Eating habits - final Flashcards
Antibiotics (small)
Substance produced naturally in minute quantity by some microbes that has the potency to inhibit growth or kill other microorganisms.
Drug
an agent that affects physiology
Semisynthetic antibiotic
antimicrobial agent part synthesized in lab and part synthesized in microbe.
ex of semisynthetic (DAAM)
doxycycline, methcillin, ampicillin, amoxycillin
Synthetic drug
antimicrobial agent synthesized in laboratory.
ex of synthetic
Isoniazid, sulfa drugs
advantages of synthetic
more effective against gram negative, long lasting, easier to adminster
antibiotics - many available..
targets, some exclusive to microbes.
Inhibition of general metabolic pathways (anti-metabolites)
blocking synthesis of essential metabolites
plasma membrane
injury
targets cell wall
targets peptidoglycan
targets protein synthesis (ribs)
ribosomes (70S vs 80S). Tetracycline
targets nucleic acid (eskimo)
enzymes
Selective toxicity (what bacteria have that we don’t)
peptioglycan and 70s vs. 80s
harm the microbe without significant damage to the host - exploits some key aspects of physiology different from eukaryotes 1. bacterial cell have peptioglycan cell wall but we don’t have it. 2. bacterial cells have 70s we have 80s. - shouldn’t be influenced by food or disease status
Agent should be bio-available (what this bio class is not)
penetrate and non-toxic
- be able to penetrate host tissue and reach microbial colony - must be effective at low, non toxic concentration to host
Antibiotic action should be either…(static - standstill) and ex.
bacteriostatic or cidal (same thing) - these kill bacterial cells. ex. penicillin. these stop bacterial growth, then body defense cells are able to kill not get overwhelmed.
Stability
should be stable in body fluids and exhibit therapeutic effect; not degraded by stomach acids
Spectrum of activity (just spectrum)
drug action on various pathogen - varies, either broad or narrow spectrum
Broad spectrum
agent targets microbes from both taxonomic (gram + and gram -) groups of bacteria
Disadvantage - broad spectrum (super)
they disturb normal microflora - normal flora prevents pathogen colonization (competing for space, nutrients, attachment site) - cause super infection ; opens doors to transient pathogens
Narrow spectrum and ex. (the original)
when antimicrobial action is limited to few microbe sps Ex: Penicillin only affects Gram (+)ve bacterial cells
Tissue distribution differs…
differ re. metabolism and excretion of the drug
Half life
time it takes to eliminate one half of the original antibiotic dose in serum. - some antibiotics ( like penicillin - 6 hrs.) have short half life- additionally liver dysfunction / kidney disease, dose needs to be adjusted accordingly because associated with slow metabolism and excretion of the drug
Combination of antimicrobials…(work)
must exhibit some effect
Synergism and ex. (S)
two drugs given simultaneously, antimicrobial effect is greater than either given alone - given individually works poorly, but well if combined Ex: Streptomycin and penicillin / vancomycin together will weaken cell wall, easier for streptomycin to enter cell.
Antagonism and ex. (tetris)
two drugs when given simultaneously, their action interfere with each other Ex: Tetracycline ( bacteriostatic - slows growth) and penicillin ( bacteriocidal - kills), acts on growing cells, disrupting peptidoglycan)
Additive (add nothing)
drug combination that are neither antagonistic nor synergistic in action
Side effects should be…
minimal
Side effects (chic in class) and ex.
undesirable effects on the host - can limit clinical usefulness of an agent; can manifest as i. trigger of allergic reactions: e.g. penicillin allergy 300 deaths / year; with fever, rash and / or anaphylactic shock