Term
| What gram positive cocci is seen in bacterial infection of the respiratory system? |
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Definition
| Staphylococcus, streptococcus, enterococcus |
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Term
| What gram negative cocci is seen in bacterial infection of the respiratory system? |
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Definition
| Neisseriaceae (N. Gonorrhoeae and N. Meningitidis), moraxella, acinetobacter |
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Term
| What gram positive bacteria are spore formers? |
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Definition
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Term
| What gram negative bacteria are anaerobes? |
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Definition
| Actinomyces, bacteroides, and clostridium |
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Term
| What are the three classifications of streptococci? |
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Definition
| Pyogenic streptococci, penumococci, and viridans |
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Term
| What is characteristic of pyogenic streptococci? |
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Definition
| Contains lancefield antigen (cell wall carbohydrate), may be alpha or beta hemolytic |
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Term
| What is characteristic of viridans (streptococci)? |
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Definition
| Non hemolytic, normal flora of oral cavity |
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Term
| What is characteristic of pneumococci (streptococci) |
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Definition
| Only one member, S. pneumoniae |
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Term
| What is the most common cause for seeking medical care in the US? |
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Definition
| Strep throat due to streptococcal pharyngitis caused by the bacteria Streptococcus pyogenes |
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Term
| What is the morphology of Streptococcus pyogenes? |
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Definition
| Gram positive oval cells growing in chains, non acid-fast, no spore, non-motile, may or may not have capsules |
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Term
| How is Streptococcus pyogenes cultured? |
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Definition
| Blood agar, cultures as small colonies with a possible surrounding zone of hemolysis, glucose fermentation yields lactic acid |
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Term
| What is the different hemolytic zones that may surround Streptococcus pyogenes cultures? |
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Definition
| Beta-hemolysis = clear zone surrounding the colony (complete hemolysis), alpha-hemolysis = hazy zone with green discoloration (incomplete hemolysis) |
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Term
| What are the symptoms of strep throat? |
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Definition
| Soreness of throat, difficult swallowing, fever, malaise, headache, red throat, which patches of pus with hemorrhagic spots or yellowish white exudates, enlarged/tender cervical lymph nodes, abdominal pain (not always) |
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Term
| Virulence of Streptococcus pyogenes is mediated by what? |
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Definition
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Term
| What is a positive sign of a rapid strep test? |
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Definition
| Visible clumps produced by antigen and antibody interaction, negative sign has a smooth, milky reaction |
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Term
| What is the only beta-hemolytic pathogen that is bacitracin sensitive? |
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Definition
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Term
| How is strep throat treated? |
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Definition
| Penicillin is the first choice, erythromycin and first generation of cephalosporin (cephalexin) may be given to penicillin sensitive patients |
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Term
| What kind of complications can arise from streptococcal pharyngitis? |
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Definition
| Scarlet fever, strawberry tongue |
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Term
| What causes scarlet fever? |
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Definition
| Infection with Streptococcus pyogenes that is itself infected with a bacteriophage, arythrogenic toxics enter blood and cause rashes |
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Term
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Definition
| Complication of streptococcal pharyngitis, antibody generated against streptococcal antigens cross-reacts with antigenic apitopes on cardiac cells, damages valves cause sub-acute bacterial endocarditis |
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Term
| What are the symptoms of rheumatic fever? |
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Definition
| Fever, joint pain, chest pain, nodules under the skin, rash, chorea |
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Term
| What must be present for a diagnosis of rheumatic fever? |
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Definition
| Must have last 2 major criteria: carditis, arthritis, chorea, subcutaneous nodules, arythema marginatum or one major and two minor criteria: fever, joint pain, electrical changes in the heart, evidence of certain proteins in the blood |
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Term
| How is rheumatic fever treated? |
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Definition
| Ten day course of penicillin or single injection of penicillin-G, aspirin for pain and inflammation, steroids are sometimes used for carditis, diazepam or haloperidol fo rChorea |
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Term
| What provides immunity to rheumatic fever? |
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Definition
| Type-specific IgA prevents adhesion and IgG against M-protein protects against invasion, though there are too many strains of GAS to prevent repetitive infections |
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Term
| What renal complications can arise from Streptococcus pyogenes? |
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Definition
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Term
| What is the causative agent of Pneumococcal pneumonia? |
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Definition
| Streptococcus pneumoniae - a gram positive diplococcus, has very thick capsule (major virulent factor) |
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Term
| Why is Streptococcus pneumoniae referred to as diplococci? |
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Definition
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Term
| Where is Streptococcus pneumoniae found? |
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Definition
| Normal flora in the upper respiratory tract that normally does not reach lower respiratory tract, compromised immune status renders individual susceptible |
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Term
| What are the symptoms of pneumonia? |
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Definition
| Runny nose, chest congestion, cough, fever with chills, chest pain, purulen sputum, shallow/rapid breathing, low oxygenation |
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Term
| Why do Streptococcus pneumoniae avoid phagocytosis when infecting lung alveoli? |
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Definition
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Term
| Streptococcus pneumoniae entering the blood stream causes what? |
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Definition
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Term
| What is the #1 cause of meningitis in adults? |
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Definition
| Pneumonia infected meninges |
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Term
| How is S. pneumoniae diagnosed? |
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Definition
| Identification of gram positive diplococci in smears in blood agar, distinguished from S. viridans by susceptibility to Optochin or by bile solubility |
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