plastids of the higher developed vascular plant Lycopersicon esculentum L. (tomato) . Ampicillin inhibits bacterial growth.

Application

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.

Use in research

Ampicillin is often used as a selective agent in molecular biology to select for and 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 in a medium containing ampicillin (typically 50–100 mg/L). 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. As a powder ampicillin is white with slight yellow cast and is soluble in water (150 mg/ml).