Microbio chp 20

Cards (60)

  • acquired resistance

    resistance that develops due to genetic changes, including mutation and horizontal gene transfer
  • antibiotic
    a compound naturally produced by molds or bacteria that inhibits the growth of or kills other microorganisms
  • antimicrobial medication

    an antibiotic or other chemical that acts by inhibiting or killing microorganisms and is used to treat an infectious disease; also called an antimicrobial drug
  • antiviral medication

    a chemical that acts by interfering with the infection cycle of a virus and is used to treat a viral infection; also called an antiviral drug
  • broad-spectrum antimicrobial

    an antimicrobial medication that is effective against a wide range of microorganisms, often including both Gram-positive and Gram-negative bacteria
  • chemotherapeutic agent

    a chemical used to treat disease
  • intrinsic resistance

    resistance due to inherent characteristics of the organism
  • narrow-spectrum antimicrobial

    an antimicrobial medication that is effective against a limited range of microorganisms
  • R plasmid
    a plasmid that encodes resistance to one or more antimicrobial medications
  • selective toxicity

    the substance causes greater harm to the microbes than to the human host
  • therapeutic index

    the lowest dose toxic to the patient divided by the dose typically used for therapy
  • narrow spectrum antimicrobials

    affect a narrow range of bacteria and are therefore less disruptive to normal flora
  • antagonistic
    counteracting combinations
  • synergistic
    combinations in which the activity of one medication enhances the activity of the other
  • additive
    combinations that are neither synergistic or antagonistic
  • dysbiosis
    an imbalance in the microbial population
  • B-lactam antibiotics

    penicillins, cephalosporins, carbapenems, and monobactams; have a shared structure
  • penicillin binding proteins (PCBs)

    a group of enzymes that catalyze the formation of peptide bridges between NAM molecules on the chains
  • natural penicillins

    narrow-spectrum antibiotics, effective against Gram positive and a few gram negative bacteria. Bacterias that produce penilcilinase are resitant
  • penicillinase-resistant penicillins
    include methicillin and dicloxacillin.
  • broad-spectrum penicillins

    active against penicillin-sensitive gram positive bacteria and also active against many gram negative bacteria. include ampicillin and amoxicillin
  • extended-spectrum penicillins

    greater activity against most of the Enterobacteria as well as Pseudomonas aeruginosa. Have less activity against gram positive bacteria. Include ticarcillin and piperacillin
  • penicillins + B-lactamase inhibitor

    a combination of agents. An example is Augementin, a combination of amoxicillin and clavulanic acid
  • cephalosporins
    structure protects them against certain B-lactamases. Some are not very effective against Gram-positive bacteria, because the antibiotics have a low affinity for their PBPs.
  • carbapenems
    effective against a wide range of gram negative and gram positive bacteria. not inactivated by the extended spectrum B-lactamases produced by certain gram negative bacteria, usually reserved as a last resort treatment. include imipenem, ertapenem, meropenem, and doripenem. There are bacteria that are resistant to these and almost all other medications
  • monobactam
    primarily effective against Enterobacteriaceae. only azetreonam. bacteria that produce B-lactamases or certain carbapenemases are resistant
  • glycopeptide antibiotics

    interfere with petidoglycan synthesis by binding to the amino side chain of NAM molecules, blocking the formation of cross-links between adjacent glycan chains. Affective only against gram positive bacteria. low therapeutic index. includes vancomycin and telavancin
  • bacitracin
    inhibits cell wall biosynthesis by interferring with the transport of peptidoglycan precursors across the cytoplasmic membrane. its toxicity limits it to topical use.
  • aminoglycosides
    bacterial antibiotics that irreversibly bind to the 30S ribosomal subunit causing it to distort and malfunction. Can cause severe side effects including damage to the inner ear and the kidney. Generally not effective against anaerobes, enerococci, and streptococci because they enter the cell during respiratory metabolism. sometimes used synergistically with penicillin. Include streptomycin, gentamycin, tobramycin, and neomycin
  • tetracyclines
    reversibly bind to the 30S ribosomal subunit blocking the attachment of tRNA and preventing translation from continuing. effective against certain Gram-positive and gram negative bacteria. has a long half life. includes doxycycline
  • glycylcyclines
    a wider spectrum of activity than tertracyclins. effective against many bacteria that have developed resistance to the tetracyclines. example is tigecycline
  • macrolide
    reversibly bind to the 50S ribosomal subunit and prevent the continuation of translation. medication of choice for patients allergic to penicillins, bacteriostatic against many gram positive bacteria, but do not pass through the outer membrane of gram negative bacteria. include erythromycin, clarithromycin, and azithromycin.
  • chloramphenicol
    binds to the 50S ribosomal subunit, preventing peptide bonds from being formed and blocking translation. bacteriostatic. active against a wide range of bacteria, but used as a last resort due to a rare but lethal side effect, aplastic anemia.
  • lincosamides
    bind to the 50S ribosomal subunit and prevents contiuation of translation, bacteriostatic. Inhibit a variety of gram negative and gram positive bacteria. example is clindamycin
  • oxazolidinones
    bind to the 50S ribosomal subunit, interferring with the initiation of translation. example linezoid. bacteriostatic against gram positive bacteria, useful against bacteria resistant to B-lactam antibiotics and vancomycin
  • pleuromutilins
    bind to the 50S ribosomal subunit, preventing peptide bonds from being formed during translation. active against many gram positive bacteria. topical use
  • streptogramins
    bind to the 50S ribosomal subunit. effective against a variety of gram-positive bacteria, generally reserved. Synercid consists of quinupristin and dalfopristin which work syngeristically to be bactericidal
  • fluoroquinolones
    synthetic compounds that inhibit one or more group of enzymes called topoisomerases, which maintain the supercoiling of DNA. Bactericidal against a wide variety of bacteria including gram positive and gram negative. examples include ciprofloxacin and moxifloxicin
  • rifamycins
    antibiotics that block bactericidal RNA polymerase from initiating transcription.bactericidal against many gram positive and some gram negative bacteria as well as members of the genus mycobacterium. example rifampin
  • metronidazole
    a synthetic compound that interferes with DNA synthesis and function, but only in anaerobic microorganisms, since anaerobic metabolism is required to activate it. Once active it binds DNA, interfering with synthesis and causing damaging breaks.