Ch.20 Antimicrobial Drugs Flashcards
History of Chemotherapy:
~ Selective toxicity: selectively finding and destroying — without damaging the —
- Pathogen
- Host
History of Chemotherapy:
~ Chemotherapy: the use of — to treat a —
- Chemicals
- Disease
The History of Chemotherapy:
~ Antibiotic: A substance produced by a — that, in small amount, — another microbe
- Microbe
- Inhibits
History of Chemotherapy:
~ Antimicrobial drugs: — substance that interfere with the — of —
- Synthetic
- Growth of Micorbes
History of Chemotherapy:
~ 1928: — discovered penicillin, produced by —
- Fleming
- Penicillium
History of Chemotherapy:
~ 1932: ——— used for streptococcal infections
Prontosil red dye
History of Chemotherapy:
~ 1940: first clinical trials of —
~ Today there is a growing problem of ——
- Penicillin
- Antibiotic Resistance
Spectrum of Antimicrobial Activity:
~ Narrow spectrum of microbial types: drugs that affect a —— of microbial types
Narrow range
Spectrum of Antimicrobial Activity:
~ Broad-Spectrum Antibiotics: affect a broad range of —— or ———
Gram-positive or Gram-negative bacteria
Spectrum of Antimicrobial Activity:
~ Superinfection: —— of normal — that is resistant to antibiotics
- Overgrowth
- Microbiota
Action of Antimicrobial Drugs:
~ Bactericidal: ———
Kills microbes directly
Action of Antimicrobial Drugs:
~ Bacteriostatic: ————
Prevents microbes from growing
Inhibition of Protein Synthesis by Antibiotics:
~ Target bacterial —— ribosome
~ —, —, —, —
- 70 S
- Chloramphenicol, Erythromycin, streptomycin, tetracyclines
Injury to Plasma Membrane of a Yeast Cell Caused by an Antifungal Drug:
~ Polypeptide antibiotics change ——
~ Antifungal drugs combine with ——
- Membrane permeability
- Membrane Sterols
The Action of Antimicrobial Drugs:
~ Inhibits —— synthesis
* Interfere with DNA replication & Transcription
~ Inhibiting synthesis of essential metabolites
* — compete with normal substrates for an enzyme
- Sulfanilamide compete with ———, stopping the synthesis of ——
- Nucleic Acids
- Antimetabolites
- Para-amino Benzoic acid (PABA)
- Folic Acid
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Pencillin
* Contain a ———
- Types are differentiated by the chemical —— attached to the ring
* Prevents the cross-linking of —, interfering with cell wall construction (especially ——)
- B-lactam ring
- Side Chains
- Peptidoglycan
- Gram-Positives
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Natural Penicillins
* Extracted from — cultures
- Penicillin G(—) and Penicillin V (—)
* —— of activity
* Susceptible to —
- Penicillium
- Injected
- Oral
- Narrow Spectrum
- Penicillinase (B-lactamases)
Antibacterial Antibiotics: Inhibitors of Cell Wall Syntheis
~ Semisynthetic Penicillins
* Contain chemically added ——, making them resistant to —
- Side chains
- Penicillinases
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Penicillinase-resistant penicllins
* — and —
Methicillin and Oxacillin
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Extended-spectrum penicillins
* Effective against —— as well as ——
- Aminopenicillins: —,—
- Gram-negatives, Gram positives
- Ampicillin & Amoxicillin
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Penicillins plus B-lactase inhibitors
* Contain clavulanic acid, a —— of —
Non competitive inhibitor of penicillinase
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Carbapenems
* Substitute a — for an — and add a — bond to the penicillin nucleus
* Broad Spectrum: — & —
- C for an S, double
- Primaxin & Doripenem
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Monobactam
* —; — ring instead of B-lactase double ring
* Low —; works against only certain gram —
- Synthetic, Single
- Toxicity, Negatives
Antibacterial Antibiotics: Inhibitors of cell wall synthesis
~ Cephalosporins
* Work similar to —
* B-lactase ring differs from —
* Grouped according to their — of —
- Penicillins
- Penicillins
- Generation of Development
Antibacterial Antibiotics: Inhibitors of Cell Wall Synthesis
~ Polypeptide Antibiotics
* —: topical application; works against gram-positives
* —: glycopeptide, last line against antibiotic-resistant MRSA
- Bacitracin
- Vanomycin
Chloramphenicol:
~ Inhibits —— formation
* Binds to the —S subunit of the —S ribosome
~ Synthesized —; — Spectrum
~ Can suppress —— and affect —— formation
- Peptide Bond
- 50, 70
- Chemically, Broad
- Bone Marrow, Blood Cell
Aminoglycosides:
~ Amino sugars link by — bonds
~ Chnage the shape of the —S subunit of the —S ribosome
~ Can cause — damage
~ —,—,—
- Glycoside
- 30, 70
- Auditory
- Streptomycin,neomycin, gentamicin
Tetracyclines:
~ Produced by ——
~ Interfere with the — attachment to the ribosome
~ Broad Spectrum; penetrates —, making them valuable against — and —
~ Can suppress normal ——
- Streptomyces spp.
- tRNA
- Tissues, rickettsias and chlamydias
- Intestinal microbiota
Injury to the Plasma Membrane:
~ Affects — of — plasma membranes
- Synthesis
- Bacterial
Injury to the Plasma Membrane:
~ Lipopeptide:
* Daptomycin: produced by —; used for — infections. Attacks the — cell membrane
* Polymyxin B: Topical; —; effective against gram —. Combined with — and — in nonprescription ointments
- Streptomycetes, Skin, bacterial
- Bacteriocidal, Negatives, bacitracin and neomycin
Nucleic Acid Synthesis Inhibitors:
~ Rifamycin
* Inhibits — synthesis
* Penetrates —; — activity
- mRNA
- Tissues, Antitubercular
Nucleic Acid Synthesis Inhibitors:
~ Quinolone and Fluoroquinolones
* Nalidixic acid: —; inhibits ——
* Norfloxacin and Ciprofloxacin: ——; relatively ——
- Synthetic, DNA Gyrase
- Broad Spectrum, Nontoxic
Sulfonamides:
~ Inhibit the —— synthesis needed for —— and — synthesis
~ Competively bind to the enzyme for — production, a folic acid precursor
~ Combination of trimethoprim and sulfamethoxazole(TMP-SMZ) is an example of drug —
- Folic Acid, Nucleic Acid and Protein
- PABA
- Synergism
Antifungal Drugs:
~ Agents affecting fungal sterols:
* Interrupt the synthesis of —, making the membrane excessively —
- Ergosterol
- Permeable
Antifungal Drugs:
~ Polyenes:
* Amphotericin B: produced by —; toxic to the —
- Streptomyces
- Kidneys
Antifungal Drugs:
~ Azoles
* Imidazoles: —; treat ——
* Triazole: treat ———
- Topical
- Cutaneous mycoses
- Systemic fungal infections
Antifungal Drugs:
~ Allylamines:
* For ———
Azole-resistant infections
Antiviral Drugs:
~ Entry and Fusion Inhibitors
* Block the — on the —— that bind to the virus
* Block — of the — and —
- Receptors, Host cell
- Fusion, virus & cell
Antiviral Drugs:
~ Uncoating, genome integration, and nucleic acid synthesis inhibitors
* Prevent viral —
* Inhibit viral —— into the host —
* —— inhibit RNA or DNA synthesis
- Uncoating
- DNA Integration, Genome
- Nucleoside Analogs
Interferons:
~ Produced by —— cells to inhibit further spread of —
~ Imiquimod: promotes ——
- Viral-Infected, Infection
- Interferon Production
Tests to Guide Chemotherapy: Diffusion Methods
~ Disk-Diffusion Method (Kirby-Bauer Test): test the effectiveness of chemotherapeutic agents
* Paper disks with a chemotherapeutic agent are placed on — containing the test organism
* Zone of inhibition around the disk determines the — of the organism to the —
- Agar
- Sensitivity, Antibiotic
Resistance to Antimicrobial Drugs:
~ Persister Cells: microbes with — characteristics allowing for their — when exposed to an —
- Genetic
- Survival
- Antibiotic
Resistance to Antimicrobial Drugs:
~ Superbugs: bacteria that are — to —— of antibiotics
- Resistant
- Large Numbers
Resistance to Antimicrobial Drugs:
~ Resistance genes are often spread — among bacteria on — or — via — or —
- Horizontally
- Plasmids or Transposons
- Conjugation or transduction
Mechanisms of Resistance:
~ —— or — of the drug
~ Prevention of — to the target site within the microbe
~ — of the drugs target site
~ Rapid — of the antibiotic
~ — of mechanisms of resistance
- Enzymatic Destruction or Inactivation
- Penetration
- Alteration
- Efflux (ejection)
- Variations
Antibiotic Misuse:
~ Misuse includes:
* Using — or — antibiotics
* Using antibiotics for the —— and other — conditions
* Using antibiotics in ——
* Failing to complete the prescribed —
* Using someone else’s — prescription
- Outdated or Weakened
- Common cold, inappropriate
- Animal Feed
- Regimen
- Leftover
Antibiotic Safety:
~ Therapeutic Index: — versus —
~ — of antibiotics with other drugs
~ Damage to —
~ Risk to the fetus
- Risk versus Benefit
- Reactions
- Organs
- Fetus
Synergism: the effect of — drugs together is — than the effects of either —
- Two
- Greater
- Alone
Antagonism: the effect of — drugs together is — than the effect of either —
- Two
- Less
- Alone
History of Chemotherapy:
~ —— developed the concept of chemotherapy to treat microbial disease; “magic bullet” kill — but not — cells.
* ——
- Paul Ehrlich
- Pathogen but not human cells
- Selective Toxicity
History of Chemotherapy:
~ —— Scottish microbiologist discovered penicillin produced by ——; its first clinical trials were done in 1940
- Alexander Fleming
- Penicillium Notatum
Selective Toxicity:
~ Goal of Antimicrobial chemotherapy is very simple: administer a — to an — person, which destroys the — agent without harming ——
- Drug
- Infected
- Infective
- Host’s Cells
~Antibacterial drugs treat — infections
* Antibiotics — treat — infections; they are NOT effective against — infections, like colds
~Antiviral drugs target — infection
~ Antifungal drugs work against — infections
~ Anti parasitic drugs treat — and — infections
- Bacterial
- Only, Bacterial, Viral
- Viral
- Fungal
- Protozoan and Worm
History of Chemotherapy:
~1928: — discovered penicillin, produced
by Penicillium
~1932: —— dye used for streptococcal infections
~1940: First clinical trials of penicillin
~Today there is a growing problem of antibiotic resistance
- Fleming
- Prontosil Red Dye
Penicillin does not directly kill bacteria. Why do cells usually die in the presence of penicillin?
It undergoes osmotic lysis
Polymyxin B is — that destroy the — of gram — bacteria
- Detergent
- Outer membrane
- Negative
Sulfonamides (Sulfa Drugs)
~ — Antimicrobial agents used to cure infections in humans
~ Dramaticly reduced —— from infections caused by — and —
~ But with extensive use, microbial — emerged and spread rapidly
- First
- Death Rates, Streptococci and Staphylococci
- Resistance
Overview of Drug Target:
1. Inhibition of cell wall synthesis: — target
* Ex. —, —, —, —
- Excellent
- Penicillins, cephalosporins, vancomycin, bacitracin
Overview of Drug Target:
2. Inhibition of protein synthesis
* Ex. —,—,—,—
Chloramphenicol, tetracycline, streptomycin, erythromycin
Overview of Drug Target:
3. Inhibition of Nucleic Acid Synthesis: the —— toxic
* —, —, some —— agents
- Least selective
- Quinolones, Rifampin, Anti-viral
- Inhibition of essential metabolite synthesis (inhibition of folic acid synthesis- — target)
- —
- Excellent
- Sulfamides
Overview of Drug Target:
5. Disruption of cell membrane- the —— toxic
* ——, — agents
- Least selective
- Polymyxin B, Antifungal
