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Published byAshley Moody Modified over 8 years ago
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Arrangement of cocci in pair or long chains Non-spore forming, non-motile Capsule, slime layers Facultative anaerobes Catalase(-), peroxidase(+) Small, non-pigmented, glistening colonies Fastidious in nutrition, drying, heat, disinfectants
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1. Hemolysis type incomplete hemolysis S.pneumoniae, S.viridans α complete hemolysis S.pyogenes, S.agalactiae β non hemolysis E.faecalis γ
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2. Lancefield group
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1. Characteristic β-hemolysis bacitracin sensitive Most strong pathogenicity Hemolytic Streptococcus to human. Streptococcus infection’s 90% (produce a large variety of toxins in vivo) young school aged children’s infection rate is the most high
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좌 : S.pyogenes / 우 : S.agalactiae
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2. Virulence Factor Cell surface antigen (C carbohydrate) Lipoteichoic acid M protein Hyaluronic acid C5a protease
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3. Major Extracellular Toxins streptolysins streptolysin O (SLO) : oxygen sensitivity streptolysin S (SLS) : oxygen-stable erythrogenic toxin (pyogenic toxin) 4. Major Extracellular Enzymes streptokinase hyaluronidase
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5. Disease impetigo pyodermapapules
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erysipelaspharyngitisnecrotizing myositis
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Scarlet feverToxic shock syndrom
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6. Treatment and Prevention Anti-microbic therapy Most S.pyogenes is very sensitive to penicillin Patients with group A infections must be isolated and high level precautions be practiced rheumatic fever acute glomerulonephritis
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1. Characteristic β-hemolysis Normal flora of humans and other mammals In vagina, pharynx, large intestine of human associated with cattle (causes bovine mastitis) main virulence factor : polysaccharide antiphagocytic capsule
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2. Diagnosis CAMP test, hippurate hydrolysis test
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3. Disease bovine mastitis neonatal pneumonia, sepsis, meningitis endocarditis 4. Treatment and Prevention Treatment : penicillin G, vancomycin, cephalosporins Prevention : Pregnant women in the third trimester should be screened for colonization.
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Group D Streptococci EnterococciE.faecalisE.faeciumE.durans Non- Enterococci S.bovisS.equinus
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1. Group D Enterococci Normal colonists of the human large intestine. Multi-drug-resistant strains → vancomycin-resistant Enterococcus (VRE) → serious nomocomial opportunists E.faecalis : Elderly patients undergoing surgery E.faecium : Neonatal meningitis Combined therapy with ampicillin and aminoglycoside 2. Group D Non-Enterococci Starch hydrolysis 6.5% salt sensitive
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Common flora of domestic animals Isolated from human upper respiratory β-hemolysis Compromised patients → bacteremia → dissenminated deep-seated infections S.equisimilis
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residents of the oral cavity, nasopharynx, genital tract, skin α-hemolysis : S.mitis, S.mutans, S.milleri, S.saliarus, S.sanguis subacute endocarditis : rheumatic fever, valve surgery dental caries : S.mutans, S.sanguis
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1. Characteristic normal flora in the nasopharynx 60~70% of all bacterial pneumonias α-hemolysis smooth or mucoid colony in blood agar, Small lancet-shaped 5~10% CO 2, lack catalase and peroxidase Delicate, Not survive out of habitat Capsule → Virulence↑ : Quellung test soluble to bile autolysis : dome, smooth shape → flat, rough shape
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2. Diagnosis Blood culture, sputum, pleural fluid, spinal fluid Gram stain Quellung test Optochin test : alpha hemolytic streptococci (-), but, Streptococcus pneumoniae (+)
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3. Disease pharynx → lung → bronchiole & alveoli → inflammatory response → the release of a torrent of edematous fluids into the lungs → drown in his own secretion → lobar pneumonia in young children (under 2 years) : otitis media, meningitis
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4. Treatment and Prevention penicillin G, penicillin V (drug sensitive test) cephalosporins, vancomycin, quinolones, erythromycin polyvalent vaccine (capsular antigen) : sickle cell anemia, lack of spleen, congestive heart failure, lung disease, diabetes, kidney disease, advanced age conjugate vaccine → recommened for children 2 to 23 months as preventive therapy for otitis media and meningitis
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You want to differentiate between The Viridans Group and S.pneumoniae. Which method should you choose? ① Hemolysis pattern ② Bacitracin test ③ Optochin test ④ Urease test ⑤ Motility
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Which disease is occurred by S. agalactiae? ① meningitis ② scarlet fever ③ rheumatic fever ④ acute glomerulonephritis ⑤ erysipelas
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What is NOT feature of Lancefield group A streptococcus? ① Most strong pathogenicity Hemolytic Streptococcus to human. ② Gram positive. ③ β-hemolysis ④ CAMP test positive ⑤ bacitracin sensitive
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Which of the following disease is/are caused by S.pneumoniae? ① otitis media ② subacute endocarditis ③ meningitis ④ rheumatic fever ⑤ dental caries
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Which is NOT the Group D streptococcus? ① Streptococcus bovis ② Enterococcus faecalis ③ Enterococcus durans ④ Streptococcus equinus ⑤ Streptococcus agalactiae
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