Medical School
- MD, University of Colorado Denver School of Medicine (2015)
Internship
- Massachusetts General Hospital Program (2016)
Residency
- Massachusetts General Hospital Program, Chief Resident, Internal Medicine (2018)
Fellowships
- University of Washington Program, Infectious Disease (2022)
Languages
English, SpanishDepartment
Medicine-Infectious DiseaseProfessional Titles
- Medical Director, UCH Antimicrobial Stewardship
Publications
- Hartlage W, Castillo AY, Kassamali Escobar Z, Bajenov M, Martinez-Paz N, Lynch JB, Bryson-Cahn C, Chan JD. Stewarding the inappropriate diagnosis and treatment of urinary tract infection: leveraging the urinalysis to understand true antibiotic overuse. Antimicrob Steward Healthc Epidemiol. 2025;5(1):e49. PubMed PMID: 40026777
- Mitaka H, Brade K, Castillo AY. Underdosed and Underappreciated: Why Japanese Community-Acquired Pneumonia Outcomes With Ampicillin-Sulbactam May Not Translate Globally. Open Forum Infect Dis. 2025 Jul;12(7):ofaf348. PubMed PMID: 40599487
- Castillo A, Hartlage W, and Bryson-Cahn C. "Protectors vs Police: How Antimicrobial Stewardship Interventions Come Across and How to Change the Narrative." Contagion. 2025;10,3.
- Castillo AY, Frost HM, Poole NM, Jenkins TC, Seibert AM, and Stenehjem E. Implementing with Intention: Advantages, Challenges, and Tactics to Optimally Utilize the AXR Metric. Antimicrob Steward Healthc Epidemiol. 2024.
- Hartlage W, Castillo AY, Kassamali Escobar Z, Bajenov M, Martinez-Paz N, Lynch JB, Bryson-Cahn C, and Chan JD. Stewarding the Inappropriate Diagnosis and Treatment of UTI: Leveraging the Urinalysis to Understand True Antibiotic Overuse. Antimicrob Steward Healthc Epidemiol. 2024.
- Ruchman SG, Fitzgerald B, Roda G, Van Ochten N, Castillo AY, and Kaplan SR. A 52-Year-Old Man with a Chronic Nasal Wound. NEJM Evid. 2024;3(6).??
- Castillo AY, Hudziec M, Totten SE, and Pisney L. Team-based IP Review Improves Inter-rater Reliability in Identification of Hospital Acquired Infections. Infect Control Hosp Epidemiol. 2024;1-3.
- Kassamali-Escobar Z, Hartlage W, Chan JD, Castillo A, et al. Antimicrobial Stewardship and Quality Improvement Strategies in Critical Access Hospitals: Findings from an Intensive Quality Improvement Cohort. Infect Control Hosp Epidemiol. 2024.
- McCormick C, Galatowitsch, J, Castillo, A. A 35-year-old Man with Fever, Liver Dysfunction, and Pancytopenia. NEJM Evidence. 2023.
- Castillo AY, Chan JD, Lynch JB, Bryson-Cahn C. How to disagree better: utilizing advocacy-inquiry techniques to improve communication and spur behavior change. Antimicrob Steward Healthc Epidemiol 2023.
- Hartlage W, Bryson-Cahn C, Castillo AY, et al. Asymptomatic bacteriuria in critical-access hospitals: Prevalence and patient characteristics driving treatment. Infect Control Hosp Epidemiol 2023.
- Castillo, A, Zelikoff, A, Chan, J, Lynch, J, Bryson-Cahn, C. Rapid Molecular SARS-CoV-2 Testing in Hospital Employees with Mild Non-specific Respiratory Symptoms Facilitates Expedient Return to Work. Infection Control & Hospital Epidemiology. 2022.
- Ankomah, A, Castillo, A, O’Neil, J, and Andrews, H. A 66-year-old Man with Fever and Confusion. NEJM Evidence. 2022 Jan; 1(1).
Professional Memberships
- Infectious Diseases Society of America (IDSA), Member
- Society for Healthcare Epidemiology of America (SHEA), Member
Practice Locations
UCHealth Infectious Disease Clinic - Anschutz Medical Campus1635 Aurora Ct
7th Floor
Aurora, CO 80045
720-848-0191
Hospital Affiliation
- University of Colorado Hospital
Specialty Information
Specialties- Internal Medicine, Board Certification (2018)
- Infectious Disease, Board Certification (2022)