Exam 3 4 Lectures

Reactivation TB is a form of tuberculosis that occurs when a latent infection becomes active again. The statement "The majority of individuals succumb to reactivation TB" is false because most individuals with reactivation TB can be successfully treated with appropriate medication. While reactivation TB can be serious if left untreated, it does not typically result in death for the majority of individuals.

The spread of M. tuberculosis outside of the lung can have serious clinical manifestations. This is because the bacteria can disseminate through the bloodstream and affect other organs, leading to conditions such as miliary tuberculosis or extrapulmonary tuberculosis. These conditions can be severe and potentially life-threatening.

The rise in serum antibody, detected by compliment fixation, is a method used to diagnose Mycoplasma pneumoniae infection. When a person is infected with Mycoplasma pneumoniae, their immune system produces antibodies to fight against the infection. Complement fixation is a laboratory technique that can detect the presence of these antibodies in the serum of the patient. This method is specific to Mycoplasma pneumoniae and can help confirm the diagnosis of the infection.

The given answer is incorrect because Mycoplasma pneumonia does not have a predilection for older individuals. It can affect individuals of all age groups. Mycoplasma pneumonia is an atypical bacterial pneumonia that is often referred to as walking pneumonia because the symptoms are milder and individuals can still carry out their daily activities. It can be treated with erythromycin or tetracycline antibiotics. The accumulation of metabolites caused by Mycoplasma pneumonia can lead to cytopathic effects.

Rickettsia prowazekii is a bacterium that causes epidemic typhus. This disease is characterized by high fever, headache, rash, and severe muscle pain. The bacterium replicates in columnar epithelial cells, which are cells that line the inner surface of organs. It is transmitted to humans through the bite of infected mosquitoes. Rickettsia prowazekii exists in two different morphologic forms, including the infectious form called elementary bodies and the replicative form called reticulate bodies. Therefore, the correct answer is that Rickettsia prowazekii causes epidemic typhus.

Leprosy is caused by Mycobacterium leprae, and two disease forms of leprosy, tuberculoid and lepromatous, are recognized. The statement correctly identifies this fact.

R. Rickettsi is the correct answer because it causes rocky mountain spotted fever. Rocky mountain spotted fever is a bacterial infection transmitted to humans through the bite of infected ticks. It is characterized by symptoms such as fever, headache, rash, and muscle pain. If left untreated, it can lead to serious complications.

Ornithosis is caused by the bacterium Chlamydophila psittaci. This bacterium is commonly found in birds, especially parrots, pigeons, and poultry. Humans can become infected with Ornithosis by inhaling the bacteria from bird droppings, feathers, or respiratory secretions. The infection can cause flu-like symptoms such as fever, headache, and muscle aches, and in severe cases, it can lead to pneumonia. Proper hygiene and handling of birds can help prevent the transmission of Ornithosis to humans.

Treponema pallidum is the causative agent for syphilis. It is a spiral-shaped bacterium that is primarily transmitted through sexual contact. This bacterium infects the skin and mucous membranes, leading to the development of various stages of syphilis. If left untreated, syphilis can cause serious complications such as cardiovascular damage, neurological disorders, and organ damage. Therefore, identifying Treponema pallidum as the causative agent is crucial for the diagnosis and treatment of syphilis.

Borrelia burgdorferi is the causative agent for Lyme disease. It is a type of bacteria that is transmitted to humans through the bite of infected black-legged ticks. These ticks are commonly found in wooded and grassy areas. Lyme disease can cause a range of symptoms, including fever, fatigue, headache, muscle and joint aches, and swollen lymph nodes. If left untreated, it can lead to more serious complications, affecting the joints, heart, and nervous system. Early diagnosis and treatment with antibiotics are crucial for managing Lyme disease.

R. Typhi is transmitted from rats to humans.

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Lyme disease can be serologically diagnosed using an immunofluorescent assay or an ELISA. These tests become more reliable as the disease progresses. This means that in the early stages of the disease, these tests may not always detect the presence of Lyme disease accurately. However, as the disease progresses, the antibodies produced by the body in response to the infection become more detectable, making these serological tests more reliable for diagnosis.

C. trachomatis (A-C) causes blindness.

A negative PPD test can be obtained from an individual who had a primary infection 20 years ago because the tuberculin skin test measures delayed-type hypersensitivity (DTH) response to the purified protein derivative (PPD) of tuberculin. After a primary infection, the immune system develops a memory response to the tuberculin antigen. However, over time, the immune response may decrease and become undetectable, resulting in a negative PPD test even if the individual had a previous infection. Therefore, a negative PPD test does not necessarily indicate that the individual is not infected with M. tuberculosis.

Penicillin would be the treatment of choice for Treponema pallidum. This is because Treponema pallidum is the causative agent of syphilis, and penicillin is the most effective antibiotic for treating syphilis. It is important to note that the assumption here is that there is no resistance to penicillin.

Fried egg is L type

Rickettsia prowazekii is a bacterium that causes endemic typhus. It is known to replicate in endothelial cells, which are cells that line the interior surface of blood vessels. This bacterium is not transmitted from birds to humans by mosquitoes, as that is the mode of transmission for a different bacterium called Chlamydia psittaci, which causes ornithosis. Rickettsia prowazekii exists in two different morphologic forms, but this information is not directly related to its ability to replicate in endothelial cells.

The given answer states that "C. Burnetti" causes Q fever. Q fever is indeed caused by a bacterium called Coxiella burnetii. This bacterium is commonly found in animals, such as cattle, sheep, and goats, and can be transmitted to humans through inhalation of contaminated particles or consumption of contaminated dairy products. Q fever can cause flu-like symptoms, including fever, headache, and muscle pain, and can sometimes lead to more severe complications. Therefore, the given answer is correct.

Lyme disease is caused by the bacterium Borrelia burgdorferi, which can infect multiple systems in the body including the nervous system, joints, heart, and skin. Therefore, it is possible to develop a multi-system infection from Lyme disease.

Mycoplasma hominis is not broken down by urease. Urease is an enzyme that breaks down urea into ammonia and carbon dioxide. Mycoplasma hominis is a bacterium that inhabits the genital and urinary tracts, and it is considered an opportunistic organism. It is sensitive to tetracycline, an antibiotic, but resistant to erythromycin.

Infection with C. pneumoniae can lead to the generation of autoantibodies to heart muscle, which can potentially result in atherosclerosis. Atherosclerosis is a condition characterized by the buildup of plaque in the arteries, leading to narrowing and hardening of the arteries. Autoantibodies are antibodies that mistakenly target and attack the body's own tissues. In the case of C. pneumoniae infection, the production of autoantibodies against heart muscle can contribute to the development of atherosclerosis in affected individuals.

Doxycycline is the preferred treatment for Ehrlichia species. It is a type of antibiotic known as a tetracycline, which is effective against a wide range of bacterial infections. Doxycycline works by inhibiting the growth and spread of bacteria, including Ehrlichia species. It is a commonly used medication for treating tick-borne diseases caused by Ehrlichia, such as human monocytic ehrlichiosis and human granulocytic anaplasmosis. Doxycycline is well-tolerated, has a high success rate in treating Ehrlichia infections, and is generally the first-line treatment recommended by healthcare professionals.

Found primarily in columnar epithelial cells

Brill's disease is a rare form of epidemic typhus caused by Rickettsia prowazekii. This bacterium is transmitted to humans through the bites of infected body lice. The symptoms of Brill's disease include high fever, severe headache, rash, and muscle pain. If left untreated, it can lead to complications such as pneumonia, heart inflammation, and central nervous system involvement. Therefore, Rickettsia prowazekii is the correct answer as it is the causative agent associated with Brill's disease.

Condylomata lata is a type of skin lesion that is typically associated with secondary syphilis, a sexually transmitted infection caused by the bacterium Treponema pallidum. Therefore, the correct answer, Borrelia burgdorferi, is incorrect.