Chapter 7
Order by
40 terms
Terms | Definitions |
|---|---|
 antimicrobial compounds | used to inhibit or kill microorganisms |
| what makes an appropriate microbial compound | easily administered selective toxicity needs to remain in the system long enough to be effective must be broken down and secreted by the host |
| selective toxicity | kill or inhibit the microorganism without simultaneously damaging the host tissue |
| goal of selective toxicity | to target specific function or structure in the pathogen that is not present in the host -cell wall (not present in humans) 70S ribosome (some toxicity to mitochondria) harder to have selective toxicity with some pathogens (fungi, helminths, and viruses) |
| chemotherapeutic agent | chemical that is used in the treatment, relief, or prophylaxis of disease |
| prophylaxis | use of a drug to prevent imminent infection of a person at risk |
| antibiotic | compound produced by one microorganism that inhibits or kills another microorganism |
| synthetic drugs | drugs that are synthesized in a laboratory |
| semisynthetic | drugs that are naturally produced but chemically altered in the laboratory |
| narrow spectrum | chemotherapeutic agent that is effective against a narrow range of microorganisms |
| broad spectrum | chemotherapeutic agent that is effective against a wide variety of microorganisms |
| Paul Ehrlich | worked into antimicrobial compounds -used an arsenic based drug that was toxic to cause syphilis |
| origins of antimicrobial drugs | antibiotics are common metabolic products of aerobic spore-forming bacteria and fungi |
| Targets of antimicrobial drugs | -inhibition of cell wall synthesis -inhibition of nucleic acid synthesis, structure or function -inhibition of protein synthesis -disruption of cell membrane structure or function |
| Penicillin and cephalosporins | react with one or more nzymes that synthesize/complete the cell wall, causing the cell to lyse |
| Penicillin | blocks the peptidase enzymes that link the cross bridges between the glycans in peptidoglycan |
| Drugs that inhibit nucleic acid synthesis | may block synthesis of nucleotides, inhibit replication, or stop transcription |
| sulfonamides and trimethoprim | block enzymes required for tetrahydrofolate synthesis needed for DNA and RNA synthesis. -these drugs are competitive inhibitors called metabolic analogs |
| synergistic effect | an additive effect, achieved by multiple drugs working together, requiring a lower dose of each |
| Aminoglycosides | streptomycin, gentamicin insert on sites on the 30S subunit and cause misreading of mRNA |
| Tetracyclines | block attachment of tRNA to stop protein synthesis |
| Drugs that disrupt cell membrane function | -cell with a damaged membrane dies from disruption in metabolism or lysis -these drugs have specificty for a particular microbial group, based on differences in types of lipids in their cell membranes |
| Penicillin consist of 3 parts | -thiazolidine ring -beta-lactam ring -variable sidechain dictates microbial activity |
| Penicillin is the drug of choice for | gram-positive cocci and some gram-negative bacteria |
| Primary problems with penicillin | allergies and resistant strains of bacteria |
| cephalosporins | -account for majority of all antibitics administered -beta-lactam ring that can be altered |
| 1st generation of cephalosporins | most effective against gram-positive cocci |
| 2nd generation of cephalosporins | more effective against gram-negative bacteria |
| 3rd generation | broad-spectrum activity against enteric bacteria with beta-lactamase |
| chromobacterium violaceum | may be used by people allergic to penicillin |
| aminoglycosides | impair ribosome function -comosed of 2 or more amino sugarsand an aminocyclitol (6C ring) |
| Aminoglycosides | broad spectrum inhibit protein synthesis especially useful against gram-negtive rods and certain gram-positive bacteria |
| examples of aminoglycosides | steptomyocin gentamicin |
| side effects of aminoglycosides | hearing loss dizziness loss of appetite nausea, vomiting |
| tetracycline | blocks protein synthsis -prevents the binding of aminoacyl tRNA to the ribosome |
| Tetracycline antibiotics | taken orally needs to be taken 2 hours after eating to prevent binding with food -also inactivated by antacids |
| side effects tetracycline antibiotics | -potential damage to developing bones of a fetus -diarrhea -discoloration of teeth in children -sensitivity to light |
| chloamphenicol | blocks peptie bond formation inhibits protein synthesis |
| chloramphenicol | typhoid fever brain abscesses rickettsial & chlamydial infections reserved for serious infections |
| chloroamphenicol-mode of action | -irreversibly binds with 50s subunit prevents the formation of peptide bond -can interact with mitochondrial ribosomes |
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