The Sterne strain poses almost no risk for infection of laboratory workers who are following good laboratory practices. The Sterne strain is sometimes used in microbiology laboratories when they are testing the ability to accurately identify and diagnose anthrax, and it is sometimes used for anthrax research. This is because the Sterne strain has lost its ability to produce a capsule, or a layer of polysaccharides, which protects it from being consumed and destroyed by our defensive immune system cells. The Sterne strain is avirulent, meaning its ability to cause illness in people or animals have been reduced. The Sterne strain (34F2) of Bacillus anthracis was discovered in the 1930s and has been used successfully as the predominant method worldwide to immunize livestock against anthrax since its discovery. What is the Sterne strain (34F2) of Bacillus anthracis and am I at risk for being infected?īacillus anthracis is a spore-forming bacterium that causes anthrax in humans and animals. Additionally, the chance of an infection becoming severe or fatal can be reduced to less than 10 -14 with the use of antimicrobial agents when necessary. With the addition of precautions such as good laboratory practices, appropriate glove use, and training for immediate first aid action, the estimated probability of percutaneous infection drops to 3×10 -10. Worst case accident scenarios are estimated to result in 3×10 -3 chance of percutaneous infection. In a worst case accident scenario, the risk exists when spores make contact with a preexisting wound, or if an injury results in a contaminated wound. 7 However, in the event of an accident during routine manipulation, there is a slight risk of infection. It is probably not possible for humans to acquire a Sterne strain infection by the respiratory or oral route. 5 Eye and face protection (i.e., goggles, masks, or face shields) should be used when splashes or sprays are possible outside of the biosafety cabinet. Good laboratory practices include the use of appropriate PPE (i.e., gloves, gowns, or laboratory coats) and the use of a biosafety cabinet for procedures with the potential to produce aerosols. Using proper laboratory precautions reduces the risk of percutaneous exposure. Risks to personnel handling this organism are no greater than those posed by other category 2 organisms and activities. Routine manipulation of the strain in a microbiology laboratory is not likely to result in exposure. What activities might lead to exposure to the Sterne strain? The Sterne strain has an excellent safety record, and has been used safely worldwide by laboratory staff involved in its preparation and by hundreds of thousands of veterinarians. It is administered to livestock in a dose containing up to 10 million viable spores. The Sterne strain is currently the predominant strain used for immunization of domesticated animals against anthrax worldwide, and has been used for this purpose for many decades. Compared with normal wild type strains which produce both the toxin and the capsule, the Sterne strain is relatively avirulent, however immunization using the Sterne strain is able to stimulate a protective immune response. The Sterne strain, discovered in the 1930s, has naturally lost its pXO2 plasmid, and consequently its ability to produce a capsule. Without its capsule, the bacteria can be phagocytised and destroyed. The pXO2 plasmid codes for the capsule, a layer of polysaccharides outside of the cell wall that protects the bacteria against phagocytosis, or consumption by defensive cells from the immune system. The pXO1 plasmid controls the production of the anthrax edema and lethal toxins, which are made of three proteins, the edema factor, the protective antigen, and the lethal factor. The resulting organism is attenuated, meaning its virulence and the ability to cause illness in people or animals have been reduced. If one of these two plasmids is missing, the organism cannot produce all of its virulence factors. anthracis has 3 main virulence factors coded on 2 plasmids, pXO1 and pXO2. What is the Sterne strain (34F2) of Bacillus anthracis?īacillus anthracis is a spore-forming bacterium that causes anthrax in humans and animals. What is the Sterne strain (34F2) of Bacillus anthracis and am I at risk for being infected?.What can those exposed do to decrease their risk of anthrax?.What activities might lead to exposure to the Sterne strain?.Can the Sterne strain cause infections in people?.What is the Sterne strain (34F2) of Bacillus anthracis?.
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