9/2/10 Wound Bacteria

Front 1

. List the most important microbial agents isolated from each of the following wounds: soil-contaminated wounds; Animal and human bite infections; infected burns, surgical site infections.

Back 1

Human & Animal bite: oral flora
(strep spp, staph aureus, bacteroides) animals = pasteurella multocida (anaerobes)

Burn wounds: nosocomial species and skin flora

Soil-contaminated wounds: anaerobic spore forming (and fungi)

Surgical: same as skin flora

Front 2

2. Compare and contrast the characteristics of the Staphylococcus genus and Streptococcus genus and describe the tests and culture techniques that can be used to differentiate between these genera.

Back 2

Staph = catalase+, G+, salt/temp resistant, facultative anaerobe, coagulase-, (epidermidis = gamma hemolytic, aureus = beta hemolytic)

Strep = catalase-,

Front 3

3. List the toxins and enzymes of Staphylococcus aureus that function as virulence factors and describe their role in pathogenesis.

Back 3

Superantigens-exfoliate toxin A and TSST-1

Cytolytic toxins that disrupt membranes

enterotoxins

hyaluronidase, staphylokinase (dissolve clots), lipase (allows survival in sebaceous areas), dnaase, coagulase (causes fibrin clot aorund staph to prevent phagocytosis)

Front 4

4. Describe the microbial surface adhesion proteins covalently bound to the cell wall peptidoglycan in staphylococci

Back 4

Adhesion proteins that make them more able to bind to certain locations in body (i.e. bone)

S.aureus: protein A - binds to Fc portion of Ab (stealth effect)

Adhesion molecules: collagen BP, fibronectin BP, sialoprotein adhesin

Anti-phagocytic polysaccharide capsule

Front 5

5. Recognize the species of Staphylococci most likely to be the etiological agent in catheter and shunt infections as well as prosthetic device infections. [ coagulase-negative staphylococcus].

Back 5

S. epidermidis

Front 6

6. Define the laboratory tests that can be used to identify and differentiate between S. aureus and S. epidermidis. [hemolysis, catalase test, coagulase test, fibrinolysin test, bacitracin susceptibility]

Back 6

Staph: G+ cocci, nonmotile, facultative anaerobe, catalase+

S. aureus: beta hemolytic, golden colonies, antiphagocytic capsule, coagulase producer

S. epidermidis: Coagulase-, gamma hemolytic, salt and temp tolerant, found on skin, causes infections in heart valves, shunts

Front 7

7. Describe the common characteristics of the bacterial species that belong to the genus Clostridium including morphology, physiology, epidemiology.

Back 7

Clostridium: G+, ubiquitous in soil, normal flora of GI tract, spore forming, obligate anaerobe, produce endo/exo/neurotoxins

Front 8

Compare and contrast the pathogenesis and virulence factors of Clostridium perfringens,

Back 8

C. perfringens: Large rectangular, gram positive anaerobic rods, spores rare, 12 toxins/4 lethal (alpha toxin = lyses RBCs, platelets, leukocytes)

Diagnostic for C. perfringens: double zone of beta hemolysis, positive reverse cAMP test, catalase-, no PMNs in smears, gas production in tissues, Nagler+

Front 9

Clostridium botulinum

Back 9

Large fastidious, spore-forming, anaerobic, rods

commonly occurs in infants

Wound and food botulism

Function of the Botulism toxin:
Blocks neurotransmission
The result is flaccid paralysis

Front 10

Clostridium tetani

Back 10

G+ rods, with terminal spores

anaerobic

no carbohydrate utilization, only proteins

Virulence factors: rapid sporulation, tetanolysin (oxygen-labile hemolysin), tetanospasmin (spastic paralysis via blocking of inhibiting neurotransmitter)
toxoid vaccine, most in neonates

Front 11

9. Compare and contrast the mechanism of action of botulinum toxin with tetanus toxin.

Back 11

Both inhibit neurotransmitter activity

Tetanus inhibits inhibitory NT
(spasms)

Botulism inhibits stimulatory NT (paralysis)

Front 12

10. Describe the treatment and prevention of botulism, tetanus, and gas gangrene.

Back 12

??? lolwut