Lecture 14 3/21/24 Flashcards
What are the general characteristics of chloramphenicol?
-binds to 50S ribosome
-bacteriostatic
-broad spectrum
-useful for protozoal and intracellular infections
What is the spectrum of chloramphenicol?
-high susceptibility of aerobic and anaerobic bact.
-some susceptibility of FAs
Which bacteria are resistant to chloramphenicol?
-some MRSA
-some MRSP
-some Enterobacter spp.
-Pseudomonas aeruginosa
-E. coli
What are the characteristics of chloramphenicol pharmacokinetics?
-high lipophilicity
-good oral absorption
-high volume of distribution
-eliminated via hepatic glucuronidation
-half-life varies with species
What is the main toxicity associated with chloramphenicol in people?
aplastic anemia
How does the development of aplastic anemia in humans exposed to chloramphenicol impact vet med?
chloramphenicol use in food animals is prohibited since the side effect is idiosyncratic instead of dose-related
Besides aplastic anemia, which other toxicities and drug interactions are associated with chloramphenicol?
-reversible, dose-related bone marrow depression
-adverse GI effects
-microsomal enzyme inhibition
-antagonization of bactericidal antibiotics
What are the characteristics of chloramphenicol clinical applications?
-banned in food animals
-few primary indications
-anaerobic infections
-serious ocular infections
-prostatitis
-otitis
-salmonellosis
What are the general characteristics of florfenicol?
-high volume of distribution
-long acting
-bacteriostatic
-combo products available
What are the clinical applications of florfenicol?
-less risk of aplastic anemia; used in food animals
-resp. diseases in cattle
-Actinobacillus pneumonia in pigs
-bact. infections in fish
What are the general characteristics of macrolides?
-bind to bacterial 50S ribosome
-bacteriostatic
-several subgroups
What is the spectrum of macrolides?
-high susceptibility of most gram pos. bact, gram neg. aerobes, and most gram neg. anaerobes
-some susceptibility of gram pos. aerobe Enterococcus
-no susceptibility of gram neg. FAs or gram neg. anaerobe Bacteroides fragilis
Which bacteria are resistant to macrolides?
-some Enterobacter spp.
-Pseudomonas aeruginosa
-E. coli
-Klebsiella spp.
-Salmonella
-Proteus spp.
What are the characteristics of macrolides pharmacokinetics?
-lipid soluble
-good oral absorption
-hepatic metabolism and biliary excretion
-well distributed/high vol. of dist.
-lung conc. greater than those in plasma
What are the characteristics of macrolide toxicity and adverse effects?
-relatively non-toxic
-tilmicosin is cardiotoxic and potentially fatal
-erythromycin and tylosin can be painful IM and cause GI upset
-can cause fatal intestinal flora disturbances in horses
What are the clinical uses of erythromycin?
-used with rifampin for Rhodococcus pneumonia in foals
-prokinetic/moves GI tract along
What are the clinical uses of tylosin?
-gram pos. aerobes and Mycoplasma in small animals (IM)
-inflammatory bowel disease in dogs (PO)
What are the clinical uses of tilmicosin/tulathromycin/gamithromycin/tildipirosin?
-bovine resp. disease
-resp. infection in pigs
What are the characteristics of tilmicosin use?
-injection is labelled for resp. infections in cattle and sheep
-inj. used extralabel in rabbits
-oral is labelled for resp. disease in pigs
-injections in horses, swine, goats, primates can be fatal
What are the characteristics of azithromycin/clarithromycin clinical use?
-high tissue distribution
-used for gram pos., gram neg., intracellular, and parasitic infections
What are the characteristics of rifampin?
-effective against gram pos. and several gram neg.
-bacteriostatic alone, bactericidal in combo.
-very lipophilic
-used to treat Rhodococcus equi
-fast development of resistance
What are the characteristics of lincosamides?
-bind to bacterial 50S ribosome
-bacteriostatic
-lipophilic
-well absorbed
-approved use in small animal, pigs, cows
What is the spectrum for lincosamides?
-high susceptibility of gram pos. anaerobes
-decent susceptibility of gram pos. aerobes, gram pos. FAs, and gram neg. anaerobes
-no susceptibility of gram neg. aerobes or FAs
Which bacteria exhibit resistance to lincosamides?
-Enterococcus faecalis
-Enterococcus faecium
-some B. fragilis
