Flashcards in LG3.6 Microbiology of Joint Infections – Dr. Pettit Deck (39):
What type of hemolysis does S. aureus cause?
Is S. aureus gram +/-?
What is the catalase, coagulase, and fermenter type of S. aureus?
Catalase positive, coagulase positive, and it is a mannitol fermentor
What are the main virulence factors of S. aureus?
-Protein A: Binds to Fc region of IgG
-Cytolytic Exotoxins: PVL
What type of hemolysis does S. epidermis have?
What is the catalase, coagulase, and fermenter type of S. epidermis?
Catalase positive, coagulase negative, and mannitol fermentor negative
What are the main virulence factors of S. epidermis
-Slime layer (attachement to tissues/prosthetics)
-Adhesins (collagen, fibrinogen, elastin)
What is the gram stain and shape of Kingella kingae?
Gram negitive and coccobacillus
Where is Kingella kingae normal microbiota?
What type of oxygen use does Kingella kingae have?
What type of hemolysis does Kingella kingae cause?
Is Kingella kingae oxidase positive or negative?
What is a leading cause of septic arthritis?
What are the virulence factors of Kingella kingae?
-Beta-hemolysin: lysis epithelial cells, synovial cells, macrophages
What is the Gram stain and shape of Neisseria gonorrhoeae?
Small Gram Negative diplococcus
What is the oxygen use of Neisseria gonorrhoeae?
Aerobe to facultative anaerobe
What are the oxidase and catalase of Neisseria gonorrhoeae?
Oxidase positive and Catalase positive
What are the main virulence factors of Neisseria gonorrhoeae?
- IgA1 protease
- Antibiotic resistance
What types of antibiotic resistance does Neisseria gonorrhoeae?
-Naturall competent for transformation
-Evidence for biofilm formation
What do Neisseria gonorrhoeae do to avoid the immune system?
-Bind sialic acid to their LOS
-Antigenic and phase variation of Opa's, pili, LOS
-Outer membrane blebbing
What are the main symptoms of Gonococcal?
-petechial skin lesions
-Septic arthritis with increased pain and swelling of joints, purulent synovial fluids, and tenosynovitis
Where and how many joints does Gonococcal normally infects?
-Polyarticular (can be mono)
-Knee, wrist, ankle and elbow
(less damage than non-gonococclal arthritis.
What are the symptoms of nongonococcal infections?
-Fever, joint pain (hot, swollen)
-Impaired ranged of motion
-Knee most common
What are the symptoms of prothetic joint infection?
-Sudden local joint pain
- Mechanical joint failure
What are the three ways that a joint can become septic?
-Direct inoculation (bite,trauma)
- Extension of osteomyelitis
What are the two major classes of septic arthritis?
-Nongonococcal (50% death rate)
-Gonococcal (low mortality rate)
What is the role of white footed mice in the life cycle of Ixodes Scapularis?
-2 year cycle of Ixodes scapulars
- Eggs uninfected
-Rodent reservoir (White footed mice) (Eats the eggs)
-Deer are not reservoirs but needed for completion of life cycle.
What is the shape and gram stain of Borrelia burgdorferi?
-Gram negitive and spirochete
What type of oxygen use does Borrelia burgdorferi have?
What is the vector of Borrelia burgdorferi?
-Blacklegged tick Ixodes
-All stages require blood meal.
How is Borrelia burgdorferi cultured?
-Fastidious and slow growing
-Limited metabolic capabilities
-Generation time under optimal conditions 12-24 hours
What are the virulence factors of Borrelia burgdorferi?
-Seems to suppress immune response in patients
-Blebs, biofilms, antigenic variation surface proteins.
-Very motile via axial filaments.
What type of rash is indicative of lyme disease?
The bulls eye rash or erythema migraines.
What are the main components of Early disseminated lyme disease?
-Dissemination to skin, heart, CNS, joints.
-Multiple erythema migrans
-Cardiac/neurologica complications. (Bell's palsy, peripheral neuropathy)
What are the main components of late lyme?
-Usually manifests as chronic arthritis
-Less often CNS problems
Why is it less useful staining/culture for lyme disease?
Few spirochetes in blood/tissues
What does it mean to do direct testing for lyme disease?
Looking for presence of microbe antigens uses known antibody
What does it mean to do indirect testing for lyme diseases?
Looking for host antibodies directed against microbe antigens uses known antigens current exposure, previous exposure.