streptococci
Download as PPT, PDF94 likes19,552 views
The document discusses the genus Streptococcus, including its classification, morphology, growth characteristics, biochemical reactions, and clinical significance. It describes various species, such as Streptococcus pyogenes and Streptococcus pneumoniae, detailing their pathogenicity, diseases caused, laboratory diagnosis, and treatment options. The document also covers epidemiology, resistance patterns, and specific infections associated with different streptococci groups.
streptococci
- 3. Commensals or Parasites of man & animals or Saprophytes of decaying matter 3
- 4. Genus Streptococcus Gram-Positive Cocci in Pairs or Chains v/s Staph – gram positive cocci in clusters (grape like) 4
- 6. Gram positive cocci in clusters 6
- 7. Classification On the basis of their growth characteristics on blood agar Alpha hemolytic Beta hemolytic Gamma hemolytic 7
- 8. Example – Streptococcus viridans (Viridans = green) Streptococcus pneumoniae 8
- 9. 9
- 10. Example – enterococcus group 10
- 11. 11
- 12. 12
- 13. Beta hemolytic streptococci Lancefield grouping Group A to Group V without I and J Divided according to differences in Cell wall carbohydrate antigen Out of all these, those of Group A known as streptococcus pyogenes produce majority of human infections Group B are known as S agalactiae 13
- 14. Group A beta hemolytic streptococci / strep pyogenes These are further subdivided according to sell surface M, T and R antigens Griffith typing 14
- 15. 15
- 16. Streptococcus Pyogenes (Group A beta hemolytic) 16
- 17. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 17
- 18. Morphology Cocci in long chains 18
- 19. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 19
- 20. Growth characteristics Facultative anaerobe, grows best in presence of 10% CO2 Grows on enriched media only Beta hemolysis around colonies on blood agar 20
- 21. 21
- 22. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 22
- 23. Biochemical reactions Ferment sugars – produce acid , no gas Catalase negative Catalase helps to differentiate staphylococci from streptococci 23
- 24. Catalase test Add hydrogen peroxide to culture material 24
- 25. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 25
- 26. Resistance Most are still susceptible to penicillin and erythromycin 26
- 27. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 27
- 28. Pathogenicity and virulence Antigenic structure Antigens on surface of strep cross react with body proteins Capsular hyaluronic acid – human joints – autoimmune arthritis Carbohydrate antigen – cardiac valves – rheumatic heart disease Toxins Enzymes Streptolysin O – ASO titre for diagnosis Streptolysin S – for hemolysis around colonies Streptokinase – lysis of clots – given iv for treatment of MI DNA ase – Anti DNAase is useful for diagnosis of S. pyogenes skin infection Hyaluronidase – breaks down tissues – helps in spread of strep infection 28
- 29. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 29
- 30. Epidemiology Source – human upper respiratory tract – throat, pharynx, nose Transmission – direct contact, fomites 30
- 31. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 31
- 32. Diseases caused Pus producing (suppurative) Respiratory infections Skin and soft tissue infections Genital infections Non suppurative Acute rheumatic fever Rheumatic heart disease Acute glomerulonephritis (kidney) 32
- 33. Respiratory infections Tonsillitis Pharyngitis 33
- 34. tonsillitis 34
- 35. pharyngitis 35
- 36. Skin and soft tissue infections Skin Erysipelas – involves lymphatics – older pts Impetigo – young children Pyoderma Soft tissue Cellulitis Necrotising fascitis 36
- 37. Erysipelas 37
- 38. Impetigo 38
- 39. Pyoderma 39
- 40. Cellulitis 40
- 41. Necrotising fascitis flesh eating bacteria (anaerobes) 41
- 42. Non suppurative complications After 1-3 weeks of primary infection Due to cross reactivity 42
- 43. Acute rheumatic fever Follows streptococcal sore throat 43
- 44. Acute glomerulonephritis Cross reaction between streptococci and kidney tissues 44
- 46. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 46
- 47. Suppurative infections Examination of pus/throat swabs Microscopy, staining and culture Gram stain Blood agar 47
- 48. Non suppurative infections Demonstration of antibodies Like ASO and anti DNA ase B 48
- 49. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 49
- 50. Treatment Penicillin Erythromycin Drugs have no effect if non suppurative complications have developed Prophylaxis – can prevent rheumatic fever, not glomerulonephritis 50
- 51. OTHER STREPTOCOCCI BETA HEMOLYTIC - GROUP B AND GROUP D ALPHA HEMOLYTIC (VIRIDANS GROUP)– STREPTOCOCCUS PNEUMONIAE 51
- 52. Group B Streptococcus Streptococcus agalactiae 52
- 53. Group B Streptococcus S. agalactiae 1. Infect newborns 2. Infection acquired through maternal vagina during birth 3. Presents as meningitis, pneumonia or septicemia 53
- 54. Diagnostic Laboratory Tests CAMP factor positive Hippurase positive 54
- 55. CAMP (Christie, atkins, munchpeterson) Factor Test aureus S. Group B Streptococcus (Spingomyelinase C) (CAMP Factor) Group A Streptococcus Enhanced Zone of Hemolysis 55
- 56. Hippurase NEG Streptococcus agalactiae not added 56
- 57. Grp B Streptococci Hippurase POS 57
- 58. Viridans group Streptococcus pneumoniae • Commonly referred to as pneumococcus 58
- 59. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 59
- 60. Lancet shaped (one end broad, other pointed) Capsulated Diplococci 60
- 61. S. pneumoniae: lancet-shaped diplococcus 61
- 64. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 64
- 65. Growth characteristics Alpha hemolysis on blood agar On further incubation, the colonies become flat with raised edges and central elevation resembling carrom coins 65
- 66. Example – Streptococcus viridans (Viridans = green) Streptococcus pneumoniae 66
- 67. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 67
- 68. Biochemical reactions Hiss serum water – fermentation of inulin Bile solubility 68
- 70. 70
- 71. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 71
- 72. Resistance Pneumococcus is sensitive to optochin – used for typing Resistance to penicillin – third generation cephalosporin like ceftriaxone May be resistant to third gen ceph also 72
- 73. 73
- 74. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 74
- 75. Pathogenicity and virulence Capsule Toxins – pneumolysin C reactive protein 75
- 76. Capsule 76
- 77. Pneumolysin Membrane damaging toxin Cytotoxic activity 77
- 78. C reactive protein Abnormal immunoglobulin against C protein of S. pneumoniae appears in serum of patients Also seen in acute phase of infections and inflammations CRP titre is tested in acute infections 78
- 79. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 79
- 80. Epidemiology Source – respiratory tract of humans Spread – droplets Carriers – pharynx Low immunity is responsible for fulminant infections RSV infection, pulmonary congestion, stress, malnutrition, alcoholism Splenectomy Sickle cell disease 80
- 81. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 81
- 82. Diseases caused Middle ear – otitis media Para nasal sinuses – sinusitis Respiratory tract – pneumonia, bronchitis, empyema Meningitis is secondary to otitis media, penumonia, sinusitis and conjunctivitis 82
- 83. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 83
- 84. Laboratory diagnosis Sample sputum – pneumonia septicemia - blood culture Otitis media - fluid from middle ear Meningitis - CSF Method Gram stain, microscopy culture 84
- 85. Latex agglutination for pneumococcal antigen in serum of patients 85
- 86. Description headings Morphology Growth characteristics Biochemical reactions Resistance Pathogenicity and virulence Epidemiology Diseases caused Laboratory diagnosis Treatment 86
- 87. Treatment Penicillin Amoxycillin ceftriaxone/ceftazidime Vancomycin 87
- 88. Prophylaxis Pneumococcal conjugate vaccine is available Given to splenectomy patients, sickle cell anemia patients and susceptible individuals 88
- 89. GROUP D STREPTOCOCCI Enterococcus faecalis Enterococcus faecium • GI tract of humans and animals • Group D carbohydrate cell wall antigen • Formerly Streptococcus 89
- 90. Cause UTI, wound infection Endocarditis Intra abdominal abcesses 90
- 91. 91