Bull Vet Inst Pulawy 55, 681-684, 2011

full text

VIRULENCE FACTORS IN COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM COWS WITH SUBCLINICAL MASTITIS

EDWARD MALINOWSKI, ANNA KŁOSSOWSKA, AND EWA ZASTEMPOWSKA

The aim of this study was to investigate the presence of virulence genes in 46 coagulase-negative staphylococci (CNS) strains isolated from 46 udder quarters of 46 cows with subclinical mastitis. The isolates were examined phenotypically (cultural features, Gram stain, catalase, coagulase, API tests) and genotypically for: icaA, icaAB, icaD, atlE, bhp, agrA, sarA, mecA, and blaZ genes. These isolates had no nuc and coa genes, and were identified as S. warneri (11 strains), S. chromogenes (10), S. xylosus (seven), S. epidermidis (one), S. hyicus (one), and other Staphylococcus species (16). The single virulence genes or their combinations were detected in nine (19.6 %) of isolates. The following genes were found: blaZ (in four isolates), mecA (3), sarA (3), agrA (3), and atlE (three). None of the strains harboured the bhp, icaA, icaD, and icaAB genes. In conclusion, subclinical mastitis in cows can be caused by different species of CNS that harbour different virulence factors.

Key words: cow, mastitis, coagulase-negative staphylococci, virulence factors.