Nevertheless, the effect of these transient whereas the long duration of undetected subclinical infections increases the effect on SCC and the possibility of spread of the causative bacteria. Although all CNS species isolated from milk in our study were evaluated using the same definition, striking differences were found among CNS species and only 4 were considered of particular interest. Persistence of S. chromogenes, S. haemolyticus, S. epidermidis, and S. simulans has been
diagnosed in previous studies by repeated isolation of the same species from the same quarter (Aarestrup and Jensen, 1997; Chaffer et al., 1999; Thorberg et al.,
2009). Our observations further confirm that particular CNS strains within these species, as evidenced by the repeated isolation of the same AFLP type, are able to
survive and persist in the udder.