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 by Lund and Tybring and is effective against Gram-negative bacteria.

    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 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 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

    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||