infectious disease 2 Flashcards
(64 cards)
what is a single celled microorganisms with well defined cell walls that can grow independently on artificial media without the need for other cells?
bacteria
what are spherical bacterial cells called?
cocci
what are rod shaped bacteria called?
bacilli
what are spiral shaped bacteria called?
spirilla or spirochetes
what are the characteristics that bacteria is classified by?
response to staining (gram positive, gram negative, or acid fast
motility (motile or nonmotile)
tendency toward capsulation (encapsulated or non-encapsulated)
capacity to form spores (sporulating or nonsporulating)
aerobic: oxygen is needed to replicate and develop
anaerobic: they can sustain life in an oxygen poor (anaerobic)
what are the four main characteristics of bacterial structure and function?
- unicellular microorganisms
- a rigid cell wall that surrounds the bacterial cell
- lack of a true nuclear membrane
- require nourishing medium to provide metabolic substrates to maintain function
what is gangrene?
the death of body tissue usually associated with loss of vascular supply and followed by bacterial invasion and putrefaction
what are the three main types of gangrene?
dry, moist, and gas gangrene
what do the dry and moist forms of gangrene result from?
loss of blood circulation
what causes gas gangrene?
wounds infected by anaerobic bacteria, leading to gas production and tissue breakdown
what are drugs that typically kill or destroy bacteria?
bactericidal
what are drugs that do not actually kill bacteria but limit their growth and proliferation?
bacteriostatic
what does the classification of bactericidal vs. bacteriostatic activity depend on?
drug dosage
what are the three basic mechanisms of antibacterial drugs?
- inhibition of bacterial cell wall synthesis and function
- inhibition of bacterial protein synthesis
- inhibition of bacterial DNA/RNA synthesis and function
what are three mechanisms of action for inhibition of bacterial cell wall synthesis and function?
- drugs cause INADEQUATE production of peptidoglycans within the cell wall
- drugs PUNCH HOLES in the bacterial cell membrane, destroying the selective permeability and separation of internal and external environment
- drugs acts as DETERGENTS that break apart the phospholipid bilayer, creating gaps and leaks in the bacterial cell membrane
what happens when antibacterial drugs bind to the bacterial ribosome?
blocks protein synthesis or causes the ribosome to misread the messenger RNA (mRNA) code which results to the production of meaningless proteins
what serves as an enzymatic cofactor in several reactions, including synthesis of bacterial nucleic acids and certain essential amino acids?
folic acid
how do drugs inhibit bacterial DNA/RNA synthesis and function?
drugs inhibit bacterial nucleic acid synthesis by inhibiting the production of folic acid
how do bacterial strains survive the effects of drugs?
certain bacterial strains have a natural defense against specific anti-bacterial drugs which allows them to become resistant
they continue to GROW and REPRODUCE similar resistant strains, thus representing a genetic selection process in which only the resistant strains survive the drug
what is antibiotic stewardship?
antibacterial drugs should be used carefully and not overused
how do you control the problem of bacterial resistance?
identify the specific pathogenic bacterial and administer a selective agent as opposed to broad spectrum antibiotics to kill resistant strains more effectively
what are some common side effects of antibacterial drugs?
hypersensitivity reactions (skin rashes, itching, and respiratory difficulty)
GI problems (nausea, vomiting, or diarrhea)
true or false: viruses are completely dependent on host cells and cannot replicate unless they invade a host cell and stimulate it to participate in the formation of additional virus particles
true
what can you use to mitigate the course of the viral illness? and what can you not use?
antiviral medications
antibiotics
