Date of Award

January 2020

Document Type


Degree Name

Master of Public Health (MPH)


School of Public Health

First Advisor

Manisha Juthani-Mehta


Introduction: Inappropriate use of antibiotics is common in healthcare settings, with urinary tract infections (UTI) being one of the most common indications for antibiotic prescriptions. This study evaluated the appropriateness of oral antibiotic therapy among adult patients with suspected UTI who were admitted to Yale New Haven Hospital during January 2018. We hypothesized that 60% of antibiotics were inappropriate, and that inappropriate therapy was associated with Clostridioides difficile infection, hospital readmission and/or mortality.

Methods: We conducted a retrospective cohort study of adult patients who were admitted to Yale New Haven Hospital from January 1, 2018 to January 31, 2018. Data was collected from the electronic medical record system Epic, and records were reviewed to collect demographics, microbiology data, and antibiotics administered.

Results: Among 312 eligible patients (median age= 77 years), only 37 had a UTI according to CDC definitions, where only 12 of those received antibiotics for 7 days or less. The duration of antibiotics was inappropriate for approximately 40% of the time. In total, 263 (95.64%) received inappropriate antibiotic therapy. The most common organisms were Escherichia coli (49.08%), Klebsiella species (17.18%), and Proteus species (11.66%). Among patients who received antibiotics (n=275, 88.14%), the most common choice during and after hospitalization was cephalosporin. While there were no significant differences in adverse drug events between the groups that received inappropriate and appropriate therapy, all 3 patients with Clostridioides difficile infections received inappropriate antibiotics.

Conclusion: The high percentage of inappropriate antibiotic therapy indicates a greater need for improved antibiotic therapy measures and suggests the importance of interventions such as antibiotic stewardship programs.


This thesis is restricted to Yale network users only. It will be made publicly available on 05/27/2022