Antibiotic Selection for Respiratory

Antibiotic selection is a probability decision, not a response to any cough, fever, or abnormal inflammatory marker. First identify the respiratory syndrome, estimate the likelihood of bacterial disease, assess severity and site of care, then match the regimen to likely organisms, local resistance, host factors, and drug safety. Most acute respiratory tract infections in adults—including uncomplicated bronchitis, the common cold, and most sore throats and rhinosinusitis—are viral. Antibiotics do not improve a viral illness, but they can cause diarrhoea, allergic reactions, Clostridioides difficile infection, drug interactions, and selection of resistant organisms. Roughly half of outpatient antibiotic prescriptions for these syndromes are unnecessary. In Canadian practice, stewardship means withholding an antibiotic when its expected benefit is negligible, choosing the narrowest effective option when bacteria are likely, and shortening or narrowing treatment as the clinical and microbiological picture allows. There is no single national Canadian adult CAP guideline that governs every setting. Provincial and regional antimicrobial guidance, the local antibiogram, institutional protocols, and patient-specific factors determine the final choice. Adult ATS/IDSA regimens are widely used as a clinical framework, but a memorized...