Gram + Bugs

Question 1

4 bugs w/ beta hemolytic light bulb + name how you identify one from the other

Answer 1

1. Staph aureus - Moses holding light bulb
   - Cat +, coag +
2. Strep pyogenes (Grp A) - light bulb keeping pie warm
   - Cat -, bacitracin sensitive
3. Strep agalactiae (Grp B) - light bulb on space tent
   - Cat -, bac resistant
4. Listeria - light bulb on top of xmas tree
   - GP ROD!!

Question 2

2 bugs are alpha hemolytic - what are they and how do you tell them apart?

Answer 2

Alpha = partial hemolysis, looks green on plates
Strep pneumo - chin exposed in armor suit (optochin sensitive)
Strep viridans - jester’s chin covered by mask

Question 3

What makes MRSA resistant to methicillin and nafcillin?

Answer 3

Altered penicillin binding protein

Question 4

Name the 3 toxins and their diseases produced by S.aureus

Answer 4

1. TSST -> toxic shock syndrome
   - Think about it, SA is a normal skin colonizer (why also get jt infections) and this is why you can get it from tampons -> TSS
2. Exfolative toxin -> scalded skin syndrome
3. Eat pre-formed enterotoxin -> rapid onset food poisoning
   - Heat stable (survives cooking)

Question 5

Explain TSS + symptoms

Answer 5

TSST binds MHC2 and T cell receptor
Resulting polycolonal T cell activation 
SYMPTOMS
- Fever
- Vomiting
- Rash // desquamation 
- End organ failure

Question 6

What is the difference between TSS caused by S.aureus and S.pyogenes

Answer 6

Pyogenes has painful skin infection too!

Question 7

Why does it make sense that S.aureus makes abscesses?

Answer 7

Coag +!!!

Fibrin clot around itself -> abscess

Question 8

S.sapro disease

Answer 8

UTI

2nd behind E.Coli

Question 9

MOPS mnemonic for S.pneumo diseases

Answer 9

Meningitis
Otitis media
Pna - rust colored mucus
Sinusitis

Question 10

2 diseases caused by strep viridans

Answer 10

Tooth decay b/c colonize the mouth

Subacute endocarditis - valves have to be pre-damaged

Question 11

J

Answer 11

Joints - arthritis in multiple jts

Question 12

Describe the likelihood of developing rheumatic fever and/or glomerulonephritis after S. pyogenes pharyngitis vs impetigo.

Answer 12

Impetigo more likely to cause glomeulonephritis

Pharyngitis can result in EITHER

Question 13

Titer to test for recent S.pyogenes infection

Answer 13

ASO titer

= ASO Abs vs stroptolysin O (virulence factor)

Question 14

What are the Ab you make against S.pyogenes?

Answer 14

Ab vs M protein

Enhances host defenses but can give risk to rheumatic fever

Question 15

Presentation of Scarlet fever

Answer 15

Scarlet rash - sand paper texture
Strawberry tongue
Pallor
Desquamation

Question 16

Where does S.agalactiae colonizes the body? What do you do about it?

Answer 16

Vagina
- Baby pna + meningitis
Screen preggos @ 35 wks
+ penicillin

Question 17

Why are there camping tents in the S.agalactiae sketchy?

Answer 17

Bacteria makes CAMP factor

Enlarges zone of B hemolysis

Question 18

3 infections due to enterococci

Answer 18

UTI
Biliary tree
Endocarditis after GI/GU procedures

Question 19

What is VRE

Answer 19

Vanco resistant enterococci

Question 20

Explain why you might get endocarditis if you have colon cancer?

Answer 20

Colon cancer -> increases risk of S.bovis bacteremia -> endocarditis
“Bovis in the blood = cancer in the colon”

Question 21

4 types of clostridium

Answer 21

C.tetani
C.boltulinum
C.perfringens
C.diff

Question 22

Tetanus pathophys

Answer 22

Puncture wound - spore in
Bacteria move retrograde to spinal cord via motor neurons
Tetanospasmin toxin @ Renshaw cells = interneurons
- Cleave SNARE
- No release GABA + glycine
Net: no inhibition of motor neurons

Question 23

What is the tetanus vaccine?

Answer 23

Toxoid vaccine = Abs vs the toxin (tetanospasmin) not the bacteria!

Question 24

What food gives boltulism to babies? What form of the bacteria do you ingest?

Answer 24

HONEY

Ingest PREFORMED toxin!!!

Question 25

How does botulism toxin work?

Answer 25

X ACh release at NMJ | Flaccid paralysis

Question 26

C.perfringens toxin + resulting disease

Answer 26

Alpha toxin -> *double zone of hemolysis on plates* | Gas gangrene

Question 27

C.diff toxin A vs B

Answer 27

A - enterotoxin - intestine brush border - cell death -> watery diarrhea B - cytotoxin that depol enterocytes -> death -> pseudomembranes -> colitis

Question 28

2 antibiotics that most increase your risk of C.diff

Answer 28

Clindamycin | Ampicillin

Question 29

What is the only bacteria with a polypeptide capsule (contains D glutamate)?

Answer 29

Bacillus anthracis | D on the viking armor

Question 30

Cutaneous anthrax

Answer 30

= black eschar | Painless but can progress to bacteremia -> death

Question 31

Pulm anthrax

Answer 31

Cause you inhaled it | Flu like -> pulm hemorrhage, mediatinitis, shock

Question 32

Treat anthrax

Answer 32

Fluro Doxy The shields in the back on ship

Question 33

You didn't properly reheat rice and now you have N&V + diarrhea. What's the bug?

Answer 33

B.cereus (think asian man saying this) | You ate the spores!

Question 34

People you're worried about getting listeria

Answer 34

Pregnant - spont abortion Babies - meningitis Elderly // IC pts - meningitis Not worried abt normal people b/c get gasterenteritis that resolves on own

Question 35

Pathophys of listeria

Answer 35

Intracell Rocket tails via actin polymerization Intracell movement + cell-cell spread Avoids antibodies

Question 36

Disease + treatment for actinomyces vs nocardia

Answer 36

``` Actinomyces - oral/facial abscesses draining sulfur granules via sinus tracts Nocardia - IC pulm infection SNAP Sulonamides - nocardia Acintomyces - penicillin ```

Question 37

+ PPD test

Answer 37

Current TB infection Past exposure False positive if BCG vaccine

Question 38

What is the Ghon complex?

Answer 38

Sign of 1ary TB infection 1. Hilary lymphadenopathy 2. Ghon focus @ low/mid lungs

Question 39

Where in the lungs does TB usually reactivate?

Answer 39

UPPER LOBES

Question 40

What is TB in the vertebrae called?

Answer 40

Potts disease

Question 41

Describe common Leprosy distribution on the body

Answer 41

Glove and stocking | Loss of sensation

Question 42

Leprosy reservoir

Answer 42

Armadillos

Question 43

Lepromatous vs tuberculoid leprosy

Answer 43

Lepromatous - all over lesions, Th2 response | Tuberculoid - few hairless skin plaques, Th1 response