Infections On Surfaces Flashcards

0
Q

What are microbiota?

A

The microorganisms that typically inhabit a bodily organ/part

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1
Q

What is a surface?

A

Interface between a solid and either a liquid or gas

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2
Q

What are mucosal flora of the eye?

A
Coagulase negative
Staphylococci
Diphtheroids
Saphrophytic
Neisseria meningitidis
Viridans group streptococci
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3
Q

Common microbiota of nares?

A

Staph aureus

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4
Q

Common microbiota of the nasopharynx?

A

Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae

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5
Q

Common bacteria of the mouth?

A
Viridans Streptococci
Neisseria
Veillonella
Lactobacillus
Acrinmyces
Candida albicans
Many more
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6
Q

Common bacteria of the stomach?

A

Helicobacter
Streptococci
Staphylococci
Lactobacilli

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7
Q

Common bacteria of the intestine?

A
Anaerobic and aerobic streptococci
Clostridium
Yeasts
Bacteroides
Lactobacillus
Coliforms
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8
Q

Common microbiota of the urethra?

A
Lactobacilli
Enterobacteriaceae
Diphtheroids
α and non-haemolytic Streptococci
Enterococci
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9
Q

How do people get infections from surfaces? Give examples of infections for each one

A

Invasion - Strep pyogenes, pharyngitis
Migration - E. coli, UTI
Innocuoation - coagulase negative staphylococci, prosthetic joint infection
Haematogenous - viridans Streptococci, endocarditis

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10
Q

Give some examples of prosthetic surface infections

A
IV lines - sepsis
Peritoneal dialysis catheters
Cardiac valves
Pacing wires
Endovascular grafts
Ventriculo-peritoneal shunts
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11
Q

Examples of natural external surface infections?

A
Cellulitis
Gastroenteritis
Pharyngitis
UTI
Conjunctivitis
Pneumonia
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12
Q

Examples of some common internal surface infections?

A

Endovascular endocarditis/vasculitis

  • viridans Streptococci
  • enterococcus faecalis
  • Staph aureus
  • Candida

Septic arthritis
Osteomyelitis
Empyema

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13
Q

Overall process of pathogenesis of infections at surfaces?

A

Adherence to host cells/prosthetic surface
Biofilm formation
Invasion and multiplication
Host response

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14
Q

How do bacteria adhere to a surface?

A

Use pilli or fimbrae

Influenza attaches to cells by haemoggluttin antigen

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15
Q

What is a biofilm?

A

A slimy matrix produced by bacteria made up of polysaccharides

Nutrients can diffuse in and out
Close proximity of cells in the matrix facilitates exchange of molecular signals that regulate behaviour

16
Q

Why are infections caused by bacteria with biofilms difficult to treat?

A

Antimicrobials will only damage outer cell layers so the biofilm community is resistant

17
Q

In the host response, what is vegetation?

A

Host response to pathological damage to a site
Low grade inflammatory process caused by the bacteria.
Involves platelets, fibrin and inflammatory cells
Poorly vascularised
Can produce a hole in the surface eg heart valve

18
Q

What are the main steps in the management of infected surfaces?

A

Diagnosis
Treatment
Prevention

19
Q

How do you diagnose an infection on a surface?

A

Identify infecting organism and its anti-microbial susceptibilities
Take blood cultures
Tissue/prosthetic material sonication to produce a culture

20
Q

Aims of treatment of an infection at a surface?

How is this done?

A

Sterilise tissue and reduce bioburden

  • antibacterials
  • remove prosthetic material
  • surgery to resect infected material
21
Q

What challenges are faced when treating an infected surface?

A

Poor antibacterial penetration into biofilm
Low metabolic activity of biofilm microorganisms
Risks of surgery

22
Q

How to prevent an infection on a surface?

A

Internal surface:
Maintain surface integrity
Prevent bacterial surface colonisation
Remove colonisation of bacteria

External surface:
Prevent contamination
Inhibit surface colonisation
Remove colonising bacteria