Antibiotics

    Cards (67)

    • Meuller-hinton Agar
      It is the standard susceptibility medium for non fastidious organisms.
    • Meuller-hinton agar
      Recommended due to low concentration of sulfonamide, trimethoprim and tetracycline inhibitor.
    • Antimicrobials
      Chemical substances produced by a microorganism with the capacity to inhibit other microorganisms.
    • Antimicrobials
      Destroy/kill the organism.
    • Narrow spectrum
      Effective against a limited number of pathogens
    • (PIGBEDCV) - Polymyxin B, isoniazid, gentamicin, Bacitracin, erythromycin, dapsone, clindamycin, and vancomycin.
    • Broad spectrum
      Destroy different kinds of organism.
    • (CARST) - Cephalosporin, chloramphenicol, ciprofloxacin, Ampicillin, rifampicin, sulfonamines, trimethoprim and tetracycline
    • Natural drugs
      Produced by bacteria or fungi.
    • Semisynthetic drugs
      Chemically modified natural drugs with added extra chemical groups.
    • Synthetic drugs
      Chemically produced drugs.
    • What classification of drugs is griseofulvin?
      Natural drugs
    • What classification pf drugs does carbenicillin belongs to?
      Semisynthetic drugs
    • What classification of drugs does dapsone belongs to?

      Synthetic drugs
    • Chloramphenicol, dapsone, erythromycin, clindamycin, isoniazid, rifampicin, sulfonamides and tetracyclines.
      Bacteriostatic agents
    • Minimal inhibitory concentration \

      Is the lowest concentration of a drug that inhibits bacterial growth.
    • Minimal lethal concentration
      Is the lowest concentration of drug that kills bacterial growth.
    • Therapeutic index
      Is the ratio of the toxic dose to the therapeutic dose.
    • Cloxacilin, dicloxacillin, mehcillin, nafcillin, oxacillin
      Beta lactamase resistant penicillin
    • Pen G
      inactivated by stomach acids
    • Penicillin V
      acid resistant (orally)
    • Ampicillin
      acid stable, effective for G+, G
    • Vancomycin
      cup shaped molecule drug; teicoplanin drug
    • Carbenicillin
      acid stable, Pseudomonas and Proteus
    • 30’S Ribosomes InhibitorsTetracycline - BACTERIOSTATIC ❖ Aminoglycosides - BACTERICIDAL
    • 50’s Ribosomes InhibitorsChloramphenicol - BACTERIOSTATIC ❖ Macrolide o Erythromycin - BACTERIOSTATIC OR CIDAL o Clindamycin - BACTERIOSTATIC OR CIDAL o Lincomycin
    • High dosage of tetracycline may lead to live and kidney damage and yellowing the teeth of children.
    • Chloramphenicol may cause temporary or permanent depression of bone marrow leading to aplastic anemia and leukemia (toxic side effect)
    • Aminoglycosides - Gentamicin, kanamycin, neomycin, streptomycin and tobramycin, they have cyclohexane ring and may cause deafness and loss of balance (toxic)
    • Chloramphenicol and erythromycin - bind to 23s rRNA on the 50s ribosomal unit.
    • Sulfonamides
      inhibit Folic acid metabolism, high there
    • Trimethoprim
      blocks tetrahydrofolate synthesis
    • Dapsone
      interferes with F.A. synthesis.
    • Intrinsic resistance
      Lack specific target site
    • Extrinisic resistance
      Cannot bind to bacterial cell
    • TEST TUBE DILUTION/ BROTH DILUTION METHOD
      Challenging the organisms of interest with antimicrobial agents in a broth.
    • Standard inoculum size of test tube dilution method / broth dilution method?
      5 x 105 CFU/ml
    • Broth volume of Microdilution?0.05-0.1 ml
    • Macrodilution Broth volume: 10 ml or greater
    • The lowest conc. of the antibiotic without bacterial growth after 16 to 24 hours of incubation is the MIC.