Pivmecillinam for Shigellosis With Limited Oral Therapeutic Alternatives: A 3-Case Series and Narrative Review of Published In Vivo Clinical Evidence.

Shigellosis remains highly relevant to military medicine because acute diarrheal illness during travel and deployment can impair operational readiness, reduce physical performance, and increase lost duty days. At the same time, oral treatment options are increasingly constrained by antimicrobial resistance, intolerance, contraindications, and occasional supply limitations in operational or austere settings. We report 3 adults with microbiologically documented shigellosis treated with oral pivmecillinam at our institution and summarize the limited published in vivo clinical evidence. In all 3 cases, pivmecillinam was used as a susceptibility-guided oral strategy when standard oral options were restricted. Clinical improvement occurred within 48 hours in each patient, and no immediate treatment escalation was required. Published evidence consists mainly of small, older randomized trials, most of them conducted in children, suggesting clinical activity of pivmecillinam against historical comparators, although 1 pediatric trial found ciprofloxacin to be bacteriologically superior. These findings suggest that pivmecillinam may represent a pragmatic oral alternative in selected cases of shigellosis when usual oral agents cannot be used. In military and other operational settings, its potential value lies in preserving an oral treatment pathway and reducing reliance on parenteral therapy. Contemporary comparative studies, especially in adults and in the context of current resistance patterns, are needed to better define its role.