Microbiology Exam Questions!

Dengue fever is caused by the Flavivirus. Flavivirus is a genus of viruses that are transmitted primarily by mosquitoes. It is known to cause various diseases in humans, including dengue fever. The virus is typically transmitted to humans through the bite of infected Aedes mosquitoes. Dengue fever is characterized by symptoms such as high fever, severe headache, joint and muscle pain, rash, and in severe cases, it can lead to dengue hemorrhagic fever or dengue shock syndrome.

Vibrio cholera is a bacterium that causes cholera, a severe diarrheal disease. Cholera is characterized by watery diarrhea, vomiting, and dehydration. The term "positive" in this context likely refers to a positive test result for Vibrio cholera, indicating the presence of the bacterium in the patient's body. This answer suggests that the string test, a diagnostic test for cholera, would be positive in cases of Vibrio cholera infection.

The KOH method is the fastest demonstration of Candida. This method involves mixing a sample of the suspected Candida with potassium hydroxide (KOH) solution, which helps to dissolve the tissues and release the fungal elements. The KOH method is commonly used in the laboratory to examine skin scrapings, nail clippings, or other clinical specimens for the presence of Candida. It allows for a quick and efficient identification of Candida by observing the characteristic hyphae and yeast cells under a microscope.

Handerson Paterson bodies are seen in Molluscum Contagiosum. These bodies are characteristic inclusion bodies found within the cytoplasm of infected cells. Molluscum Contagiosum is a viral skin infection caused by the Molluscum contagiosum virus. It is characterized by the presence of small, raised, flesh-colored or pinkish-white bumps on the skin. The presence of Handerson Paterson bodies helps in the diagnosis of Molluscum Contagiosum.

ELISA (Enzyme-Linked Immunosorbent Assay) is a commonly used diagnostic test for invasive amoebiasis. It detects the presence of specific antibodies or antigens in a patient's blood sample. ELISA is highly sensitive and specific, making it a reliable method for diagnosing amoebiasis. Microscopy can also be used to visualize the amoebae in a patient's stool sample, but it may not always be conclusive. Indirect haemagglutination is not commonly used for diagnosing amoebiasis. Therefore, ELISA is the most appropriate and reliable method for investigating invasive amoebiasis.

Plasmodium falciparum sporozoites are described as sickle-shaped. This means that they have a curved or crescent shape, resembling the blade of a sickle. This shape allows the sporozoites to move efficiently through the bloodstream and invade liver cells, which is an essential step in the lifecycle of the Plasmodium falciparum parasite.

Entamoeba histolytica is a parasite that causes the disease known as amoebiasis. It primarily infects the human gastrointestinal tract and is transmitted through the ingestion of contaminated food or water. Unlike Salmonella and Campylobacter jejuni, which can also infect animals, Entamoeba histolytica solely relies on humans as its reservoir. This means that humans are the only source of infection for this particular parasite.

Histoplasmosis is a fungal infection caused by the inhalation of spores from the fungus Histoplasma capsulatum. It primarily affects the lungs but can also spread to other organs. The symptoms of histoplasmosis can vary, ranging from flu-like symptoms to severe respiratory problems. It is commonly found in soil contaminated with bird or bat droppings, and can be more prevalent in areas with high bird or bat populations. Treatment typically involves antifungal medications, especially for severe cases or those with weakened immune systems.

Ionizing radiation is a method used to sterilize catgut sutures. This process involves exposing the sutures to high-energy radiation, such as gamma rays or electron beams, which effectively kills microorganisms and spores present on the sutures. This method is commonly used for sterilizing heat-sensitive materials, like catgut, as it does not require high temperatures that could damage the material. Autoclave and dry heat oven are not suitable for sterilizing catgut sutures as they may cause degradation or melting of the material. Ethylene dioxide is another commonly used method for sterilization, but it is not the correct answer in this case.

Robertson's cooked meat media is used for the culture of Clostridium. This media contains pieces of cooked meat which provide essential nutrients for the growth of Clostridium bacteria. It also creates an anaerobic environment which is necessary for the growth of these bacteria. Thioglycolate media is not specifically used for Clostridium culture, although it can support the growth of some anaerobic bacteria. McLeod's media is not commonly used for Clostridium culture. Therefore, the correct answer is Robertson's cooked meat media.

Babes Ernest granules are seen in diphtheria. Diphtheria is a bacterial infection caused by Corynebacterium diphtheriae. Babes Ernest granules are characteristic structures found in the cytoplasm of infected cells during diphtheria. These granules are aggregates of the bacteria and can be observed microscopically. The presence of Babes Ernest granules is a diagnostic feature of diphtheria and helps differentiate it from other similar diseases such as fowl pox and small pox.

Rubeola, also known as measles, can cause white salt-like crystals to form on the buccal mucosa. This is due to the presence of Koplik spots, which are small white spots surrounded by a red halo. These spots typically appear a few days before the rash associated with measles develops. Rubella, mumps, and rabies do not typically cause this specific finding on the buccal mucosa.

Cowdry type A-bodies are eosinophilic intranuclear inclusions that are seen in both herpes and yellow fever infections. These inclusions are composed of viral components and host cell proteins. In herpes infections, Cowdry type A-bodies are commonly found in infected cells, while in yellow fever infections, they can be observed in hepatocytes. Therefore, the correct answer is "Both".

Cold immunoglobulin refers to a specific type of immunoglobulin that is involved in the immune response against cold-agglutinin disease. This disease is characterized by the presence of antibodies, specifically IgM, that cause red blood cells to clump together at low temperatures. Therefore, the correct answer is IgM.

Tuberculoid leprosy is the correct answer because it is a form of leprosy that typically occurs in individuals with a strong immune response. In this type, the immune system is able to effectively control the infection, leading to few skin lesions and a low bacterial load. Lepromatous leprosy, on the other hand, occurs in individuals with a weak immune response and is characterized by numerous skin lesions and a high bacterial load. Therefore, tuberculoid leprosy is more likely to develop in immunocompetent patients.

Thumbprint appearance in culture is seen in Bordetella. This refers to the characteristic appearance of colonies of Bordetella pertussis on culture media, which resemble the ridges and valleys of a thumbprint. This unique appearance helps in the identification of Bordetella species in the laboratory. Bartonella henselae and Franscicella do not exhibit this thumbprint appearance.

Medusa lock appearance is seen in Ascariasis. Ascariasis is a parasitic infection caused by the roundworm Ascaris lumbricoides. The term "medusa lock" refers to the appearance of the worm when it is expelled from the body. The worms have a coiled appearance, resembling the locks of Medusa, a monster from Greek mythology with snakes for hair. This characteristic appearance helps in identifying the infection.

Staphylococcus albus is not a known pathogen in causing postoperative endocarditis. The correct answer is Staphylococcus aureus, as it is a common cause of this condition.

Mucormycosis is a fungal infection that has an affinity for blood vessels. It is caused by a group of fungi called mucormycetes, which can invade blood vessels and cause tissue death. This infection primarily affects individuals with weakened immune systems, such as those with uncontrolled diabetes or undergoing immunosuppressive therapy. Mucormycosis can manifest in various forms, including rhino-orbital-cerebral, pulmonary, cutaneous, and gastrointestinal. Prompt diagnosis and treatment are crucial to prevent further tissue damage and potential life-threatening complications.

Id reaction, also known as dermatophytid or autosensitization reaction, is a cutaneous hypersensitivity reaction that occurs in response to a fungal infection in another part of the body. It is characterized by the development of small, itchy, papulovesicular lesions on the skin that are not directly related to the primary infection site. Candidiasis, caused by the fungus Candida, is one of the fungal infections that can trigger an id reaction. Therefore, the correct answer is Candidiasis.