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Streptococcus Tao Chuanmin

Streptococcus Tao Chuanmin. Widespread in nature Some strains as virulent pathogens Other strains live harmoniously Transient colonizers of skin Resident colonizer of mucous membranes Normal flora of alimentary, respiratory and genital tracts. Classification. 40 species and subspecies

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Streptococcus Tao Chuanmin

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  1. StreptococcusTao Chuanmin

  2. Widespread in nature Some strains as virulent pathogens Other strains live harmoniously Transient colonizers of skin Resident colonizer of mucous membranes Normal flora of alimentary, respiratory and genital tracts

  3. Classification • 40 species and subspecies • Traditional rules • Hemolytic reactions • α hemolytic • βhemolytic • γ hemolytic • Lancefield serological tests • A、B、C、D、E…

  4. Clinical significant Group A streptococci(S. pyogenes) Impressive human pathogen Acute pharyngitis,respiratory infection Skin (impetigo and erysipelas) and soft tissue infection

  5. Endoarditis, meningitis, scarlet fever and more serious toxic shock-like symptoms Acute glomerulonephritis, rheumatic fever Numerous virulence factors M protein, Pyrogenic exotoxins, Hyaluronic acid capsule, Hemolysins etc.

  6. Group B streptococci(S. agalactiae) Neonatal infection sepsis and meningitis Group C and G streptococci Similar to S. pyogenes Viridans Streptococci Normal flora Subacte bacterial endocaditis(SBE)

  7. Streptococcus pneumoniae Community-acquired pneumonia, bacteremia Otitis media, sinusitis, meningitis, and endocarditis

  8. Microbial Characters GPC Arranged：single,pairs,chains S. pneumoniae：

  9. Facultatively anaerobe Chemical reaction: active metabolism Catalase：negative

  10. Microbial diagnostics procedure specimen Smear and stain culturedirect examination colony Smear and stain biochemical serologyantibiotic identificationidentification susceptibility 返回

  11. Microbial diagnostics Specimen collection Throat swab, sputum, pus and blood, et al Specimen direct diagnostics Smear and Gram stain Direct antigen detection

  12. Culture and identification βhemolytic PYR test：Group A Bacitracin-susceptible：Group A VP(Voges-Proskauer) test CAMP test：Group B

  13. Non β hemolytic Optochin test Bile solubility test Bile esculin test

  14. Serologic tests：Streptolysin O Antibiotic susceptibilities：A、B、C group Evaluation, interpretation and reporting of results Beta-hemolytic streptococci and pneumococci are virulent pathogens, all reporting PRSP(penicillin resistant Streptococcus pneumonia)

  15. Enterococcus Common description Widespread in nature Gastrointestinal and genitourinary tract flora Hospital-acquired infection pathogen Classification E. feacalis and E. faecium

  16. Clinical significant • Urinary tract infections(UTIs)：underlying structural abnormalities and undergone urologic manipulations • Abdominal and pelvic infections • sepsis

  17. Microbial Characters GPC(single, pairs, short chains) Facultative anaerobes PYR test positive Higher resistance to chemical and physical agents Bile-esculin positive Resistance to several antibiotics

  18. Microbial diagnostics procedure Specimen collection Direct detection Culture and identification Catalase negative Grow in 6.5% NaCl broth Bile-esculin positive

  19. Antibiotic susceptibilities A group Penicillin or ampicillin B group Vancomycin C groupTetracycline, erythromycin, chlormphenicol, Rifampin D group Ciprofloxacin, Norfloxin high-level resistance(HLR) to aminoglycosides Enterococcus 500ug/ml gentamicin 2000ug/ml streptomycin vancomycin resistant Enterococcus (VRE) 6ug/ml vancomycin

  20. Neisseria and Branhamella Neisseriaceae Neisseria, Branhamella, Moraxella, Kingella and Acinetobacter Mainly pathogens N. gonorrhoeae N. meningitidis B. catarrhalis

  21. Clinical significant • N. gonorrhoeae • Common sexual transmitted diseases(STD) • Transmitted by direct, close, usually sexual • Transmission to neonates usually occurs during birth

  22. virulence factor :pili

  23. N. meningitidis • Meningitis, meningococcemia • Usually transmitted by direct contact with contaminated respiratory secretions or air-borne droplets • School-age children, adolescents, and young adults • B. catarrhalis • Acute localized infections: otitis media, sinusitis, and bronchopneumonia • Life-threatening systemic diseases: endocarditis and meningitis

  24. Microbial Characters • Gram-negative diplococci • Adjacent sides flattened to give a characteristic kidney or coffee bean appearance • Nonmotile，no endospores，some species are encapsulated • Cell may autolyze in culture

  25. Complex growth requirements aerobe The growth is enhanced by humidity and CO2 Oxidase positive catalase positive

  26. Microbial diagnostics • Procedure • Collection • Direct detection • Direct microscopy • Antigen and nucleate detection

  27. Culture and identification • Selective media：MTM，ML，NYC（N. gonorrhoeae） • Nonselective media：Chocolate agar or blood agar • 5%CO2

  28. Colonial appearance • N. G：small,smooth • N. M：small,smooth,flat,mucoid • B. C：small, friable

  29. Presumptive identification • GNC，OX+ • Confirmatory identification • G.M：acid production from glucose and maltose • G.N：acid production from glucose • B.C：DNase +，nitrate reduction + (-) (+) 氧化酶 DNA酶试验 硝酸盐还原试验阳性

  30. Antibiotic Susceptibilities • Penicillin, cephalosporin、tetracycline、ciprofloxacin • Resistant strains • G.N：3rd cephalosporins、new fluoroquinolone • B.C：extended-spectrum penicillin＋penicillinase inhibitory

  31. Evaluation, interpretation and reporting results • N.G • confirm：depend on culture and identification • Early and rapidly diagnosis

  32. Summary • Staphylococcus • Streptococcus • Enterococcus • Neisseria and Branhamella • Classification、Clinical Significance、Microbial Characters、Microbial diagnostics

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