Pharm - Antimicrobial Intro Flashcards
define antibiotic
molecule that kills OR stops (arrests)growth of bacteria
further classify “chemotherapeutics”
includes anticancer and antimicrobials
antimicrobials include antibiotics, as well as anti viral, antifungal, anti parasite
true or false
antibiotics are SPECIFICALLY antibacteria
true
true or false
antimicrobials include solely antibiotics
FALSE
also antifungals, anti parasites, etc
name 5 bacterial/fungal/viral targets
enzymes
DNA synthesis
metabolism
cell wall
ribosome
what are the methods of DNA synthesis in bacteria
could be chromosomal or plasmid
true or false
humans and bacteria have relatively the same enzymes
false - different
that’s why they can be a target for antibiotics
why is it important to design antibiotics to target bacterial-specific features
to limit human toxicity
we don’t want to target and kill/suppress growth of our own cells
name 3 things that can be a “reservoir” for the causative agent (bacteria/fungus/virus)
animal
plant
inanimate object (fomite)
name 4 ways the causative agent can exit the reservoir
blood
intestinal tract
respiratory tract
skin
name 3 things that make a host susceptible to infection
age
chronic illness
immunocompromised
what is the “vector” mode of transmission
through animals/insects
name 5 “portals of entry” for the causative agent
blood
intestinal tract
respiratory tract
non-intact skin
mucous membranes
what is antimicrobial susceptibility testing
you obtain a specimen from the patient and check its susceptibility to various antimicrobial agents to see which antibiotic will work for the infeciton
involved with antimicrobial stewardship to prevent resistance. want to choose the correct drug
explain what “MIC” and “MBC” are
MIC = minimum inhibitory concentration. it is the lowest concentration of the medicinal agent that prevents visible growth
MBC = minimum bactericidal concentration. same concept, this term is just used if the antibiotic is bacterioCIDAL and not static
name 3 methods of susceptibility testing
broth/agar dilution
disk diffusion (kirby-bauer method)
gradient diffusion (Etest)
who defines the 3 methods of antimicrobial susceptibility testing
USp
what is “ZOI”
used in disk diffusion/Kirby-Bauer test of antimicrobial suceptibility
refers to the diameter of the “clear” area around the antimicrobial disk in which the antibiotic was killed/growth was inhibited
Drug A has large ZOI
Drug B has small ZOI
which drug is better suited for the patient’s infection
Drug A
explain the specializes assay for seeing if a patient has beta lactamase, and thus resistance to beta lactams
uses a chromogenic beta lactam substrate
if the beta lactam ring is cleaved and the pt does in fact have beta lactamase, the cells will turn BLUE. if not, they will be green as the molecule is still intact
explain how you can use a specialized assay to test for MRSA (methicillin resistant staph aureus)
PBP2 exists in a patient in which staph aureus is susceptible to methicillin
however, in MRSA, this protein is instead a LOW AFFINITY PBP – called 2’ (2a) or PBP2’ (PBP2a)
this is extracted from MRSA and mixed with a latex reagant + a monoclonal antibody against PBP2a. If CLUMPS FORM, it indicates MRSA
which antigen is used to diagnose strep throat
Strep A ohydrate antigen
name 3 different ways in which antibiotics can be classified
-the class and spectrum of the microorganism it kills
-the biochemical pathway it interferes with
-the chemical structure of its pharmacophore
as mentioned, 1 way antibiotics can be classified as as the “class and spectrum” of the microorganism it kills
give an example
antibacterial broad spectrum
or
antibacterial gram positive/negative
how can antibiotics be classified based on the “biochemical pathway it interferes with”
ie: protein synthesis inhibitor
how can antibiotics be classified based on the “chemical structure” of its pharmacophore
ie: beta lactam antibacterial or aminoglycoside or glycopeptide
true or false
there are MANY biochemical processes of bacteria that antibiotics can interfere with
true
differentiate between bactericidal and bacteriostatic antibiotics
bactericidal - has direct action on bacteria and kills/lyses them
bacteriostatic - does NOT directly kill, but inhibits growth/reproduction, but doesn’t directly kill
they essentially slow the growth of bacteria so that the IMMUNE SYSTEM can destroy/kill them
explain HOW bactericidal antibiotics kill the bacteria
they target biochemical pathways involved in assembling the CELL WALL
the result is that the bacteria produce a cell wall which is either missing components or has altered components. as they continue dividing and reproducing, each division has a weaker and weaker cell wall
eventually, the integrity fails and the cells lyse and the bacteria die
explain in which patients bactericidal antibiotics are important in and why
immunocompromised people (ie: HIV) and for certain infections like meningitis
generally, we want to kill them ALL to prevent a relapse, but there are some exceptions
true or false
it is always better to give a bactericidal antibiotic rather than bacteriostatic
FALSE - not always the case
there are many factors involved
bactericidal antibiotics can further be divided based on ______
pharmacokinetics
can be concentration-dependent kill or time-dependent kill
in general, bactericidal antibiotics that use TIME-DEPENDENT KILL mechanism are mostly…
involved with affecting the cell wall
in general, bactericidal antibiotics that use concentration-dependent kill mechanism are mostly..
protein synthesis inhibitors/nucleic acid synthesis inhibitors
name 2 classes that are bacterical - concentration-dependent kill and include their MOA
aminoglycosides - protein synthesis inhibitors
quinolones - nucleic acid synthesis inhibitors
name 2 bactericidal antibiotic classes that use time-dependent kill mechanism
beta lactams and vancomycin
bacteriostatic antibiotics tend to inhibit what bacterial mechanism
protein synthesis inhibitors mainly, and some nucleic acid synthesis inhibitors
what is a concern with bacteriostatic patients, mainly in immunocompromised patients or bacteria who cause certain deadly diseases
there is a potential for relapse - the effect may be reversible
fully classify vancomycin
bactericidal, time dependent kill
cell. inhibits synthesis of bacterial cell walls
macrolides
are they bacteriostatic or cidal?
bacteriostatic
sulfonamides - bacteriostatic or cidal
alone - they are static
however, they are mainly used in combination with trimethoprim, and this combination is bactercidal
aminoglycosides - fully classify
bactericidal protein synthesis inhibitor
an exception to the “bactericidal-cell wall” rule
true or false
vancomycin works through concentration dependent kill
false - time dependent
bacitracin is bacteriostatic or cidal
bactericidal
cloramphenicol is bacteriostatic or cidal
static
clindamycin is bacteriostatic or cidal
static
the beta lactam antibiotics are bacteriostatic or cidal
cidal
ethambutol is bacteriostatic or cidal
static
aminoglycosides are bacteriostatic or cidal
cidal
trimethoprim (on its own) is bacteriostatic or cidal
static
(in combo with sulfonamides = cidal)
polymyxins - bacteriostatic or cidal
cidal
rifampin - bacteriostatic or cidal
cidal
tigecycline - bacteriostatic or cidal
static
glycopeptide antibiotics - static or cidal
cidal
quinolones - static or cidal
cidal
macrolides - static or cidal
static
daptomycin - static or cidal
cidal
isoniazid - static or cidal
cidal
metronidazole - static or cidal
cidal
tetracyclines - static or cidal
static
ketolides - static or cidal
cidal
pyrazinamide - static or cidal
cidal
nitrofurantoin - static or cidal
cidal
oxazolidinones - static or cidal
static
streptogramins - static or cidal
cidal
in GENERAL, bacteriostatic agents are what biochemical class
protein synthesis inhibitors and nucleic acid synthesis inhibitors
a lot of the bactericidal agents are involved in what MOA
inhibiting cell wall synthesis
