Lecture 21 Flashcards
1
Q
Chemotherapeutic Agent
A
Chemical substance used to treat/prevent a disease
2
Q
Antimicrobial Agent
A
Chemotherapeutic drug used to treat/prevent an infection
3
Q
Antibiotic
A
- Naturally occurring microbial compound that inhibits/kills other microbes
- Also includes semi- and synthetic compounds
4
Q
Effectiveness of Antimicrobial Agents
A
- Selective toxicity- destroys or inhibits microbe without affecting host cells
- Non-allergenic to host- should not cause adverse reactions in host
- Should not disturb host’s normal flora causing secondary (super) infections produced by opportunists
- Affordable cost
5
Q
Effectiveness of Antimicrobial Agents
A
- Broad spectrum- effective against a wide variety of organisms
- Non-mutagenic - does not include development of resistant strains
- Stable in body fluids-not easily broken down or excreted, to maintain constant and effective levels
- Absorbed by tissues- delivery to the site of infection
6
Q
Paul Ehrlich
A
- Envisioned the “Magic Bullet”
- Developed an arsenic compound called SALVARSAN
- Used to treat syphilis
- Later rejected because of side effects
7
Q
Gerhard Dogmack
A
- Anti-microbial dyes were produced for treating fabrics
- Dogmack tested Prontosil on living animals
- Effective against Staph. and Strep. infections
- Active ingredients is sulfanilmide
- He received the 1939 Nobel Prize in Absentia
8
Q
Ernest Duchesne
A
- French medical student
- Discovered mold could inhibit the growth of Staph.
- Published a paper but couldn’t isolate the agent
9
Q
Alexandra Fleming
A
- Rediscovered the phenomenon
- Named the agent from the mold Penicillin
- Could not get funding for further studies
- It was forgotten again
10
Q
Howard Florey and Ernst Boris Chain
A
- They re-isolated penicillin
- Conducted tests with it
- Presented its medical potential to USDA in Peoria
- They won a Nobel Prize
11
Q
Selman Waksman
A
- Discovered that M. tuberculosis died when added to certain soils
- Isolated Streptomycin from S. griseus
- He coined the term “antibiotic”
12
Q
Genera that Produce Antibiotics
A
- Streptomyces
- Half of the anitbiotics
- Bacillus
- Bacitracin
- Polymyxin
- Penicillium
- Penicillins
- Cephalosporium
- Cephalosporins
- Micromonospora
- Gentamycin
13
Q
Antibiotics Mode of Action
A
- Inhibition of
- Cell wall synthesis
- Protein synthesis
- Nucleic acid synthesis
- Enzyme activity
- Injury to plasma membrane
14
Q
Sulfonamides
A
- Mode of action
- Competitive inhibition
- Used to treat UTI Gram (-) rod infections
15
Q
Isoniazid
A
- Mode of action
- Cell wall inhibition
- Inhibits Mycobacterium tubercolosis
16
Q
Ethambutol
A
- Inhibits mycobacterium
* Other microbes are resistant to it
17
Q
Nitrofurans
A
*Used widely for urinary tract infections
18
Q
Metronidazole
A
- Flagyl
- An effective amebecide
- Used for Trichomoniasis and Giardiasis
19
Q
Antibiotics
A
- Inhibitor of cell wall synthesis
- Inhibitors of protein synthesis
- Inhibitors of nucleic acid synthesis
- Affect cell membranes
20
Q
Inhibitors of Cell Wall Synthesis
A
- Penicillin
- Cephalosporins
- Bacitracin
- Vancomycin
21
Q
Penicillin
A
- Most widely used antibiotic
- Low cost
- Thousands of derivatives
- Low toxicity
- Natural Penicillins
- Penicillin G and Penicillin V
- Limitations
- Destroyed by stomach acid
- Susceptible to penicillinase
- Allergic reactions
22
Q
Penicillin–Semi synthetic
A
- Developed by adding side chains to penicillin nucleus
- Amoxicillin, Ampicillin
- Acid resistant, broad spectrum
- Carbenicillin
- broad spectrum for UTI’s
- Methicillin, Oxacillin
- Penicillinase resistant
- S. aureus is becoming resistant to methicillin
23
Q
Cephalosporins
A
- Produced by marine fungi–Cephalosporium
- Resembles penicillin structure and action
- Advantages:
- Penicillinase resistant
- Broad spectrum
- Disadvantages:
- Poorly absorbed through GIT
- Expensive
- Ex:
- Keflex, Keflin, Kefzol
24
Q
Bacitracin
A
- Produced by Bacillus subtillis
- Narrow spectrum
- streptococci and staphylococci
- Usually skin infections
- Found in neosporin topical ointment
- In combination with
- Neomycin and polymyxin
- Requires no prescription
25
Q
Vancomycin
A
- Produced as metabolic waste from Streptomyces
* Used to treat Methicilin and Penicillin resistant Staph infections
26
Q
Inhibitors of Protein Synthesis
A
- Aminoglycosides
- Tetracyclines
- Chloramphenicols
- Erythromycin
- Moxalactam
27
Q
Aminoglycosides
A
- Bind to bacterial ribosomes
- Streptomycin
- Produced by streptomyces grisesus
- From the throat of a chicken
- Isolated by Selman Waksman
- Effective against Tularemia, Tuberculosis and The Bubonic Plague
- Disadvantages:
- Toxic
- May cause hearing loss or deafness
28
Q
Aminoglycosides–Neomycin
A
- Non prescription drug
- Used in topical ointments
- Used against bacterial conjuctivitis
- Found in neosporin
29
Q
Aminoglycosides–Kanamycin
A
- Broad spectrum
* Used for Gram (-) infections
30
Q
Aminoglycosides–Gentamycin
A
- Produced by Micromonospora
* Used against Enteric and Pseudomonas infections
31
Q
Tetracyclines
A
- Semisynthetic
- Original molecule is produced by Streptomyces
- Broad spectrum and bacteriostatic
- Disadvantages:
- Cause yellow/gray/brown discoloration of teeth
- Contraindicated for pregnant women as it retards bone growth in children
- Diarrhea
32
Q
Chloramphenicol
A
- Produced by streptomyces venezuelae
- Now its synthesized
- Broad Spectrum
- Very Toxic
- May cause Apalstic Anemia
- Used only in serious infections like meningitis and typhoid fever
33
Q
Erythromycin
A
- Produced by Streptomyces
- Used as a substitute for Penicillin G for allergic patients
- Effective against Legionnaire’s disease
34
Q
Moxalactam
A
- Produced by Chromobacter Violaceum
- Used widely against gram - infections
- Especially noscomial infections (acquired in a hospital)
35
Q
Antibiotic–Polymyxin
A
- Produced by bacillus polymyxia
- Effective against Gram - infections
- Especially pseudomonas
- Used as a topical ointment
- No prescription needed
36
Q
Antibiotics–Amphotericin B
A
- Produced by Streptomyces
- Damages fungal membranes
- Used to treat systemic fungal infections
- Histplasmosis, cryptococcosis
37
Q
Antibiotic–nystatin
A
- Produced by Streptomyces
* Used to treat Candida albicans infections
38
Q
Griseofulvin
A
- Produced by Penicillium
- Interferes with Mitosis
- Used to treat Dermatophytic Funga Infections
39
Q
Rifampin
A
- Original compound is isolated from Streptomyces
* Used to treat Tuberculosis and Leprosy
40
Q
Antiviral/Acyclovir
A
- Inhibits DNA production in a virus
* Used to treat genital herpes
41
Q
Antiviral/Idoxuridine
A
- It is base analog to thymine
- Prevents DNA from replicating
- Used to treat herpes infections of the eyes
42
Q
Antiviral/ Azidothymidine
A
*Used in treating AIDS patients
