Term
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Definition
| resistance that develops through mutation or acquisition of new genes |
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Term
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Definition
| compound naturally produced by molds/bacteria that kills or inhibits growth of microorganisms |
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Term
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Definition
| kills or inhibits growth of microorganisms, includes antibiotics and chemically synthesized drugs |
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Term
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Definition
| interferes with infection cycle of a virus |
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Term
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Definition
| chemical used to treat disease |
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Term
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Definition
| innate - due to inherent characteristics of the organism |
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Term
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Definition
| a plasmid that encodes resitance to one or more antimicrobial drugs |
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Term
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Definition
| antibiotics produced by natural species, but then chemically modified for properties such as stability |
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Term
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Definition
| lowest toxic dose / typical therapeutic dose (higher is less toxic) |
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Term
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Definition
| cause greater harm to microbes than to human host, but is relative to concentration |
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Term
| who discovered penicillin |
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Definition
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Term
| what was the original penicillin molecule, modified later |
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Definition
| Penicillin G - benzyl penicillin |
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Term
| ampicillin active mainly against |
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Definition
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Term
| which soil-living species do most modern antibiotics come from |
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Definition
| Streptomyces, Bacillus (bacteria), Penicillium, Cephalosporium (fungi) |
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Term
| sulfa drugs - bactericidal or bacteriostatic |
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Definition
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Term
| how do bactericidal drugs kill |
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Definition
| antimicrobial induced cell damage overwhelm's its ability to detoxify ROS |
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Term
| broad spectrum important when |
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Definition
| treating acute life threatening disease, no time to culture & identify pathogen |
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Term
| disadvantage of broad spectrum |
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Definition
| disrupt normal microbiota, leaves patient predisposed to other infections |
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Term
| combination therapy can be (3) |
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Definition
| synergistic, antagonistic, additive |
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Term
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Definition
| rate of elimination, time for body to reduce serum concentration by 50% |
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Term
| ex. Of drug with short half-life, long half-life |
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Definition
| penicillin V short, azithromycin long |
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Term
| what are adverse effects of antimicrobial drugs? (3) |
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Definition
| allergic rxns, toxic effects, suppression of normal microbiota |
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Term
| ex. Of antimicrobials with high toxicity risks |
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Definition
| streptomycin (aminoglycides), chloramphenicol - |
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Term
| what does chloramphenicol toxicity cause |
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Definition
| aplastic anemia - unable to make white and red blood cells, used only as last resort |
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Term
| what is a key organism that can overgrow when normal microbiota is suppressed |
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Definition
| Clostridium Difficile - causes serious intestinal damage when normal microbiota killed |
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Term
| what is mycoplasma's innate resistance mechanism |
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Definition
| lacks a cell wall - resitant to drugs interfering with peptidoglycan synthesis (penicillin) |
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Term
| how are gram-negative bacteria innately resistant |
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Definition
| lipid bilayer of outer membrane prevents the drug from entering |
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Term
| how is acquired resistance achieved |
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Definition
| spontaneous mutation or horizontal gene transfer |
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Term
| what are the target mechanisms of action of antibacterial drugs? (5) |
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Definition
| cell wall (peptidoglycan) synthesis, nucleic acid synthesis, cell membrane integrity, metabolic pathways (folate synthesis), protein synthesis |
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Term
| ex. Classes (3) Of cell wall synthesis-targeting drugs |
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Definition
| Beta-lactam, vancomycin, bacitracin |
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Term
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Definition
| penicillins, cephalosporins |
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Term
| how do bacteria resist the effects of beta-lactam drugs |
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Definition
| synthesize Beta-lactamase - breaks the lactam ring |
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Term
| which type (gram) produces a more extensive array of beta-lactamase |
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Definition
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Term
| natural penicillins active primarily against (gram-type) |
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Definition
| gram positive, few gram negative |
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Term
| broad spectrum is what and active against which type(s) |
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Definition
| ampicillin, amoxicillin - similar to natural, but more gram negative activity |
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Term
| extended spectrum penicillins have activity against what |
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Definition
| Pseudomonas (gram negative) - unaffected by many antimicrobials |
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Term
| cephalosporins generally more effective towards (gram -type), why |
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Definition
| gram Negative, structure is more resistant to inactivatino by Beta-lactamases |
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Term
| cephalosporins made by what |
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Definition
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Term
| vancomycin active against (gram-type), how |
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Definition
| gram - positive, binds peptide chain of NAM in cytoplasmic membrane (not actual cell wall) |
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Term
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Definition
| serious systemic infections and sever C. Diff associated disease |
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Term
| bacitracin active against (gram-type), common in what |
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Definition
| gram - positive, common in non-prescription antibiotic ointments |
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Term
| how do antibacterials work that inhibit protein synthesis, why not host damage |
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Definition
| target prokaryotic 70S ribosome (not 80S - euk, though euks have 70S in mitochon.) |
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Term
| classes of protein synthesis targeting antibacterials |
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Definition
| aminoglycides, tetracyclines, glycylcyclines, macrolides, chloramphenicol, lincosamides |
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Term
| key protein synthesis targeting antibacterials |
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Definition
| streptomycin, tetracycline, erythromycin, azithromycin, chloramphenicol |
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Term
| what class is considered the drug of choice for people allergic to penicillin |
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Definition
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Term
| what microlides effective against gram positives & walking pneumonia |
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Definition
| erythromycin, azithromycin, clarithromycin |
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Term
| what microlide is generally active against a wide range, but generally a last resort to avoid aplastic anemia |
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Definition
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Term
| which class has greatest risk for developing C. Diff |
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Definition
| lincosamide - (clindamycin) - because C. Diff resistant |
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Term
| what is considered the antibiotic of "last resort" & why |
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Definition
| vancomycin - will treat B-lactam resistant drugs, severe C. diff |
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Term
| classes of nucliec acid synthesis-inhibiting antibacterials (3) |
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Definition
| fluorquinolones, rifamycins, metronidazole |
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Term
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Definition
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Term
| rifamycin primarily used to treat |
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Definition
| tuberculosis (mycoplasma), hansen's/leprosy, prevent meningitis after exposure - causes reddish/orange tint in tears/urine |
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Term
| metronidazole also called, only works on what type of org, & 2 diseases |
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Definition
| flagyl, anaerobic - bacterial vaginosis & C. Diff |
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Term
| antibacts that interfere with metabolic pathways - inhibit what |
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Definition
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Term
| 2 classes of metabolic pathway inhibitors |
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Definition
| sulfonamides (sulfa drugs), trimethoprim |
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Term
| antibacterials interfering with cell membrane integrity, do what |
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Definition
| cause cells to leak, leads to cell death |
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Term
| ex of cell membrane integrity targeting antibacts |
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Definition
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Term
| what are key factors in mycobacterium tuberculosis being hard to target |
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Definition
| waxy cell wall & slow growth |
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Term
| what are first line drugs (5) for myco. Tb |
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Definition
| Ethambutol, Isoniazid, Pyrazinamide - streptomycin, rifampin |
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Term
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Definition
| minimum inhibitory concentration |
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Term
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Definition
| lowest concentration of a drug needed to prevent growth (of a bacteria) in vitro |
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Term
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Definition
| fixed amount of bacteria added to serial dilutions of the drug, incubated at least 16 hrs, examined for turbidity (indicating growth) |
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Term
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Definition
| minimum bactericidal concentration |
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Term
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Definition
| lowest concentration of a specific drug that kills 99.9% of bacterial cells (of a given strain) in vitro |
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Term
| what is the Kirby Bauer disc diffusion test |
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Definition
| discs of known amount of a drug placed on a bacteria-swabbed agar plate, look for clearing zones |
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Term
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Definition
| like a KB test, except will make teardrop zone of clearing, read where growth intersects the strip (numbered strips) |
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Term
| how many strains of S. aureus was Pencillin G resistant to when introduced and now |
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Definition
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Term
| what becomes resistant - the microbe or the host? |
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Definition
| the microbe becomes resistant |
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Term
| what are the (4)mechanisms for microbes to become resistant |
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Definition
| decreased uptake, increased elimination, inactivating enzyme, alteration in target molecule |
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Term
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Definition
| porin proteins in Gram Negative selectivly permit small hydrophobic molecules - changes to these can prevent entry into the cell |
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Term
| what is increased elimination |
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Definition
| drug enters the cell, but efflux pump ejects it |
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Term
| what is a drug inactivating enzyme |
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Definition
| an enzyme modifies the drug and inactivates it, ex. Penicillinase & chloramphenicol acetyltransferase |
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Term
| what is an alteration in target molecule |
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Definition
| target molecule is altered and drug cannot bind it - can be even minor structural changes |
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Term
| which type of resistance mechanism is particularly worrisome & why |
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Definition
| increased elimination - it might allow an organims to be resistant to several drugs simultaneously |
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Term
| what are the 2 ways antimicrobial resistance is acquired |
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Definition
| spontaneous, or horizontal gene transfer |
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Term
| when is spontaneous mutation less likely to result in resistance |
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Definition
| when a drug has several different targets or multiple binding sites on a single target |
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Term
| what is combination therapy |
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Definition
| drugs that have a single point mutation-causing resistance, are paired with one or more drugs - chance of both simultaneously developing resitance is lower |
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Term
| what drug is typically used in combination |
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Definition
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Term
| how are genes encoding for resistance most commonly spread |
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Definition
| conjugative transfer of R plasmids |
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Term
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Definition
| plasmids that often carry several different resistance genes |
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Term
| what are (5) microorganims showing increasing antimicrobial resistance? |
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Definition
| enterococci, staphylococcus aureus, streptococcus pneumoniae, mycobacterium tuberculosis, enterobacteriaceae |
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Term
| what practices are needed to slow the resistance |
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Definition
| use narrow spectrum antibiotic medications as much as possible, reinforce compliance, patients need to comply with instructions, understand they won't cure viral diseases, keep antibiotics in animal feeds to a minimum |
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Term
| why is using antibiotics for viral illnesses problematic |
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Definition
| misuse causes more selection for antibiotic resistant bacteria in normal flora. Normal flora then become reservoirs for R plasmids & transfer genes to infection pathogen later |
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Term
| why is it difficult to find a target for selective toxicity in a virus |
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Definition
| because viruses rely almost exclusively on the host cell's metabolic machinery for replication |
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Term
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Definition
| cell walls, ribosomes, or any other structure targeted by antibiotics |
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Term
| what are potential targets for antiviral drugs |
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Definition
| polymerases - many viruses encode their own |
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Term
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Definition
| drugs that interfere with viral replication |
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Term
| are there any broad spectrum antiviral agents? |
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Definition
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Term
| mechanisms of action of viral agents - targeted processes (need to know?) |
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Definition
| inhibit entry, viral uncoating disrupted, nucleic acid synthesis disrupted, integrase inhibitors, assembly & release of viral particles |
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Term
| which mechanism is used by most effective antiviral drugs |
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Definition
| interfering with nucleic acid synthesis - primarily herpesviruses and HIV |
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Term
| do these drugs cure latent viral infections |
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Definition
| no - they shorten the active infection only, latent viruses can still reactivate and cause symptoms to occur later |
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Term
| what do fungi resemble more closely human cells or bacteria |
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Definition
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Term
| why are there relatively few antifungal agents that are well tolerated in humans |
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Definition
| eukaryotic pathogens (such as fungi) more closely resemble human cells, so hard to find targets that don't harm host |
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Term
| what is the target of most antifungal drugs |
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Definition
| ergosterol - found in plasma membrane of fungal, but not human cells |
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Term
| targets (4) of antifungal drugs - need to know? |
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Definition
| cell division, plasma membrane, nucleic acid synthesis, cell wall synthesis |
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Term
| what do polyenes affect and what produces them |
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Definition
| fungal plasma membrane, produced by Streptomyces (Nystatin is an example) |
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Term
| what do most antiparasitic drugs do |
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Definition
| interfere with biosynthetic pathways of parasites or neuromuscular function of worms |
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Term
| why are they not well understood |
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Definition
| little research because primarily effect poorer areas of the world, can't afford research |
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Term
| what is metronidazole also used to treat |
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Definition
| infection by anaerobic bacteria |
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