Objectives: The urgent global threats of the climate crisis and antimicrobial resistance have the potential to be addressed in part by increasing the use of outpatient antimicrobial therapy (OPAT). Our study aimed to appraise the environmental impact of three commonly used OPAT pathways, and the traditional inpatient model of IV antimicrobial therapy.

Methods: We assessed the CO2, waste and water footprint associated with self-care, nurse assisted and outpatient OPAT care pathways and inpatient administration of intravenous antibiotics to adult patients for whom OPAT was a viable treatment option.

Results: We found that the administration of IV antibiotics in hospital is associated with a substantial environmental impact compared to OPAT. When OPAT is self-administered in the patient’s home, we discovered a CO2 reduction of 85%, a water use reduction of 78% and a 91% reduction in the amount of waste generated compared with the traditional inpatient treatment pathway. Nurse administered OPAT, either in the home or outpatient department, also results in lower use of water, generation of waste and CO2 emissions compared to the inpatient pathway.

Conclusions: Our study demonstrates that using OPAT reduces the environmental impact of delivering antimicrobial therapy compared to inpatient treatment. As it is delivered away from the hospital setting, it may also reduce the risks to health associated with inpatient care. While we have shown that the reduction in CO2 emissions, water used and waste generated is significant for all three forms of OPAT studied, the greatest impact is seen with the use of self-administration OPAT.

Cole A, Aspin J, Laird S, Acri F, Galley S, Collins M. The environmental impact of intravenous antimicrobial therapies: a comparison of OPAT and inpatient administration care pathways. JAC Antimicrob Resist. 2025 Mar 11;7(2):dlaf030. doi: 10.1093/jacamr/dlaf030. PMID: 40070892; PMCID: PMC11894253.