Vaccines and Antimicrobial Drugs

Question 1

What are vaccines?

Answer 1

Stimulates primary immune responses to produce memory cells that can be activated if pathogenic material is encountered at a later time.

Question 2

What are the categories of vaccines?

Answer 2

1. live attenuated vaccines
2. whole agent inactivated vaccines
3. subunit vaccines
4. toxoid vaccines

Question 3

What are live attenuated vaccines?

Answer 3

Contain weakened pathogen (accomplished by mutation) that can adsorb and penetrate but not replicate. It stimulates both antibody and cell mediated immunity. It can spontaneously mutate back to the wild-type.

Question 4

What are whole agent inactivated vaccines?

Answer 4

contain inactivated virus incapable of adsorption or penetration and only stimulates antibody mediated immunity.

Question 5

What is a subunit vaccine?

Answer 5

Contains non-infectious purified proteins (antigens) taken from pathogenic bacteria and virus that stimulate antibody mediated immunity

Question 6

What are toxoid vaccines?

Answer 6

Consist of bacterial toxins that have been modified to maintain the same antigenic properties of the actual toxin, despite being incapable of causing the same effects. It only stimulates antibody mediated immunity and often provide short-lived protection (needs booster shots)

Question 7

What are conjugated vaccines?

Answer 7

Contain antigens bound to polysaccharides so that naive immune systems that have trouble recognizing polysaccharide bacteria will produce memory B cells that can recognize the polysaccharide coat and target future polysaccharide bacteria.

Question 8

When are antimicrobial drugs used?

Answer 8

When immunization has not occurred and immune system has difficulty eliminating infection

Question 9

What are antimicrobial drugs?

Answer 9

Compounds that display selective toxicity to kill or control the growth of microorganisms while preventing damage to the host

Question 10

How are antimicrobial drugs categorized?

Answer 10

1. Synthetic (lab made) and natural (naturally occuring)
2. bacteriostatic (prevention of growth) or bacteriocidal (killing cells)
3. broad spectrum (targets many bacteria) or narrow spectrum (targets specific bacteria)

Question 11

What do antibiotics target?

Answer 11

1. Cell wall synthesis
2. DNA replication
3. Protein biosythesis
4. Lipid biosynthesis
5. Cell membrane
6. Folic Acid metabolism

Question 12

What are cell wall active antimicrobial drugs?

Answer 12

Most widely used class of antibiotics that are offer selective toxicity, especially lactam antibiotics.

Question 13

What are beta lactam antibiotics? Where does it occur? How can it be modified?

Answer 13

Cell wall antibiotic featuring the beta-lactam ring, which is susceptible to beta-lactamases. It is naturally occurring as a product of penicillium and cephalosporium fungi and can be modified in the lab to produce semi-synthetic drugs with a modified spectrum of activity.

Question 14

What are penicillins? What do they do?

Answer 14

Narrow spectrum BL antibiotic with five membered ring attached to the beta-lactam ring. It targets transpeptidation in gram positive bacteria because it cannot penetrate the outer membrane of gram negative bacteria.

Question 15

What is transpeptidation?

Answer 15

Chemical reaction that forms the peptide cross-links or bonds during the synthesis of peptidoglycan in the bacterial cell wall.

Question 16

What are cephalosporins?

Answer 16

Broad spectrum BL antibiotic with six membered ring attached to the beta-lactam ring. It targets transpeptidation in gram positive bacteria with better resistance against beta lactamases and is grouped into generations.

Question 17

What are growth factor analogs?

Answer 17

chemicals which are structurally similar to a bacterial growth factor but which do not fulfill its metabolic function in the cell (e.g. sulfa drugs and isoniazid)

Question 18

What are sulfa drugs?

Answer 18

Growth factor analog that inhibit growth of bacteria by inhibiting folic acid synthesis and thus nucleic acid synthesis. Often used in combinations with other analogs, which minimizes the likelihood of resistance.

Question 19

What are Isoniazids?

Answer 19

Growth factor analog with extremely narrow spectrum cell wall active agent. Analog of mycolic acid component needed by mycobacterium sp.

Question 20

What are quinolones?

Answer 20

Synthetic antimicrobial that inhibits DNA gyrase (prevents supercoiling of DNA) and is active against both Gram-negative and positive bacteria. Includes Ciprofloxacin, Rifampin, Actinomycin.

Question 21

What is ciprofloxacin?

Answer 21

Fluorinated quinolone (fluoroquinolone) useful against life threatening infections

Question 22

What is Rifampin?

Answer 22

quinolone that binds to RNA polymerase and prevents transcription

Question 23

What is Actinomycin?

Answer 23

quinolone that binds to DNA template blocking transcription elongation

Question 24

What are protein synthesis inhibitors?

Answer 24

Antimicrobials that target 70S ribosomes and have good selective toxicity, however may cause issues due to the 70S ribosomes in the human mitochondrial matrix. (e.g. Aminoglycoside, Tetracycline)

Question 25

What are aminoglycosides? What happens during treatment?

Answer 25

Narrow spectrum (gram -ve) protein synthesis inhibitor that bind to the 30S subunit of 70S ribosomes to block translation. Used as a last resort drug as it is damaging to the kidneys and ears. (e,g. streptomycin, gentamycin, neomycin)

Question 26

What is tetracycline? What does it do and what is it made of? What does it treat?

Answer 26

Broad spectrum protein synthesis inhibitor produced by species of the streptomyces genus that bind to the 30S subunit of 70S ribosomes. Consists of natural and modified semisynthetic drugs that bind to calcium, damaging teeth and bone and are used in veterinary medicine to promote animal growth.

Question 27

What are macrolides? What do they do? What does it treat?

Answer 27

Broad spectrum protein synthesis inhibitor that binds to the 50S ribosomal subunit. IT only inhibits the translation of some proteins which creates a detrimental protein imbalance inside of the cell. It is useful to treat infection in patients with allergies to beta lactam antibiotics. (e.g. erythromycin and azithromycin; both produced by streptomyces)

Question 28

What is daptomycin in terms of structure and specific treatment?

Answer 28

Cyclic lipopeptide active against gram positives (e.g. pathogenic straphylococcal / streptococcal species) by forming pores in plasma membrane, causing depolarization and cell death.

Question 29

What is platensimycin in terms of spectrum, function, and specific treatment?

Answer 29

Broad spectrum (gram positive) antibiotic produced by streptomyces platensis that inhibits fatty acid biosynthesis. It is useful against important resistant gram positive pathogens and does not cause toxicity in the host.

Question 30

What is antibiotic resistance?

Answer 30

When an organism develops a mechanism to elude the activity of an antimicrobial drug that it should otherwise be susceptible to due to encoding on a plasmid/genome. Prevalent due to incorrect use of antibiotics.

Question 31

What are ways to prevent antibiotic resistance?

Answer 31

1. Infection prevention
2. Rapid and conclusive diagnosis
3. Appropriate/prudent use of antibiotics
4. Prevention of transmission