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Unformatted text preview: Bacterial Diseases of the Respiratory System Microbial diseases of the respiratory system may occur in the upper or lower regions. The upper region consists of the nose, pharynx, and other structures such as the middle ear and sinuses. Although many defensive mechanisms exist in this part of the body, such as ciliated hairs and mucous membranes, infections are common because of the proximity to the external environment. The lower portion of the system consists of the respiratory tubes and alveoli of the lungs. Infection occurs here because of the excessive moisture and rich supply of nutrients. Strep throat. The common strep throat is due to a group A betahemolytic streptococcus known as Streptococcus pyogenes. This Gram-positive organism is encapsulated and produces streptokinase, which breaks down fibrin clots and permits the organism to spread to other tissues. streptokinase, which breaks down fibrin clots and permits the organism to spread to other tissues....
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- Fall '08