Visualization of Staphylococcus aureus in the bovine mammary gland by fluorescence in situ hybridization

Bovine mastitis poses significant challenges to the dairy industry. Staphylococcus aureus is particularly problematic because of its ability to cause long-lasting infections. The aim of this study was to visualize S. aureus in infected mammary gland tissues via a specific fluorescent oligonucleotide probe and confocal microscopy. Tissue samples were obtained from cows with confirmed positive S. aureus milk cultures. Fluorescent in situ hybridization revealed the existence of large bacterial aggregates, spanning 30-50 μm in size and specifically located within the mammary parenchyma. This is the first direct visualization of S. aureus aggregates within the udder of naturally infected cows.