Antibiotics and antifungals Flashcards

1
Q

What is the definition of and antibiotic

A

chemical substance produced by a microorganism which destroys OR inhibits growth of bacteria and other microbes
Can be naturally ( penicillin G )or synthetically produced ( amoxicillin semi synthetic )

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2
Q

What is a bactericidal antibiotic

A

One that KILLS the microorganism

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3
Q

What is a bactericidal antibiotic

A

One that does NOT KILL the bacteria but INHIBITS its growth allowing the body time to mount an immune response and fight the infection

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4
Q

What is the difference between “-cidal” vs “-static: medications

A

-Cidals KILL - statics inhibit growth
eg fungicidal kill the fungi , fingistakics - inhibit growth

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5
Q

Why use antibiotics in oral health

A

To treat acute infections so spread does not occur through out the body or tissue
Preventative ( prophylaxis ) - to stop a “ at risk patient getting an infection eg immunocompromised people ( radiation, cancer meds etc )or those at risk of developing endocarditis , or have prosthesis

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6
Q

Name 4 mechanisms by how antibiotics work ( and an 2 examples of each )

A

They target essential cellular functions
1. Inhibit cell wall synthesis ( block peptidoglycan synthesis of bacteria - so cell fragile and bursts (penicillins/cephalosporins ) bacteriocidal

2.Inhibit protein synthesis via 50S subunit or 30S (tetracyclines/erythromycin)-bacteriostatic
so- mRNA not translate into proteins so cell processes disrupted and not grow further - die

  1. Inhibit nucleic acid synthesis(DNA/RNA synthesis )-Rifamycin ( RNA polymerase ) ,Quinalones DNA gyrase ( both bactericidal)

4.Disrupts cell membrane function -polymyxin (bactericidal)- by interacting with Lipopolysaccahrides (LPS) so increased leakage out of cells

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7
Q

How 4 ways antifungals work-with an example

A
  1. Inhibit cell wall synthesis by inhibiting gluten synthesis eg echinocandins
  2. Inhibit nucleic acid synthesis (DNA/RNA synthesis )
    eg 5-fluorocystosine ( fungicidal )
  3. Inhibit membrane integrity - eg Polyenes - so H+ and K+ leak out ( fungicidal ) - lots SE if give iv
  4. Stop sterol biosynthesis - eg -azoles ( fluconazole ) ( fungistatic )
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8
Q

How do we treat oral candidiasis-3 options

A

1.Amphotercin B lozenges (Polyene - stops membrane integrity )-fungicidal

2.Miconazole oral gel - (stops sterol synthesis ) fungistatic

3.Fluconazole tablets - lots side effects ( stops sterol synthesis )

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9
Q

Name 2 potential therapy issues of oral candidosis treatment

A

Fluconazole resistance
Reoccurrence
Patient compliance
Other side effects (lots if give polyenes iv)

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10
Q

What is an ideal antibiotic

A

One that targets a specific pathogen(s) with NO resistance developed -

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11
Q

What is antibiotic resistance

A

Worldd wide problem
As most antibiotics are BROAD SPECTRUM , they cause collateral damage to the microbiome killing off good bugs as well as some strains develop resistance and pass that down as survive

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12
Q

Name a way to overcome antibiotic resistance in pathogens

A

Use double antibiotic treatment

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13
Q

Name some unwanted side effects of antibiotics

A

Beta lactam - diarrhoea /allergy
Polymyxins/Amphotercin B /Aminoglycosides - kidney damage
Tetracycline- teeth stained yellow
Rifampicin - red man syndrome
metronidazole - Black hairy tongue

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14
Q

What is red man syndrome

A

Seen with rifampacin treatment - bright red/orange sweat/saliva/urone and skin red - due to metabolic products of drug accumulating and get removed by sweat glands ( can wash away BUT )
Can cause liver damage - can be permanent

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15
Q

What’s a bacteriocin

A

Non traditional antibiotic - they are a proteinaceous antimicrobial produced by a bacteria that kills or inhibits growth of a species closely related to the producer organism- 4 different classes for Gram +ve and 4 types for Gram -ve

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16
Q
A