A bacteriolytic agent that detects and kills Bacillus anthracis

Abstract

The dormant and durable spore form of Bacillus anthracis is an ideal biological weapon of mass destruction. Once inhaled, spores are transported by alveolar macrophages to lymph nodes surrounding the lungs, where they germinate; subsequent vegetative expansion causes an overwhelming flood of bacteria and toxins into the blood, killing up to 99% of untreated victims. Natural and genetically engineered antibiotic-resistant bacilli amplify the threat of spores being used as weapons, and heighten the need for improved treatments and spore-detection methods after an intentional release. We exploited the inherent binding specificity and lytic action of bacteriophage enzymes called lysins for the rapid detection and killing of B. anthracis. Here we show that the PlyG lysin, isolated from the gamma phage of B. anthracis, specifically kills B. anthracis isolates and other members of the B. anthracis 'cluster' of bacilli in vitro and in vivo. Both vegetative cells and germinating spores are susceptible. The lytic specificity of PlyG was also exploited as part of a rapid method for the identification of B. anthracis. We conclude that PlyG is a tool for the treatment and detection of B. anthracis.

Treatment of Experimental Anthrax with Recombinant Capsule Depolymerase

“…The availability of antibacterial enzymes for the treatment of anthrax, however, may prove valuable, particularly against antibiotic-resistant strains for which no treatment may be available. Recent reports indicate that such an approach can be used to treat experimental infections with B. anthracis using phospholipase A 2 (35) or Bacillus cereus using phage lysin (38) when enzyme is administered shortly after infection. CapD, while not directly bactericidal, facilitates host cell phagocytic killing of encapsulated bacilli, possibly by exposing pathogen-associated molecular patterns and promoting complement deposition on the bacterial surface.…”

Antimicrobial bacteriophage-derived proteins and therapeutic applications

“…The clinical spectrum of infections include food poisoning, systemic infections (e.g., meningitis, endocarditis, osteomyelitis, and bacteremia), periodontal disease, and localized infections related to trauma. 88 Many members of this genus are spore formers, providing a means of survival during harsh conditions. Inhalation of these spores that germinate and vegetatively propagate causes an overwhelming flood of bacteria and toxins in the blood of humans.…”

Molecular microbiology in antibacterial research

“…Once a temperate phage lysogenizes its bacterial host cell, it can affect the physiological traits of the bacterial lysogen, which can be regarded as a symbiotic state: superinfection exclusion, virulence, motility, antibiotic resistance and other traits can be affected by the balance between prophage activity and bacterial immunity, in part represented by the CRISPR (clustered regularly interspaced short palindromic repeats)-mediated adaptive immune system. Old phage proteins with muralytic activity to hydrolyze peptidoglycans have been shown to successfully eliminate bacterial pathogens upon direct administration into infected animals (Schuch et al, 2002). These phage proteins are endolysins that are normally synthesized inside cells and thus should be translocated by the holin complex.…”