Abstract
Klebsiella pneumoniae (K. pneumoniae) is an opportunistic and environmental mastitis pathogen prevalent in dairy herds worldwide. Owing to their genetic and genomic diversity, K. pneumoniae strains associated with bovine mastitis exhibit significant variation in virulence. Certain types of mastitis-causing K. pneumoniae strains exhibit enhanced pathogenicity and mammary adaptability, posing a serious threat to global public health. Bovine mastitis-causing K. pneumoniae strains can cause ultrastructural damage to bovine mammary epithelial cells (bMECs), leading to inflammatory injury, oxidative damage, apoptosis, pyroptosis, and immune evasion in bMECs. In this review, we summarize the prevalence, virulence genes, and pathogenic mechanisms of K. pneumoniae strains related to bovine mastitis. Given the increasing multidrug resistance of K. pneumoniae, we also outline the methods and mechanisms of phage therapy for K. pneumoniae infections, as well as future directions for treatment and prevention. These findings contribute to a deeper understanding of the population structure of mastitis-associated K. pneumoniae and provide valuable insights for future research on pathogenic mechanisms, vaccine development, and control strategies.