Lecture 8 Antibiotics Flashcards
Survey of ____ and _____ sold in the US supermarket found relatively high levels of antibiotic resistant bacteria
•Beef
•Poultry
Antibiotic resistant strains of Salmonella are commonly isolate from ______ ____
Minced beef
How to treat Citrus stubborn disease
Spray crops with Erythromycin
Define Antibiotics
metabolic products of one microorganism that inhibit or kill other microorganisms
Define Antimicrobial drugs
Synthetic drugs produced by chemical procedures in a laboratory
Define Bacteriocidal
Kills the organism
Define Bacteriostatic
Inhibits organisms growth long enough for immune system to clear it
Define narrow spectrum
Only effective against species groups of microbes
Define broad spectrum
Effective against a variety of gram positive and gram negative bacteria
Define selective toxicity
Chemical being used should inhibit or kill the intended pathogen without seriously harming the host
Name the cell wall active agents
a)β-lactams, e.g. penicillin,
b)Cefotaxime affect cross-linking of peptidoglycan
c)Glycopeptides, e.g. vancomycin, binds to peptide side chains of peptidoglycan and prevents cross linking
What do ß-lactate durely bind to
Transpeptidase enzyme and inhibit it’s function
What do Glycopeptudes bind to
Peptide side chains of NAM and prevent transpeptidase from cross linking
Describe appearance of bacterial DNA
One long single circular molecule
What does DNA Gyrase supercoil
DNA
What does DNA topoisomerase unwind
Supercoiled DNA during DNA replication
What inhibits Transcription
Rifampicin
What does Sulphonamides and trimethoprim inhibit
Enzymes involved in synthesis of DNA and RNA
•Sulfonamides - inhibit pteridine synthesase
•Trimethoprim inhibits dihydrofolic acid reductase
how many S ribosome subunits in bacteria
50S and 30S
how many S ribosome subunits in humans
60S and 40S
What inhibits Translation
•Aminoglycosides
•Tetracyclines
•Macrolides
Mutations arise at what rate per cell division
10-8-10-10 per cell
•Streptomycin
protein synthesis inhibitor)
Mutation in 30S ribosomal subunit prevents drug binding in 1 in 10-10 cells in E.Coli
Name the RNA polymerase inhibitor
Rifsmipcin
Plasmids with multiple antibiotic resistance genes predominate within
Hospital Bacteria
Mechanism of antibacterial resistance
•Producing enzyme to inactivate or destroy the drug e.g. β-lactamase
•Altering the target/receptor of the drug
•Preventing entry of the drug into the cell or efflux of the drug from the cell
Mutation and plasmid acquisition normally occur in _______
Bacteria
What fraction of antibiotic prescriptions are unnecessary
1/3
What is a Zoonosis
Infection passed from animals to humans
What is Immunisation
the process of inducing or providing immunity against infection artificially
Can be active or passive
What is a Vaccine
A suspension of live attenuated or inactivated microorganisms or fractions thereof administered to induce immunity and thereby prevent infectious disease
Name the subunit vaccine comprising the hepatitis B coat
Hepatitis B vaccine
What is Active Immunisation
is the administration of a vaccine or a toxoid in order to stimulate the production of antibody or other immune responses
What is Passive immunisation
is the administration of preformed antibodies in order to provide temporary immunity
