PPT 3

Cards (41)

  • Bactericidal agents
    Kill bacteria
  • Bacteriostatic agents

    Arrest the growth of bacteria
  • Narrow-spectrum antimicrobial agents
    Target specific types of microorganisms
  • Broad-spectrum antimicrobial agents

    Target a wide range of microorganisms
  • Mechanisms of bacterial resistance to antimicrobial agents
    • Inactivation of the antimicrobial agent
    • Alteration of the antimicrobial target
    • Decreased uptake of the antimicrobial agent
    • Increased efflux of the antimicrobial agent
  • MRSA
    Methicillin-resistant Staphylococcus aureus
  • MRSE
    Methicillin-resistant Staphylococcus epidermidis
  • β-lactam ring
    Structural component of β-lactam antibiotics
  • β-lactam antibiotics
    Antibiotics that contain a β-lactam ring
  • β-lactamase
    Bacterial enzyme that destroys the β-lactam ring
  • Actions to help in the war against drug resistance
    • Prescribe antimicrobial agents judiciously
    • Avoid unnecessary use of antimicrobial agents
    • Ensure proper dosing and duration of antimicrobial therapy
    • Implement effective infection control measures
    • Develop new antimicrobial agents
    • Educate healthcare providers and the public about antimicrobial resistance
  • Empiric therapy
    Antimicrobial treatment initiated before the causative pathogen is identified
  • Factors considered before prescribing an antimicrobial agent
    • Suspected pathogen
    • Antimicrobial susceptibility patterns
    • Patient's medical history
    • Patient's age and weight
    • Severity of the infection
    • Potential for adverse effects
  • Undesirable effects of antimicrobial agents
    • Selection of resistant organisms
    • Allergic reactions
    • Toxicity
  • Superinfection
    Overgrowth of microorganisms that are resistant to the antimicrobial agent(s) being used
  • Diseases that can result from superinfections
    • Yeast vaginitis
    • Clostridium difficile infection
    • Antibiotic-associated diarrhea
  • Synergism
    Antimicrobial agents that work together to enhance their effectiveness
  • Antagonism
    Antimicrobial agents that work against each other, reducing their effectiveness
  • Paul Ehrlich, the Father of Chemotherapy, was a German chemist who began searching for "magic bullets" that would destroy bacteria without damaging normal body cells
  • Alexander Fleming invented the first antibiotic, penicillin
  • Penicillin and cephalosporins are produced by molds, while bacitracin, erythromycin, and chloramphenicol are produced by bacteria
  • Penicillin interferes with the synthesis and cross-linking of peptidoglycan, inhibiting cell wall synthesis
  • Penicillin does not destroy human cells because human cells do not have cell walls
  • Antiprotozoal agents are usually quite toxic to the host, either by interfering with DNA and RNA synthesis or by interfering with protozoal metabolism
  • The first antiviral agent effective against HIV was zidovudine (AZT), introduced in 1987
  • Superbugs are strains of bacteria, viruses, parasites and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause
  • MRSA and MRSE are resistant to all anti-staphylococcal drugs except vancomycin and one or two more recently developed drugs
  • Vancomycin-resistant Enterococcus spp. (VRE) are resistant to most anti-enterococcal drugs, including vancomycin
  • Multidrug-resistant M. tuberculosis (MDR-TB) is resistant to the two most effective first-line therapeutic drugs, isoniazid and rifampin
  • Selecting for resistant organisms is an undesirable effect of antimicrobial agents, where the resistant ones survive while the susceptible ones die
  • Penicillin G in low doses can sensitize patients prone to allergies, leading to severe reactions like anaphylactic shock or hives upon subsequent exposure
  • Cephalosporins are β-lactam drugs produced by molds that interfere with cell wall synthesis and are bactericidal
  • Tetracyclines are broad-spectrum, bacteriostatic drugs that inhibit the 30S ribosomal subunit, hindering the binding of aminoacyl-tRNA
  • Aminoglycosides are broad-spectrum, bactericidal drugs that inhibit protein synthesis and are effective against aerobic Gram-negative bacteria
  • Macrolides are bacteriostatic at lower doses but bactericidal at higher doses, inhibiting protein synthesis
  • Fluoroquinolones are bactericidal drugs that inhibit DNA synthesis
  • Multidrug therapy is used when a single antimicrobial agent is not sufficient to destroy all the pathogens, with two or more drugs used simultaneously
  • Mechanisms of action of antifungal agents
    • Binding with cell membrane sterols
    • Interfering with sterol synthesis
    • Blocking mitosis or nucleic acid synthesis
  • Many antimicrobial agents are toxic to humans, with some like chloramphenicol and streptomycin causing severe side effects
  • Superinfections are population explosions of microorganisms that are resistant to the antibiotic(s) being used