Mecillinam is a broad-spectrum β-lactam antibiotic in the penicillin class, specifically an amidinopenicillin. It is effective against Gram-negative bacteria and was first described in 1972 by Lund and Tybring.
|Mechanism of Action||β-lactams interfere with penicillin binding protein (PBP) activity involved in the final phase of peptidoglycan synthesis. PBP’s 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||Mecillinam targets primarily Gram-negative bacteria involved in urinary tract infections. It has minimal activity against Gram-positive organisms.|
|Microbiology Applications||Mecillinam is commonly used in clinical in vitromicrobiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram- negative microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options .
Representative MIC values include:
Lund, F., and L. Tybring. 1972. 6 -amidinopenicillanic acids -a new group of antibiotics. Nat. New Biol. 236(66):135-137 PMID 4402006
Maioli E, Debbia EA, Gualco L, Marchese A (2008) In vitro interaction between mecillinam and piperacillin-tazobactam in the presence of azithromycin against members of the Enterobacteriaceae family and Pseudomonas aeruginosa. New Microbiol.31(1):37-46 PMID 18437840
New HC (1976) Mecillinam, a novel penicillanic acid derivative with unusual activity against Gram-negative bacteria. Antimicrob. Agents. Chemother. 9(5):793-790
Pitout JD, Sanders CC, Sanders WE (1997) Antimicrobial resistance with focus on beta-lactam resistance in gram-negative bacilli. Am J Med 103:51
|MIC||Aeromonas spp.| ≥1|| Bacteroides fragilis (NCTC 9343)| ≥128|| Campylobacter spp.| ≥4|| Enterobacteriaceae| 0.03 － >128|| Escherichia coli| 8 - 16|| Plesiomonas shigelloides| ≥1|| Salmonella spp.| ≥2|| Shigella spp.| ≥16|||