Gram Negative Bacteria

Question 1

Give an example of a coagulase positive and coagulase negative streptococcus bacteria

Answer 1

positive - Staph aureus

negative - Staph epidermis

Question 2

Which is a common cause of infective endocarditis?

Answer 2

Staph aureus

Question 3

What is the most common joint infection bacterium (e.g. septic arthritis/joint post surgery)?

Answer 3

Staph aureus

Question 4

Is Staph epidermis more likely to infect in hospitals or community and why? (2 reasons)

Answer 4

Hospitals - as it is part of normal skin flora requires disruption of the physical barrier (skin) e.g. in surgery/wounds. Also it’s major virulence factor is forming biofilms which form over medical devices in hosp e.g. catheters/pacing wires

Question 5

What does Staph aureus look like on gram stain?

Answer 5

Purple, clusters of cocci like grapes

Question 6

Where does Staph aureus naturally inhabit?

Answer 6

Skin and mucosal surfaces e.g. nose/respiratory tract

Question 7

Which bacteria does MRSA relate to?

Answer 7

Methicillin resistant Staph aureus

Question 8

How do you treat someone who has a prosthetic device with a biofilm on?

Answer 8

Need to remove device as can’t currently remove/destroy biofilms