Background
Antibiotic resistance mechanisms originating in low- and middle- income countries are among the most common worldwide. Reducing unnecessary antibiotic use in India, the world's largest antibiotic consumer is crucial to control antimicrobial resistance globally. Limited data describing factors influencing Indian clinicians to start or stop antibiotics is available.

Methods
Febrile adults and children admitted to a public tertiary care hospital in Pune, India were enrolled. Antibiotic usage and clinical history were recorded. Immunoassays for mosquito-borne disease and bacterial cultures were performed by protocol and clinician directed testing. Clinical factors were assessed for association with empiric antibiotic initiation and discontinuation by day 5 using multivariable logistic regression and propensity score matched Cox proportional hazard models.

Results
Among 1486 participants, 683 (82%) adults and 614 (94%) children received empiric antibiotics. Participants suspected of having mosquito-borne disease were less likely to receive empiric antibiotics, adjusted odds ratio (AOR) 0.5, 95% confidence interval (CI) 0.4-0.8. Empiric antibiotics were discontinued in 450 (35%) participants by day 5. Dengue or malaria testing performed before day 4 was positive in 162 (12%) participants, and was associated with antibiotic discontinuation (AOR 1.7, 95% CI [1.2 - 2.4]). In a propensity score matched model accounting for admission suspicion of mosquito borne disease, positive dengue or malaria tests increased hazard of antibiotic discontinuation (hazard ratio 1.6, 95% CI 1.2-2.0).

Conclusions
Most patients with acute febrile illness in an Indian public hospital setting receive empiric antibiotics. Mosquito-borne disease identification is associated with reduced empiric antibiotic use and faster antibiotic discontinuation.

Clinical Infectious Diseases