Infectious Disease Flashcards
(201 cards)
Cell cultures with mixed infections of feline calicivirus and feline herpesvirus can sometimes result in feline herpesvirus outgrowing feline calicivirus, resulting in only FHV. T/F?
False - it is other way around (feline calici can outgrow FHV)
Timeline for blood cultures for:
- acute febrile illness
- acute endocarditis
- nonacute disease
acute febrile illness: two sets from separate sites, all within 10 minutes. +/- third set
acute endocarditis: 3 sets from 3 separate sites, within 1-2 hours
nonacute disease: 3 sets from separate sites within 24h, spaced at intervals of at least 3 hours
In animals with renal failure, concentration-dependent drugs that require renal clearance should be have reduced (dosage or dosing frequency).
Dosing frequency
Extended-spectrum beta-lactamase have only been described in what type of bacteria?
Gram negative bacilli (E coli, Klebsiella pneumoniae)
Dogs with liver disease require dosing adjustments with penicillins. T/F?
False (dosing interval extended with renal disease but hepatic impairment has little effect on pharmacokinetics)
How is cefpodoxime different than other third generation cephalosporins? (in terms of spectrum)
Most active against Staph, less active against gram negative and anaerobic infections
What is the benefit of adding cilastatin to imipenem?
Cilastatin inhibits dehydropeptidase-1 (brush border enzyme in renal tubules). Dehyropeptidase-1 degrades imipenem into nephrotoxic metabolite.
Meropenem is a good treatment option for methicillin resistant staph. T/F?
False = MRS are generally resistant to carbapenems.
Mechanism of action of beta-lactam antibiotics
Bind and inhibit penicillin binding proteins and inhibit cell wall biosynthesis
Mechanism of action of fluoroquinolones
Bind to DNA gyrase (topoisomerase II) and topoisomerase IV
Topoisomerase II is more common in gram positive/negative bacteria.
Negative; topoisomerase IV is more common in positive [and FQs has less affinity for topoisomerase IV, hence why FQs are better for gram negative)
Which fluoroquinolone has the highest activity against anaerobes?
Pradofloxacin
Rapid IV administration of fluoroquinolone can result in what?
Hypotension, tachycardia, and cutaneous erythema (suspected due to histamine release)
Cephalosporin and fluoroquinolones can cause false positive results on urine test strips for what?
Glucose
Give physical exam findings and fundic findings for cats with enrofloxacin retinotoxcity.
Bilateral mydriasis and tapetal hyperreflectivity. This results due to functional defect in FQ transport protein.
Mechanism of action of metronidazole
Diffuses into cells as prodrug, activated in cytoplasm. Preferentially accepts electrons and creates free radical that damages DNA.
Metronidazole is metabolized by which organ?
Liver
Mechanism of action of rifampin
Inhibit beta-subunit of DNA dependent RNA polymerase in bacteria
Drugs like steroids, cyclosporine, itraconazole should be increased/decreased when given with rifampin. Why?
Increased. Rifampin is one of the most potent inducers of hepatic microsomal enzymes and efflux proteins, such as P-glycoprotein
Mechanisms of action of trimethoprim and sulfonamides? Why administer together?
Trimethoprim - inhibits bacterial dihydrofolate reductase
Sulfonamides - analogs of para-aminobenzoic acid (PABA) and competitively inhibit incorporation of PABA = decreased folic acid synthesis.
When administered together = bactericidal (bacteriostatic on their own)
What breeds should you use caution before using TMS?
Dobermans, Samoyeds, miniature schnauzer
Tear tests should be monitored if using TMS drug for more than what period of time?
1 week
Mechanism of action of aminoglycosides?
Bind to outer cell membrane and displace Mg and Ca (which link LPS molecules), then they are taken up into cytoplasm and bind to 30s subunit of ribosome
Resistance to 1 aminoglycoside does not imply resistance to others. T/F?
True