Short communication: Lack of intramammary niche recolonization during a sanitation program for the contagious mastitis pathogen Staphylococcus aureus genotype B

摘要

In Switzerland, sanitation programs of dairy herds infected with the contagious mastitis pathogenStaphylococcus aureusgenotype B (GTB) have been established for several years. In recent years,Streptococcus uberisand non-aureusstaphylococci have emerged as the bacteria most frequently isolated from bovine milk samples. The latter cause subclinical mastitis, and some species are more persistent or pathogenic than others. The present study aimed to investigate the developments in the intramammary colonization spectrum of 5 dairy herds undergoing a sanitation program forStaph. aureusGTB. We collected single-quarter milk samples aseptically from all lactating cows at 3-mo intervals during the sanitation period; after classical bacteriological analysis, MALDI-TOF mass spectrometry was used to identify the isolates to the species level. Non-aureusstaphylococci were found to be the bacterial group most frequently occurring on the selected farms, withStaphylococcus chromogenesandStaphylococcus xylosusbeing predominant. The present study demonstrated that GTB-infected cows treated with antibiotics lacked systematic recolonization with other bacteria during herd sanitation for the contagiousStaph. aureusGTB.