Antimicrobial Resistance in People and Animals

Background

Antimicrobial resistance (AR), when germs like bacteria and fungi develop the ability to defeat the drugs used to kill them, is a One Health issue affecting not only people, but animals, plants, and the environment. The use of antimicrobials anywhere – such as in a hospital or on a farm – can contribute to AR, making infections in both people and animals harder to treat. Like humans, animals sometimes carry germs, including AR germs, that can make people sick. People can get sick from these germs by eating contaminated food or by touching animals and their environments.

CDC has worked diligently with partners to improve how antimicrobials are used in hospitals and on farms (antimicrobial stewardship), to increase awareness of AR spread and emphasize the importance of working with veterinarians when considering using antimicrobials to care for animals.

Working with experts

A decision making tool

In 2016, an outbreak of multidrug-resistant Salmonella was linked to dairy calves, highlighting the need for farm-level tools to prevent infections and ensure proper stewardship of antimicrobials in animals.

This outbreak led to CDC working with Dr. Greg Habing at The Ohio State University and partners at the University of Wisconsin-Madison to trace the spread of Salmonella in the dairy calf production process: in markets, on farms, during transportation, and in slaughter holding pens. Dr. Habing also conducted a survey among calf producers to discover where antimicrobials were being used unnecessarily throughout the calf production process.

The team then developed a decision-making tool to encourage calf producers to correctly use veterinarian-developed treatment protocols. Informed stewardship training and decision-making tools for producers may help reduce inappropriate antimicrobial use and slow the development of resistant bacteria and outbreaks, like Salmonella, in calf production.

Collaboration with partners

CDC also worked with Dr. Paul Plummer and Iowa State University to learn about how susceptible Campylobacter bacteria are to becoming resistant in mother dogs and puppies in breeding kennels. From 2016 to 2018, a severe outbreak of Campylobacter in humans was linked to pet store puppies, resulting in illnesses in people across 18 states – demonstrating the need for research on antimicrobial use and infection control practices in breeding kennels.

An antimicrobial use survey was given to dog breeders to capture details about how common Campylobacter is in kennels, and the use of antimicrobials in breeding operations. Improving standardized infection control practices could help prevent the spread of diarrhea among puppies, reducing a top reason breeders use antibiotics. Overall, the results show a need to reduce unnecessary antibiotic use in breeder kennels. CDC is continuing to work with partners including the pet industry to address this need.

Prescription practices

Learning about what influences veterinarians' prescribing practices and attitudes toward AR is crucial to understand and address AR in animal medicine. CDC worked with Dr. Dan Taylor and the Colorado Integrated Food Safety Centers of Excellence School of Public Health to assess veterinary prescription practices, identify veterinarian attitudes about AR, and find knowledge gaps. Using a survey, Dr. Taylor found that more recently trained veterinarians prescribed unnecessary antimicrobials less often than veterinarians further out of training. Client pressures also seemed to influence prescribing practices, as veterinarians often prescribe unnecessary antimicrobials to maintain client satisfaction. Insightful research studies like this can inform the development of trainings and resources to improve prescribing and combat AR.

Recently, Taylor also led a nationwide survey that assessed opinions of antimicrobial use in small animal practice. Results of this work are published in Zoonoses and Public Health.

Next steps

CDC will continue to work with partners and invest in innovative projects to better understand and share how AR germs impact the health of people and animals. In December 2021 as a part of CDC's AMR Exchange, CDC hosted a webinar with these experts to focus on the important issue of AR in animals and highlighting these project impacts. Follow @CDC_AR to hear about upcoming webinars and to learn more about CDC's AR activities, resources, and events.