Staphylococcus

Question 1

What does staphylococcus have a lot of?

Answer 1

virulence factors

Question 2

Why is staph- thought to be able to survive on the skin?

Answer 2

because it is salt tolerant

Question 3

What is the difference between S. aureus and S. epidermidis?

Answer 3

S. aureus= yellow pigment, coagulase positive (make blood coagulate), beta-hemolysis on blood agar plates meaning complete breakdown of Hb in RBC

S. epidermidis= white pigment, coagulase negative (can’t make blood coagulate)

Question 4

What are common skin infections of S. aureus?

Answer 4

boils, pimple, sialidentitis, parotitis, sinusitis, impetigo

Question 5

What are serious infections of S. aureus?

Answer 5

endocarditis, osteomyelitis, pneumonia, toxic shock

Question 6

What are 3 dental associations of staph?

Answer 6

1. salidentis/parotitis (ONLY REAL ASSOCIATION WITH STAPH)
2. angular cheilitis (Canada albicans)
3. Ludwigs agina/ facial cellulitis (periodontal microbiota infection)

Question 7

What type of bacteria is Staphlyoccus aureus?

Answer 7

gram + growing in clusters

Question 8

What virulence factors does S. aureus have?

Answer 8

• surface binding protein adhesion, exported toxins and enzymes, inflammatory fins from peptidogylcan and teichoic acid, protein A which binds anti bodies backwards and is ant-phagocytic

Question 9

What are the enzymes involved in S. aureus?

Answer 9

coagulase (cause clotting and bacteria adherence) and catalase (detoxify neutrophil oxygen radical killing)

remember, strep is catalase negative and staph epidermis is coagulase negative

KEY: coagulase tells the difference between the 2 staphs.. catalase tells the difference between staph and strep

Question 10

What is the tx for S. aureus?

Answer 10

initially: B-lactams or vancomycin with or without rifampin

both inhibit cell wall but in different mechanisms

Question 11

How common is S. aureus to drug resistance?

Answer 11

VERY #2 deaths worldwide associated with drug resistance

Question 12

T/F: S. aureus are also involved in osteomyelitis and arthritis

Answer 12

True!

Question 13

What is the most common cause of endocarditis?

Answer 13

S. aureus
(next up is the viridans group s. oralis)

Question 14

What are the toxins needed to know for S. aureus?

Answer 14

• a toxin (beta hemolysis) that degrades tissues
• leukocidans that lyse neutrophils and macrophages
• enterotoxins that cause food poisoning
• exfoliative that causes scalded skin
• TSST-1 that causes toxic shock because it is a super antigen