Molecular biology of enterotoxic genes profiles of staphylococcus aureus associated with sub-clinical mastitis in dairy cows in Sulaimanyah province

الملخص EN

The study were conducted on 250 dairy cows (985 quarters) selected randomly from six selected dairy herds and also from individual cows from areas around the Sulaimani region to investigate the coagulase negative and coagulase positive Staphylococcus species caused clinical and sub-clinical mastitis in dairy cattle.

The prevalence of bovine mastitis was 80 % (200 cows).

Production of enterotoxins A, B, C and D were detected by a reverse passive latex agglutination test (RPLA).

Among 246 coagulase positive staph.

(CoPS) isolates, 113 (45.9%) were found to be positive for production of one or more of enterotoxin types A, B and C, while none of the coagulase negative staph.

(CoNS) isolates had the ability to produce enterotoxin.

The technique of polymerase chain reaction was applied to determine the presence of gene that coded for staphylococcal pantone-valantine lucocidine (luk gene) and staphylococcal enterotoxin (se gene).

Among 246 S.aureus and 95 CoNS isolates only 10 isolates(4.1%) were found to carry the luk gene.

None of the CoNS isolates carried the (luk gene).

And also from 246 Staphylococcus aureus isolates, 125 isolates (45.9%) were found to be involved in production of one or more se genes, out of 125 S.

aureus enterotoxin producer, it was found that 66 isolates (52.8 %) produce enterotoxin type A; 27 isolates (21.6%) produce enterotoxin type B; 20 isolates (16 %) produce enterotoxin type C and 12 isolates (9.6 %) produce enterotoxin type E.

None of the isolates tested produce enterotoxin type D.

The results indicated that S.

aureus isolated from bovine mastitis has the ability to produce enterotoxin, while CoNS did not have the ability to produce enterotoxin.

Additionally, it was demonstrated that S.

aureus causing mastitis in Sulaimanian dairy herds harbored the sea, seb, sec and see genes and produced the SEA, SEB ,SEC and SED toxin, suggesting that it may play a role in bovine mastitis pathogenesis.