Module 10: Antimicrobials

Question 1

Give two examples of earlier ways of dealing with infection.

Answer 1

Amputation, cauterization

Question 2

What are two earlier ways that syphilis was treated?

Answer 2

Mercurial compounds, arsenicals

Question 3

Describe the process of the creation of penicillin (3 years in particular).

Answer 3

1928: Accidental discovery of penicillin by A. Fleming
1935: Accidental discovery of sulfa drugs.
1942: Purification & production of penicillin

Question 4

Differentiate between antibiotics, antibacterials, antivirals, and antimicrobials.

Answer 4

Antibiotics = natural source
Antibacterials = kill bacteria
Antivirals = kill viruses
Antimicrobials = kill microbes

Question 5

Disinfectants are _______
compounds that may be able to
eliminate ____________ but are
usually too ________ for human use
(other than topical)

Answer 5

Chemical, microorganisms, toxic

Question 6

What are the most antibiotic-resistant infections?

Answer 6

MSK infection, skin
and soft tissue infections, UTIs, Pneumonia/Intra-abdominal
infection

Question 7

A single mutation causes what? A series of mutations?

Answer 7

Single: lowers affinity to antibiotic
Series: resistance

Question 8

How do bacteria share resistance?

Answer 8

They acquire resistance genes through transfer of DNA (plasmids)

Question 9

What are the three mechanisms of resistance?

Answer 9

1. altered target site for drug
2. altered uptake/increased efflux
3. drug inactivation

Question 10

What are the 3 ways to classify an antibacterial?

Answer 10

1. bactericidal vs. bacteriostatic
2. mechanism of action
3. chemical structure

Question 11

What is the difference between bactericidal and bacteriostatic antibacterials?

Answer 11

Bactericidal kill, immune system cleans up cellular fragments.
Bacteriostatic inhibits, immune system must still be actively fighting disease.

Question 12

What are the three target sites for mechanism of action?

Answer 12

1. cell wall synthesis
2. protein synthesis
3. nucleic acid synthesis

Question 13

A peptidoglycan layer is specific to _______ and is the optimum target for ________ _________.

Answer 13

Bacteria, selective toxicity

Question 14

Name 3 examples of beta-lactams. What makes them beta-lactams?

Answer 14

Penicillin, amoxicillin, ampicillin. Intact ring structure, which is essential for antibacterial activity.

Question 15

What enzymes break down beta-lactams?

Answer 15

Beta-lactamases

Question 16

Penicillin binds, utilizing what? What do these inhibit?

Answer 16

Pencillin-binding proteins (PBPs). Inhibit transpeptidases (TBPs) which normally catalyze the formation of peptidoglycan.

Question 17

Penicillin only kills cells when bacteria are..?

Answer 17

Growing. Only impacts during log phase

Question 18

Name two bacteria that penicillin affect.

Answer 18

Neisseria, treponema pallidum

Question 19

Name two bacteria that ampicillin/amoxicillin impact.

Answer 19

Salmonella, E-coli.

Question 20

Name the bacteria that nafcillin or dicloxacillin impact.

Answer 20

Staphylcoccus aureus.

Question 21

___________, ____________, and __________ decrease the effectiveness of birth control pills.

Answer 21

Ampicillin, amoxicillin, rifamycin

Question 22

Name three disadvantages of penicillin.

Answer 22

1. limited effectiveness for gram-negative bacteria.
2. need frequent doses
3. can be inactivated by beta-lactamases

Question 23

Cephalosporins have a 6-sided _____ attached to a _________ group. What is the difference between first and later generation cephalosporins?

Answer 23

Ring, beta-lactam. First = only effective against gram-positives. Later = gram-positive and gram-negative

Question 24

When are cephalosporins used? What is it commonly used to treat (2)?

Answer 24

Prophylactically before/after surgery. Gonorrhea, GBS (if penicillin not possible).

Question 25

Glycopeptides are _________ agents only active against ____- _____ bacteria.

Answer 25

Bactericidal, gram postive

Question 26

Glycopeptides inhibit the addition of _________ to the ___________ ___________. What is helpful about glycopeptides?

Answer 26

Subunits, peptidoglycan backbone. They act at an earlier stage than beta-lactams.

Question 27

Glycopeptides treat ________ _______, the main nosocomial disease. Why are gram-negatives naturally resistant?

Answer 27

Clostridium difficile. Gram negs are resistant because glycopeptides are too large to move through the outer memes.

Question 28

Name 2 antibacterial units that are grouped in the 30S subunit of the ribosome.

Answer 28

Aminoglycosides, tetracyclines.

Question 29

Name 2 antibacterial agents that are grouped in the 50S subunit of the ribosome.

Answer 29

Erythromycin, clindamycin.

Question 30

What are two mechanisms of action for aminoglycosides?

Answer 30

1. binds to proteins in 30S subunit. 2. misread mRNA, bacterium dies.

Question 31

What are 2 types of bacteria that aminoglycosides commonly affect? When is it given to pregnant people?

Answer 31

Aerobic gram-negative, facultative anaerobe. Given to those with prolonged rupture of membranes or infants with sepsis.

Question 32

Are aminoglycosides recommended during pregnancy?

Answer 32

No, category D because it is ototoxic and nephrotoxic.

Question 33

How do tetracyclines act on bacteria?

Answer 33

Inhibit the binding of tRNA to the ribosome to prevent protein syntheiss.

Question 34

When are two infections that tetracyclines treat? How are they resistant?

Answer 34

Chlamydia, mycoplasma. Bacteria make new cytoplasmic membrane proteins, pump out tetracycline.

Question 35

What are two side effects in children when given tetracyclines? What about adults?

Answer 35

1. permanent tooth/bone issues 2. photosensitive allergic reaction Adults: GI issues

Question 36

How do macrolides act? Are they bactericidal or bacteriostatic? When are they sued?

Answer 36

Prevents release of tRNA after peptide formation. Bacteriostatic. Used for STIs, especially during pregnancy (less harmful).

Question 37

Erythromycin is a great alternative treatment for what? What are they typically active against?

Answer 37

Streptococcus. Chlamydia, mycoplasma.

Question 38

A single 1g dose of _________ is as effective as a 7-day course of ______________ for what?

Answer 38

azithromycin, doxycycline. Chlamydial cervicitis, urethritis.

Question 39

What does clindamycin do? What does it treat?

Answer 39

Lincosamide that inhibits peptide formation. Active against chlamydia, gonorrhea, GBS, BV.

Question 40

What are the two categories of antibacterial agents?

Answer 40

1. inhibitors of DNA replications 2. folic acid synthesis inhibiton

Question 41

What do quinolones inhibit? What is the MAIN quinolone, is it bactericidal or bacteriostatic?

Answer 41

Inhibit DNA gyrase. Ciprofloxacin, bactericidal.

Question 42

Quinolones are administered _________ and are used to treat _______. It can also treat which 2 conditions?

Answer 42

Orally, UTIs. Chlamydia, gonorrhea.

Question 43

Why can't quinolones be given to pregnant women/children?

Answer 43

Effect on cartilage development, especially 1st semester.

Question 44

Sulfonamides inhibit _______ _______ _______, are administered _____, and typically treat _________.

Answer 44

Folic acid synthesis, orally, UTIs.

Question 45

Are sulfonamides bactericidal or bacteriostatic? Why don't we prescribe to pregnant women?

Answer 45

Bacteriostatic. Possible effect on folic acid, affects bilirubin in fetus.

Question 46

_________ and ___________ are also effective sulfonamides that treat UTIs.

Answer 46

Trimethoprim, sufamethoxazole.

Question 47

Metronidazole is only effective against ____________ organisms. It is also active against a wide range of ______, which can help treat ____.

Answer 47

Anaerobic, protozoa, BV.

Question 48

What are the best three treatments for GBS?

Answer 48

1. penicillin 2. cefazolin (cephalosporin) 3. clindamycin/erythromycin