Characterization of Staphylococcus simulans strains isolated from cases ofbovine mastitis

This study was conducted to characterize Staphylococcus simulans isolated f rom cases of bovine mastitis. A total of 134 isolates of S. simulans select ed from 80 quarters from 61 cows or heifers in 37 different herds were char acterized by EcoRI ribotyping. From 22 quarters two to seven consecutive is olates taken at weekly intervals were selected. Furthermore, three isolates from clinical infections in humans and two reference strains were included . A total of 16 different ribotypes were found, however, two types predomin ated. In most herds more than one type was found. From the 22 different qua rters, where 76 paired or multiple isolates were at disposal, the same ribo type was constantly found in the same quarter. This study showed that S. si mulans causing bovine mastitis could be divided into relatively large numbe r of different types, but that two types predominated. More than one type c ould be found in the same herd and within different quarters of the same co w, but ribotyping confirmed that S. simulans could be the cause of persiste nt and stable infections. (C) 1999 Elsevier Science B.V. All rights reserve d.