Population genomics of Staphylococcus pseudintermedius in companion animals in the United States

Area of Science:

• Veterinary microbiology
• Population genomics
• Antimicrobial resistance

Background:

• Staphylococcus pseudintermedius is a common dog bacterium and opportunistic pathogen.
• Methicillin-resistant S. pseudintermedius (MRSP) is an emerging threat.
• Understanding MRSP evolution and spread is crucial for canine health.

Purpose of the Study:

• To investigate the population genomics of Staphylococcus pseudintermedius in the New England region.
• To identify the mechanisms driving the emergence and dissemination of MRSP and multidrug-resistant clones.
• To compare MRSP lineages in New England with those in other regions, such as Texas.

Main Methods:

• Conducted a population genomics study of 130 clinical S. pseudintermedius isolates from dogs and cats.
• Analyzed genetic diversity and accessory gene pools within the bacterial population.
• Compared findings with existing data from a Texas population.

Main Results:

• Identified co-circulating, phylogenetically diverse S. pseudintermedius lineages.
• Observed extensive horizontal gene transfer and acquisition of resistance determinants.
• Found evidence of clonal expansion and long-distance dissemination of MRSP lineages, particularly when compared to a Texas population.

Conclusions:

• S. pseudintermedius exhibits significant diversification, influenced by horizontal gene acquisition.
• Multiple MRSP and multidrug-resistant clones have emerged independently and spread widely.
• Clonal expansion of MRSP is a significant concern, highlighting the need for surveillance and control strategies in companion animals.