Infections On The Surface Flashcards

1
Q

What is a surface

A

Inter surface between a solid and either a liquid or gas

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2
Q

Give examples of human surfaces

A

SKIN : epithelium , hair and nails

Mucosal surfaces : eg GI , Urinary , respiratory tract

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3
Q

Give examples of skin viruses

A
  1. Papilloma

2. Herpes simplex ( cold sores )

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4
Q

How do people generally tend to get infections on surface ?

A

Microbiota

Microorganisms carried on skin and mucosal surfaces are normally harmless or even benefitical. However the transfer to other sites can be harmful.

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5
Q

How can microbiota transfer to other sites ?

A
  1. Invasion
  2. Migration for example E. coli travels from anus to vagina.
  3. Inoculation eg during surgery
  4. Haematogenous eg endocarditis
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6
Q

What are examples of natural surface infections ?

A

External : cellulitis , pharyngitis , conjunctivitis , UTI , pneumonia , gastroenteritis

Internal :

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7
Q

What is prosthetic valve endocarditis

A

Endovascular , microbial infection occurring on parts of the prosthetic valve

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8
Q

What are causative organisms for prosthetic joint infections ?

A

Coagulate negative staphylococci

Staphylococcus aures

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9
Q

What are causative organisms for cardiac pacing wire endocarditis ?

A

Coagulate negative staphylococci

Staphylococcus aures

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10
Q

Outline the process in the pathogens is of infection at surfaces

A
  1. Adherence to host cells or prosthetic surface
  2. Biofilm formation - which invovles the formation of extracellular material such as polysaccharides , nucleic acids which are secreted which produces a slimey layer. This facilitates attachment and produces an ECM.
  3. Invasion and multiplication
  4. Host response involves pyogenic ( neutrophil number increases ), granulomatous formation ( fibroblasts , lymphocytes and macrophages increase in number which results in nodular inflammatory lesions)
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11
Q

What is quorum sensing ?

A

Quorem sensing bacteria control sporulation , biofilm formation and virulence factors secretion

There are three principles :

  1. Quorem sensing bacteria release signalling molecules such as autoinducers which binds to cell surface or cytoplamsic receptors
  2. This helps to regulate gene expression.
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12
Q

How to manage surface infections ?

A
  1. Antibacterial
  2. Remove prosthetic material

3, surgery to resect infected material

  1. Want to sterilise tissues
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13
Q

What are challenges faced when it comes to management of surface infections ?

A

Poor antibacterial penetration into biofil,

Low metabolic activity of biofilm microorganisms

Dangers and difficulties of surgery

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14
Q

How to prevent surface infections ?

A

Natural surface : maintain surface integrity eg moisturising

  1. Prevent bacterial surface colonisation
  2. Removing colonising bacteria

PROSHETIC SURFACES :

  1. Prevent contamination
  2. Inhibit surface colonisation
  3. Removing colonising bacteria
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