Biology of microbes
Philip A. Geis in Cosmetic Microbiology, 2006
Very few Bacillus spp. are pathogenic. The exceptions are B. anthracis and B. cereus. B. anthracis can cause anthrax, a cutaneous disease caused by spores that enter the skin through small cuts and abrasions. The organism is invasive because of the production of virulence factors that include polysaccharide capsules and exotoxins that produce edema and cell death. The initial disease presents as a papule that becomes increasingly necrotic and then ruptures to form a painless black scab called an eschar. B. anthracis can also cause pulmonary anthrax from inhalation of airborne spores. The onset of this form of anthrax is rapidly fatal within a few hours after septicemia occurs. The toxins produced cause capillary thrombosis and cardiovascular shock. At one time, when natural animal hair was used, shave brushes were significant sources of B. anthracis. The transmission by this route was ideal. The spores on the bristles were deposited directly into the skin when an individual cut himself in the course of shaving.
Anthrax
Meera Chand, John Holton in Case Studies in Infection Control, 2018
Inhalational anthrax results from the inhalation of B. anthracis spores, which may occur while working with contaminated animal products such as wool, hides, or bone meal. Inhalational anthrax also has occurred from deliberate and accidental release of weaponized spore preparations. Spores are phagocytosed by alveolar macrophages and transported to mediastinal lymph nodes where they germinate, multiply, and release toxins causing haemorrhagic necrosis. The incubation period for inhalation anthrax is estimated to be 1 to 7 days, although it may be significantly longer. Early symptoms are entirely nonspecific but experience from the 2001 bioterrorism outbreak in the US (where exposed individuals were identified early) shows that early disease may respond to antibiotics. Without treatment, the prodromal phase is followed by a fulminant bacteraemic phase with an almost universally fatal outcome.
Medical microbiology
Lois N. Magner, Oliver J. Kim in A History of Medicine, 2017
The anthrax bacillus has been called the ideal biological weapon. In 2001, five people died in the United States and 13 became ill because of contact with letters containing anthrax spores. The strain used in the anthrax attacks was identified as the Ames strain, which could be found in several laboratories in the United States. Misinformation promulgated by the media in the wake of the anthrax attacks demonstrated the dangers of widespread scientific illiteracy. Confused and misleading descriptions of anthrax contributed to panic and hysteria. Commentators ignored the difference between viruses and bacteria, antibodies and antibiotics, and indiscriminately described anthrax as a virus, toxin, poison, fungal spore, or a dangerous chemical. Some media “experts” claimed that since anthrax was not a virus it was not contagious.
Efficacy assessment of a triple anthrax chimeric antigen as a vaccine candidate in guinea pigs: challenge test with Bacillus anthracis 17 JB strain spores
Published in Immunopharmacology and Immunotoxicology, 2021
Masoud Abdous, Sadegh Hasannia, Ali Hatef Salmanian, Seyed-Shahryar Arab
Anthrax is a zoonotic disease with global dispersion caused by inhalation, ingestion or contact of skin abrasions with Bacillus anthracis [1]. Prevention of anthrax infection in animals, in addition to reducing animal deaths and economic losses, decreases human exposure to this disease. Anthrax, if not treated, usually leads to fatal systemic diseases. However, antibiotics may be used to eliminate the bacteria, but the level of toxins is often very high in the bloodstream. Thus, removing the bacteria alone is not sufficient for prevention and long-term protection is only achieved by combining appropriate antibiotic therapy with post-exposure vaccination. Therefore, it is necessary to determine the role and the importance of vaccine components and vaccination strategy in anthrax prevention [2,3]. It has been proved that the pathogenicity of B. anthracis depends on the presence of a D-glutamic acid capsule and different toxins including protective antigen (PA, 83 kDa), edema factor (EF, 89 kDa), and lethal factor (LF, 93 kDa). The toxins and the capsule are encoded by several genes located on two plasmids, pXO1 and pXO2, respectively [4]. Anthrax toxins neutralizing antibodies are effectively capable of affecting various steps involved in toxin entry, including (i) PA83 binding to its receptors, (ii) PA83 cleavage by furin, (iii) PA20 release, (iv) PA63 heptamerization, (v & vi) binding of LF/EF to the heptamer by targeting PA63, and (vii) endocytosis of toxins by target cells [5].
Anthrax prevention through vaccine and post-exposure therapy
Published in Expert Opinion on Biological Therapy, 2020
Manish Manish, Shashikala Verma, Divya Kandari, Parul Kulshreshtha, Samer Singh, Rakesh Bhatnagar
Anthrax is primarily a disease of herbivore mammals that occasionally infect other carnivores or omnivores including humans. Although anthrax is endemic to parts of Africa, Asia, the Americas, and Europe where it is frequently reported in the wild, the incidences of naturally acquired anthrax in humans are rare [1,2]. The etiological agent of anthrax is primarily the Gram-positive spore-forming bacterium Bacillus anthracis carrying the virulence plasmids pXO1 and pXO2, but at rare instances, it also occurs as a result of infection with other similar plasmid carrying B. cereus group isolates, e.g., B. cereus and B. thuringiensis [3–5]. Depending on the site of infection and clinical manifestations, anthrax can be cutaneous, gastrointestinal, inhalational, and injectional [5]. Injectional anthrax resulting from the use of contaminated heroin has been reported prominently since 2009. Cutaneous anthrax is the most commonly observed form mainly reported as an occupational disease in people handling animals and animal products while gastrointestinal anthrax is commonly reported from people eating wild kills [1,6]. Inhalational anthrax, though quite rare, is the most fatal form that is primarily associated with the intentional aerial release or the secondary aerosolization of B. anthracis spores. For example, in the well documented postal bioterror attack of the USA in the year 2001 where individuals contracted inhalational anthrax as a result of inhaling the spores aerosolized on the opening of the spores laden envelops, 5 out of 11 patients contracting the disease died despite the best supportive care and aggressive multidrug antibiotic treatment provided [7]. Similarly, in injectional anthrax, the high mortality rate has been observed in the documented cases, i.e., 26 deaths out of 70 confirmed cases [8].
Vaccines against anthrax based on recombinant protective antigen: problems and solutions
Published in Expert Review of Vaccines, 2019
Olga A. Kondakova, Nikolai A. Nikitin, Ekaterina A. Evtushenko, Ekaterina M. Ryabchevskaya, Joseph G. Atabekov, Olga V. Karpova
We believe that the key to developing a successful rPA-based vaccine will also depend on an effective delivery system. Mucosal administration of vaccine may be important in fighting against the inhalation form of anthrax. This could be provided by using a delivery system based on live bacterial or viral vectors, or the development of mucosal adjuvants for rPA. Devising an effective vaccine may require a combination of different strategies and heterologous prime-boost vaccination schemes.
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