Genetic Characterization and Molecular Docking of Flavonoid Compounds Against Klebsiella pneumoniae and Bovine Herpesvirus Type 1 (BoHV-1) Isolated From Clinical Dairy Cattle Cases.

Klebsiella pneumoniae and Bovine Herpesvirus Type 1 (BoHV-1) are two significant pathogens of dairy cattle that cause debilitating diseases in the respiratory, reproductive, and mammary gland systems. Conventional antimicrobials have become less effective due to the emergence of antimicrobial-resistant strains, and other molecules are needed for therapeutic purposes. This study was designed to identify Klebsiella pneumoniae and BoHV-1 infection in dairy cows and to assess the antimicrobial activity of flavonoids derived from plants as alternative drugs. A total of 50 samples were collected, including 40 milk samples from cows with clinical mastitis and 10 nasal swabs from cattle with respiratory symptoms between December 12, 2023, and April 15, 2024. Mastitis-associated Klebsiella pneumoniae was recovered from 15/40 milk samples (37.5%), and BoHV-1 was found in nasal swabs of 50% of the animals. The molecular docking studies found that the binding affinity of quercetin with Klebsiella pneumoniae OmpA (-8.2 kcal/mol) was higher than the binding affinity of cefotaxime with the same OmpA (-6.9 kcal/mol). Kaempferol proved to have dual inhibitory activity against both pathogens (-7.5 kcal/mol). All isolates contained a conserved G→T transversion at Position 21, which is based on multiple sequence alignment with the BoHV-1 gB reference sequence MG407791.1. The results indicate that flavonoids, specifically quercetin and kaempferol, showed good binding properties with the targeted bacteria and viruses and warrant further research to investigate their therapeutic potential.