Micro2- FA Resp Drugs

  1. Describe the pathogenesis of BRD.
    • viral infection followed by bacterial infection within 3-5 days
    • 1. Attachment
    • 2. Evasion of host defense
    • 3. Multiplication and/or spread
    • 4. Damage to host
    • 5. Transmission b/w animals
  2. What are the viruses involved in BRD? (5)
    • IBR- BHV-1
    • PI3
    • BRSV
    • BVDV
    • +/- coronavirus
  3. What are the bacteria involved in BRD? (6)
    • Pasteurella multocida
    • Histophilus somnus
    • Mannheimia hemolytica
    • [chronic] Truperella pyogenes
    • [chronic] Mycoplasma bovis
    • Bibersteinia trehalosi
  4. Describe the microbial characteristics of M. hemolytica.
    • Gram -
    • facultative anarobe
    • LPS
    • leukotoxin
    • Sialoglycoprotease
    • neuraminidase
    • commensal on mucosal surfaces
  5. Describe the microbial characteristics of Bibersteinia trehalosi. (5)
    • Gram -
    • facultative anaerobe
    • commensal of respiratory tract
    • Bighorn and domestic sheep, cattle, goats, wild cervids
    • Virulence conferred by leukotoxin
  6. Describe the microbial characteristics of Pasteurella multocida. (4)
    • Gram -
    • aerobic, microaerophilic, anaerobic conditions
    • commensals of oropharynx
    • LPS +/- other virulence factors
  7. Describe the microbial characteristics of Histophilus somnus. (6)
    • Gram -
    • facultative anaerobe
    • commensals of oropharynx and genital tract
    • Lipooligosaccharide (LOS)
    • TBP (transferrin binding protein) virulence factor
    • hemolysin, capsule
  8. What syndromes are caused by Histophilus in ruminants? (4)
    • BRD
    • thrombotic meningoencephalitis
    • abortion
    • endocarditis
  9. M. hemolytica causes...
    per-acute fibrinous bronchopneumonia
  10. What is the timeline of Histophilus- associated disease?
    usually >30 days in feedlot
  11. What are antimicrobial options for treating BRD in food animals? (9)
    • Beta-lactam: Ceftiofur (Naxcel, Excenel, Excede)
    • Macrolides: Tilmicosin (Micotil), Tulathromycin (Draxxin), Gamithromycin (Zactran), Tildipirosin (Zuprevo)
    • Fluoroquinolones: Enrofloxacin (Baytril), Advocin (Danofloxacin)
    • Amphenicol: Florfenicol (Nuflor, Resflor)
    • Tetracycline: Oxytet (LA-200)
  12. What is the MOA of macrolides?
    inhibit protein synthesis by binding the 50S ribosomal subunit
  13. Describe the pharmacodynamic properties of macrolides.
    • Bacteriostatic (maybe cidal?)
    • Time-dependent
  14. What is the spectrum of macrolides?
    • Gram + and Gram - aerobes/ facultatives
    • EXCEPT: Not good for enterics, anaerobes, Pseudomonas, Enterococcus
  15. Macrolides have diminished activity under what conditions?
    pH < 7 (don't work in abscesses, necrotic debris)
  16. What are dosing intervals for Micotil, Draxxin, and Zactran?
    • Tilmicosin: 72hr
    • Tulathromycin: 7 days
    • Gamithromycin: 10 days
  17. What are potential adverse reactions to macrolides?
    • Tilmicosin- fatal in humans, alpacas; do NOT give IV
    • Erythromycin, Azithromycin- GI disturbances (Equine)
    • Any Atb with high Vd- anorexia, GI disturbances
  18. What are the uses of Erythro, Azithro, Clarithromycin?
    • Equine- Rhodococcus pneumonia
    • Be careful- causes diarrhea, hyperthermia in foals (d/t motilin activity)
  19. What is florfenicol labelled for in food animals?
    bacterial BRD and Mycoplasma bovis in non-lactating dairy cattle and pigs
  20. What are the fluoroquinolones labelled for in food animals?
    • BRD pathogens and Mycoplasma bovis
    • NO ELDU!!!!!!!!!!!!!
  21. What are the labelled uses for Ceftiofur in food animals?
    • BRD, foot rot, metritis (0-14 days post-partum, 2 doses)
    • can use ELDU for different indications but MUST follow labelled route, dose, and interval
  22. What is tetracycline used for in food animals?
    • widespread use d/t broad spectrum
    • good for Mycoplasma, Treponema (spirochetes), Chlamydia, Rickettsia (gets intracellular)
Author
Mawad
ID
329117
Card Set
Micro2- FA Resp Drugs
Description
vetmed Micro2
Updated