PREPARED BY: Infectious Disease Prevention
DATE: 2026-09-24
SUBJECT: Antimicrobial Stewardship
BACKGROUND
Antimicrobial resistance (AMR) is a growing public health threat that makes infections more difficult to treat, worsens health outcomes, and increases mortality.1,2,3,4 Inappropriate antimicrobial use remains a key driver of AMR, with approximately one in four prescriptions in Ontario considered unnecessary.1,2,4 Windsor-Essex County has the highest antibiotic prescribing rate in Ontario, at 787 prescriptions per 1,000 population annually.3 AMR is projected to place a substantial burden on the health care system, with costs to Canada estimated at $120 billion by 2050.5
AMR affects human, animal, agricultural, and environmental health, requiring a coordinated One Health approach and strong antimicrobial stewardship (AMS) efforts.6,7 Challenges include social and economic inequities that increase vulnerability to infections, limited AMS structures in community-based settings, and insufficient surveillance of resistance and prescribing practices.6,8,9 Addressing these challenges requires provincial and federal policies that address the social determinants of health; investments in vaccination, infection prevention strategies, and surveillance of antimicrobial use; and sustainable national and provincial funding and coordination to support comprehensive, cross-sectoral AMR mitigation efforts.1,6,8,9
Given these challenges, this report provides an evidence-informed overview of antimicrobial resistance (AMR) and antimicrobial stewardship (AMS) initiatives, highlights the Windsor-Essex County Health Unit’s (WECHU) leadership and contributions, and informs coordinated public health action to mitigate the impacts of AMR.
DISCUSSION
Antimicrobial resistance occurs when bacteria, viruses, fungi, and parasites evolve mechanisms that reduce or eliminate the effectiveness of antimicrobial medications used to treat infections. As resistance increases, infections become more difficult to treat, resulting in prolonged illness, increased healthcare utilization, treatment failure, and death2,4.
The burden of AMR is already substantial and continues to increase. Globally, antimicrobial resistance was associated with approximately 4.7 million deaths in 2021, including an estimated 1.14 million deaths directly attributable to resistant infections4. Resistant infections contribute to longer hospital stays, increased use of healthcare resources, more expensive treatment options, and poorer patient outcomes.
In Canada, modelling suggests that if resistance to first-line antimicrobials increases from 26% in 2018 to 40% by 2050, AMR could contribute to approximately 13,700 deaths annually, $120 billion in healthcare costs, and $388 billion in losses to Canada's gross domestic product5. These impacts extend beyond healthcare and affect labour productivity, food production, economic growth, and overall community well-being.
Antimicrobial Resistance as a One Health and Health Equity Issue
AMR is increasingly recognized as a One Health challenge because resistance develops and spreads through interconnected human, animal, agricultural, and environmental systems. Antimicrobials are used in human healthcare, veterinary medicine, food production, and agriculture, and resistant organisms can move through animals, food chains, water systems, soil, and human populations. Actions taken within one sector may therefore influence resistance patterns within other sectors6,7.
The environmental dimensions of AMR are receiving increasing attention internationally. Antimicrobial residues and resistant organisms may enter wastewater systems, agricultural environments, and natural ecosystems, creating environmental reservoirs that contribute to the persistence and spread of resistance. Consequently, effective AMR mitigation requires collaboration among healthcare professionals, veterinarians, environmental scientists, public health practitioners, governments, and industry partners.
Recognizing these interconnections, Canada's Pan-Canadian Action Plan on Antimicrobial Resistance adopts a One Health framework that promotes coordinated action across public health, healthcare, agriculture, animal health, and environmental sectors6.
AMR is also increasingly recognized as a health equity issue. The burden of resistant infections is not distributed equally across populations. Social and structural determinants of health influence exposure to infectious diseases, access to preventive services, healthcare utilization, antimicrobial prescribing patterns, and outcomes associated with resistant infections.
Individuals experiencing poverty, inadequate housing, residential crowding, food insecurity, barriers to healthcare access, and reduced access to sanitation infrastructure are disproportionately affected by both infectious diseases and antimicrobial-resistant organisms. A global evidence review found that lower educational attainment, lower income, inadequate access to healthcare, residential crowding, and higher levels of socioeconomic deprivation were consistently associated with increased risks of colonization or infection with priority antimicrobial-resistant pathogens8.
These findings suggest that AMR mitigation requires more than stewardship alone. Improving housing, access to primary healthcare, vaccination coverage, infection prevention measures, health literacy, and broader social determinants of health can contribute to reducing infection burden, decreasing antimicrobial use, and limiting the development of resistance. Addressing health inequities should therefore be considered an important component of AMR mitigation efforts.
Drivers of Antimicrobial Resistance
Although antimicrobial resistance occurs naturally through evolutionary processes, inappropriate antimicrobial use remains the most significant modifiable driver of resistance. Exposure to antimicrobials creates selective pressure that allows resistant microorganisms to survive, multiply, and spread throughout communities and healthcare settings1,2.
Public Health Ontario estimates that approximately one in four antibiotic prescriptions in Ontario may be unnecessary, while many additional prescriptions are issued for longer durations than recommended by current clinical evidence1. Unnecessary prescribing contributes to resistance without improving patient outcomes and increases the likelihood of medication-related adverse events.
Because most antimicrobial prescribing occurs outside hospital settings, particularly within primary care and long-term care environments, stewardship efforts in community settings are critical. Common respiratory tract infections, urinary tract infections, and other frequently encountered conditions account for a substantial proportion of antibiotic prescribing and represent important opportunities for optimization.
Research examining outpatient antibiotic prescribing patterns across Ontario demonstrated substantial regional variation, with Windsor-Essex County reporting the highest outpatient antibiotic prescribing rate in the province at approximately 787 prescriptions per 1,000 population annually3. While prescribing rates alone do not determine appropriateness, this variation suggests opportunities to improve consistency and alignment with evidence-based clinical recommendations.
Given Windsor-Essex County's historically high prescribing rates, local stewardship initiatives have particular importance in reducing unnecessary antimicrobial use and preserving the effectiveness of existing therapies.
Antimicrobial Stewardship as a Mitigation Strategy
Antimicrobial stewardship refers to coordinated interventions that promote the appropriate use of antimicrobial medications by ensuring the right medication, dose, route, and duration are selected when treatment is clinically indicated1.
The objective of AMS is not to limit access to antimicrobials when they are needed. Rather, stewardship seeks to optimize patient outcomes while reducing unintended consequences associated with antimicrobial use, including adverse drug events infections, unnecessary healthcare costs, and the development of antimicrobial resistance.
Evidence demonstrates that AMS programs can improve prescribing practices without compromising patient care. Stewardship initiatives have been associated with reduced antimicrobial consumption, improved adherence to clinical guidelines, fewer medication-related harms, and reduced rates of resistant organisms1.
Effective stewardship interventions include:
- Clinical decision-support tools;
- Evidence-based prescribing guidelines;
- Healthcare provider education;
- Audit and feedback initiatives;
- Infection prevention and control measures;
- Vaccination programs; and
- Diagnostic stewardship activities1,9.
Because the majority of antimicrobial prescribing occurs within community settings, strengthening stewardship within primary care, pharmacy, long-term care, and community healthcare environments remains a significant opportunity to reduce unnecessary antimicrobial use.
The Role of Public Health
Historically, antimicrobial stewardship efforts have focused primarily on hospitals, where accreditation requirements and established pharmacy oversight structures support stewardship implementation. Comparable structures are often limited in community-based healthcare settings despite the fact that most antimicrobials are prescribed outside acute care environments.
A scoping review identified 122 examples of antimicrobial stewardship and AMR surveillance initiatives involving local public health agencies across OECD countries9. Common activities included healthcare provider education, public awareness initiatives, antimicrobial use evaluations, surveillance, development of clinical guidance, and partnership development.
The review concluded that public health agencies are uniquely positioned to contribute to AMR mitigation through knowledge translation and dissemination of evidence, population-level surveillance, healthcare provider education, public awareness activities, health equity integration, and strategic leadership that facilitates collaboration across sectors9.
These responsibilities align closely with the Ontario Public Health Standards and with public health's broader mandate to prevent disease, promote health, and address population-level health challenges.
Current WECHU Antimicrobial Stewardship Initiatives and Leadership
The WECHU has established a leadership role in advancing antimicrobial stewardship and AMR awareness.
A key component of this work has been the development of a dedicated antimicrobial resistance resource webpage for healthcare professionals. The webpage provides access to stewardship resources, evidence-based prescribing guidance, clinical decision-support tools, and links to national resources, including AMMI Canada's antimicrobial prescribing guidance available through the Firstline application.
The WECHU has also supported antimicrobial stewardship education for nursing and postgraduate medical trainees in Windsor. These educational initiatives focus on stewardship principles, evidence-based prescribing practices, emerging resistance trends, and opportunities to optimize antimicrobial use.
Recognizing the importance of a One Health approach, the WECHU has contributed to discussions and environmental research initiatives examining AMR pathways and opportunities for cross-sector collaboration.
The WECHU joined local partners and organizations around the world in recognizing AMR Awareness Week from November 18 to 24, 2025. To mark the occasion, the WECHU’s Windsor office was illuminated in blue to raise awareness of the growing global threat posed by antimicrobial resistance and highlight the importance of responsible antibiotic use. The year’s theme, "Preventing Antimicrobial Resistance Together," called on individuals, health care providers, and organizations to take collective action.
On November 24, 2025, the WECHU hosted an AMS workshop titled "Optimizing Antibiotic Use: Practical Tools for AMS in Community Settings." The session brought together experts in infectious diseases, pharmacy, and public health to discuss AMR trends, share practical prescribing guidance, and highlight resources that support stewardship collaboration across Ontario. It also featured the Association of Medical Microbiology and Infectious Disease Canada’s national antimicrobial prescribing guidelines in the Firstline app, demonstrating how these resources can support consistent, evidence-informed antibiotic use. In preparation for the event, the WECHU developed an AMR webpage to share AMS resources, prescribing guidelines, and tools with community partners.
Following the November 2025 workshop, the WECHU convened health partners to establish the Windsor-Essex Antimicrobial Stewardship Community of Practice (CoP). The Community of Practice, now lead by Erie Shore HealthCare serves as a structured forum for collaboration among organizations involved in antimicrobial prescribing, infection prevention and control, surveillance, pharmacy, laboratory medicine, public health, primary care, long-term care, academia, and health system planning.
The CoP was established in recognition of the growing threat posed by AMR, Windsor-Essex’s historically high outpatient antibiotic prescribing rate, and the limited stewardship infrastructure available in many community-based healthcare settings. The primary goal of the Community of Practice is to strengthen capacity to address antimicrobial resistance through collaboration, knowledge exchange, and coordinated stewardship initiatives. Since its establishment, two Community of Practice meetings have been held. Participants have engaged in discussions related to stewardship best practices, emerging evidence, educational opportunities, prescribing resources, and local priorities for action.
Future priorities include expanding stewardship education opportunities, strengthening partnerships, exploring environmental and wastewater surveillance opportunities, advancing One Health collaborations, and supporting implementation of provincial and national AMS initiatives. By establishing the Community of Practice, the WECHU has created a coordinated mechanism for advancing antimicrobial stewardship across sectors where formal programs may be limited. This initiative reflects emerging evidence demonstrating that sustained progress in AMR mitigation requires collaboration, surveillance, education, and public health leadership.
Implications for Public Health and the Windsor-Essex County Health Unit
Antimicrobial resistance represents an emerging and increasingly significant public health challenge for Windsor-Essex County. The region's historically high outpatient antibiotic prescribing rates highlight the importance of local stewardship efforts that promote appropriate antimicrobial use, strengthen surveillance, and support collaboration across healthcare sectors.
The WECHU will continue to provide leadership in AMS across health sectors in Windsor-Essex County by collaborating with local partners to strengthen regional AMS networks. This work aligns with the WECHU’s strategic priority to lead collaborative action on community health priorities.
REFERENCES
- Public Health Ontario (PHO). (2023). At a Glance: Opportunities in Public Health to Improve Antibiotic Use in Ontario.publichealthontario.ca
- World Health Organization (WHO). (2015). Global Action Plan on Antimicrobial Resistance. who.int
- Schwartz, K. L., Achonu, C., Brown, K. A., Langford, B., Daneman, N., Johnstone, J., & Garber, G. (2018). Regional variability in outpatient antibiotic use in Ontario, Canada: a retrospective cross-sectional study. Canadian Medical Association Open Access Journal. cmajopen.ca
- Public Health Agency of Canada (PHAC). (2025). Canadian Antimicrobial Resistance Surveillance System (CARSS): 2025 Key Findings. canada.ca
- Public Health Agency of Canada (PHAC). (2026). Antimicrobial Resistance: What Canada’s doing. canada.ca
- Public Health Agency of Canada (PHAC). (2026). Pan-Canadian Action Plan on Antimicrobial Resistance: Year 2 Progress Report (June 2024 to May 2025). canada.ca
- Al-Khalaifah, H., Rahman, M. H., Al-Surrayai, T., Al-Dhumair, A., & Al-Hasan, M. A. (2025). One-Health Perspective of Antimicrobial Resistance (AMR): Human, Animals and Environmental Health. Life (Basel). pmc.ncbi.nlm.nih.gov
- Blackmon, S., Avendano, E., Nirmala, N., et al. (2024). Socioeconomic status and the risk for colonisation or infection with priority bacterial pathogens: A global evidence map. The Lancet Microbe, 6.
- Leung, V., Ashiru-Oredope, D., Hicks, L., Kabbani, S., Aloosh, M., Armstrong, I. E., Brown, K. A., Daneman, N., Lam, K., Meghani, H., Nur, M., Schwartz, K. L., & Langford, B. J. (2024). Leveraging local public health to advance antimicrobial stewardship (AMS) implementation and mitigate antimicrobial resistance (AMR): A scoping review. JAC Antimicrobial Resistance. pmc.ncbi.nlm.nih.gov