Antimicrobial interfering bacterial protein synthesis Flashcards
quiz 1
What are the target bacterial ribosome for bacterial protein synthesis inhibitors?
- bacterial - 70s (50S/30S)
2. Mammalian - 80 S ( 60S/40S)
What are the 30S binders for inhibitors of bacterial protein synthesis ?
- Aminoglycosides
2. Tetraycyclines
what are the 50S binder for inhibitors of bacteria protein synthesis ?
- Macrolides
- Lincosamides
- Chloramphenicol and derivatives
what is the source for aminoglycoside ?
- streptomycin sp.
2. Micromonospora sp.
what are kinetics of amino glycoside ?
- Aminocyclitols
- basis polycation
- polar organic bases
- low lipid solubility
what are type of Aminoglycoside drugs?
- Streptomycin
- Neomycin
- Kanamycin
- Gentamicin
- Tobraymycin
- Apramycin
- Amikacin
- Paromomycin
what is the mechanism of action for aminoglycoside drugs?
- bactericidal
- penetration into bacterial cells- biphasic
- permeate susceptible bacteria
what are the phases in the mechanism of action for ahminoglycosides?
- passive diffusion ( concentr. dependent)
2. active transport ( O2 dependent )
What type of condition will inhibit transport of aminoglycoside ?
anaerobic conditions
what are the consequences of aminoglycosides binding irreversible to the receptor protein on 30S ribosomal subunit
- irreversible binids
- interfers w/ mRNA translation
- Non functional protein
- prevents initiation of DNA replication
- Irreversible lethal effects
What is the efficacy of aminoglycosides ?
type I - concentration dependent
-max [drug] = Max bactericidal action
what are characteristic of aminoglycosides?
- posses post - antibiotic effect
- single dose over 24 hrs
- administered long intervals
what are the antibacterial spectrum for aminoglycosides?
- gram - aerobic bacteria
2. Gram + aerobic bacteria
Can aminoglycosides be used to treat anaerobes ?
No
what are the most active aminoglycosides for treating gram - aerobic bacteria?
- Gentamicin
- tobramycin
- amikacin
what aminoglycoside is used to treat against few staphlococci sp. & mycobacterium sp. which are gram + aerobic bacteria?
Gentamicin
-parenteral
what are the antibacterial activity of aminoglycosides ?
- influenced by local environment pH
- Alkaline pH increases antimicrobial activity
- Acidic pH & presence of Ca & Mg cations decrease antimicrobial activity
what are the pharmacokinetics of absorption for aminoglycosides?
- Poor Oral absorption
- Parenteral : IM/SC/IV
- Eye/ear drops
Why does aminoglycosides have poor oral absorption ?
highly polar & cationic nature
What type of administration has rapid & good absorption in aminoglycosides?
- IM
- SC
100%
what type of administration has a bioavailability of 40%?
intrauterine administration
what are the pharmacokinetics of distribution of aminoglycosides?
- low diffusion across cell membrane
- low concentr. in specific areas of the body
- Restricted to extracellular space ; accumulates in tissue
- 20% Protein binding
- Selective binding to anionic cell membrane in specific areas of the body
- long w/drawal period
- increase distribution in lean cachectic animals
What areas of the body is the distribution of aminoglycosides have low concentration ?
- brain
- CSF
- ocular fluid
- respiratory secretion
what areas of the body is the distribution of aminoglycosides has selective binding to anionic cells membrane phospholipids which causes accumulation?
- Proximal renal tubules cells ( renal cortex)
2. Cochlear tissue ( inner ear)
what is the pharmacokinetics of metabolism in aminoglycosides ?
not biotransformed
what are the pharmacokinetics of excretion in aminoglycosides?
kidney
- glomerular filtration
What should be done w/ the dose of aminoglycosides if the animal has renal insufficiency ?
adjusted
what are the adverse effects of aminoglycosides ?
- Nephrotoxicity
- Ototoxicity
- Neuromuscular blockade
what type of toxicity is caused when aminoglycosides binds to basolateral membrane of renal proximal tubular epithelium to cause to acute tubular necrosis ?
Nephrotoxicity
What major condition can increase nephrotoxicity in aminoglycosides?
dehydration
what is ototoxicity caused by aminoglycosides ?
- accumulates in perilymph & endolymph of inner ear
- can affect auditory
- can affect vestibular function
- irreversible toxicity
what animal can you see ototoxicity that will affect the auditory ?
dogs
what animal can you see ototoxicity that will affect the vestibular function ?
cats
How can neuromuscular blockade toxicity by aminoglycosides be caused ?
rapid IV bolus administration
what is neuromuscular blockade toxicity that is cause by aminiglycosides?
- curare - like (non-depolarizing)
2. Respiratory arrest
what are the types of bacterial resistance to aminoglycosides?
- enzymatic inactivatyion
- ribosomal alteration
- reduced permeability of antibiotic
How can the bacteria cause enzymatic inactivation of aminoglycosides ?
acquires gene encoding enzymes
-inactivates antibiotics
what is the source for streptomycin?
streptomyces griseus
what is the source for gentamicin?
micromonospora purpurea
what is the source for Apramycin & tobramycin?
streptomyces tenebrarius
what aminoglycoside can be added to the water or feed for pigs?
Apramycin
what aminoglycosides can be used in small animals to treat P. aeruginosa?
Tobramycin
what is the source for Neomycin?
Streptomyces fraidiae (sulfated)
How can Neomycin be administered ?
- oral
2. Topical
what is the source for amikacin?
semi-synthetic derived from kanamycin
-given parenteral
what aminoglycosides is broad spectrum that can be used for treating gram + , gram - & protozoal?
Paromomycin
what protozoa can paromomycin treat ?
- Giardia
2. entamoeba
what is the source for parmomycin?
- streptomyces ramous var. paromomycin
what is the source for tetracycline ?
streptomyces sp.
but now produced by hydrogenolysis of chlortetracycline
what are the kinetics for tetracycline ?
- broad spectrum
- bacteriostatic
- acidic & hygroscopic compound
- hydrochloride formation to increase stability
what are the 2 categories of tetracycline dugs ?
- natural
2. semisynthetic
what are the natural tetracycline drugs?
- chlortetracycline
- tetracycline
- oxytetracycline
what is the source of chlortetracycline ?
streptomyces aureofaciens
what is the source of oxytetracycline?
streptomyces rimosus
what are the semisynthetic tetracycline drugs?
- minocycline
2. doxycycline
what is the mechanism of action for tetracycline ?
- penetration into bacterial cells
2. drug concentration in susceptible bacteria
How does tetracycline drugs penetrate into the bacterial cells ?
- passive diffusion
2. active transport
What is the mechanism of action for tetracycline in susceptible bacteria?
inhibits initiation step of DNA
- binds reversible to 30S ribosomal subunit
- blocks binding tRNA at acceptor site on mRNA-ribosomal complex
- inhibits new amino acids to peptide chains
what is the microbial susceptibility of tetracycline?
broad bacteriostatic action
- gram + aerobic bacteria
- gram - aerobic bacteria
- anaerobes
- spirochetes
- intracellular organism
- intracellular organism
- rickettsia
what species of gram + aerobic bacteria can be treated with tetracycline ?
- staphylococci
2. streptococci
what species of gram - aerobic bacteria can be treat with tetracycline ?
- E.coli
- klebsiella sp.
- pasteurella
- salmonella
what are the species of anaerobes that can be treat with tetracycline ?
- actinomycetes sp.
- clostridium sp.
- bactericides sp.
- fusobacterium sp.
what species of spirochete can be treated by tetracycline ?
leptospira sp.
what species of intracellular organism can be treated with tetracycline?
- Brucella
- Mycoplasma
- chlamydia sp.
what is the species of rickettsia that can be treated with tetracycline ?
- Ehrlichia sp.
- Anaplasma
- Haemobartonella
what is the drug of choice for treating Chlamydia psittaci in birds ?
Doxycycline
what’s the drug of choice for treating Equine monocytic Ehrlochiosis ?
Oxytetracylinie
what is the drug of choice for treating staphylococcus aureus ?
minocycline
Why is doxycycline administration important in heart worm infected dogs?
- sterilized female peartworms
- prevents infected dogs from infecting other dogs by mosquitoes
- improves heart worm adulticide treatment
- reduce inflammation & risk of serious adverse rxn to melarosmine drug
what is the pharmacokinetics of oral absorption for tetracycline ?
- well oral absorption
- absorption varies on formulation / species
- half life → 7- 19 hrs
- forms chelation complexes w/ divalent & trivalent cations
what tetracycline drug has complete absorption?
doxycycline
what is the pharmacokinetic of parenteral absorption for tetracycline ?
- oxytetracycline good absorption
- IM/IV for immediate release
- deep IM for long acting
what type of animals can be treated w/ ophthalmic oxytetracycline ?
- dogs
- cats
- cattle
- horses
what is the pharmacokinetics of distribution for tetracycline ?
- widely distributed
- lipid solubility
- binds to plasma proteins
what tetracycline drugs bind to plasma protein to have a prlonged 1/2 life ?
- doxycycline
- minocycline
- 80 & 90 % binding
what tetracycline drug has 18- 50% of binding to plasma proteins ?
oxytetracycline
What tetracycline drugs are the most lipid soluble ?
- minocycline
2. doxycycline
Where does tetracycline drugs accumulate in the body?
- liver
2. kidneys
where does minocycline and doxycycline penetrate in the body?
- brain
- spinal fluid
- bronchial fluid
- prostate
What are adverse effects of tetracycline drugs when they form chelate complexes w/. Ca?
- deposit in active sites of ossification in bone
2. developing teeth of young animals
what is the pharmacokinetics of metabolism in tetracycline?
very low except Minocycline & doxycycline
-oxidation in liver
What is the pharmacokinetics of excretion of tetracycline ?
- excreted in urine (about 60% of dose)- glomerular filtration
- excreted in feces (about 40%)
- undergoes enterophepatic circulation
what tetracycline is excreted in bile & by bile diffusion in to large intestine & excreted in feces?
Doxycycline
What type of patient is it preferred using doxycycline ?
renal function impaired patients
What are the adverse effects of tetracycline ?
- GI disturbances
- Esophageal lesions
- hepatotoxicity
- local irritaton
- collapse
- anaphylactic shock
- Photoxicity
what are the types of GI disturbances as adverse effects in tetracycline?
- vomiting
- anorexia
- diarrhea
What type of tetracycline will cause esophageal lesion in cats given oral adminstration?
doxycycline hyclate
What type of patients will you see Hepatoxicity as an adverse effect of tetracycline ?
Renal disease pt
What type of administration will you see local irritation as an adverse effect of tetracycline ?
IM injection
How does rapid IV injection cause collapse as an adverse effect of tetracycline ?
- Chelates Ca in blood
- decrease Ca availability for heart concretion
- collapse
what type of administration will cause anaphylactic shock in the dogs?
IV injection
What adverse effect will doxycycline cause in horses when given IV?
cardiac arrhythmia ( fatal)
what adverse effect will oxytetracycline in horses when given orally?
alters commensal microflora → enteritis
what adverse effect will chronic administration or outdate products of tetracycline cause ?
Renal damage
what adverse effects will chelation of tetracycline to Ca deposit in teeth dentin?
tooth mottling
What type of animals will you see inhibit growth of long bones?
young animals
what animal can you see hypersensitivity & drug fever as an adverse effect of tetracycline?
Cats
What are the type of bacterial resistance for tetracycline?
- impaired permeation of drug
- Tetracycline efflux
- ribosomal alteration
what is the efficacy of tetracycline?
Type III antimicrobial
-time dependent killing kinetics w/ moderate persistent effects