Lecture 361. Understand the major streptococcal diseases a. Streptococcus pyogenesi. Often referred to in medical settings as group A strepii. Gram-positive cocci; usually grow in long chainsiii. Often found colonizing healthy adults with no illnessiv. Mainly found un upper respiratory tract, but can also infect other tissues b. Cause of streptococcal pharyngitisi. Most isolates produce toxins that lyse red blood cells (B-hemolysis)c. Group A streptococci are responsible for about ½ of all severe sore throat2. Where does Streptococcus pyogenes infect a. Tonsils, mouth throat area3. Know what diseases it can cause (only the ones discussed in lecture) a. Can cause Scarlet feveri. Can result form certain strains of group A streptococci that carry a toxin gene on a prophageii. Produces an erythrogenic exotoxin (causes pink-red rash)b. Rheumatic fever- Bacterial cell surface antigen resembles normalhuman surface antigeni. Patients immune system begins attacking normal tissues such as heart, kidneys, joints, (an autoimmune disease)ii. Can lead to rheumatic heart disease: damage to heat valves and other heart injuries c. Invasive infections- Some virulent strains can invade deep tissues:i. Exotoxins and “M-protein” of bacterial surface act as a superantigen (elicits a hyper-immune response leading to tissue destruction; 30% fatality rate.ii. Necrotizing fasciitis- flesh eating bacteria 4. What is hemolysis a. Lyses of the blood cells5. What diseases are caused by Group A and B a. Group A strep: Most common group; many asymptomatic carriers; strep throat, necrotizing fasciitis, impetigo, typically Strepococcis pyogenesb. Group B: Newborn babies (most commonly sepsis and meningitis), pregnant women , the ederly and adults with other illnesses i. Name: Streptococcus agalactiaeii. Most common cause of life threatening infections in infant siii. About 25% of women are asymptomatic carriers of group Bstrep in vagina6. What are the sequelae to Strep. Infections a. Scarlet fever7. What diseases does Streptococcus pneumoniae commonly cause a. Pneumonia- Impairment of lung function, due ro an infection of bacteria viral or fungusb. Bacterial Meningitis – Meninges- membrane f=ground brain/spinal cord8. Know what virulence factor aids adherence of Bordetella pertussis a. Filamentous hemagglutinin- Surface protein on bacteria helps with adhesion to upper respiratory tractb. Pertussis exotoxin- Damages cells of tissues surrounding infection site. Messes upcell regulation and results in cell damage 9. Define post exposure prophylaxisa. With antibiotics is recommended for all family members and other who have contact with an active pertussis individual 10. In general terms, be able to describe how pertussis toxin damages host cells a. By messing up cell regulation which then results in cell damage11. Tuberculosisa. pathogen: mycobacterium tuberculosis, M. bovis and others infect animals b. what type of host cells it infects: they’re intracellular parasites that live inside the macrophage cells of the immune system c. how it’s transmitted: through inhalation of droplet nucleid. how tubercles are formed: hypersensitivity immune response forms around infection sites creating nodules e. antibiotic-resistant forms of M. tuberculosis: MDR-TB (multi-drug resistant) and XDR-TB (extensively drug
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