Antibiotics I Flashcards
the bacterial cell wall is composed of what molecule?
peptidoglycan
what constitutes gram positivity of bacteria?
thick peptidoglycan wall
what constitutes gram negativity of bacteria?
thin peptidoglycan wall
what makes up the outer membrane structure of gram negative bacteria?
LPS
LPS makes up the outer membrane structures of gram negative or gram positive bacteria?
gram negative
what is the effect of LPS on antibiotics?
retards or prevents penetration of bulky, high MW abx (eg erythromycin)
what is the effect of the lipid bilayer of the cytoplasmic membrane on antibiotics?
severely hinders penetration of water soluble drugs
what component of bacteria retards or prevents penetration of bulky, high MW abx (eg erythromycin)? are these characteristic of gram negative or gram positive bacteria?
LPS
gram negative
what component of bacteria severely hinders penetration of water soluble drugs? are these characteristic of gram negative or gram positive bacteria?
lipid bilayer of the cytoplasmic membrane
gram negative AND gram positive
what is the effect of hydrophilic pores on antibiotics?
allow penetration of water soluble molecules up to 650 daltons (eg sulfonamides)
what components of bacteria allow penetration of water soluble molecules up to 650 daltons (eg sulfonamides)? are these characteristic of gram negative or gram positive bacteria?
hydrophilic pores
gram negative
what components of bacteria are used by agents structurally related to nutrients? are these characteristic of gram negative or gram positive bacteria?
nutrient receptor proteins on outer membrane
gram negative
what is the effect of nutrient receptor proteins on the outer membrane?
agents structurally related to nutrients use these receptors
what is the effect of teichoic acid and teichuronic acid on antibiotics?
strong anion character affects rate of penetration
what component of bacteria affects rate of penetration? are these characteristic of gram negative or gram positive bacteria?
teichoic acid and teichuronic acid
gram positive
what is the effect of nutrient transport proteins of the cytoplasmic membrane?
facilitate rapid penetration of agents similar in structure
what components of bacteria facilitate rapid penetration of agents similar in structure?
nutrient transport proteins of the cytoplasmic membrane
what are the three common strategies for killing or inhibiting microorganism growth?
- disrupt coding / genetic machinery
- blocking protein synthesis
- disrupting cell wall or membrane synthesis
prophylactic therapy
treatment in absence of infection in order to prevent (eg travel)
preemptive therapy
treatment of high risk patients who have become infected but are asymptomatic
empirical therapy
treatment of SYMPTOMATIC patient without further testing or confirmation of organism
definitive therapy
treatment once pathogenic organism has been identified and appropriate drug identified
suppressive therapy
generally a low dose therapy used as secondary prophylaxis
treatment in absence of infection in order to prevent (eg travel)
prophylactic therapy
treatment of high risk patients who have become infected but are asymptomatic
preemptive therapy
treatment of SYMPTOMATIC patient without further testing or confirmation of organism
empirical therapy
treatment once pathogenic organism has been identified and appropriate drug identified
definitive therapy
generally a low dose therapy used as secondary prophylaxis
suppressive therapy
what are the most common drug resistant bacteria?
ESKAPE
enterococcus faecium staph aureus klebsiella pneumo acinetobacter baumanni pseudomonas aeruginosa enterobacter species
what is the therapeutic use for daptomycin?
complicated skin infections
bacteremia
endocarditis
what is a common way to overcome tetracycline sensitivity?
expression of reflux pump
what gene mutation results in daptomycin resistance? what is the result?
mprF
change in membrane charge - overall net positive charge repels antibiotics that have cationic properties
what are the therapeutic uses for tetracycline?
BSA for acne, bronchitis, gonorrhea, syphilis
what are the common organisms that are resistant to tetracycline?
neisseria gonorrhoeae
e. coli
strep pneumo
pseudomonas aeruginosa
what are the therapeutic uses for metronidazole?
abdominal infections
vaginitis
c. diff colitis
brain abscess
what is the mechanism of resistance for metronidazole?
mutation of rdxA gene alters or decreases activation of drug (no longer becomes reduced for activation)
what are the therapeutic uses for aminoglycosides (streptomycin)?
combination therapy for endocarditis, tularemia, plague, TB
what is the mechanism of resistance for aminoglycosides?
aminoglycoside modifying enzymes chemically modify the antibiotic and alter binding of drug to target
what are the therapeutic uses for amoxicillin?
BSA for a variety of infections
what is the mechanism of resistance for amoxicillin?
expression of beta lactamase which can hydrolyze the lactam ring of amoxicillin (and other penicillins and cephalosporins)
what are the therapeutic uses for trimethoprim and sulfonamides?
combination for UTIs
what is the mechanism of resistance for trimethoprim and sulfonamides?
expression of drug resistant enzymes dihydropteroate synthase and DHFR
what are the therapeutic uses for vancomycin?
bloodstream infections
endocarditis
meningitis
what is the mechanism of resistance for vancomycin?
substitution on peptidoglycan stem so that agent can no longer bind to target
