Clinical Resource

Antimicrobial Stewardship

Companion Animal In-Clinic Decision Guide

💊 Right Drug

⏰ Right Time

⚖ Right Dose

📅 Right Duration

🧭 Should I Prescribe an Antibiotic? — Clinical Decision Flow

Is there clinical evidence of a bacterial infection?

Proceed to Step 2

STOP. Do not prescribe. Investigate other causes. Avoid "shotgun" therapy.

Can you obtain Culture & Susceptibility (C&S)?

Collect sample before starting antibiotics. Submit C&S. Proceed to Step 3 for empirical therapy while awaiting results.

Document why C&S was not obtained. Use local antibiogram data + clinical judgment. Proceed to Step 3.

Select empirical therapy: Start NARROW spectrum first.

1st Line: Amoxicillin, Amox/Clav, Cephalexin, TMS | 2nd Line (if 1st fails or C&S indicates): Doxycycline, Clavamox, Chloramphenicol | Reserve: Fluoroquinolones, 3rd-gen Cephalosporins

Will the drug reach the infection site at therapeutic concentrations?

Consider: UTI (urine concentration), abscess (penetration), bone (distribution), CNS (blood-brain barrier). Match PK profile to site.

Determine dose, route, frequency & duration.

Concentration-dependent (fluoroquinolones, aminoglycosides): maximize peak. Time-dependent (beta-lactams): maintain time above MIC. Factor in client compliance & cost for full course completion.

Re-evaluate: C&S results back? Clinical response at 48–72 hrs?

Responding + C&S sensitive: Continue or de-escalate to narrowest effective agent. Complete full course.

Not responding or resistant: Adjust per C&S. If no C&S was done, obtain now. Consider alternative diagnosis.

Document everything in the medical record.

Diagnosis, drug chosen, dose, route, frequency, duration, rationale for selection, C&S results, and follow-up plan.

🧪 When to Culture (C&S) — Quick Reference

Always Culture

Recurrent or relapsing infections
Deep tissue / surgical site infections
Life-threatening or systemic infections
Prior antibiotic treatment failure

Strongly Recommended

UTIs (cystocentesis sample)
Respiratory infections (tracheal wash/BAL)
Otitis media / deep ear disease
Post-operative infections

Consider Based on Case

First-episode simple skin infections
Simple superficial wounds
Uncomplicated first-episode UTI

Empirical OK (Document Why)

Acute, uncomplicated, first occurrence
C&S cost prohibitive for client
Sample collection not feasible

⛔ STOP — Do NOT Prescribe Antibiotics When:

• No clinical evidence of bacterial infection • Viral or self-limiting condition suspected • Subclinical bacteriuria without clinical signs • Client pressure without clinical justification • "Just in case" or prophylactic convenience • Fever alone without identified source

40%

of canine antibiotics prescribed
with no evidence of infection*

1.2M

deaths linked to AMR
worldwide (2019)

10M

projected annual deaths by 2050
without stewardship changes

*Data from veterinary teaching hospital study

Clinical Resource

Drug Selection & ELDU Guide

Companion Animal — Dogs & Cats

💊 Empirical Antibiotic Selection — Common Companion Animal Infections

Infection	1st Line (Narrow Spectrum)	2nd Line (If 1st Fails / per C&S)	Key Notes
UTI (Sporadic)	1st Amoxicillin Alt: TMS (watch for KCS in dogs)	2nd Amox/Clav, Cephalexin Per C&S results	ISCAID guidelines. Cystocentesis for sample. C&S strongly recommended. 3–5 day course for uncomplicated.
UTI (Recurrent)	C&S MANDATORY — Treat per susceptibility results only. Investigate underlying cause.		Rule out anatomic, endocrine (Cushing's, DM), or immune causes. Never repeat same empirical therapy without C&S.
Skin (Superficial Pyoderma)	1st Cephalexin Alt: Amox/Clav	2nd Clindamycin, Doxycycline Topical chlorhexidine adjunct	Consider topical-only for localized lesions. Duration: 7 days past clinical resolution. C&S if recurrent.
Skin (Deep Pyoderma)	C&S Required before systemic Tx	Per C&S. Often Cephalexin, Amox/Clav at higher doses	Minimum 4–6 weeks. Treat 14 days past clinical cure. Always investigate underlying cause (allergies, endocrine).
Respiratory	1st Doxycycline (dogs) Amox/Clav (cats)	2nd Azithromycin (cats) Fluoroquinolone per C&S only	Rule out viral etiology first. Dogs: consider kennel cough (often self-limiting). Cats: consider Mycoplasma.
Wound / Abscess	1st Amox/Clav (broad anaerobic coverage) Cats: often bite wound → Amox/Clav	2nd Clindamycin Metronidazole (anaerobic)	Surgical drainage/debridement is primary Tx. Antibiotics adjunctive. Culture deep tissue if available.
Otitis Externa	1st Topical therapy preferred (antibiotic/antifungal/steroid)	2nd Systemic if otitis media suspected C&S from middle ear	Cytology first, not empirical systemic Tx. Treat underlying cause (allergies, anatomy). Avoid systemic for simple OE.

⚠ Transdermal Antibiotics Warning
Generally unreliable systemic absorption (especially enrofloxacin). Creates resistance risk without therapeutic effect. Exception: Miconazole topical (antifungal, not systemic antibiotic).

⛔ Reserve Antibiotics — Use ONLY per C&S
Fluoroquinolones (enrofloxacin, marbofloxacin, pradofloxacin): Never empirical 1st line. 3rd-gen cephalosporins (cefovecin/Convenia, cefpodoxime): High resistance risk if overused.

📋 Extra-Label Drug Use (ELDU) — Companion Animal Decision Flow (AMDUCA)

Step 1
Approved drug for
this species + condition?
→ Use as labeled

▶

Step 2
Approved animal drug
(any species) effective?
→ Use extra-label + VCPR

▶

Step 3
Compound from approved
animal or human drug?
→ Compound + document

▶

Step 4
Bulk chemical
compounding
→ Last resort (FDA guidance)

⚠ ELDU Enrofloxacin Example: Using the large animal injectable (100 mg/mL) in dogs instead of labeled small animal formulation (22.7 mg/mL) is ELDU and strongly discouraged — highly alkaline formulation causes severe adverse reactions.

📝 Stewardship Documentation Checklist — Every Antibiotic Prescription

☑ Confirmed bacterial infection (how?)

☑ C&S submitted? If not, why?

☑ Drug name, dose (mg/kg), route

☑ Dosing frequency & total duration

☑ Rationale for drug selection

☑ Spectrum justification (narrow first?)

☑ Re-evaluation plan (48–72 hr check)

☑ C&S result & any therapy adjustment

☑ Client communication (compliance plan)

☑ ELDU documented if applicable

🗣 Handling Client Pressure — Quick Scripts

"Can't you just give Baytril like last time?"
"I understand that worked before, but using the strongest antibiotics first can make bacteria resistant over time. Let's start with a targeted option and test to make sure we pick the right one. This protects [pet name] long-term."

"It's just one dog, does it really matter?"
"Every prescription matters. Resistant bacteria from one patient can spread to other pets, to your family, and into the environment. By being precise now, we help ensure antibiotics keep working when [pet name] really needs them."

🧬 PK/PD Quick Reference — Dosing Strategy by Drug Class

CONCENTRATION-DEPENDENT

Goal: Maximize peak concentration (Cmax/MIC)

Strategy: Higher dose, less frequent

Examples: Fluoroquinolones, Aminoglycosides, Metronidazole

TIME-DEPENDENT

Goal: Maximize time above MIC (T>MIC)

Strategy: Frequent dosing, maintain steady levels

Examples: Beta-lactams (Amoxicillin, Cephalexin), Clindamycin

📚 Key Resources

ISCAID
UTI & Infection
Guidelines

AVMA
Stewardship
Position Statements

U of MN
AMR Initiative
& Antibiogram Data

FDA / NARMS
Resistance Monitoring
& ELDU Guidance