Principles antibiotic module Flashcards

1
Q

Define bacteriocidal.

A

Antibiotics which kill bacteria.

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2
Q

Define bacteriostatic.

A

Antibiotics which inhibit the growth of bacteria.

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3
Q

Name an issue with oral administration of antibiotics.

A

In oral antibiotic administration, antibiotics are absorbed from the small intestine and spread to all parts of the body. However, large amounts are excreted unchanged in the faeces,

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4
Q

How do antibiotics work?

A

Act on bacterial cell wall, bacterial ribosomes and bacterial DNA.

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5
Q

Give features of penicillins.

A

Penicillins are bactericidal, and inhibit cell wall synthesis. They are safe in pregnancy and excreted rapidly by kidneys.

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6
Q

Give features of cephalosporins.

A

Cephalosporins are bactericidal and inhibit cell wall synthesis by preventing cross-linking of peptidoglycan. They are excreted in the urine by the kidneys.

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7
Q

Give features of glycopeptides.

A

Glycopeptides, e.g. vancomycin IV. They are bactericidal, weakening bacterial cell wall by interfering with peptidoglycan synthesis. They are active only against gram positive organisms. Toxic levels may cause kidney damage.

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8
Q

Give features of macrolides.

A

Macrolides, e.g. erythromycin, clarithromycin and azithromycin inhibit bacterial protein synthesis. They are excreted by the liver.

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9
Q

Give features of aminoglycosides.

A

Aminoglycosides, e.g. gentamicin IV. Are bactericidal, binding to ribosomes to inhibit protein synthesis. They are mainly active against gram-negative aerobic organisms, e.g. coliforms and pseudomonas aeruginosa. Excreted in urine.

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10
Q

What is the 2nd line antibiotic in the treatment of serious staph. and strep. infections (particularly in penicillin allergic patients)?

A

Clindamycin. It is also active against true anaerobes and inhibits protein synthesis,

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11
Q

Describe tetracyclines.

A

Tetracyclines inhibit bacterial protein synthesis, They are bacteriostatic. They are excreted by the liver. Useful in treating atypical pneumonia and chest/skin infections in the penicillin allergic.

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12
Q

Describe metronidazole.

A

Metronidazole acts by causing strand breakage of bacterial DNA. It is used in true anaerobe infection and protozoa infection.

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13
Q

Describe trimethoprim.

A

Trimethoprim inhibits bacterial folic acid synthesis by interfering with bacterial enzymes. May be given with sulphamethoxazole as co-trimoxazole. Active against both positive and negative gram bacteria. Excreted in urine.

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14
Q

Describe fluoroquinolones.

A

Fluoroquinolones interact with topoisomerases (enzymes responsible for supercoiling and uncoiling of bacterial DNA) to prevent bacterial replication. They are bactericidal. Only antibiotics that may be given orally to treat pseudomonas infection. Oral is as effective as IV. Excreted in the urine. Use is severely restricted.

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15
Q

Describe ciprofloxacin

A

Ciprofloxacin may be given IV or oral. It is used for complicated UTI and sometimes UTIs in young men.

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16
Q

Describe levofloxacin.

A

Levofloxacin is used ONLY in severe community acquired pneumonia in penicillin allergic patients. It is IV administration only.

17
Q

Give a side effect of aminoglycosides.

A

Gentamicin is an aminoglycoside which may damage the kidneys and cause deafness/dizziness.

18
Q

Give a side effect of glycopeptides.

A

Vancomycin is a glycopeptide, it may damage the kidneys and cause allergic reactions.

19
Q

Give a side effect of tetracyclines.

A

Tetracyclines may cause permanent staining of teeth and bones in children <12years.

20
Q

Give a side effect of metronidazole.

A

Metronidazole interacts with alcohol, and may cause headaches and metallic tastes.

21
Q

Give a side effect of quinolones.

A

Quinolones may weaken tendons, leading to rupture. They may damage joints in children and cause seizures.

22
Q

Penicillin allergy is what type of hypersensitivity reaction?

A

Penicillin allergy causes a type 1 hypersensitivity reaction (itchy rash, difficulty breathing, swelling of URT, low BP and swelling at injection site).

23
Q

What antibiotics should not be given to pregnant woman at all?

A

Gentamicin, tetracyclines and fluoroquinolones.

24
Q

What antibiotics should be avoided in the first 3 months of pregnancy?

A

Trimethoprim and metronidazole.

25
Q

What antibiotics are generally safe to use in pregnancy?

A

Cephalosporins and penicillins,

26
Q

How do bacteria acquire antibiotic resistance?

A
  1. Genetic mutation.

2. Transfer of DNA coding for antibiotic resistance between bacteria.