22 - Emergence and mechanism of antibiotic resistance

What is Prophylactic treatment?

Low level in feed prevent low level infection in animals

What does Campylobacter jejuni cause?

Serious food poisoning

What are Fluoroquinolone?

A DNA gyrase inhibitor used prophylactically & as growth promotor

Superbugs

some pathogenic bacteria are resistant to most usual antibiotics

What is pneumococci resistant to, in result of overuse?

Penicillin

What is Staphylococcus aureus resistant to, in result of overuse?

Methicillin

What are 2 examples of Natural resistance?

Lack of target structure / impermeable to antibiotic

What are alternative names for natural resistance?

Intrinsic / innate

What are all the ways sensitive bacteria develop resistance (acquired)?

enzymatic inactivation of antibiotic / mod of target / organism pumps out antibiotic

How does antibiotic resistance develop on a genetic level?

Selection pressure of antibiotic (Darwinism) / horizontal gene transfer

What are the 2 ways R-gene can transfer?

Transformation (naked DNA) / transduction (phages)

Transformation:

R gene come from free DNA

Transduction:

R gene transferred by ‘phages

What does conjugation MEAN?

Transfer of plasmids

Conjugation mechanism:

1. 1. donor cell contain plasmid

2. 2. recipient cell do not

3. 3. mating pairs form

4. 4. pilus retract / R plasmid transfer to recipient cell

5. 5. mating involve cell to cell contact

What properties do resistance genes code for?

Inactivation of antibiotic / efflux of drug / mod of target

How does resistance against penicillin work?

B-lactamases cleave and inactivation B-lactam ring in penicillin

What does tetracycline bind to?

bind to 30s ribosomal subunit