LG3.6 Microbiology of Joint Infections – Dr. Pettit Flashcards Preview

NMSK A Test 2 > LG3.6 Microbiology of Joint Infections – Dr. Pettit > Flashcards

Flashcards in LG3.6 Microbiology of Joint Infections – Dr. Pettit Deck (39):
1

What type of hemolysis does S. aureus cause?

Beta

2

Is S. aureus gram +/-?

positve

3

What is the catalase, coagulase, and fermenter type of S. aureus?

Catalase positive, coagulase positive, and it is a mannitol fermentor

4

What are the main virulence factors of S. aureus?

-Protein A: Binds to Fc region of IgG
-Fibronectin-binding protein
-Cytolytic Exotoxins: PVL

5

What type of hemolysis does S. epidermis have?

Gamma hemolysis

6

What is the catalase, coagulase, and fermenter type of S. epidermis?

Catalase positive, coagulase negative, and mannitol fermentor negative

7

What are the main virulence factors of S. epidermis

-Slime layer (attachement to tissues/prosthetics)
-Adhesins (collagen, fibrinogen, elastin)
-Lipases, proteases
-Biofilms

8

What is the gram stain and shape of Kingella kingae?

Gram negitive and coccobacillus

9

Where is Kingella kingae normal microbiota?

oropharynx

10

What type of oxygen use does Kingella kingae have?

Facultative anaerobe

11

What type of hemolysis does Kingella kingae cause?

Beta hemolytic

12

Is Kingella kingae oxidase positive or negative?

Positive

13

What is a leading cause of septic arthritis?

Kingella kingae

14

What are the virulence factors of Kingella kingae?

-Pili
-Beta-hemolysin: lysis epithelial cells, synovial cells, macrophages

15

What is the Gram stain and shape of Neisseria gonorrhoeae?

Small Gram Negative diplococcus

16

What is the oxygen use of Neisseria gonorrhoeae?

Aerobe to facultative anaerobe

17

What are the oxidase and catalase of Neisseria gonorrhoeae?

Oxidase positive and Catalase positive

18

What are the main virulence factors of Neisseria gonorrhoeae?

-Adhesins
-Opa
- pili
- IgA1 protease
- Antibiotic resistance

19

What types of antibiotic resistance does Neisseria gonorrhoeae?

-Efflux pumps
-Naturall competent for transformation
-Conjugation plasmids
-Evidence for biofilm formation

20

What do Neisseria gonorrhoeae do to avoid the immune system?

-Bind sialic acid to their LOS
-Facilitated intracellular
-Antigenic and phase variation of Opa's, pili, LOS
-Outer membrane blebbing

21

What are the main symptoms of Gonococcal?

-low-grade fever
-petechial skin lesions
-migratory polyarthralgia
-Septic arthritis with increased pain and swelling of joints, purulent synovial fluids, and tenosynovitis

22

Where and how many joints does Gonococcal normally infects?

-Polyarticular (can be mono)
-Knee, wrist, ankle and elbow
(less damage than non-gonococclal arthritis.

23

What are the symptoms of nongonococcal infections?

-Fever, joint pain (hot, swollen)
-Impaired ranged of motion
-Usually monoarticular
-Knee most common

24

What are the symptoms of prothetic joint infection?

-Sudden local joint pain
- Mechanical joint failure

25

What are the three ways that a joint can become septic?

-Hematogenous spread
-Direct inoculation (bite,trauma)
- Extension of osteomyelitis

26

What are the two major classes of septic arthritis?

-Nongonococcal (50% death rate)
-Gonococcal (low mortality rate)

27

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.

28

What is the shape and gram stain of Borrelia burgdorferi?

-Gram negitive and spirochete
-Large size

29

What type of oxygen use does Borrelia burgdorferi have?

microaerophile

30

What is the vector of Borrelia burgdorferi?

-Blacklegged tick Ixodes
-Forest dweller
-All stages require blood meal.

31

How is Borrelia burgdorferi cultured?

-Fastidious and slow growing
-Limited metabolic capabilities
-Generation time under optimal conditions 12-24 hours

32

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.

33

What type of rash is indicative of lyme disease?

The bulls eye rash or erythema migraines.

34

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)
-Ocular manifestations

35

What are the main components of late lyme?

-Usually manifests as chronic arthritis
-Less often CNS problems

36

Why is it less useful staining/culture for lyme disease?

Few spirochetes in blood/tissues

37

What does it mean to do direct testing for lyme disease?

Looking for presence of microbe antigens uses known antibody

38

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.

39

What is the typical synovial WBC count for lyme arthritis?

Less than other bacterial arthritis etiologies, 20,000 to 60,000 cells/uL.