The S3 (Simplified Spectrum Score) was developed to harmonize and standardize the ranking of antimicrobial drugs according to their spectrum of activity using evidence-based medicine. The S3 app was developed for researchers working in the field of antimicrobial resistance. The information provided by the S3 app is for general informational purposes only. All content within the app, including text, graphics, images, and other materials, is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on the S3 app.