Background Inappropriate antibiotic prescribing practices predispose to resistance emergence. Despite the inclusion of the topic in medical school curricula worldwide, it is uncertain whether newly graduated medical interns have confidence in proper antibiotic prescription.

Objectives This study aimed to explore the antibiotic prescribing behaviours of the medical interns in Hong Kong and their barriers to appropriate antibiotic prescription.

Methods Two focus groups were conducted among medical interns with training experiences in different public hospitals. Their prescribing behaviours and barriers were further examined with a questionnaire survey just before completion of internship.

Results Focus group interviews identified a variety of hospital workplace cultures, including inappropriate empirical prescriptions and dosages, interns’ passive roles in prescribing antibiotics and varied guidelines between different departments. Defensive medicine and lack of clinical experience were other barriers encountered. The interns believed that the incorrect practice learnt would perpetuate in their minds and affect their future practice. The top barriers reported by the survey respondents were adaptation to prescription culture of different hospitals (93.5%), lack of experience in antibiotic prescription (88.3%), inadequate knowledge in the choice of antibiotics (85.7%) and compliance with the seniors’ instructions (80.6%). However, some focus group participants perceived weaker barriers in paediatric departments which provided close monitoring of antibiotic use.

Conclusions Inadequate knowledge and low confidence in antibiotic prescription led to the passive role of medical interns in antibiotic prescription, predisposing to future inappropriate practice. Inconsistent guidelines and prescription cultures between different hospitals and departments might further exacerbate their barriers.