Pathophysiology
Clinical meaning
Pediatric antibiotic selection requires understanding that common pathogens differ by age: neonates are susceptible to Group B Streptococcus, E. coli, and Listeria; infants and toddlers to S. pneumoniae, H. influenzae, and M. catarrhalis; school-age children to Group A Streptococcus and S. aureus. Antibiotic pharmacokinetics differ in children due to developmental changes in renal and hepatic clearance, higher volume of distribution, and age-related differences in protein binding. Antimicrobial stewardship is critical because unnecessary antibiotic use promotes resistance, disrupts the developing microbiome (increasing risk of C. difficile, allergic disease, and obesity), and exposes children to adverse effects including tendon damage (fluoroquinolones), tooth discoloration (tetracyclines), and bone marrow suppression (chloramphenicol).