staphylococcus

Question 1

Staphylococcus genus

• Structure
• Subtypes

Answer 1

Gram +ve, Cocci in Clusters
- Catalase +ve

Coagulase Test
- S. Aureus is positive
- otherwise, Coagulase Negative Staphylococcus CNS
eg S. epidermidis;

Question 2

Staph Aureus

• Location
• compare w Strep Pneumoniae
• Agar

Answer 2

Location

• skin + URT
• is coagulase +ve, strep P is -ve
• Salt Agar, Blood agar can also

– note FREE coagulase test;

Question 3

S. Aureus Virulence [6]

Answer 3

A - alpha toxin - lyses cells;
Enterotoxin
TSSToxin 1
Epidermolytic toxin

Cell Wall - Protein A for adhesion;
Coagulase

Question 4

S. Aureus damages [5]

Answer 4

Food poisoning possible;
- Salt agar for S. Aureus

Toxic Shock Syndrome

• superantigen cross links MHCII to TCR away from complementary determining region
• causing cytokine storm
• • Rash, fever, hypotension, shock;
• • distributive shock! aka vasodilatory shock when not enough perfusion

SSSS
= Staph Scalded Skin Syndrome
- epidermolytic toxins, impetigo, cellulitis, pus, abscess
- large blisters, bullae;

Sepsis: Bone, Joint Systemic Abscess,

EC, Pneumonia after viral;

• Pneumonia note is 2nd top cause after GN bacteria
• HAP, Bronchopneumonia

Question 5

MSSA treatment

Answer 5

Drain Pus

• Cloxacillin - Penicillinase Resistant Penicillin
• Erythromycin also can;

Question 6

MRSA what isit

Answer 6

PBP2 change, by MecA gene
- resistant to PCC;

S to ceftriaxone KIV
- zam Vancomycin

Question 7

Line-related sepsis think what

Answer 7

Staph Aureus + CNS!

• check endocarditis
• CNS vancomycin can also

Question 8

Note S. aureus in blood cultures is commonly a contaminant

Note MSSA vs MRSA is cos resistance is due to Penicillinase vs PBP change

Answer 8

Lmao