Infection - Infections On Surfaces Flashcards Preview

CJ: UoL Medicine Semester Two (ESA2) > Infection - Infections On Surfaces > Flashcards

Flashcards in Infection - Infections On Surfaces Deck (18)
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1
Q

Define a ‘surface’

A

An interface between a solid and either a liquid or a gas

2
Q

What are the sites of potential surface infections on a patient?

A
  • skin (epithelium, hair, nails)

- mucosal surfaces (conjunctival, gastrointestinal, respiratory, genitourinary)

3
Q

What are the viruses found on skin?

A

Papilloma, herpes simplex

4
Q

What are the gram positive bacteria found on skin?

A

Staph aureus, coagulase negative staphylococci, corynebacterium

5
Q

What are the gram negative skin microorganisms?

A

Enterobacteriaceae

6
Q

What fungi can be found on the skin?

A

Yeasts and dermatophytes

7
Q

What parasites can be found on the skin?

A

Mites

8
Q

What are commensals?

A

Microorganisms carried on the skin and mucosal surfaces which are normally harmless/beneficial, but can be harmful if transferred to other sites

9
Q

How can a patient get an infection from bacteria which is already in their body?

A
  • invasion by the pathogen
  • migration to somewhere it shouldn’t be
  • inoculation, eg. infection of a prosthetic joint
  • haematogenous (spread through bloodstream)
10
Q

What is the difference between the causation of prosthetic valve endocarditis less than 1 year post-operation and over one year post-operation?

A

Less than one year post operation it is most likely to be caused by viridans streptococci, enterococcus faecalis, staph aureus, HACEK group and candidia. Over 1 year post-op, its more likely to be coagulase negative staphylococci

11
Q

What are the most common causative organisms of prosthetic joint infections and cardiac pacing wire endocarditis?

A

Coagulase negative staphylococci and staphylococcus aureus

12
Q

What are the processes in the pathogenesis of infections at surfaces?

A
  • adherence to host cells or prosthetic surfaces
  • biofilm formation
  • invasion and multiplication
  • host response (may be pyogenic or granulomatous)
13
Q

What is a biofilm?

A

An assemblage of microbial cells which is irreversibly associated with a surface and enclosed in a matrix of primarily polysaccharide material

14
Q

What is quorum sensing?

A

This is a way that bacteria are able to signal each other through three principles - signalling molecules (‘autoinducers’), cell surface/cytoplasmic receptors, and gene expression

15
Q

What does quorum sensing control?

A

Sporulation, biofilm formation and virulence factor secretion

16
Q

What are the challenges of treating biofilms?

A

Poor antibacterial penetration into the biofilm, low metabolic activity of biofilm microorganisms, dangers/difficulties of surgery

17
Q

How can infections on a natural surface be prevented?

A

Maintain surface integrity, prevent bacterial surface colonisation, remove colonising bacteria

18
Q

How can infections on prosthetic surfaces be prevented?

A

Prevent contamination, inhibit surface colonisation, remove colonising bacteria

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