Microbiology: Tuberculosis and Rickettsial Infections

The primary site of infection in pulmonary tuberculosis is called the 'Ghon focus.'

One reason for the high death rate caused by tuberculosis is the increasing number of cases in developing countries due to malnutrition and poor hygiene.

T-lymphocytes help limit primary tuberculosis infection by forming granulomas, which are structures that contain the infection.

<p>Secondary tuberculosis infection typically occurs due to reactivation of the primary lesion, often influenced by factors such as HIV or malnutrition.</p> Signup and view all the answers

<p>Two clinical symptoms of tuberculosis affecting the lungs are persistent cough and hemoptysis.</p> Signup and view all the answers

<p>The protein produced by mycobacteria prevents the fusion of the phagosome with the lysosome, allowing the bacteria to escape degradation.</p> Signup and view all the answers

<p>Granulomatous lesions serve to contain the infection by forming a barrier against the spreading bacteria.</p> Signup and view all the answers

<p>The biphasic life cycle of Chlamydiae involves two forms: the Elementary Body (EB), which is infectious and metabolically inert, and the Reticulate Body (RB), which is non-infectious and metabolically active.</p> Signup and view all the answers

<p>Chlamydia trachomatis primarily causes sexually transmitted infections and the eye disease trachoma, while Chlamydophila pneumoniae is associated with atypical pneumonia.</p> Signup and view all the answers

<p>The Weil-Felix reaction is a serological test used to identify infections caused by certain rickettsial species, specifically helping to differentiate these infections from others.</p> Signup and view all the answers

<p>Broad-spectrum antibiotics such as doxycycline, tetracycline, and chloramphenicol are effective treatments for rickettsial infections.</p> Signup and view all the answers

<p>Avoidance of infected arthropods, which are vectors for rickettsial infections, offers a key method of prevention and control.</p> Signup and view all the answers

<p>Leprosy is caused by the bacterium <em>Mycobacterium leprae</em>, which is an obligate intracellular parasite that lacks many genes necessary for independent survival.</p> Signup and view all the answers

<p>The average incubation period for leprosy is approximately one year, but it can extend up to 20 years.</p> Signup and view all the answers

<p>Disfigurement in leprosy is caused by skin anesthesia leading to infections, resorption of bone, and skin infiltration resulting in thickening.</p> Signup and view all the answers

<p>The type of leprosy a person develops is influenced primarily by their immune response and may also involve genetic factors.</p> Signup and view all the answers

<p>Armadillos and chimpanzees can also contract leprosy.</p> Signup and view all the answers

<p>The tuberculoid form of leprosy is treated with dapsone and rifampin.</p> Signup and view all the answers

<p>Leprosy cannot be grown on artificial media because it replicates intracellularly within certain host cells.</p> Signup and view all the answers

<p>Preventive measures include isolation of lepromatous patients, treatment of cases, and chemoprophylaxis with dapsone for exposed children.</p> Signup and view all the answers

<p>BCG vaccination provides partial protection against leprosy, though no specific vaccine is available.</p> Signup and view all the answers

<p>Mycoplasma are the smallest free-living, wall-less organisms with a flexible cell membrane and complex nutritional requirements.</p> Signup and view all the answers

<p>They stain poorly due to the absence of a cell wall, which is essential for retaining the dye in Gram staining.</p> Signup and view all the answers

<p>Mycoplasma pneumoniae attaches to host cells using a tiny arm coated in protein.</p> Signup and view all the answers

<p>Colony morphology has a characteristic 'fried-egg' shape.</p> Signup and view all the answers

<p>It causes atypical pneumonia and is transmitted by respiratory droplets.</p> Signup and view all the answers

<p>Infection can lead to the production of autoantibodies against red cells, known as 'cold agglutinins.'</p> Signup and view all the answers

<p>The incidence is highest in winter.</p> Signup and view all the answers

<p>Immunity to Mycoplasma pneumoniae is incomplete, allowing for second episodes of disease.</p> Signup and view all the answers

<p>Common findings include a non-productive dry cough and fever.</p> Signup and view all the answers

<p>'Walking Pneumonia' refers to the milder symptoms and rapid spread in crowded areas, allowing patients to remain ambulatory.</p> Signup and view all the answers

<p>It means the causative bacterium cannot be isolated on routine media and the disease has milder symptoms with prolonged course.</p> Signup and view all the answers

<p>It detects IgM autoantibodies against type O RBCs that agglutinate at 4°C but not at 37°C.</p> Signup and view all the answers

<p>They are not helpful except in excluding other pathogens due to the nature of Mycoplasma species.</p> Signup and view all the answers

<p>The main treatment options are erythromycin, azithromycin, or tetracycline.</p> Signup and view all the answers

<p>They depend on host cells for growth and cannot grow in artificial media.</p> Signup and view all the answers

<p>The Typhus Group is associated with epidemic typhus, and the Spotted Fever Group is associated with Rocky Mountain spotted fever.</p> Signup and view all the answers

<p>They can be transmitted by bites of ectoparasites, inoculation of infectious fluids, or inhalation of infectious material.</p> Signup and view all the answers

<p>It is a serological test that shows non-specific microagglutination between patient serum and Proteus vulgaris antigens.</p> Signup and view all the answers

<p>Common symptoms include skin rash, fever, and headache.</p> Signup and view all the answers

<p>Hypotension can occur as a result of systemic infection.</p> Signup and view all the answers