Detection of adhesin genes by PCR and analysis of their distribution in Staphylococcus aureus strains isolated from bovine mastitis.

摘要

126 strains of Staphylococcus aureus from bovine mastitis were divided into 2 spa types according to the number of repeat elements in the X region: spa <=7 type (a number of repeats seven or fewer than 7) and spa >7 type (a number of repeats more than 7). It was observed that there were 66% of spa >7 type and 34% of spa <=7 type strains. Somatic cell count of milk samples from quarters infected with strains of spa >7 type was significantly higher than that from quarters infected with the other type. All the strains were investigated by PCR for the presence of adhesin genes (fnbA, fnbB, fib, clfA, clfB, bbp, cna, eno ebpS and spa). Strains with fbbA were found only among spa >7 type (32%). Significantly more strains of this type possessed the fnbB gene compared with strains of spa <=7 type (4.65% and 68.67%, respectively). The prevalence of bbp, cna, and ebpS positive strains was significantly higher (P<0.05) in spa <=7 type (16.28%, 27.91% and 100%, respectively) than in spa >7 type (2.41%, 2.41%, and 51.80%, respectively). All of 126 strains harboured eno. Genes of clfA, clfB, and fib were detected in 125, 124 and 116 strains, respectively..