In One Health, what is meant by environmental reservoirs contributing to antimicrobial resistance?

• A. Non-host environments like soil and water that harbor resistant microbes outside hosts.
• B. The human gut microbiome.
• C. Animal fur.
• D. Laboratory cell lines.

Answer: (B)

Environmental reservoirs are non-host environments where resistant bacteria and resistance genes persist outside animals and people—things like soil, freshwater, wastewater, and manure. They matter in One Health because these environments can maintain resistance, foster gene exchange, and spread resistance to humans and animals through contact, water, crops, or contaminated resources. The human gut microbiome is a reservoir for resistance, but it’s inside a host, not an environmental reservoir. So while gut bacteria play a big role in AMR dynamics, the concept being tested here focuses on external, environmental sources. The other options describe surfaces or systems that don’t capture the environmental reservoir idea as clearly.