Stewardship in your pocket: launching Colorado's free antimicrobial mobile application

The aim was to describe the development and implementation of Firstline (www.Firstline.org), a mobile antimicrobial stewardship (ASP) application (app) created to address barriers to robust ASP in Colorado hospitals.

A mixed-methods pragmatic implementation study using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework was conducted from October 2023-December 2025.

ASP teams at Children's Hospital Colorado and Denver Health partnered with Firstline to develop the app using locally curated content. The app launched in October 2023 with a multifaceted dissemination campaign. Reach was assessed using geocoded user data. Effectiveness and adoption were evaluated using cross-sectional surveys at two time points. Implementation was characterized by analyzing utilization patterns. Maintenance was assessed by tracking monthly active users over two years.

Within the first year, 4,409 unique Colorado users downloaded the app, representing 15% of state clinicians (19% in Denver Metro; 5-17% in rural regions). Survey respondents (n = 215) reported high satisfaction: 63.9% and 72.9% found the app very easy to use, 71.3% and 83.2% reported enhanced antibiotic selection knowledge, and 100% advocated for ongoing support. Among respondents, 10% reported their facilities had formally adopted Firstline guidelines. The most frequently accessed content included common, high-impact infections. Monthly active users remained stable (average 871) over two years.

We demonstrated use of Firstline across Colorado, with increasing engagement in rural areas. High user satisfaction, sustained engagement, and emerging institutional adoption suggest this "stewardship in your pocket" model offers a unique, scalable approach to extending ASP support beyond academic medical centers.