New research presented at the ESCMID Global Congress highlights the significant role that pet dogs and cats play in the spread of antibiotic-resistant bacteria. The study, conducted in Portugal and the UK, found evidence of direct transmission of multidrug-resistant bacteria between pets and their owners, emphasizing the need for enhanced monitoring and improved hygiene practices within pet-owning households.

The research, led by Juliana Menezes from the Antibiotic Resistance Lab at the Centre of Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, examined samples from both pets and owners. Fecal and urine samples, as well as skin swabs, were collected from 43 households in Portugal and 22 households in the UK. The study focused on identifying Enterobacterales strains, including E. coli and Klebsiella pneumoniae, that were resistant to common antibiotics such as third-generation cephalosporins and carbapenems.

Alarmingly, the study revealed that pet dogs and cats in both countries harbored the same antibiotic-resistant bacteria as their owners, amplifying concerns that pets can act as reservoirs of resistance and contribute to the spread of resistance to vital medicines. In Portugal, one dog was found to be colonized by an OXA-181-producing multidrug-resistant Escherichia coli strain, while in the UK, one dog was colonized by two strains of multidrug-resistant E. coli producing NDM-5 beta-lactamase.

Further analysis showed that in some households, pets and owners were carrying the same strains of antibiotic-resistant bacteria, with genetic analysis confirming their transmission between pets and humans. Notably, in three homes in Portugal, the timing of positive tests strongly suggested that the bacteria were passed from pets to humans.

The World Health Organization (WHO) has previously identified antibiotic resistance as one of the greatest threats to public health. With drug-resistant infections causing over 1.2 million deaths annually, this issue demands immediate attention. The findings of this study add to the mounting evidence that the transmission of antimicrobial resistance (AMR) bacteria between humans and animals, including pets, is pivotal in maintaining resistance levels.

Ms. Menezes emphasized the importance of including pet-owning households in national programs that monitor antibiotic resistance levels. She believes that understanding and addressing the transmission of antibiotic-resistant bacteria from pets to humans is crucial in combating the global crisis of antimicrobial resistance effectively.

To prevent the transmission of antibiotic-resistant bacteria between pets and humans, the researchers suggest practicing good hygiene, such as washing hands after petting the animals, handling their waste, and isolating unwell pets in a separate room. These measures can help minimize the spread of bacteria throughout households.

It is worth noting that all of the dogs and cats involved in the study were successfully treated for their infections, and their owners did not require treatment as they remained infection-free. The study's findings underscore the importance of comprehensive monitoring, improved hygiene practices, and targeted interventions to safeguard both animal and human health.

The study's results will be presented at the ESCMID Global Congress, which will take place in Barcelona, Spain, from April 27 to April 30, 2024, providing valuable insights for tackling the escalating threat of antibiotic resistance in the future.