Which one of the methods is used to identify cytoplasmic inclusions?

Correct Answer: A

Rationale: The correct answer is A: Neisser staining. This method is specifically used to identify cytoplasmic inclusions by staining them with a specific dye that highlights these structures. Neisser staining is designed to selectively target and visualize cytoplasmic inclusions, making it the most appropriate choice for this purpose. Option B: Clett staining, Option C: Ziehl-Nielsen staining, and Option D: Gram staining are not typically used for identifying cytoplasmic inclusions. Clett staining is not a commonly known staining method for this purpose. Ziehl-Nielsen staining is primarily used to detect acid-fast bacteria like Mycobacterium tuberculosis. Gram staining is used to differentiate bacteria into Gram-positive and Gram-negative based on cell wall characteristics. Therefore, these options are not suitable for identifying cytoplasmic inclusions.

Correct Answer: A

Rationale: The presence of acid-fast bacilli stained red against a blue background indicates mycobacteria, specifically Mycobacterium tuberculosis in this case. Ziehl-Neelsen staining is commonly used to detect tuberculosis. Diphtheria is caused by Corynebacterium diphtheriae, which does not stain with Ziehl-Neelsen. Pneumonia is a general term for lung infections caused by various pathogens. Leprosy is caused by Mycobacterium leprae, which requires special staining methods different from Ziehl-Neelsen.

Correct Answer: B

Rationale: The correct answer is B: Biological oxidation. Haematrophic bacteria obtain energy through biological oxidation, where they break down organic compounds to generate ATP for cellular processes. This process involves the transfer of electrons from the substrate to an electron transport chain to produce energy. Heat production (A) is a byproduct of metabolism, not the primary way to obtain energy. In biosynthetic reactions (C), energy is utilized rather than generated. Cultivation in culture media (D) is a method of growing bacteria but does not directly provide energy. Therefore, the correct answer is B as it aligns with the metabolic process of haematrophic bacteria.

Correct Answer: A

Rationale: Rationale: The correct answer is Amebiasis (choice A) because the patient's symptoms of acute gastrointestinal disorders and prolonged stay in an African country suggest exposure to Entamoeba histolytica, the causative agent of amebiasis. This protozoal infection commonly occurs in tropical regions, including Africa. Trypanosomosis (choice B) is caused by Trypanosoma species transmitted by tsetse flies, primarily found in sub-Saharan Africa. Leishmaniasis (choice C) is transmitted by sandflies and presents with skin lesions or visceral involvement, not acute gastrointestinal symptoms. Malaria (choice D) is caused by Plasmodium parasites transmitted by mosquitoes and typically presents with fever, not acute gastrointestinal disorders. Therefore, choices B, C, and D are incorrect based on the patient's clinical presentation and travel history.

Correct Answer: A

Rationale: The correct answer is A: Anthrax. The symptoms of fever, headache, weakness, and the skin lesion described (hyperemic with a dark red infiltration, black center, and pustules) are characteristic of cutaneous anthrax. The black center is known as an eschar. Anthrax is caused by the bacterium Bacillus anthracis, commonly found in cattle. Plague (choice B) typically presents with swollen lymph nodes (buboes) and is caused by Yersinia pestis. Tularemia (choice C) presents with fever, ulcer at the site of infection, and lymphadenopathy, caused by Francisella tularensis. Furuncle (choice D) is a localized skin infection typically caused by Staphylococcus aureus, presenting as a red, swollen, and painful bump.

Correct Answer: D

Rationale: The correct answer is D: Fibers at the vertices of the icosahedron. Adenoviruses have fibers at the vertices of the icosahedron, which give them their distinctive pattern. These fibers help in attaching to host cells. Choices A, B, and C are incorrect because adenoviruses do not have a lipid envelope, helical capsid, or ssDNA. Adenoviruses have a non-enveloped icosahedral capsid and contain dsDNA. This makes choice D the correct answer as it specifically relates to the unique structural feature of adenoviruses.

Correct Answer: C

Rationale: The correct answer is C: beaded. In an agar slant, beaded colonies appear as separate or semiconfluent, forming small, round colonies with gaps between them. This term accurately describes the appearance of the colonies in this context. A: Filiform colonies are dense and opaque with smooth edges, not separate or semiconfluent. B: Echinulate colonies have spiny projections, not the characteristic of separate or semiconfluent growth. D: Effuse colonies spread out extensively and lack defined borders, unlike the distinct appearance of separate or semiconfluent colonies.

Correct Answer: A

Rationale: The correct answer is A: HSV-1. Herpes simplex infections on lips and in the mouth are most commonly caused by HSV-1 due to its preference for infecting oral mucosa. HSV-2 typically causes genital herpes. HSV-6 and HSV-7 are less common and not typically associated with oral infections. Therefore, based on the typical presentation and epidemiology of herpes simplex infections, HSV-1 is the most likely cause in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Borrelia burgdorferi. Borrelia burgdorferi is the bacteria responsible for causing Lyme disease. It is transmitted to humans through the bite of infected black-legged ticks. Treponema pallidum causes syphilis, Leptospira interrogans causes leptospirosis, and Rickettsia rickettsii causes Rocky Mountain spotted fever. Borrelia burgdorferi is specifically associated with Lyme disease due to its transmission through tick bites and the characteristic symptoms it causes.