Development of bacterial resistance to antibiotics has become a considerable threat to human health. Because bacteria can adapt so quickly to new drugs, better approaches are needed to continue to develop novel strategies and tactics to combat these pathogenic bacteria.

Microbe-specific muramidase proteins have the potential for use to treat infections caused by specific groups of microbes. LLNL has synthesized and purified milligram quantities of two muramidases and developed a cell-based lysis assay to test these proteins.It has demonstrated that these purified muramidases lyse B. anthracis Sterne when applied externally to these cells. Their methods can be generally applied to identify and rapidly screen for similar lytic proteins encoded by other bacterial pathogens that could be further developed as antimicrobial compounds to destroy these pathogens.


LLNL researchers have combined a novel approach or using bioinformatics with cell-free expression to identify and characterize a class of proteins that kill Gram-positive bacteria with extremely high specificity. The class of proteins is collectively known as muramidases and possess bacterial lytic activity. Muramidases generally represent a potential class of novel antimicrobials for use against other Gram positive and, potentially, against Gram-negative infectious microorganisms. Strategies for effectively delivering these antimicrobial agents are being developed. These lytic proteins attack for the outside of the cells and circumvent mechanisms of antibiotic resistance that are found in many of the so-called drug-resistant superbugs. As such, they should be effective against these antibiotic resistant pathogens. These lytic proteins can also be used to specifically lyse target bacteria in complex mixtures resulting in rapid, specific, and quantitative release of DNA and other macromolecules from complex mixtures, facilitating development of automated assays that do not require physical disruption techniques for release of these diagnostic molecules.


The competitive advantages of LLNL's targeted antimicrobials based on recombinant muramidases include:

  • A novel approach to attacking pathogens of interest by the rapid production of recombinant lytic proteins encoded by the pathogen's own genome.
  • A novel pipeline for rapidly identifying and producing new antimicrobials capable of specifically killing known bacterial pathogens.
  • Recombinant compounds that mimic a known naturally occurring mechanism for bacteriophage release from the bacteria and are known to be required for bacterial cell wall synthesis and metabolism and can be rapidly produced in milligram quantities.
  • Provides an essential component to the scientific community that enables the rapid lysis of many different bacterial species including those classes that are difficult to lyse such as the bacilli.
  • Technological leap forward for cell lysis approaches needed to improve automated detection and characterization methods that rely on real-time aerosol analysis of bacteria and bacterial pathogens.
Potential Applications

Potential applications for use include:

  • Basic biochemical research
  • Removing live bacteria for spore isolation
  • Treatment and removal of select bacterial pathogens
  • Antibody based detection of pathogens
  • Surface treatment of instrumentation and hard surfaces
  • Cleaning surgical instruments
  • DNA preparative reagent to lyse bacteria
  • Additive to topical lotions as antimicrobial agent
  • Additive to bandages to kill bacterial pathogens
  • Fermentation to remove undesirable bacteria, food additive, or wash
  • Reagent to destroy biofilms
  • Species-specific antimicrobials that destroy specific antibiotic-resistant pathogens without the use of broad-spectrum antibiotics
Development Status

This technology has been awarded US Patent No. 8,821,860 Targeted Antimicrobials and Related Compositions, Methods and Systems.

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