Antimicrobial Drugs

Question 1

Drugs

Answer 1

chemicals that affect physiology in any manner

Question 2

Chemotherapeutic agents

Answer 2

drugs that act against diseases

Question 3

Antimicrobial agents (antimicrobials)

Answer 3

drugs that treat infections

Question 4

Semisynthetics

Answer 4

chemically altered antibiotics that are more effective, longer lasting, or easier to administer than naturally occurring ones

Question 5

Synthetics

Answer 5

antimicrobials that are completely synthesized in a lab

Question 6

Selective toxicity

Answer 6

an effective antimicrobial agent must be more toxic to a pathogen than to the pathogen’s host

Question 7

Inhibition of cell wall synthesis

Answer 7

Penicillin, bacitracin, cephalosporin, vancomycin
The two, all penicillin and all cephalosporins are antimicrobials whose functional portions contain beta lactam rings that bind to enzymes that helps to cross-link NAM subunits, and the bacteria weakens and eventually lyses from osmotic pressure because the integrity of peptidoglycan has not been maintained. Vancomycin and Bacitracin are non-beta lactams.
Prevents bacteria from increasing in peptidoglycan, no effect on existing layer, effective for growing cells, not on dormant ones.

Question 8

Semisynthetic derivates of beta lactams

Answer 8

Altered natural beta-lactams, such as penicillin G, to semisynthetic derivates such as methicillin and imipenem which are more stable in acidic environments, more absorbed, less susceptible to deactivation, and more active against different types of bacteria.

Question 9

Vancomycin

Answer 9

a semisynthetic that disrupts cell wall formation by interfering with bridges that link NAM subunits in many Gram-positive bacteria, results in cell lysis

Question 10

Bacitracin

Answer 10

prevents cell wall formation by blocking the transport of NAG and NAM across the cytoplasmic membrane to the wall, results in cell lysis

Question 11

Isoniazid

Answer 11

disrupts mycolic acid formation in mycobacterial species

Question 12

Disruption of cell membrane function

Answer 12

polymyxin
Nystatin and Amphotericin both attach to ergosterol in fungal membranes, which helps form a channel in the cytoplasmic membrane disrupting the function and causing lysis of the cell. However, most bacterial membranes lack sterols, so polymyxin is effective against gram negative bacteria, but is reserved for external pathogens that are resistant to other antibacterial drugs

Question 13

Inhibition of protein synthesis

Answer 13

tetracycline, erythromycin, streptomycin, chloramphenicol
Classes: Tetracyclines contains tetracycline, and Chloramphenicol is in its own class

Question 14

Aminoglycosides

Answer 14

streptomycin

Question 15

Macrolides

Answer 15

erythromycin

Question 16

Inhibition of nucleic acid synthesis

Answer 16

rifamycin, quinolones interfere with genetic material

Question 17

Action as antimetabolites

Answer 17

sulfanilamide is a antimetabolic drug that competes with PABA, which is responsible for the synthesis of nucleotides required for DNA and RNA synthesis

Question 18

Amphotericin B

Answer 18

is polyenes, used for systemic infections; route 4

Question 19

Nystatin

Answer 19

is polyenes, used for Candida infections; route T, O

Question 20

Griseofulvin

Answer 20

used for infections of skin, hair, or nails; route T, O

Question 21

Quinine

Answer 21

used for malaria; route O

Question 22

Chloroquine

Answer 22

used for malaria; route O

Question 23

Primaquine

Answer 23

used for chloroquine to prevent relapses; route O

Question 24

Metronidazole

Answer 24

Antiprotozoal: used for Trichomonas, Giardia, and amoebic infections; route O
Antibacterial: effective against anaerobic bacteria

Question 25

Spectrum of Action

Answer 25

Narrow spectrum is effective against few organisms Broad spectrum is effective against many organisms

Question 26

Effectiveness

Answer 26

several tests evaluate antimicrobbial efficacy Diffusion susceptibility test involves a petri dish and the zone of inhibition Minimum inhibitory concentration test involves the more concentration of a drug the less cloudy appearance of test tubes An Etest involves a plastic strip of which the zone of inhibition would reach a certain metric unit.

Question 27

Routes of Administration

Answer 27

Topical application of drug for external infections. Oral route requires no needles and is self-administered

Question 28

Toxicity

Answer 28

ideally there shouldn't be harmless to humans however, there are some side effects that causes to humans.

Question 29

Therapeutic index

Answer 29

the ration of the dose of a drug that can be tolerated to the drug's effective dose divide maximum tolerable dose by minimum therapeutic dose, the higher the TI the safer the drug

Question 30

Allergies of drugs

Answer 30

they are rare, but can be life threatening and cause anaphylactic shock

Question 31

Disruption of normal microbiota

Answer 31

drugs that disrupt the normal microbiota and cause secondary infections such as Candida albicans and Clostridium difficile

Question 32

Resistance to Antimicrobial Drugs

Answer 32

some pathogens are naturally resistant to drugs; resistance can be acquired in two ways through new mutations of chromosomal genes or acquisition of R plasmids via transformation, transduction, and conjugation

Question 33

Seven mechanisms of microbial resistance

Answer 33

Produce enzyme that destroys or deactivates drug Slow or prevent entry of drug into the cell Alter target of drug so it binds less effectively Alter their own metabolic chemistry Pump antimicrobial drug out of the cell before it can act Bacteria in biofilms can resist antimicrobials Mycobacterium tuberculosis produces MfpA protein which Binds DNA gyrase, preventing the binding of fluoroquinolone drugs

Question 34

Multiple drug resistance

Answer 34

are resistant to at least three antimicrobial agents

Question 35

Cross resistance

Answer 35

can occur when drugs are similar in structure

Question 36

Synergism

Answer 36

occurs when one drug enhances the effect of a second drug

Question 37

Antagonism

Answer 37

occurs when drugs interfere with each other