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18 Cards in this Set
- Front
- Back
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what are the 4 major genera of microbes used to produce antibiotics?
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streptomyces, bacillus, penicillium, and cephalosporium
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what are the five properties of an ideal antibiotic agent?
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the drug should be low in toxicity to the host's cells while destroying or inhibiting the disease agent (selective toxicity), the drug should not induce hypersensitivity, the drug should be the narrowest spectrum to treat the clinical disease, the host should not destroy, neutralize, or excrete the drug until after the drug has performed its function (pharmacokinetics), the org should not readily become resistant to the drug
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what are the beta lactam antibiotics? aminoglycosides? peptides? lipopeptides?
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penicillins, cephalosporins, cefamycins, carbapenams, monobactrim. streptomycin, kanamycin, amikacin. bacitracin, vancomycin, polymyxin. daptomycin.
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in terms of viability and turbidity, what makes an antibiotic bacteriocidal?
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if viability decreases
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what is an example of synergistic antibiotic combo? antagonistic combo?
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penicillin and aminoglycoside. macrolide and clindamycin.
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define MIc and MBC.
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MIC is the minimum concentration of antibiotic that it takes to inhibit the growth of the organism. MBC is the lowest concentration that will kill 99.9% of the population
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what are two tests used to determine the MIC?
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disk diffusion (agar plate clear zone) and dilution test (use broth and see find the lowest concentration of clear solution)
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describe the D test disk diffusion.
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compares two antibiotics and results show if one antibiotic can influence the resistance of another thus a positive D shaped disk.
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what is an antibiogram.
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an in vitro antimicrobial susceptability profile for specefic organisms of a specefic population (hospital).
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compare and contrast the MIC and the MBC of bacteriocidal orgs. bacteriostatic orgs.
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cidal- each is similar. Static: the MBC is much higher than MIC
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describe the mechanisms of drug resistance by bacs and state which is the most common.
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modification of the target so that it is insensitive to an inhibitor but still functional. duplicate the target enzyme. prevent access to the target. depression of a metabolic activity that normally converts an inert agent into an active target. most common -- synthesis of enzymes that inactivate an antimicrobial agent or modify the agent to alter entry or binding to a target
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describe the mechanism of resistance to cephalosporins and penacillins. tetracycline? chloramphenicol? aminoglycosides? sulfonamides and trimethoprim? erythromycin and lincomycin? fluoroquinolones?
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B lactamase enzyme use or altered PBP's that do not bind the penicillins. interference with transport (efflux pump). detox the drug via acetylation of the hydroxyl group. enzymatic modification of drug via adenylation, phosphorylation, or acetylation. drug resistant replacement enzymes. methylation of 23S rRNA. altered gyrase/topoisomerase or use of efflux pump.
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what are the most common ways bacs BECOME drug resistant.
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inheritance NOT mutation... plasmids, transposons, integrons, conjugation, transformation and transduction. NOTE that antibiotics themselves increase exchange frequency
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what are the major antibiotic resistant bigs that are a problem now?
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MRSA (also resistant to oxacillin). VRE and VRS. Multiple antibiotic resistant gram neg bacilli. Multiple antibiotic resistant mycobacterium tuberculosis. Multi drug resistant Acinebacter baumannii (in Iraq) and linezolid RE. also have superbugs resistant to it all.
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what antibiotics may cause nephrotoxicity and ototoxicity?
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aminglycosides and amphotericin B
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what antibiotics may impair bone growth and are not recommended for pregnant women and children?
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fluoroquinolones and tetracyclines
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whatr antibiotic is known to suppress the bone marrow?
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choramphenicol
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how can antibiotics cause pseudomembranous colitis?
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they disrupt the normal flora of the GI and allow Clostridium difficle to overgrow
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