Community pharmacies occupy a consequential position in antimicrobial stewardship because decisions about antibiotic supply occur where clinical need, patient expectations, professional obligations, regulatory arrangements, and commercial relationships can intersect. Existing stewardship approaches commonly emphasize pharmacist knowledge, education, guideline adherence, or enforcement. These remain important, yet they do not fully explain why stewardship-consistent restraint may be difficult to sustain when pharmacies operate within competitive local markets and cannot assume comparable restraint by other outlets. This article develops an Institutional Stewardship Model to examine how customer-retention pressure, professional legitimacy, competing institutional logics, and collective expectations shape community-pharmacy antimicrobial stewardship. The model distinguishes individual compliance from collectively stabilized restraint and treats commercial pressure as conditional rather than determinative. Professional legitimacy may make refusal, referral, or delayed supply more defensible to customers and other stakeholders, while weak legitimacy can increase the relational cost of stewardship. However, legitimacy at the individual-pharmacist level may remain insufficient where pharmacies anticipate that competing outlets will satisfy displaced demand. Sustainable stewardship therefore depends partly on institutional conditions that make professional restraint recognizable, reciprocally expected, and less commercially asymmetric. The model generates a basis for distinguishing educational, legitimating, coordinative, and regulatory interventions and for specifying when each is likely to matter.
