Scrub Typhus Antibiotic Resistance Trial

Study type: Randomized Control Treatment Trial Study population: Male and female patients with ≥15 years of age and acute scrub typhus Duration: 2 years Study Design: Prospective, open-label, randomized-controlled treatment trial in patients ≥15 years old admitted to hospital with acute scrub typhus. Randomization into 3 oral treatment arms (each n=59 patients, total n=177): i) 7 days of doxycycline, ii) 3 days of doxycycline, and iii) 3 days of azithromycin Primary Objective: To evaluate the clinical and microbiological responses in scrub typhus patients to three oral treatment regimens: 7 days of doxycycline, 3 days of doxycycline, and 3 days of azithromycin Secondary Objectives: 1. To perform pharmacokinetic/pharmacodynamics (PK/PD) characterization of the therapeutic responses for doxycycline and azithromycin, incl. serial bacterial load measurements. 2. To define clinical, bacterial, pathophysiological and pharmacological factors associated with disease severity, fever-clearance times (FCT), treatment failures and relapse/re-infection. 3. To determine the minimum inhibitory concentrations (MIC) of clinical Orientia tsutsugamushi isolates to doxycycline, azithromycin and chloramphenicol, using in vitro growth-inhibition assays 4. To genotype all clinical isolates using whole genome sequencing for comparative genomics. 5. To dissect the natural immune response in scrub typhus, using antigen-specific cellular immune and antibody studies, and cytokine profiling

NCT Number	NCT03083197
Lead Sponsor	University of Oxford Collaborators: Shoklo Malaria Research Unit, Chiangrai Prachanukroh Hospital, Mae Suai District Hospital, Mae Chan District Hospital, Mae Fa Luang District Hospital
Conditions	Scrub Typhus
Enrollment	177 participants
Start Date	2017-10-15
Primary Completion	2026-10-31 (estimated)
Study Completion	2028-10 (estimated)
Updated on ClinicalTrials.gov	2026-04-28