SKU: M001  / 
    CAS Number: 32887-01-7



    Mecillinam is a broad-spectrum β-lactam antibiotic in the penicillin class, specifically an amidinopenicillin. It was first described in 1972 (Lund and Tybring) and was developed by the Danish pharmaceutical company Leo Pharmaceutical Products (now LEO Pharma).  The product is effective against Gram-negative bacteria.  Mecillinam is slightly soluble in chloroform.

    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.  It has minimal activity against Gram-positive organisms.
    Microbiology Applications

    Mecillinam is commonly used in clinical in vitro microbiological antimicrobial susceptibility tests (panels, discs, and MIC strips) against Gram-negative microbial isolates. Medical microbiologists use AST results to recommend antibiotic treatment options.

    MIC values include:

    • Escherichia coli 8 µg/mL
    • For a representative list of Mecillinam MIC values, click here.
    Molecular Formula C15H23N3O3S

    Lund F and Tybring L (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

    Thomas K, Weinbren MJ, Warner M, Woodford N and Livermore D (2006) Activity of Mecillinam against ESBL producers in vitro. J. Antimicrob. Chemother. 57(2):367-368

    Tybring L and Melchior NH (1975)  Mecillinam (FL 1060), a 6β-Amidinopenicillanic acid derivative: Bactericidal action and synergy in vitro.  

    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||