MLS 335 Practice Exam 4 Lecture 15

Blastomyces dermatitidis is a fungal pathogen that causes blastomycosis. To identify this fungus, a compound called KOH (potassium hydroxide) is commonly used. KOH helps in the digestion of tissues and cells, making it easier to visualize the fungal elements. Additionally, Calcoflur white stain is used to highlight the fungal structures. It binds to chitin, which is a component of fungal cell walls, making the fungal elements more visible under a microscope. Therefore, the correct answer is KOH and Calcoflur white stain.

Dimorphic systemic organisms are microorganisms that can exist in two different forms depending on the environmental conditions. These organisms can cause systemic infections in humans. The question asks for the samples that can be used to diagnose these infections. The correct answer is sputum or bronch wash. Sputum is the mucus that is coughed up from the respiratory tract, and a bronch wash is a procedure where a sample of fluid from the bronchial tubes is collected. These samples can contain the dimorphic organisms, allowing for their diagnosis and identification.

Coccidioides immitis is known as the most virulent of all the human mycotic agents. This means that it is the most aggressive and harmful among all the fungal agents that can cause diseases in humans. It is known to cause a severe respiratory infection called coccidioidomycosis, or Valley fever, which can lead to serious complications and even death in some cases. Its high virulence makes it a particularly dangerous pathogen.

The correct answer suggests that the Direct Microscopic Exam of Blastomyces dermatitidis shows yeast cells with double walls and buds connected by a broad base. This indicates that the organism is Blastomyces dermatitidis. Blastomyces dermatitidis is a dimorphic fungus that causes blastomycosis, a fungal infection that primarily affects the lungs but can also spread to other parts of the body. The characteristic double-walled yeast cells with buds connected by a broad base are a distinguishing feature of Blastomyces dermatitidis under microscopic examination.

The infectious cycle of Coccidioides immitis involves the inhalation of only a few arthroconidia, which then convert to spherules. These spherules produce endospores, which can further spread the infection. This explanation highlights the specific process by which the fungus is transmitted and how it reproduces within the body.

The diagnostic measures for Coccidioides immitis include obtaining samples such as sputum, tracheal aspirates, lung biopsy tissue, cerebrospinal fluid (CSF), and blood. These samples can be used to detect the presence of the fungus and confirm the diagnosis of coccidioidomycosis. Skin scrapings and hair shaft samples may be collected in cases where there are cutaneous manifestations of the infection, while nail scrapings may be useful in detecting fungal involvement of the nails.

Paracoccidioides brasiliensis involves the lymph nodes. This means that the fungus specifically affects or infects the lymph nodes in the body. It does not target the kidneys or liver.

Blastomyces dermatitidis is identified through the conversion from mold to yeast at 37C. This conversion is a characteristic feature of this fungus and is used as a diagnostic tool. At 37C, the mold form of Blastomyces dermatitidis transforms into the yeast form, which can be observed and identified under a microscope. This conversion is important in distinguishing Blastomyces dermatitidis from other similar fungi and confirming the presence of this specific pathogen.

The Fungal Immunodiffusion Test (FID) is used to detect exoantigens. Exoantigens are antigens that are released by fungi into the surrounding environment. This test involves the diffusion of patient's serum and fungal antigens on an agar plate, and if there is a reaction between the two, it indicates the presence of exoantigens and suggests a fungal infection. This test is commonly used to diagnose systemic fungal infections such as aspergillosis or histoplasmosis.

Histoplasma capsulatum is an endemic fungus found in certain regions of North America. The correct answer, Ohio, Mississippi, and Missouri, indicates that these three states are areas where the fungus is commonly found. This means that individuals living in or visiting these states are at a higher risk of contracting histoplasmosis, a respiratory infection caused by Histoplasma capsulatum. It is important for people in these areas to take necessary precautions to prevent exposure to the fungus.

The correct answer is Asymptomatic-> Pulmonary disease-> Invasive disease. Blastomyces dermatitidis is a fungal infection that typically begins with asymptomatic inhalation of spores. This can progress to pulmonary disease, where the infection spreads to the lungs and causes symptoms such as cough, fever, and chest pain. In some cases, the infection can then become invasive, spreading to other organs such as the skin, bones, and central nervous system. This progression from asymptomatic to pulmonary to invasive disease is characteristic of Blastomyces dermatitidis infection.

Coccidioides immitis is prominent in the San Joaquin Valley in California, as well as in Arizona and Texas. This fungal pathogen is commonly found in these regions and is responsible for causing coccidioidomycosis, also known as Valley fever.

Dissemination in Paracoccidioides brasiliensis leads to the formation of ulcerative granulomatous lesions in the buccal, nasal, and gastrointestinal mucosa. This means that the infection spreads throughout the body, causing the development of open sores and inflammatory nodules in these specific areas.

The correct answer is pus from draining lymph nodes or scrapings from ulcers. Paracoccidioides brasiliensis is a fungal infection that primarily affects the lungs but can also spread to other parts of the body. To diagnose this infection, samples of pus from draining lymph nodes or scrapings from ulcers are collected and examined under a microscope or cultured in a laboratory. These samples can help identify the presence of the fungus and confirm the diagnosis of Paracoccidioides brasiliensis infection.

Penicilliosis marneffei is caused by the fungus Penicillium marneffei and primarily affects HIV-infected individuals in Thailand and Southern China. The infection involves the mononuclear phagocytic system, which includes cells such as macrophages and monocytes that play a role in the immune response against pathogens. This explanation highlights the key information about the infection and its association with the mononuclear phagocytic system and specific geographical regions.

Coccidioides immitis is known as valley fever. This fungus is responsible for causing a respiratory infection called coccidioidomycosis, which is commonly found in arid regions such as the southwestern United States. The infection occurs when individuals inhale fungal spores present in the soil. Symptoms of valley fever can range from mild flu-like symptoms to severe pneumonia. Therefore, Coccidioides immitis is the correct answer for the given question.

The correct answer is sputum & exudative material from cutaneous lesions and tissue. Blastomyces dermatitidis is a fungus that causes blastomycosis, a fungal infection. To diagnose this infection, samples of sputum (mucus coughed up from the respiratory tract) and exudative material from cutaneous lesions and tissue (fluid or pus from skin lesions) are collected and examined for the presence of the fungus. These samples provide valuable information for confirming the diagnosis of Blastomyces dermatitidis infection.

Blastomyces dermatitis is endemic in the Mississippi and Ohio river basin. This means that the disease is commonly found and regularly occurs in this particular region of North America. The presence of Blastomyces dermatitis in this area suggests that the environmental conditions or factors in the Mississippi and Ohio river basin are conducive to the growth and spread of the disease.

Systemic diseases are those that affect the entire body, rather than being localized to a specific area. The mode of transmission refers to how the disease is spread from one person to another. In the case of systemic diseases, the correct answer is inhalation of infectious conidia. This means that the disease-causing agents, known as conidia, are inhaled into the respiratory system, allowing them to enter the bloodstream and spread throughout the body. Ingestion of infectious conidia refers to swallowing the disease-causing agents, while cutaneous exposure of conidia refers to the agents entering the body through the skin. However, for systemic diseases, inhalation is the most common and effective mode of transmission.

Penicilliosis marneffei is a fungal infection caused by the fungus Penicillium marneffei. It primarily affects individuals with weakened immune systems, such as those with HIV/AIDS. The infection typically presents with skin lesions, which resemble molluscum contagiosum-like lesions. These lesions are small, raised, and usually painless. They may appear on the face and trunk of the affected individual. It is important to note that the other options, macroconidia-like lesions and microconidia-like lesions, are not associated with Penicilliosis marneffei.

Histoplasma capsulatum is a fungus that causes the respiratory infection histoplasmosis. It is commonly found in soil contaminated with bird and bat droppings. These droppings provide an ideal environment for the growth and survival of the fungus. When the contaminated soil is disturbed, the fungal spores can become airborne and be inhaled by humans, leading to infection. Therefore, the correct answer is bird and bat guano.

Direct microscopic examination of Histoplasma capsulatum shows small yeast cells and a neck between mother and daughter. This is because Histoplasma capsulatum is a dimorphic fungus, meaning it can exist in both a mold form and a yeast form. In its yeast form, it appears as small round cells, which can be visualized under a microscope. The presence of a neck between mother and daughter cells indicates the process of budding, where new cells are formed from the parent cell. This characteristic morphology helps in the identification of Histoplasma capsulatum.

The correct answer is elliptical fission (septate) yeasts inside phagocytes. This answer suggests that when examining Penicilliosis marneffei under a microscope, one would observe yeasts that are elliptical in shape and undergo fission (division) in a septate (divided into compartments) manner. These yeasts are found inside phagocytes, which are cells that engulf and destroy foreign particles or microorganisms. This information helps in identifying and diagnosing Penicilliosis marneffei.

The supernatant solution used for the Fungal Immunodiffusion Test (FID) is concentrated. This is because the FID test requires a high concentration of fungal antigens in order to accurately detect the presence of specific fungal antibodies in a patient's serum. By using a concentrated supernatant solution, the test is able to provide more sensitive and reliable results.

Histoplasma capsulatum and Penicillium marneffei are primarily found in HIV patients. These organisms are dimorphic, meaning they can exist in two different forms depending on the environment. In HIV patients with weakened immune systems, these fungi can cause opportunistic infections. Histoplasma capsulatum is commonly found in soil contaminated with bird or bat droppings, while Penicillium marneffei is found in soil and decaying organic matter in certain regions of Southeast Asia. These infections can be severe and potentially life-threatening in individuals with compromised immune systems.

Blastomyces dermatitidis is a fungus that causes a respiratory infection known as blastomycosis. While most cases of blastomycosis are mild and resolve on their own, severe cases can be life-threatening. Therefore, Blastomyces dermatitidis can indeed be fatal, making the statement "Blastomyces dermatitidis is not fatal" false.

Paracoccidioides brasiliensis is the correct answer because it is the causative agent of a fungal infection known as paracoccidioidomycosis, which is commonly found in South America, particularly in Brazil. This infection primarily affects the lungs but can also spread to other organs. The other options, Histoplasma capsulatum and Blastomyces dermatitidis, are causative agents of different fungal infections, histoplasmosis and blastomycosis, respectively. Therefore, Paracoccidioides brasiliensis is the most appropriate answer based on its association with South American or Brazilian blastomycosis.

Blastomyces dermatitidis resembles H. capsulatum microscopically.

The exoantigen identified in H. capsulatum is H and M.

The correct answer is Fluorescent Antigen. Stained Blastomyces dermatitidis shows the presence of fluorescent antigens. This means that when the organism is stained and viewed under a fluorescent microscope, it emits fluorescence due to the presence of specific antigens. This technique is commonly used in diagnostic laboratories to identify and study various microorganisms.

Histoplasma capsulatum is a fungus that causes a respiratory infection called histoplasmosis. It is commonly found in soil and bird droppings, particularly in areas with high nitrogen content. Nitrogen is an essential element for the growth and survival of many microorganisms, including Histoplasma capsulatum. Therefore, it is likely that this fungus resides in soil with a high concentration of nitrogen.

Histoplasma capsulatum is a dimorphic fungus, meaning it can exist in two different forms depending on the environmental conditions. At 25 degrees Celsius, which is the temperature mentioned in the question, Histoplasma capsulatum grows as a mold. The color of the mold culture is typically white to brown. Therefore, the correct answer is "white to brown."

Blastomyces dermatitidis is most prevalent in middle-aged men due to exposure to soil. This fungus is commonly found in soil and can cause an infection called blastomycosis. Middle-aged men may be more susceptible to this infection due to their outdoor activities or occupation that involves frequent contact with soil.

The colony culture characteristics of Blastomyces dermatitidis at 25C are described as white, fluffy, and concentric circles. This means that the colonies of this fungus appear white in color, have a fluffy texture, and exhibit concentric circles when grown on a culture medium at a temperature of 25 degrees Celsius.

In a healthy person, Histoplasma capsulatum, a fungus found in soil contaminated with bat or bird droppings, usually does not cause any symptoms. It is estimated that around 80% of people who are infected with this fungus do not develop any noticeable symptoms. However, in individuals with weakened immune systems, such as those with HIV/AIDS or undergoing chemotherapy, Histoplasma infection can cause severe symptoms and even lead to life-threatening complications.

The correct answer is "mode of transmission, dimorphism, systemic dissemination." This is because organisms that cause systemic diseases typically have a specific mode of transmission, such as through bodily fluids or vectors. Dimorphism refers to the ability of these organisms to exist in different forms, such as a yeast-like form and a filamentous form. Systemic dissemination means that the organisms can spread throughout the body, affecting multiple organs and systems. These characteristics are commonly observed in organisms that cause systemic diseases.

Coccidioides immitis is a fungus that causes coccidioidomycosis, a respiratory infection. The culture of Coccidioides immitis produces fertile hyphae at right angles with alternating hyaline arthroconidia. This means that the fungus forms branching structures (hyphae) that have alternating spore-like structures (arthroconidia) attached to them. These hyphae and arthroconidia are important for the reproduction and spread of the fungus. The yellowish-brown reverse mentioned in the question is not related to the culture of Coccidioides immitis.

Paracoccidioides brasiliensis needs an acidic pH soil to live. This means that the soil should have a low pH level, typically below 7. The acidic environment provides the ideal conditions for the growth and survival of Paracoccidioides brasiliensis, allowing it to thrive and carry out its biological processes effectively.

Penicilliosis marneffei is a fungal infection caused by the fungus Penicillium marneffei. It is primarily found in Southeast Asia, particularly in areas where bamboo rats are present. Bamboo rats are known to be natural reservoirs for this fungus, and they play a crucial role in the transmission of the infection to humans. Therefore, the correct answer is bamboo rats.

Penicilliosis marneffei is a fungal infection caused by the fungus Penicillium marneffei. It primarily affects individuals with weakened immune systems, such as those with HIV/AIDS. The infection presents with symptoms similar to tuberculosis and leishmania, two other infectious diseases. This includes fever, weight loss, cough, and skin lesions. The similarity in symptoms can make it difficult to differentiate between these infections without proper diagnostic testing. Therefore, tuberculosis and leishmania are the two infections that Penicilliosis marneffei mimics.

The correct answer is "Sputum, bone marrow, blood, bronch wash." This is because Penicilliosis marneffei is a systemic fungal infection caused by the fungus Penicillium marneffei. It primarily affects immunocompromised individuals and can lead to severe illness if left untreated. The fungus can be detected in various body fluids and tissues, including sputum, bone marrow, blood, and bronchial washings. Therefore, these samples are essential for the diagnosis of Penicilliosis marneffei. Pus from lesions, skin scrapings, and nail scrapings may not provide enough evidence for an accurate diagnosis.

Dimorphic systemic organisms refer to organisms that exhibit sexual dimorphism, meaning they have distinct differences in physical characteristics between males and females. The question asks about the primary gender in which these organisms are found. Since they are dimorphic, it suggests that the primary gender in which they are found is male, as they have distinct characteristics that differentiate them from females.

The mature growth of the Histoplasma capsulatum culture produces large echinulate or tuberculate macroconidia. This means that when the culture reaches maturity, it produces large spores (macroconidia) that have a rough or spiny surface (echinulate or tuberculate). These spores are important for the dispersal and reproduction of the fungus.

Histoplasma capsulatum is a fungus that can cause several disorders. Reticuloendothelial cytomycosis, cave disease, and spelunker's disease are all caused by Histoplasma capsulatum. These disorders are characterized by respiratory symptoms, as the fungus is commonly found in soil contaminated with bird or bat droppings. The spores of Histoplasma capsulatum can be inhaled, leading to infection in the lungs. In severe cases, the infection can spread to other organs, causing systemic symptoms. Conidia's disease is not a recognized disorder caused by Histoplasma capsulatum, making it an incorrect answer.

Paracoccidioides brasiliensis's yeast cells resemble a mickey mouse cap under the microscope. This suggests that the shape and arrangement of the cells resemble the iconic shape of Mickey Mouse's cap, possibly due to the presence of distinct structures or patterns that resemble the cap's design.

Penicilliosis marneffei appears as a diffusable red pigment under the microscope. This means that when observed under the microscope, the cells of Penicilliosis marneffei are stained or appear red in color. This characteristic color helps in identifying and differentiating this particular organism from others.

Paracoccidioides brasiliensis produce small-sized conidia.

Yeast forms at a temperature of 37C, while mold forms at a temperature of 25C.

The correct answer is "Oviod to dumbbell shaped." Blastomyces dermatitidis is a dimorphic fungus that exists in two forms: a mold form at lower temperatures and a yeast form at higher temperatures. At 25C, it is in the mold form, which is characterized by oval to dumbbell-shaped cells. This morphology helps in distinguishing Blastomyces dermatitidis from other fungi.

The exoantigen identified in B. dermititidis is antigen A.