Biofilms and abscesses

Question 1

What is a biofilm?

Answer 1

A structured community of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface.

Question 2

Why does plaque form on teeth?

Answer 2

Teeth are uniquely the only non-shedding surface colonised by bacteria in the human body.

Question 3

Describe the steps in biofilm formation.

Answer 3

1. Initial attachment (reversible).
2. attachment becomes irreversible.
3. growth and division of bacteria.
4. Formation of minimum number of bacteria to form a biofilm, a quorum, results. Exopolymer production and biofilm formation.
5. attachment of other organisms to biofilm.

Question 4

Why are biofilms difficult to treat?

Answer 4

adherent bacterial cells on inert surfaces are resistant to antibodies, phagocytosis and antibiotics, yet phagocytes are attracted to the biofilms and release enzymes that are more damaging to surrounding host tissue.

Question 5

List the checklist to go through when an infection is not responding to antibiotis.

Answer 5

Is it an infection?
Is there pus that needs drainage? a blockage that needs unblocking?
Is there a foreign body that needs removing? (line, catheter, implant)
Is the patient on the right antibiotic? right dose?
Is the patient compliant with antibiotic treatment?

Question 6

How does an abscess form?

Answer 6

An organism is deposited, a massive influx of neutrophils follows, and the infective site is walled off. The organism grows and generates an anaerobic environment within the abscess.