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
Vancomycin
* Produced as metabolic waste from Streptomyces
| * Used to treat Methicilin and Penicillin resistant Staph infections
26
Inhibitors of Protein Synthesis
* Aminoglycosides
* Tetracyclines
* Chloramphenicols
* Erythromycin
* Moxalactam
27
Aminoglycosides
* 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
Aminoglycosides--Neomycin
* Non prescription drug
* Used in topical ointments
* Used against bacterial conjuctivitis
* Found in neosporin
29
Aminoglycosides--Kanamycin
* Broad spectrum
| * Used for Gram (-) infections
30
Aminoglycosides--Gentamycin
* Produced by Micromonospora
| * Used against Enteric and Pseudomonas infections
31
Tetracyclines
* 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
Chloramphenicol
* 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
Erythromycin
* Produced by Streptomyces
* Used as a substitute for Penicillin G for allergic patients
* Effective against Legionnaire's disease
34
Moxalactam
* Produced by Chromobacter Violaceum
* Used widely against gram - infections
* Especially noscomial infections (acquired in a hospital)
35
Antibiotic--Polymyxin
* Produced by bacillus polymyxia
* Effective against Gram - infections
- Especially pseudomonas
* Used as a topical ointment
* No prescription needed
36
Antibiotics--Amphotericin B
* Produced by Streptomyces
* Damages fungal membranes
* Used to treat systemic fungal infections
- Histplasmosis, cryptococcosis
37
Antibiotic--nystatin
* Produced by Streptomyces
| * Used to treat Candida albicans infections
38
Griseofulvin
* Produced by Penicillium
* Interferes with Mitosis
* Used to treat Dermatophytic Funga Infections
39
Rifampin
* Original compound is isolated from Streptomyces
| * Used to treat Tuberculosis and Leprosy
40
Antiviral/Acyclovir
* Inhibits DNA production in a virus
| * Used to treat genital herpes
41
Antiviral/Idoxuridine
* It is base analog to thymine
* Prevents DNA from replicating
* Used to treat herpes infections of the eyes
42
Antiviral/ Azidothymidine
*Used in treating AIDS patients
