S6) Surface Infections Flashcards Preview

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Flashcards in S6) Surface Infections Deck (17)
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1

Define a surface

A surface is an interface between a solid and either a liquid or a gas

2

In terms of the infection model for surface infections, identify and describe the two types of surfaces involved 

- Skin: epithelium, hair, nails

- Mucosal surfaces: GI, GU, resp, conjunctival

3

Identify the types of micro-organisms found on the skin and provide examples

Viruses – papilloma, herpes simplex

- Bacteria – S.aureus, Coagulate negative staphylococci, Enterobacteriaceae

- Fungi – yeasts, dermatophytes

- Parasites – mites

4

Identify 5 different ways people get surface infections and provide examples of each

- Microbiota 

- Invasion e.g. Strep pyogenes in pharyngitis

- Migration e.g. E.coli in UTI

- Inoculation e.g. Coagulate negative staphylococcus in prosthetic joint infection

- Haematogenous e.g. viridans Strep in endocarditis

5

Provide some examples of external natural surface infections

- Cellulitis

- Pharyngitis

- Conjunctivitis

- Gastroenteritis

- UTI

6

Provide some examples of internal natural surface infections

- Endocarditis

- Septic arthritis

- Osteomyelitis

- Empyema

7

Provide 5 medical devices/procedures which could give rise to prosthetic surface infections

- Intravascular lines

- Peritoneal dialysis catheters

- Prosthetic joints

- Cardiac valves

- Pacing wires

8

What are the causative organisms for prosthetic valve endocarditis?

- Prosthetic valve endocarditis > 1 year post-operation: viridans Streptococci, Staph aureus

- Prosthetic valve endocarditis < 1 year post-operation: Coagulase negative staphylococci 

9

What are the causative organisms for prosthetic joint infections?

- Coagulase negative staphylococci 

- Staphylococcus aureus 

10

What are the causative organisms for cardiac pacing wire endocarditis?

- Coagulase negative staphylococci 

- Staphylococcus aureus 

11

In 4 steps, outline the pathogenesis of surface infections

⇒ Adherence to host cells / prosthetic surface

⇒ Biofilm formation

⇒ Invasion and multiplication

⇒ Host response

12

Identify and describe the two possible host responses in the pathogenesis of surface infections

- Progenitor: neutrophils → pus

- Granulomatous: fibroblasts, lymphocytes, macrophages → nodular inflammatory lesions

13

Explain the process involved in biofilm formation in the pathogenesis of surface infections

Biofilm formation is a process whereby microorganisms irreversibly attach to and grow on a surface and produce extracellular polymers that facilitate attachment and matrix formation

 

14

In detail, explain how micro-organisms cause disease

15

In management of a surface infection, outline the diagnosis of it

Aim is to identify infecting organism and its antimicrobial susceptibilities:

- Blood cultures

- Tissue/prosthetic material sonication and culture

16

In management of a surface infection, outline the treatment of it

Aim is to sterilise the tissue and reduce bioburden:

- Antibacterials 

- Remove prosthetic material

- Surgery – resect infected material  

17

In management of a surface infection, outline the prevention of it

Natural surfaces: maintain surface integrity, prevent bacterial surface colonisation, remove colonising bacteria

- Prosthetic surfaces: prevent contamination, inhibit surface colonisation, remove colonising bacteria