Micro soft tissue and bone infections cont

  1. What gram stain is Streptococcus pyogenes?
    Gr+
  2. What shape is Streptococcus pyogenes?
    Cocci
  3. Is Streptococcus pyogenes catalase positive or negative?
    Negative
  4. Is Streptococcus pyogenes anaerobe or aerobes?
    Facultative anaerobe
  5. How motile is Streptococcus pyogenes?
    Nonmotile
  6. Can Streptococcus pyogenes do hemolysis?
    Yes, beta hemolysis
  7. True/False: Streptococcus pyogenes is not sensitive to bacitracin
    False, Streptococcus pyogenes is bacitracin sensitive, will not grow if there is bacitracin in agar
  8. True/False: some Streptococcus pyogenes requires carbon dioxide
    True, some are capnophilic
  9. What type of agar is used for Streptococcus pyogenes?
    Blood agar
  10. Is Streptococcus pyogenes fastidious or non-fastidious?
    Fastidious
  11. Streptococcus pyogenes group A could be found where?
    • Has a human reservoir
    • Normal microbiota of oropharynx
  12. Streptococcus pyogenes has what kind of capsule?
    Hyaluronic
  13. What kind of infections are caused by Streptococcus pyogenes?
    • Necrotizing fasiciitis
    • Myositis
    • Acute rheumatic fever
    • Acute post-streptococcal glomeruloneph
    • Etc.
  14. What are some virulence factors of Streptococcus pyogenes?
    • (SMASHED)
    • Streptolysins
    • M protein
    • Against C5a peptidase
    • Streptokinase
    • Hyaluronidase
    • Exotoxin B
    • DNases
  15. What is the function of hyaluronic acid?
    It is non immunogenic because we have this too, so our immune system won’t recognize it
  16. What is ScpC?
    A cell envelope proteinase that prevents neutrophil recruitment by clipping IL-8
  17. What is C5a peptidase?
    Blocks phagocyte chemotaxis by inactivating C5a
  18. What is M protein?
    • Adhesins, binds fibronectin, keratinocytes
    • Antiphagocytic
  19. Which hemolysins can Streptococcus pyogenes produce?
    Streptolysin S and Streptolysin O
  20. What is streptolysin S?
    • B-hemolysin that causes rapid Cl- into cells that lead to lysis
    • Works in aerobic condition
  21. What is streptolysin O?
    B-hemolysin that works only in anaerobic condition, more antigenic than S
  22. What are some extracellular spreading factors of Streptococcus pyogenes?
    • Streptokinase
    • Hyaluronidase
    • DNases A-D
  23. What are superantigens?
    Pyrogenic exotoxins formed by S.pyogenes
  24. What is exotoxin B?
    A superantigen formed by S.pyogenes that degrades immune proteins
  25. What gram stain is Clostridium perfringens?
    Gr+
  26. What shape is Clostridium perfringens?
    Rods
  27. Is Clostridium perfringens anaerobic or aerobic?
    Aertotolerant to anaerobic
  28. Do Clostridium perfringens for endospores?
    Yes, they are one of the two major clinical bugs that form endospores
  29. What is characteristic of Clostridium perfringens when it is related to necrotizing infection?
    Gas gangrene
  30. What is characteristic of gas gangrene?
    Bronze discoloration
  31. What is typically associated with gas gangrene?
    Deep penetrating wound
  32. Where are Clostridium perfringens found?
    • Soil
    • Water
    • Normal microbiota of GI tract
    • Normal microbiota in female GU tract
  33. Do Clostridium perfringens have a capsule?
    Yes
  34. Are Clostridium perfringens motile or nonmotile?
    Nonmotile
  35. Do Clostridium perfringens have hemolytic abilities?
    Yes, double zone hemolysis from alpha and theta toxins
  36. How fast do Clostridium perfringens grow?
    Very fast in culture
  37. What are some virulence factors of Clostridium perfringens
    • Alpha-toxin = lecithinase
    • Theta-toxin
  38. What are alpha-toxins (lecithinase)?
    Phospholipases that disrupt host cell membrane, causing disorganization and responsible for hemolysis and tissue destruction
  39. What are theta-toxin?
    Disrupts cholesterol and lysis of RBC and WBC
  40. What are some spreading factors of Clostridium perfringens?
    • DNase
    • Hyaluronidase
    • Collagenase
  41. When do gas gangrene usually occur?
    <24 hours after deep, penetrating/traumatic injury
  42. What is the shape and gram stain of Brucella?
    Gr negative Coccobacilli
  43. Is Brucella aerobic or anaerobic?
    Aerobes
  44. Where do Brucella live in host?
    Facultative intracellular – can survive inside macrophages and PMNs
  45. How fast do Brucella grow?
    slow grower
  46. What kind of agar do Brucella grow in?
    Blood agar with carbon dioxide
  47. What are the source of human Brucella infections?
    Pigs, cattle, goats, dogs
  48. What is the mode of Brucella transmission from animal to human?
    • Ingestion of unpasteurized dairy products
    • Direct contact
    • Inhalation
  49. How do humans show symptoms of Brucella?
    • Granulomatous response
    • Undulant fever
    • Nonspecific flulike symptoms
    • Enlarged lymph nodes, liver, spleen
  50. How is Brucella diagnosed?
    Bone marrow culture is gold standard
  51. What is the shape and gram stain of Pasteurella multocida?
    Gr negative coccobacilli
  52. What is the common source of human Pasteurella multocida infection?
    Infected dogs or cats
  53. What is the mode of transmission of Pasteurella multocida from animal to human?
    Bite, lick, scratch
  54. Do Pasteurella multocida have capsule?
    yes
  55. Where could Pasteurella multocida be found in its animal source?
    Normomicrobiota animal oropharynx
  56. What are diseases in human that are due to Pasteurella multocida?
    • Localized cellulitis and lymphadenitis
    • URI
  57. Systemic infection for immunocompromised patients
  58. What could happen in Pasteurella multocida infections are left untreated?
    Could lead to osteomyelitis and septic arthritis
  59. What is the shape and gram stain of Bartonella henselae?
    Gr negative Rod
  60. What are other names for Bartonella henselae?
    • Cat scratch disease
    • Bacillary angiomatosis
  61. What is the source of human Bartonella henselae infection?
    Cats
  62. What is the mode of transmission of Bartonella henselae from animal to human?
    Bite, lick, scratch
  63. Where do Bartonella henselae live in its host?
    Facultative intracellular
  64. What is a physiological response induced by Bartonella henselae?
    Angiogenesis
  65. How fast do Bartonella henselae grow?
    Slow grower
  66. What diseases are caused by Bartonella henselae?
    • Localized, chronic lymphadenopathy in children
    • Possible complications including endocarditis, encephalopathy, granulomatous lesion on liver and spleen in immunocompromised patients
  67. What is a disease caused by Bartonella henselae in HIV patients?
    Bacillary angiomatosis
  68. What are symptoms of bacillary angiomatosis?
    • Multiple cutaneous or subQ vascular lesions that bleed profusely when traumatized
    • Fever
    • Liver lesions
    • Osteolytic bone lesion of the long bones
  69. What is Bartonella quintana mode of transmission?
    Body louse
  70. What is another name for Bartonella quintana?
    Trench fever
  71. True/False: Bartonella henselae is more common cause of bacillary angiomatosis than B.quintana
    False
  72. Which population are Bartonella quintana prevalent in?
    • Homeless population
    • Wars
  73. What is necrotizing fasciitis?
    • Community acquired deep-seated infection of SubQ tissues
    • Progressive destruction of fascia and fat
    • May spare skin
  74. What microbe usually causes necrotizing fasciitis type II?
    Group A Streptococcus pyogenes (GAS)
  75. Describe pathogenesis of necrotizing fasciitis?
    • Could occur any part of body, usually begin as cellulitis
    • Spreads along fascial planes and causes destruction of those plus fat
    • Lead to systemic symptoms
  76. What are symptoms of necrotizing fasciitis?
    • Fevers, hypotension, tachycardia
    • Pain out of proportion
    • Erythema, skin induration
    • Bullae (blue, large blisters)
    • Darken, reddish purple color skin within 24-48 hours
  77. What could happen to patient with necrotizing fasciitis?
    • Multiple organ failure
    • Death
  78. How id necrotizing fasciitis diagnosed?
    • When symptoms fail to respond to broad spectrum IV abx
    • Cutaneous manifestation
  79. How is necrotizing fasciitis treated?
    • immediate surgical debridement
    • Abx
    • Hemodynamic support
  80. What is myonecrosis?
    Necrotizing infection of the muscle
  81. What is gas gangrene?
    Necrotizing infection of muscle that is caused by Clostridia instead of Streptococcus
  82. What are symptoms of gas gangrene?
    • Sever pain
    • Edema, tenderness
    • Discoloration
    • Crepitus at subQ tissue/muscle
    • Systemic findings of toxicity
    • Shock
  83. What could happen to patients with gas gangrene if left untreated within 48 hours?
    Multiorgan failure, death
  84. How is gas gangrene diagnosed?
    • Confirm with gram stain, anaerobic cultures
    • Double zone hemolysis on blood agar
    • Lecithinase activity on egg yolk agar
  85. What is pyomyositis?
    Purulent infection of soft tissue infection that spread to the bone, usually with abscess caused by S.aureus or S.pyogenes
  86. What is osteomyelitis
    Subacute to chronic infection to the bone
  87. What is the common cause of osteomyelitis?
    S.aureus
  88. What are some symptoms of osteomyelitis?
    • Fevers
    • Chills
    • Malaise
    • Localized pain
    • Edema
    • Erythema
  89. What are the risk factors for osteomyelitis?
    • Diabetes
    • Immunocompromised patients
    • IV drug users
    • Elderly
  90. What are some types of osteomyelitis?
    • Hematogenous (monomicrobial)
    • Contiguous (polymicrobial)
  91. How is osteomyelitis diagnosed?
    • Patient unable to bear weight
    • Unilateral extremity pain
    • Recent trauma or puncture wound
    • Chronic draining ulcer
  92. What are some diagnostic methods for osteomyelitis?
    • MRI imaging
    • Gold standard – isolation of microbe from bone bx
  93. How to treat osteomyelitis?
    • Abx after bone bx
    • Debridement either surgically or non-surgically
    • Could consider amputation
Author
lykthrnn
ID
343029
Card Set
Micro soft tissue and bone infections cont
Description
NMSK Exam 2 Microbio bugs soft tissue and bone infections
Updated