Antimicrobial Stewardship (AMS) in the Outpatient Setting

‍PATHCHAT Edition No. 26
Please contact your local Ampath pathologist for more information.

Author: Dr. Adrian J Brink, MBChB (Pret), MMed (Med Micro) (Pret)
Consultant Clinical Microbiologist, Ampath National Laboratory Services
Co-chair, South African Antibiotic Stewardship Programme (SAASP)

Introduction

🔹 Key Facts About Outpatient Antibiotic Use:

• Most antibiotics are prescribed in outpatient settings.
• Acute respiratory tract infections (ARTIs) and urinary tract infections (UTIs) are the most common reasons for prescriptions.
• General practitioners (GPs) prescribe approximately 80% of all antibiotics.
• Nearly half of outpatient antibiotic prescriptions are unnecessary.

🔹 Consequences of Inappropriate Prescribing:

• Antibiotic resistance development.
• Negative patient-level impact (lasts up to 12 months).
• Community-wide resistance pressure.
• Unnecessary side effects, costs, and complications.

🔹 Why Clinicians Overprescribe Antibiotics:

• Time constraints.
• Lack of awareness of resistance risks.
• Diagnostic uncertainty.
• Patient and parental pressure.

✅ Antimicrobial stewardship (AMS) aims to optimize antimicrobial use by ensuring appropriate selection, dosage, route, and duration while minimizing resistance, adverse effects, and costs.

Strategy-Based Approach to AMS in the Community

Strategy 1: Treat Bacterial Infections Only

🔹 Challenges in Diagnosing Bacterial Infections:

• Many infections are viral and self-limiting.
• Distinguishing bacterial from non-bacterial infections is difficult.
• C-reactive protein (CRP) testing has limited value in primary care.

✅ Key Recommendations:

• Avoid antibiotics for viral upper respiratory tract infections (URTIs) and acute coughs.
• Do not rely solely on CRP testing for pneumonia, URTIs, or COPD exacerbations.
• Use clinical guidelines (SAASP) for diagnosis and severity assessment.

Strategy 2: Judicious Antibiotic Prescribing

✅ Principles of Rational Antibiotic Use:

• Prescribe antibiotics only when there is clear evidence of bacterial infection.
• Choose the most effective agent using pharmacodynamic principles.
• Use the shortest effective duration to reduce resistance risk.

🔹 Key Practices for AMS:

1️⃣ Target Maximum Bacterial Eradication:

• Suboptimal antibiotics may appear effective due to natural recovery (Pollyanna phenomenon).
• Bacterial eradication should be the primary goal.

2️⃣ Use Pharmacokinetic/Pharmacodynamic (PK/PD) Principles:

• Different antibiotic classes require different dosing strategies.

3️⃣ Optimize Duration of Therapy:

• Shorter courses (e.g., 5 days) are often sufficient for mild infections.
• For acute bacterial rhinosinusitis, pneumonia, and otitis media, studies show no added benefit from prolonged antibiotic courses.

4️⃣ Know Your Local Pathogens:

• Pathogens and resistance patterns differ by region.
• South African clinicians should consult local antibiograms (SASCM).

5️⃣ Minimize “Collateral Damage” from Broad-Spectrum Antibiotics:

• Avoid fluoroquinolones, 2nd-/3rd-generation cephalosporins, and clindamycin unless absolutely necessary.
• These antibiotics promote Clostridioides difficile infections, MRSA, and extended-spectrum beta-lactamase (ESBL)-producing bacteria.

Strategy 3: Vaccination as an AMS Strategy

🔹 How Vaccines Reduce Antibiotic Use:
✅ Bacterial vaccines (e.g., pneumococcal conjugate vaccine, Hib vaccine) reduce direct infections.
✅ Vaccines prevent bacterial carriage, lowering community-wide transmission.
✅ Vaccination programs reduce unnecessary antibiotic prescriptions.

🔹 Impact of Pneumococcal Conjugate Vaccine (PCV) in South Africa:

• Penicillin-resistant pneumococcal infections dropped by 82%.
• Ceftriaxone-resistant pneumococcal infections dropped by 85%.
• Multidrug-resistant (MDR) infections dropped by 84%.

✅ Influenza vaccination also lowers antibiotic use by preventing viral infections that commonly lead to unnecessary antibiotic prescriptions.

Strategy 4: Delayed vs. Immediate vs. No Antibiotic Prescription

✅ Delaying antibiotic prescriptions reduces unnecessary use.

• Patients given delayed prescriptions often do not use them.
• Delayed prescriptions are effective for conditions like acute otitis media and pharyngitis.

✅ South Africa-Specific Considerations:

• In poor socio-economic settings, antibiotics may be necessary at the first visit.
• Acute pharyngitis (Group A Streptococcus) requires antibiotics in high-risk groups to prevent rheumatic fever.

Strategy 5: Raising Public Awareness & Patient Education

✅ Patient expectations drive antibiotic overprescription.

• Providing patients with educational materials about self-limiting infections reduces antibiotic use.
• Patients who understand symptom duration are less likely to demand antibiotics.

🔹 Expected Duration of Common Respiratory Infections:

• Acute otitis media: 4 days.
• Acute sore throat/pharyngitis: 7 days.
• Common cold: 10–11 days.
• Acute rhinosinusitis: 17–18 days.
• Acute cough/bronchitis: 21 days.

✅ Educating patients about expected recovery times improves satisfaction and reduces unnecessary antibiotic use.

Strategy 6: AMS Education for Healthcare Providers

✅ Multifaceted interventions work best:

• Educational materials alone do not significantly change prescribing habits.
• Audit and feedback on prescribing patterns improve compliance with AMS guidelines.
• Online AMS certification ("antibiotic license") is under consideration in South Africa.

Strategy 7: Expanding AMS to Nurses & Pharmacists

✅ Nurses and pharmacists play a key role in AMS.

• Nurses provide patient education and triage for appropriate antibiotic use.
• Community pharmacists can reinforce delayed prescriptions and symptomatic treatments.

🔹 Evidence Supporting Expanded AMS Roles:

• Patients seen by nurse practitioners receive more education and longer consultations.
• Pharmacists can guide patients on symptom relief instead of unnecessary antibiotic use.

Strategy 8: Implementing AMS Governance in Primary Care

✅ AMS should extend beyond hospitals to GP practices, clinics, and pharmacies.

• Outpatient AMS programs should include leadership commitment and accountability.
• Real-time prescribing audits and feedback can improve antibiotic stewardship.

🔹 Example of Successful AMS Intervention:

• A study in primary care showed that clinician education plus personalized feedback reduced broad-spectrum antibiotic prescriptions.

Key Takeaways for Clinicians

✅ AMS in outpatient settings is essential to combat antibiotic resistance.
✅ Only prescribe antibiotics when bacterial infections are likely.
✅ Use pharmacodynamic principles to select optimal antibiotic therapy.
✅ Shorter antibiotic courses are often as effective as longer ones.
✅ Vaccination is a powerful AMS tool that reduces the need for antibiotics.
✅ Delayed prescriptions can significantly reduce unnecessary antibiotic use.
✅ Educating patients on symptom duration reduces antibiotic expectations.
✅ Expanding AMS roles to nurses and pharmacists improves antibiotic use.
✅ Real-time feedback on prescribing patterns enhances AMS efforts.