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34 Cards in this Set
- Front
- Back
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What is bacteremia?
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presence of bacterial in the blood stream
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What enzyme does pneumococcus lack>
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catalase= catalyzes the decomposition of H2O2 to H20 and O2
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what does large amounts of H2O2 cause?
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inhibits the growth of competitive microflora and with toxin pneumolysin, it can damage host tissue and inhibit the host from clearing it out.
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What kind of bacteria is pneumocci and what is it's cell wall like?
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Gram + and it is thick and encapsulated with noncovalently bond polysachs
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What type of immunity recognizes pneumococci and what does it stimulate?
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innate and an inflammatory response
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What is autolysin?
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it is an enzyme that when expressed causes destruction of its own cell wall in pneumococci, which further contrbutes to the release of these inflammatory mediators. It occurs during the stationary phase of growth.
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What is the Quellung Reaction?
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it is used to visualize a normally transparent capsule zone. You add and antibody which causes and antibody-antigen precipitate in that zone
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what are examples of encapsulated organisms?
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Bacteria: streps, staph aureus, menigococcus, klesibella pneumonia, E. coli, influenza, bacteroids
Fungi: cryptococcus neoformans |
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Which disease predispose people to a pneumococcal infection and what season is most common?
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HIV, alcoholism, sickle cell, multiple myeloma, hodkins, abscense of a functional spleen ; most common in the winter and early spring
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what are some common and extreme infections pneumococcus can cause?
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common: otitis media, acute sinusitis, chronic bronchitis
Extreme: peritonitis (if ascites), spetic arthritis, endocarditis, meningitis |
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What is the first step in host-pathogen interaction?
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colonization on the mucosal surface of upper resp. tract
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What are the 3 outcomes of colonization?
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1. clearance
2. carrier state: asymptomatic persistence for several months. 3. progression to disease |
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Most common modes of transmission?
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resp droplets from either asymptomatic or symptomatic people; can also be through secretions onto the hand
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How many stages occur in the inflammatory process of the pneumonic process?
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four
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What occurs in the first stage of pneumonic process?
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alveoli fill with serous fluid with many organisms, but FEW inflam cells. The fluid serves as a culture medium for multiplying organisms and spreading the infection to adjacent alveloi through pores of Kohn and nearby areas of the lung via small airways. THIS WILL IMPACT GAS EXCHANGE
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What occurs in the second stage (early consolidation)?
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Alveoli infiltrated by neutrophils and RBCs. Chemotactic signals produced by the pneumococci and complement pathway recruit neutrophills--> acute inflammatory response; little phagocytosis occuring
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How does the CRP work?
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C-reactive protein, a serum component, binds to the phosphorylchlorine on the surface of pneumococcal teichoic acid of the bacteria and leads to activation of complement cascade.
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What does it mean in CRP base-line serum levels are low?
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they are more susceptible to pneumoccocal disease.
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What is ACUTE PHASE REACTANT?
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Normally CRP levels rise when exposed to inflammatory diseases
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What occurs during the third stage (late consolidation)?
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Alveoli are packed with neutrophils that have phagocytosed pneumococci and only a few pneuomocci remain.
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What is hepatization?
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during the third stage when on a microscopic level the affected areas of the lungs resemble liver cells
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What occurs during the four stage (resolution)?
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neutrophils are replaced with macrophages, which clear the debris from the inflammatory process.
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Does pneumococcal pneumonia result in fibrosis scar tissue?
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No, this type of pneumonia usually results in lung tissue being restored to normal, unlike many others that result in necrosis and eventually scar tissue
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What is a common local complication of pneumonia?
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Pleural effusion, which is usually of sterile fluid
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What is empyema?
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Purulent infection of the pleural space (infection of pus); it may need drainage.
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How do distant complications occur?
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They are spread via the blood stream. They are drain via lymphatics to the thoracic duct and then eventually to the blood stream where they can infect distant areas (ie. meninges)
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What are examples of humoral factors that assist with filtering bacteria?
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anti-bodies, complement, and CRP assist macrophages in SPLEEN (very important), liver, and lymphnodes with filtering.
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What can be indicative of a making a pneuomococcal diagnosis?
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10 or more Gram positive stained lancet shaped diplococci and neutrophills present in a sputum sample
***IF NEG, it does not rule out this diagnosis |
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What can be indicative of a making a pneuomococcal diagnosis?
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culturing the bacteria on a blood agar. Colonies will be surrounded by alpha-hemolysis (this is similar for many other bacteria of upper resp. infection)
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What is number 1 thing used for treatment?
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PENICILLIN! can use erythromycin if allergic to penicillin
***will NOT be effective in the CNS |
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What is the short-term affect of using antibiotics to cure the infection
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increased inflammatory response due to the products of the cell wall being broken down; can be deleterious to some people
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What kind of drug is penicillin?
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Beta-lactam, which are used to treat gram-positive bacteria
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What happens in penicillin resistance?
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The pencillin binding proteins are altered an no longer bind penicillin, which will inactivate the cross-linking of the cell wall.
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What is transformation?
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the process by strong selective pressure caused by the presence of anti-bitoics coupled with the natural ability of the organism to adapt by taking up and intergrating DNA in its envt.
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