Empiric Antibiotic Selection Flashcards
What do we mean by empiric antibiotic therapy?
Choosing an antibiotic based on experience
What are the two major questions you must ask yourself when empirically treating an infection?
Which bacteria most commonly causes infection at this site?
What antibiotic will treat those bacteria at that site?
T/F: In general, 1st line antibiotics aren’t that important to human medicine
True
When should we pursue first line treatment?
Common, non-life-threatening infections
Prior to using second line antibiotics, it is recommended to _________
Submit culture and sensitivity
A lil kitten at the shelter is brought to the clinic for conjunctivitis, congestion, and sneezing. Does this kitty need antibiotics?
Probably not - likely viral
A 5yo MC dog presents to your clinic with acute diarrhea. Does this patient need antibiotics?
Probably not
Antibiotics are commonly used inappropriately in horses. What are some examples of overprescription in horses?
Treatment of cough - consider asthma
Wounds over non-vital structures (ex. Wound over the flank compared to a wound over the pastern)
Only administering TMS once daily when it should be twice
A dog has a dry, harsh, hacking cough that developed after a week in a kennel. The patient is otherwise normal. Does this patient need antibiotics?
Not at this time - highly suspicious of bordetella, which is often a self-limiting disease
What clinical criteria might you use to decide to treat with antibiotics?
Fever, anorexia, lethargy
Purulent discharge
Cytology
Duration of CS >10d
Worsening CS
Infections like sepsis, pneumonia, pyoderma, and UTIs often require drugs with a _________ Vd as the infection is located in the ___________.
Small; plasma ISF
What locations of bacterial infections would require an antibiotic with a wide volume of distribution?
Eye
CNS
Prostate
Name some drugs with a wide volume of distribution
Macrolides
Lincosamides
Chloramphenicol
Fluoroquinolones
Tetracyclines
Metronidazole
Discuss of immune status would affect which antibiotic you choose
Immunocompromised patients are often in need of bactericidal, broad-spectrum antibiotics
T/F: Systemic antibiotics are always indicated in cases of superficial bacterial folliculitis (SBF)
False - must take severity, chronicity, and underlying cause into consideration when treating cases of SBF
Instead of using systemic antibiotics for SBF, you should consider __________
Topicals
Name some commonly used drugs for skin and ST infections (remember, this location is connected to ECF)
Amoxicillin (+clav)
Ampicillin
TMS
Enrofloxacin
Cefovecin
T/F: Once you prescribe a patient with SBF antibiotics, you can expect the infection to heal in about 7 days without reoccurrence.
False - always look for underlying conditions
If this patient has allergies, a metabolic condition, or is immunocompromised, the infection is likely to recur unless the primary cause is addressed.
When treating a bite wound, what kind of bacteria should we suspect might be involved?
Anaerobes - can treat with doxycycline, clindamycin, or clavamox
What are the three kinds of urinary tract “infections”?
Subclinical cystitis
Uncomplicated, sporadic, simple cystitis
Recurrent bacterial cystitis (3 or more episodes in a 12 month period)
What can we sometimes use drugs with intermediate sensitivities to treat UTIs?
A lot of drugs concentrate in the urine
Do NOT use drugs listed as resistant on C&S
What are some reasons that treatments for a UTI could fail?
Inappropriate duration
Calculi or epithelial tissue harboring bacteria
Increased urine production (administer drugs at night)
Prolonged corticosteroid therapy
Local factors affecting antibiotic efficacy
Infection isn’t in the urine, but might be in the kidney or prostate
What characteristics would you like to see in a drug for treatment of prostatitis?
Low protein binding
Unionized
Lipophilic
Doses high enough to provide a concentration gradient for diffusion
Side note: using basic drugs could lead to ion trapping in the prostate, which would increase prostatic concentrations
T/F: the lungs are difficult to penetrate with antibiotics and often require advanced techniques for delivery
False - Relatively few barriers to drug penetration into the lung
What types of infections are common in the respiratory tract?
Mixed! - Aerobic and anaerobic bacteria are likely, so start with broad spectrum treatment
What two drugs are commonly used for empiric antibiotic therapy for RTIs until C&S results are available?
Beta-lactams and aminoglycosides/FQs
Bones and joints are an extension of the _____
ECF!
Overall, joints and bones aren’t hard to reach with antibiotics; however, there are some exceptions, can you name some?
Joints with excessive purulent debirs
Sequestration
Implants and biofilms
Discuss the relationship between tetracyclines and bone
Tetracyclines are chelated by calcium, basically becoming stuck in the bone. There is a question of whether this inactivates the drug and contributes to therapeutic failure.
T/F: because transient bacteremia is likely during dental procedures, providing prophylaxis is almost always indicated
False - we really only use antibiotics for dental disease when there is a severe infection, the patient is immunosuppressed, the patient has underlying heart or renal/hepatic disease
What kind of bacteria are commonly found in the mouth?
Anaerobes
For a septic patient, what kind of antibiotic therapy should you initiate?
Broad-spectrum
Often use combination therapy of FQ and potentiated amino penicillin or cephalosporin
What bacteria are commonly involved in cases of bacterial endocarditis? What should we do to figure out who is involved?
Staphs, streps, E. coli
Erysipelothrix
Corynebacteria
Bartonella
Anaerobes like bacterioides
Culture the blood!
What kind of antibiotic should you use for empiric therapy of bacterial endocarditis?
Bactericidal
IV
Most cases utilize penicillin/BLI and FQ
What drugs are commonly used to treat hepatobiliary disease in dogs and cats? Horses?
Dogs & Cats - Clavamox, Enro, Metro
Horses - TMS, Enro, Metro
_____________ is used to treat histiocytic ulcerative colitis in boxers
Enrofloxacin
A client brings their 2yo MC Great Pyrenees (outdoor, working dog) into the clinic for itchy, gross skin (pustules, papules, and crusted lesions).
The patient is not on any preventatives, so you suspect this might the result of a flea infestation. What can you do for this dog?
Find the fleas and get started on preventatives!
Because the patient is showing signs of a skin infection, we can empirically treat.
We can suggest topicals, but if the owner cannot bathe the dog 3x per week (which sounds like she can’t b/c outdoor and working, we can use first line antibiotics like clavamox, clindamycin, and cephalexin.
