Lecture 5 - Pyogenic Gram + Bacteria

Question 1

Staphylococci contain ____, while Streptococci lack it.

Answer 1

Catalase

Question 2

Staph species are resistant to _____/heat and many antibiotics

Answer 2

Drying

Question 3

A test that helps differentiate staph aureus from the other types is the ____ test. Staph aureus is has this enzyme that leads to clotting.

Answer 3

Coagulase

Question 4

The pathogenic capacity of staph aureus is a combination of _____ molecules + ______ factors + toxins.

Answer 4

Surface molecules + Extracellular factors + toxins

Question 5

Staph aureus surface molecules include Fibronectin binding protein, which acts as an _____. It also has protein ____, which binds to the ____ portion of IgG antibodies.

Answer 5

Adhesin

Protein A

Fc

Question 6

Among the extracellular factors Staph aureus produces is ___ toxin, which is a hemolysin. It forms transmembrane _____ that disrupt plasma membrane stability.

Answer 6

Alpha toxin

Channels

Question 7

Some staph aureus strains produce ____-1, which is a superantigen that causes ____ shock syndrome.

Answer 7

TSST-1

Toxic shock syndrome

Question 8

Staph aureus also produces _____ toxins, which are exotoxins that act as proteases and cleave _______ proteins. This leads to “Scalded skin syndrome” characterized by blisters and sloughing off of skin. It also produces enterotoxins that act as ______ in the GI leading to symptoms of food poisoning.

Answer 8

Exfoliative

Desmosomal

Superantigens

Question 9

Skin infections caused by staph aureus include:

1. Impetigo starts as ___-filled epidermal blisters that break and leave a thick yellowish crust.
2. Folicullitis
3. Furuncle (boil)
4. Carbuncle (confluence of boils.)

Answer 9

pus-filled

Question 10

Staph aureus food poisoning occurs through intoxication with the ______, which is heat stable. The bacteria themselves don’t survive the stomach.

Answer 10

Enterotoxin

Question 11

Hospital acquired MRSA have a large “______ island” that is nonmobile and is composed of multiple transposon elements.

Answer 11

Pathogenicity

Question 12

Community acquired MRSA has a small “______ island” which is mobile.

Answer 12

Pathogenicity

Question 13

There are essentially two types of hemolysis results from a blood agar hemolysis test.

1. ____ hemolysis results in green “halos” –> the heme group is altered in the RBCs.
2. ____ hemolysis results in clear zones from RBC lysis.

Answer 13

Alpha

Beta

Question 14

Strep Pyogenes is ____ hemolytic, while Enterococcus faecium, V. Streptococci, and S. pneumoniae are all _____ hemolytic.

Answer 14

Beta

Alpha

Question 15

Strep Pyogenes is in the Lancefield group ___.

Answer 15

A

Question 16

Strep Pyogenes has multiple virulence factors including ___ protein which prevents ______, and elicits an _____ response. It also produces IgAase which destroys sIgA, preventing _____.

Answer 16

M protein

Phagocytosis

Immune response

Opsonization

Question 17

Strep Pyogenes produces ______ exotoxins (fever inducing), including ____.

Answer 17

Pyrogenic

TSLS

Question 18

Strep Pyogenes is the most common cause of the skin infections ______ and erysipelas, the latter of which presents with raised areas and _____ edges.

Answer 18

Cellulitis

Discrete

Question 19

To distinguish between E. Faecalis from V. Streptococci and S. pneumoniae, test using NaCl and or/_____. E. Faecalis is NaCL ______ and can hydrolize ______.

Answer 19

Esculin

Esculin