Antibiotics 1

Question 1

What are the key structural features of bacteria?

Answer 1

Cell Wall:
Peptidoglycan: in the cell wall. Thick gram +
Lipopolysaccharide: in Gram - bugs
Cytoplasmic membrane: sterols makes diff
Cytoplasm: have some unique floaters

Question 2

Explain why bacteria can cause disease in a host?

Answer 2

Have features that allow it to evaid the immune defense and also to reak havoc on the natural cells.

Question 3

What is the diff between

Bacteriocidal and Bacteriostatic?

Answer 3

• Bacteriocidal: agent will kill bacteria
• Bacteriostatic: agent inhibits growth but not kill. If give one of these, relying on teh immune system to clear those agents. keeping bacterial burden at level that immune system can handle

Question 4

Principle of drug resistance.

example.

Answer 4

agent is no longer or less effective toward an organism.
Changes to drug entry, export, changing targets,
by acquiring new genetic material, or mutation.

Question 5

Define:
Chemotherapy
Narrow Spectrum
Broad Spectrum
Selective Toxicity
Prophylactic Therapy
Preemptive Therapy
Empirical Therapy
Definitive Therapy
Suppressive Therapy

Answer 5

• Chemotherapy: tx of dz with chemicals to impair growth of microorg or Ca cell
• Narrow Spectrum: drug that has an effect on one type or species of organism. need to know what the organism is. less likely for resistance, microbiota not effected.
• Broad Spectrum: drug that has an effect on a wide variety of organisms.
• Selective Toxicity: aimed at killing organism without harming host
• Prophylactic Therapy: treatment in absence of infection to prevent: travelers
• Preemptive Therapy: tx of high-risk patients that have become infected but are asymptomatic: multiple kids in a home all susceptible to strep throat and they all share illness. Prescribe abx for all kids.
• Empirical Therapy: tx of symptomatic patient without further testing or confirmation of the organism. happens most often, can lead to Overprescribing
• Definitive Therapy: Tx once teh pathogenic organism has been identified and drug identified
• Suppressive Therapy: Generally in low dose therapy to keep infection from coming back. secondary prophylaxis. Tx for UTIs in susceptible women.

Question 6

Identify Key mechanisms of resistance known to occur for specific classes of agents.

Answer 6

Key resistant bugs: ESKAPE (E. Faecium, Staph Aureus, Klebsiella pneumoniae, Actinobacter, Pseudomonas, Enterobacter species
Daptomycin: gene mutation results in membrane charge (become more pos) which repels abx that have + charge
Tetracycline: efflux pump
Metronidazole: PFOR is mutated so that it cannot be reduced and activated.
Aminoglycosides such as streptomycin: Enzymes change the chemical structure of the DRUGS so that it is ineffective
Amoxacillin: Lactamase cleaves the drug and inactivates.
Trimethoprim/Sulonamides: expression of drug insensitive enzymes
Vancomycin: Substitution on the peptidoglycan that still allow it to form membrane and resistance

Question 7

Identify the three general pharmacological targets of antibacterial agents.

Answer 7

Disrupt coding/genetic machinery
Blocking protein synthesis
Disrupting Cell wall/membrane synthesis

Question 8

Minimum Inhibitory Concentration?

Minimum Bactericidal Concentration?

Answer 8

MIC - lowest conc that will inhibit the visible growth of bacteria
MBC - conc from the original MIC plate that shows NO GROWTH after subculture