Bacillus anthracis

About: Bacillus anthracis is a research topic. Over the lifetime, 3994 publications have been published within this topic receiving 128122 citations.

Biochemical Characterization of β-Lactamases Bla1 and Bla2 from Bacillus anthracis

Abstract: The Sterne and Ames strains of Bacillus anthracis carry chromosomal genes bla1 and bla2, which confer beta-lactam resistance when expressed in Escherichia coli. MIC measurements and steady-state kinetic analyses indicate that Bla1 possesses penicillinase activity while Bla2 possesses penicillinase, cephalosporinase, and carbapenem-hydrolyzing activities.

Protocol for Real-Time PCR Identification of Anthrax Spores from Nasal Swabs after Broth Enrichment

Abstract: A mass-screening protocol for the diagnosis of anthrax from nasal swabs based on an enrichment step in liquid medium was devised. Incubation for growth was performed in autoclavable vials and racks which allow real-time PCR analysis of sterilized cultures. A dual-color PCR was set up with primers and probes for the chromosomal marker rpoB and the plasmid marker lef. Specific primer and probe sets were designed for the differentiation of Bacillus anthracis from B. cereus and for the differentiation of the Sterne vaccine strain from field isolates and the Ames strain, which was used in the recent anthrax bioterrorist attack. The present protocol thus combines the high specificity and sensitivity of real-time PCR with excellent biosafety and the low hands-on time necessary for the processing of large numbers of samples, which is extremely important during control programs involving the processing of large numbers of samples.

Anthrax – an overview

Abstract: Anthrax, a disease of mammals (including humans), is caused by a spore-forming Gram-positive bacilli called Bacillus anthracis. Anthrax is one of the oldest threats to humanity, and remains endemic in animals in many parts of the world. The incidence of anthrax has decreased in developed countries, but it remains a considerable health problem in developing countries. The disease is transmitted to humans by contact with sick animals or their products, such as wool, skin, meat etc. Capsular polypeptide and anthrax toxin are the principal virulence factors of B. anthracis. Anthrax toxin consists of three proteins called protective antigen, edema factor, and lethal factor, each of which is nontoxic but acts synergistically. Human anthrax has three major clinical forms: cutaneous, inhalational, and gastrointestinal. The diagnosis is easily established in cutaneous cases, characterized by black eschar. Severe intoxication and collapse during the course of bronchopneumonia or hemorrhagic enteritis should prompt suspicion of anthrax. Treatment with antibiotics is mandatory. If untreated, anthrax in all forms can lead to septicemia and death. Recently, considerable attention has been focused on the potential for B. anthracis to be used in acts of biological terrorism. The ease of laboratory production and its dissemination via aerosol led to its adoption by terrorists, as shown by recent events in the USA. A good knowledge of anthrax, its epidemiology, pathogenesis, clinical forms and potential as a biological weapon is essential for timely prevention and treatment. This review summarizes the current knowledge on anthrax.

The Germination-Specific Lytic Enzymes SleB, CwlJ1, and CwlJ2 Each Contribute to Bacillus anthracis Spore Germination and Virulence

Abstract: The bacterial spore cortex is critical for spore stability and dormancy and must be hydrolyzed by germination-specific lytic enzymes (GSLEs), which allows complete germination and vegetative cell outgrowth. We created in-frame deletions of three genes that encode GSLEs that have been shown to be active in Bacillus anthracis germination: sleB, cwlJ1, and cwlJ2. Phenotypic analysis of individual null mutations showed that the removal of any one of these genes was not sufficient to disrupt spore germination in nutrient-rich media. This finding indicates that these genes have partially redundant functions. Double and triple deletions of these genes resulted in more significant defects. Although a small subset of DeltasleB DeltacwlJ1 spores germinate with wild-type kinetics, for the overall population there is a 3-order-of-magnitude decrease in the colony-forming efficiency compared with wild-type spores. DeltasleB DeltacwlJ1 DeltacwlJ2 spores are unable to complete germination in nutrient-rich conditions in vitro. Both DeltasleB DeltacwlJ1 and DeltasleB DeltacwlJ1 DeltacwlJ2 spores are significantly attenuated, but are not completely devoid of virulence, in a mouse model of inhalation anthrax. Although unable to germinate in standard nutrient-rich media, spores lacking SleB, CwlJ1, and CwlJ2 are able to germinate in whole blood and serum in vitro, which may explain the persistent low levels of virulence observed in mouse infections. This work contributes to our understanding of GSLE activation and function during germination. This information may result in identification of useful therapeutic targets for the disease anthrax, as well as provide insights into ways to induce the breakdown of the protective cortex layer, facilitating easier decontamination of resistant spores.