Contributors to antibiotic resistance + antibiotic examples

Mutations can cause:

1. enzymatic destruction of the drug

2. prevention of penetration of drug

• from changes to cell wall structure

3. alteration of drugs target site

• changes of internal structures (proteins, enzymes)

4. rapid ejection of the drug

Resistance genes are often

on plasmids or transposons that can be duplicated and transferred between bacteria.

misuse

• using outdated, weakened antibiotics

• using antibiotics for the common cold or other inappropriate conditions

• use of antibiotics in animal feed

• failure to complete prescribed regimen

• using someone else’s leftover prescription

Polymyxin B

Causes injury to the plasma membrane

• alters the outer membrane permeability of bacterial cells

• targets gram negative bacteria

• results in destabilization of LPS layer of the outer membrane layer

Rifamycins

Inhibitor of nucleic acid synthesis

• Rifampin - similar to a macrolide

• inhibits RNA synthesis by stopping RNA polymerase

Quinolones and Fluoroquinolones

Inhibitors of nucleic acid synthesis

• ciprofloxacin - broad spectrum that inhibits DNA synthesis

Sulfonamides

Competitive inhibitors of the synthesis of essential metabolites

• target the enzymes in the metabolic pathway that leads to folate creation, shutting the pathway down

• kills the cell

• broad spectrum

• unique to prokaryotes