Penicillin is a member of the β-lactam antibiotics and was one of the first discovered antibiotics.
Penicillin G sodium salt is sparingly soluble in aqueous solution (0.210 mg/mL). Click here for more forms of penicillin.
|Mechanism of Action||β-lactams interfere with PBP (penicillin binding protein) activity involved in the final phase of peptidoglycan synthesis. PBP’s are enzymes which catalyze a pentaglycine crosslink between alanine and lysine residues providing additional strength to the cell wall. Without a pentaglycine crosslink, the integrity of the cell wall is severely compromised and ultimately leads to cell lysis and death. Resistance to β-lactams is commonly due to cells containing plasmid encoded β-lactamases.|
|Spectrum||Penicillin is targets primarily Gram positive bacteria including Staphylococcus and Streptococcus species|
|Microbiology Applications||Penicillin is commonly used in clinical in vitro microbiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against gram positive microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options for infected patients. Representative MIC values include:|
Mycoplasma Media Supplements
Penicillin can be used as a selective agent in several types of isolation media:
Mycoplasma Agar - Mycoplasma Supplement G
Mycoplasma Agar - Mycoplasma Supplement P
Guzmán, Flavio, MD. "Beta Lactams Antibiotics (penicillins and Cephalosporins) Mechanism of Action.” Medical Pharmacology. Pharmacology Corner, 29 Nov. 2008. Web. 21 Aug. 2012.
Pitout JD, Sanders CC, Sanders WE Jr. Antimicrobial resistance with focus on beta-lactam resistance in gram-negative bacilli. Am J Med 1997; 103:51.
|MIC||Bacillus cereus| ≥2|| Bacillus pumilus| ≥1|| Escherichia coli| ≥15.11|| Micrococcus kristinae| ≥1|| Proteus vulgaris| ≥1|| Pseudomonas aeruginosa| ≥512 || Salmonella spp.| ≥4|| Shigella flexneri| ≥8|| Staphylococcus aureus| 1 － >32|||