The laboratory for especially dangerous infections conducts microscopic examination of pathological material from a patient with suspected plague. The sample was stained by Burri-Gins technique. What property of the causative agent can be identified by this technique?

Correct Answer: A

Rationale: The Burri-Gins staining technique is used to identify the presence of capsules around bacteria. Capsules are protective structures that some bacteria produce to evade the immune system. This technique stains the capsule, making it visible under a microscope. Therefore, the correct answer is A: Capsule formation. Incorrect: B: Spore formation - Spores are not typically identified using the Burri-Gins staining technique. C: Acid resistance - This property is not specifically identified by Burri-Gins staining. D: Alkali resistance - This property is not specifically identified by Burri-Gins staining.

Correct Answer: D

Rationale: The correct answer is D: Protoplast. Lipopolysaccharides of Gram-negative bacteria consist of three main components: O-specific polysaccharide chain, R-specific polysaccharide chain, and Lipid A. Protoplast is not a component of lipopolysaccharides. O-specific polysaccharide chain is responsible for serotype specificity, R-specific polysaccharide chain varies among strains, and Lipid A is the endotoxin component. Protoplast refers to a bacterial cell devoid of a cell wall, which is not a component of lipopolysaccharides.

Correct Answer: D

Rationale: The correct answer is D: Gram-negative coccobacillus. Francisella tularensis is a Gram-negative coccobacillus because it has a unique shape that is between a coccus (spherical) and a bacillus (rod-shaped) and it stains pink/red in the Gram staining process. It is important to note that it is not a coccus (choice B) or a Gram-positive bacterium (choice A). Choice C is too general and does not specify the coccobacillus shape of F. tularensis. So, the correct answer is D due to its specific characteristics as a Gram-negative coccobacillus.

Correct Answer: A

Rationale: The correct answer is A: Bacteriological. This method involves isolating and culturing the causative bacteria from the wound material to determine the species. This allows for further testing to confirm gaseous gangrene and identify the specific pathogen. Choice B: Allergic is incorrect as it pertains to immune responses, not identifying bacteria. Choice C: Bacterioscopic is incorrect as it refers to microscopic examination of bacteria, not species identification. Choice D: Serological is incorrect as it involves testing for antibodies in the blood, not identifying the causative agent directly.

Correct Answer: D

Rationale: The correct answer is D because antigenic shift is a major change in the influenza virus where genetic material from different influenza viruses mix to create a new subtype. This is a large-scale change that results in a novel virus with a different antigenic composition. Option A and B are incorrect because antigenic shift does involve the exchange of genetic information between animal and human influenza A viruses, and it does occur when animal or avian influenza viruses of type A directly pass into the human population. Option C is incorrect because antigenic shift is not related to the recirculation of a previously circulating influenza strain.

Correct Answer: D

Rationale: The correct answer is D. Botulism typically presents with symptoms such as dry mouth, difficulty swallowing, blurred vision, diplopia, and descending flaccid paralysis. Chills, fever, and loss of consciousness are not typical of botulism. Botulism is caused by a neurotoxin produced by Clostridium botulinum bacteria, which affects the nervous system leading to muscle weakness and paralysis, not fever or altered consciousness. Therefore, choice D is the correct answer.

Correct Answer: D

Rationale: The correct answer is D: Erysipeloid. Erysipeloid is a bacterial infection caused by Erysipelothrix rhusiopathiae commonly found in animals like cattle. The patient's occupation as a cattle-ranch worker puts them at risk for this infection. Symptoms such as high body temperature, severe headache, carbuncle on the forearm with edema, and regional lymphadenitis are typical of erysipeloid. Anthrax (A) is more associated with skin lesions and severe systemic symptoms. Carcinoma of skin (B) presents differently with slow-growing skin lesions. Erysipelas (C) is a different bacterial infection characterized by red, swollen patches on the skin.

Correct Answer: C

Rationale: The correct answer is C because transcription is the process in which messenger RNA transcripts are produced from DNA. During transcription, a specific segment of DNA is transcribed into mRNA by RNA polymerase. Choice A is incorrect because translation, not transcription, involves converting mRNA into protein. Choice B is incorrect as it describes DNA replication, not transcription. Choice D is incorrect because it refers to translation, where polypeptides are synthesized from mRNA. Therefore, choice C is the correct answer as it accurately describes the process of transcription.

Correct Answer: A

Rationale: The correct answer is A: Clostridium botulinum. This bacterium is responsible for causing botulism due to its production of botulinum toxin, which is one of the most potent neurotoxins known. Clostridium botulinum thrives in anaerobic conditions like improperly canned foods. Staphylococcus aureus (B), Bacillus anthracis (C), and Pseudomonas aeruginosa (D) do not produce the botulinum toxin and are not associated with botulism. Staphylococcus aureus is known for causing food poisoning, Bacillus anthracis for anthrax, and Pseudomonas aeruginosa for various infections, but not botulism.