7.3 Infections, Antimicrobial Stewardship & Public Health

7.3 Infections, Antimicrobial Stewardship & Public Health

Antimicrobial resistance (AMR) represents one of the greatest global public health threats. Pharmacists play a pivotal role in enforcing national prescribing guidelines, applying antimicrobial stewardship principles, identifying clinical deterioration (sepsis), and delivering immunisation services.

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SARI Guidelines & National Prescribing Standards

In Ireland, the Subcommittee on Antimicrobial Resistance in Ireland (SARI) establishes national primary care prescribing guidelines (available via antibioticprescribing.ie). Primary principles include:

1. Empirical Narrow-Spectrum Selection: Prescribe narrow-spectrum agents targeting the most likely pathogen to preserve broad-spectrum options.
2. Limiting Broad-Spectrum Classes: Avoid unindicated use of Co-amoxiclav, 2nd/3rd generation Cephalosporins, and Fluoroquinolones. These '4C' antibiotics (Co-amoxiclav, Cephalosporins, Ciprofloxacin/quinolones, Clindamycin) strongly drive Clostridioides difficile infection, MRSA, and Extended-Spectrum Beta-Lactamase (ESBL) resistance.
3. Shortest Effective Duration: Align treatment duration with guidelines (e.g., 3 days for uncomplicated female UTI; 5 days for mild CAP) to limit resistance emergence.

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Community-Acquired Pneumonia (CAP) & CURB-65

Severity assessment using the CURB-65 score determines the appropriate care setting (outpatient vs. inpatient) and empirical antibiotic selection.

CURB-65 Criteria (1 Point for Each)

• C: Confusion (abnormal mental test score or new disorientation).
• U: Urea >7.0 mmol/L.
• R: Respiratory rate >=30 breaths/minute.
• B: Blood pressure (Systolic BP <90 mmHg OR Diastolic BP <=60 mmHg).
• 65: Age >=65 years.

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Urinary Tract Infections (UTI)

Management of lower UTI (cystitis) versus upper UTI (pyelonephritis) depends on gender, pregnancy status, and renal function.

                  IRISH SARI UNCOMPLICATED FEMALE LOWER UTI
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   Step 1: First-Line Choice
   └── Nitrofurantoin 100 mg modified-release b.i.d. for 3 days
       *CONTRAINDICATION: Do NOT use if CrCl < 45 mL/min (ineffective + toxicity)
       *PREGNANCY: Avoid at term (36+ weeks) due to neonatal haemolysis risk.
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   Step 2: Alternative First-Line (If Nitrofurantoin contraindicated/unsuitable)
   └── Trimethoprim 200 mg b.i.d. for 3 days
       *PREREQUISITE: Only if local resistance rate is < 20% or guided by culture.
       *PREGNANCY: Avoid in 1st trimester (folate antagonist / neural tube risk).

Complicated UTI & Acute Pyelonephritis

• Symptoms: Flank pain, fever, rigors, costovertebral angle tenderness.
• Treatment: Requires 7-10 days of systemic antibiotics: Cefuroxime 500 mg b.i.d., Co-amoxiclav 625 mg t.i.d., or Ciprofloxacin 500 mg b.i.d..
• Male UTI: Considered complicated by default; treat for 7 days minimum with Nitrofurantoin or Trimethoprim (or Fluoroquinolone if prostatitis is suspected).

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Sepsis Management & Community Red Flags

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.

HSE National Sepsis Pathway Community Red Flags

If infection is suspected, the presence of ANY ONE of the following Red Flags indicates high risk of sepsis:

• Respiration Rate: >= 25 breaths/minute.
• Blood Pressure: Systolic BP <= 90 mmHg (or drop >40 mmHg from baseline).
• Heart Rate: > 130 beats/minute.
• Neurological: Altered mental status, new confusion, or unresponsiveness.
• Dermatological: Non-blanching purpuric rash, cold mottled extremities.
• Renal: Anuria (no urine output in 18 hours) or severe oliguria (<0.5 mL/kg/h).
• Lactate: Blood lactate >2.0 mmol/L.

Immediate Actions: Call 999 for emergency transfer. Administer high-flow oxygen, take blood cultures, and administer IV broad-spectrum antibiotics within 1 hour ('The Golden Hour' Sepsis Six protocol).

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Antimicrobial Stewardship Principles & WHO AWaRe

Antimicrobial Stewardship (AMS) protocols promote optimal antibiotic selection, dosing, and duration.

• 'Start Smart then Focus': Empirical treatment must be re-evaluated at 48-72 hours with microbiology culture results to step down to narrow-spectrum, switch to oral, or discontinue.
• Delayed (Deferred) Prescribing: A prescription provided for self-limiting upper respiratory infections (e.g., otitis media, low Centor score sore throat) to be filled only if symptoms worsen after 48-72 hours.

WHO AWaRe Classification

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Community Pharmacy Vaccination Services in Ireland

Under the Medicinal Products (Prescription and Control of Supply) Regulations, registered pharmacists in Ireland who complete approved training (CPR, Anaphylaxis management, vaccine administration) are legally authorized to supply and administer specified vaccines without a prescription.

Core Pharmacy Vaccination Protocols

1. Seasonal Influenza Vaccine: Quadrivalent Inactivated Vaccine (QIV) for adults; Live Attenuated Influenza Vaccine (LAIV nasal spray) for children aged 2-17 years.
2. COVID-19 Vaccine: mRNA vaccines administered per NIAC booster schedules.
3. Pneumococcal Vaccine: Pneumococcal Polysaccharide Vaccine (PPV23) for adults aged >=65 and clinical risk groups (e.g., asplenia, chronic heart/lung/liver disease).

Emergency Anaphylaxis Protocol

                  VACCINE ANAPHYLAXIS EMERGENCY PROTOCOL
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   Step 1: Recognize Symptoms (Bronchospasm, airway edema, hypotension, urticaria)
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   Step 2: Administer IM Adrenaline (Epinephrine) 1:1000 (1 mg/mL)
           └── Dose: 0.5 mL (500 micrograms) IM into mid-outer thigh
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   Step 3: Call Emergency Services (999 / 112)
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   Step 4: Repeat IM Adrenaline after 5 minutes if no clinical improvement occurs
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   Step 5: Patient Observation: Mandatory minimum 15 minutes post-vaccination