Term
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Definition
| tx of infectious diseases with specific chemical agents |
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Term
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Definition
| substances produced by microorganisms which suppress growth of other microorganisms |
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Term
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Definition
| an agent should be able to inhibit or destroy the pathogen without hamring the host |
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Term
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Definition
| penicillins, cephalosporins, aminoglycosides, vancomycin, aztreonam, impipenem, fluoroquinolones, metronidazole, polymyxins, quinupristin-dalfopristin, bacitracin |
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Term
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Definition
| erythromycin, clindamycin, tetracyclines, chloramphenicol, sulfonamides, trimethoprim, nitrofurantoin |
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Term
| Characteristics of Ideal Antibiotics |
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Definition
| selective toxicity, bactericidal instead of bacteriostatic, little to no resistance, broad spectrum of activity, NOT allergenic, causes serious adverse effects and toxic side effects, be able to penetrate site of infection, be stable & active in presence of plasma, fluids, or exudate, AND cost effective |
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Term
| penicillins, cephalosporins, vancomycin, bacitracin |
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Definition
| agents that inhibit synthesis of bacterial cell walls |
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Term
| polymyxin B, amphotericn B, nystatin |
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Definition
| agents taht alter cell membrane permeability |
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Term
| chloramphenicol, macrolides (erithromycin, azithromycin, clarithromycin, telithromycin), clindamycin, quinupristin/dalfopristin, linezolid |
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Definition
| agents that inhibit bacterial protein synthesis by affecting 50S subunit of ribosome |
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Term
| aminoglycosides (streptomycin, tobramycin, gentamicin, amikacin), tetracyclines (tetracycline, minocycline, doxycycline) |
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Definition
| inhibition of bacterial protein synthesis by affecting 30S subunit of ribosome |
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Term
| fluoroquinolones (ciprofloxacin, levofloxacin) |
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Definition
| agents that inhibit nucleic acid synthesis by inhibiting DNA gyrase |
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Term
| trimethoprim, sulfonamides |
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Definition
| metabolic analogs that block metabolic steps - folic acid synthesis |
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Term
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Definition
| when identity of infectious microbe is unknown, start with broad spectrum antibiotic or a combination of antibiotics |
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Term
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Definition
susceptibility of pt's bacterial isolate to various antibiotics is performed;
use Kirby-Bauer disc diffusion test, MIC determination, and MBC determination to make decisions on which antibiotic is better able to treat the bug |
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Term
| Minimum Inhibitory Concentration (MIC) |
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Definition
| minimal concentration of an antibiotic that prevents visible growth (bacteriostatic) |
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Term
| Minimum Bactericidal Concentration (MBC) |
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Definition
| minimum concentration of an antibiotic needed to kill the bacteria (99.9%) |
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Term
| Factors that cause Bacterial Resistance |
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Definition
| indiscriminate use; delay in optimal therapy; administering suboptimal dose; therapy during a dormant stage; inability of a drug to reach site of infection due to certain barriers; defective functional status of host defense mechanism; agricultural use of antibiotics in livestock animals |
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Term
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Definition
Mutation & Selection;
Genetic exchange - transduction, transformation, conjugation;
Decreased permeability of organism to drug; Inactivation of antibiotic by enzymes: beta-lactamases, acetylation, phosphorylation, adenylation;
Alterations to drug target site - penicillin binding proteins w/ altered affinity |
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Term
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Definition
| 4-fold or greater reduction in MIC or MBC when a drug combo is used versus when used alone; |
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Term
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Definition
| when >50% of MIC of each drug is needed to produce an inhibition of growth; occurs when bactericidal drug is given with bacteriostatic drug |
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Term
| Clinical Uses of Combination Antibiotics |
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Definition
1) tx of mixed bacterial infections;
2) empirical tx of severe infections when cause is unknown;
3) synergistic effect to produce more complete bactericidal effect - Ex) enterococcal endocarditis --> penicillin + aminoglycoside;
4) combined therapy to prevent emergence of resistant microorganisms |
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Term
| Prophylactic Use of Antibiotics |
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Definition
1) protect healthy individuals from infection by specific organisms - ex) prevent gonorrhea or syphilis;
2) prevention of recurrent dx in susceptible pts - ex) heart valve defects, frequent UTIs;
3) antimicrobial prophylaxis in surgical procedures (most common reason) |
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Term
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Definition
appearance of a new infection during chemotherapy for another infection;
Occur because:
1) therapeutic dose of antibiotic can inhibit growth of normal flora;
2) these resident bacteria normally inhibit growth of opportunistic bacteria;
3) Enterobacteriacea, Pseudomonas, & Candida or other fungi are most common cause |
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Term
| Increased risk of superinfection |
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Definition
1) broad spectrum antibiotics;
2) longer courses of antimicrobial therapy;
3) more common with oral administration of antibiotic |
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