What are the general criteria for deciding to initiate empirical treatment (treatment without waiting for culture and susceptibility results) in small animal medicine?
You have a good reason to believe an infection is present
AND
Should a first line choice of drug be a broad spectrum or a narrow spectrum drug?
Narrow spectrum
- Effective against expected organisms
- if doesn’t work then culture
Should a sneezing cat with a serous nasal discharge be automatically put on an antibiotic?
Should a pollakiuric cat with hematuria and no other medical problems be automatically put on an antibiotic?
- Serous nasal discharge = No tx
- pollakiuric cat = No tx
According to Dr. Guptill, what 4 antimicrobials usually should NOT be chosen as first line drugs for “simple” infections because of concern of resistance?
- Fluoroquinolones
- Vancomycin
- Carbebenems
- 3rd generation cephalosporins
/According to Dr. Guptill, bactericidal drugs should be chosen over bacteriostatic drugs under what three critical conditions?
Choose bactericidal for critical infection
- CNS infections
- Neutropenic patients w/ systemic infection
- Immunocompromised patients
With what type of antimicrobials should beta lactams not be used with? Why?
- Batceriostatic –bc the NEED rapidly replicating cells
Beta lactams are considered to be synergistic with what other group of antimicrobials?
Aminoglycocides
–both bactericidal via diff pathway
If a young, healthy animal with no other medical problem and no previous history of UTI (urinary tract infection) presents with pollakiuria, some WBC/RBCs in urine, and 1+ bacteria, should we use a broad spectrum antibiotic?
NO! (amoxicillin, cephalexin)
- tx w/ narrow spec w/ assumption that it is from GI flora
- culture if not working
What is the importance of biofilm to antimicrobial use?
What is the role of the glycocalyx of the biofilm in the resistance of the organisms in the biofilm?
–> sequester themselves –> Resistance of antimicrobials
- protects bacteria from external environment
Besides implants, name other locations or medical objects listed by Dr. Lescun on which biofilm may generate.
- bone
- cather
As a general rule, does it appear that parenterally administered antibiotics (those administered by injection) penetrate bone tissue better or worse than orally administered antibiotics?
- IV best initially
The activity of fluoroquinolones is enhanced by what other antimicrobial?
- Rifampin
Is metronidazole effective against anaerobic bacteria?
YEPPERS!
What abx is the drug of choice for treating serious MRSA infections in people?
Why does that influence whether or not we use that drug in veterinary medicine?
- Vancomycin
* prevent resistance but limiting use
According to Dr. Lescun, generally how long should abx tx be given in cases of osteomyelitis?
What would dictate that treatment be longer than the minimum?
- 3-4 weeks beyond the resolution of clinical signs
- Longer if surgical debridement or implant removal not performed
What is metronidazoles use in orthopedics?
- high concentration in bone achieved
- drug of choice for anaerobes
- drug of choice with a traumatic orthopedic wound
rifampin
- high concentration in bone achieved
- synergy between fluoroquinolones and rifampin
- does get intracellularly and penetrates osteoblasts where Staph organisms may exist
What four orally administered antimicrobials have excellent bone penetrating ability?
- Metronidiazole
- Rifampin
- Fluoroquinolone (fair/good)
- Trimethoprim - Sulfamethoxazole (good)
- Tetracycline –Doxy
