A Case of Sepsis Caused by ST80 Multidrug‐Resistant <i>Enterococcus faecium</i> With Concurrent <i>Klebsiella pneumoniae</i> Infection in a Dog

BACKGROUND: Enterococcus faecium is a Gram-positive opportunistic pathogen commonly found in the gastrointestinal tract of humans and animals. OBJECTIVES: The objective of this study was to describe a clinical case of multidrug-resistant E. faecium ST80 respiratory tract infection that progressed to sepsis in a dog. METHODS: An 8-year-old, 20-kg castrated male mixed-breed dog presented with acute respiratory distress, haemoptysis and systemic inflammatory signs. The clinical condition deteriorated, progressing to acute respiratory distress syndrome and respiratory fatigue, which ultimately resulted in mortality. Diagnostic evaluation included cytological examination, bacterial and viral infection testing and histological analysis of tissue samples. RESULTS: Enterococcus faecium isolates from the nasal swab, liver, kidney and rectum exhibited identical resistance profiles and resistance to all antibiotics tested except vancomycin, nitrofurantoin and chloramphenicol. Enterococcus faecium isolates from the liver, kidney and rectum were characterised using whole-genome sequencing. The isolates carried multiple antibiotic resistance and virulence genes (scm, acm, efaAfm and sgrA). Additionally, a high genetic similarity was observed among E. faecium isolates from the liver and kidney, supporting systemic dissemination of a single E. faecium clone consistent with sepsis. CONCLUSIONS: The findings emphasise the clinical significance of enterococcal infections and their potential role in disease progression, underscoring the importance of managing virulent and drug-resistant Enterococcus infections in dogs.