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Antibacterial agents that inhibit lipid A biosynthesis
H R Onishi1, B A Pelak, L S Gerckens
1Department of Microbiology, Merck Research Laboratories, Rahway, NJ 07065, USA.
Science (New York, N.Y.)
|November 8, 1996
Summary
New synthetic antibacterials targeting lipid A biosynthesis show potent activity against Gram-negative bacteria. These inhibitors effectively kill Escherichia coli and protect mice from lethal infections.
Area of Science:
- Microbiology
- Medicinal Chemistry
- Drug Discovery
Background:
- Lipid A is a crucial component of the Gram-negative bacterial outer membrane.
- Inhibition of lipid A biosynthesis presents a promising target for novel antibacterial agents.
Purpose of the Study:
- To identify and characterize synthetic antibacterials that inhibit lipid A biosynthesis.
- To evaluate the efficacy of these inhibitors against Gram-negative bacteria, including Escherichia coli.
Main Methods:
- Synthesis of chiral hydroxamic acids with hydrophobic aromatic moieties.
- Enzyme inhibition assays to determine the potency against the lipid A deacetylase.
- Bacterial growth inhibition assays (minimal inhibitory concentration) and time-kill studies.
- In vivo efficacy studies in a mouse model of Escherichia coli infection.
Main Results:
- Identified potent inhibitors of the lipid A deacetylase, a key enzyme in lipid A biosynthesis.
- The most potent analog exhibited an inhibition constant (Ki) of approximately 50 nM.
- Demonstrated a minimal inhibitory concentration (MIC) of ~1 µg/mL against Escherichia coli.
- Achieved three logs of bacterial killing within 4 hours and successfully treated lethal E. coli infections in mice.
Conclusions:
- Synthetic chiral hydroxamic acids are effective inhibitors of lipid A biosynthesis.
- These compounds represent a promising new class of antibacterials against Gram-negative pathogens.
- The identified inhibitors show significant potential for therapeutic development against bacterial infections.