Section 3- Bacteriology Flashcards Preview

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Flashcards in Section 3- Bacteriology Deck (82)
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1

Coagulase

Clumping factor enzyme made by bacteria
Virulence factor- helps bacteria wall itself off so immune cells cannot reach it
Takes fibrinogen (soluble) and along with thrombin, makes fibrin (insoluble) which helps blood clot
+ = s. aureus
Can test on a slide (surface coagulase) or in a tube (secreted coagulase)

2

Mannitol Salt Agar (MSA)

Selective
Mannitol sugar fermentation results in acid production and media turns yellow
+ = S. aureus
- = S. epidermidis, S. saprophyticus

3

Blood Agar

Standard medium
Almost everything grows on
NOT Neisseria gonorrhoeae

4

Sepsis

Signs= fever, elevated pulse, respiratory distress and kidney failure
Indicative of bacterial infection

5

Pleural effusion

Excess fluid between pleura layers
Evidence of infection

6

HAP

Hospital Acquired Pneumonia

7

Nosocomial pneumonia pathogens (7)

Pseudomas aeruginosa
Klebsiella
Escherichia coli
Acinetobacter
Haemophilus influenzae
Staphylococcus aureus
Streptococcus pneumoniae

8

Alpha toxin

Hemolysin
Causes hemolysis of RBCs

9

MRSA

Methicillin resistant S. aureus
Emerged as nosocomial infection in U.S.
Community acquired
Current epidemic in U.S.
Necrotizing pneumonias

10

von Willebrand factor binding protein (vWbp)

Cell wall associated
Binds host vW factor
Facilitates adhesion in blood vessels

11

Protein A (SpA)

Cell wall associated
Binds to Fc region of IgG and binds to Fab region of BCR
Prevents immune cell recognition and complement activation

12

Leukocidins

Target WBCs to form pores

13

Hemolysins

Target RBCs to form pores

14

Toxic Shock Syndrome Toxin (TSST-1)

Superantigen
Causes TSS
Superantigens cross-link MHC class II molecules with TCRs, Polyclonal T cells activated, Massive pro inflammatory cytokine release, then toxic shock (cytokine storm) and organs fail

15

Staphylococcal Enterotoxin B (SEB)

Superantigen
Heat stable
Released when bacteria replicate in food and causes staphylococcal food poisoning

16

Epidermolytic/Exfoliative Toxins (ET-A and ET-B)

Cause scalded skin syndrome
Released by S. aureus during growth

17

Skin and Soft Tissue Infections (SSTIs)

Infection of hair follicles, spectrum
Can be superficial or deep
Folliculitis (surface)
Boil (into pore of hair)
Carbuncle (follicle infection)
Impetigo (young children, fluid filled blisters; bullous and nonbullous)
Stye (sebaceous gland of eyelashes infection)
Abscess (Collection of pus in a tissue in response to infection)
Cellulitis (rapid dissemination of bacteria under superficial skin layers; rash appearance)
Treated with surgical drainage (I&D-Incision and Drainage) if necessary and antibiotic therapy (not beta lactams)

18

Staphylococcal Scalded Skin Syndrome (SSSS)

Post infectious complication of soft tissue infections
Caused by exfoliative toxins

19

Staphylococcal food poisoning

Meat mixes (Mayonnaise), Cooked ham or sausage, Dairy
Bacteria replicate in food and release SEB
Vomiting, diarrhea, stomach cramps
Very quick onset and resolves on own

20

Toxic Shock Syndrome (TSS)

Very serious
Rare, life-threatening
Results from exposure to TSST-1
Most commonly associated with use of superabsorbent tampons, surgical dressings, and nasal packing
Symptoms= Hypotension, high fever, diffuse erythematous rash, desquamation of palms and feet, vomiting, diarrhea, liver damage, renal distress, Altered mental status, myalgia
Treat with Clindamycin** (kills bacteria and stops toxin production)

21

Catalase

(+) = Staph, N. gonorrhoeae
(-) = Strep

22

M protein

Binds to factor H and prevents opsonization by complement

23

Capsule virulence

Blocks phagocytosis by neutrophils
Antigenic
Vaccine component sometimes

24

Lipoteichoic acid (LTA)

Helps with cell attachment

25

Streptococcal pyrogenic exotoxins

Superantigens
Cytokine storm

26

Streptolysin S

Beta hemolysis

27

Hylurodinase, Streptokinase, Deoxyribonucleases

Assist with tissue invasion

28

Scarlet Fever

Caused by release of Streptococcal Pyrogenic Exotoxin A (SpeA)
Perioral rash
Strawberry tongue
Usually children

29

Necrotizing Fasciitis

Severe infection of subcutaneous tissues and fascia
Very rapid dissemination of bacteria
Must debride dead, damaged, and infectious tissues
May have to amputate
Give large dose penicillin and/or clindamycin

30

Acute Rheumatic Fever (ARF)

Anti-M protein antibodies cross-react with epitopes on heart, joint, skin, and brain leading to tissue damage
Type II Hypersensitivity
Can lead to Carditis and congestive heart failure and also subcutaneous nodules (painless, not severe)