Abstract

OCCURRENCE OF MASTITIS AND THE DETECTION OF VIRULENCE FACTORS IN STAPHYLOCOCCI ISOLATED FROM MASTITIC EWES

*Zigo F., Veszelits Lakti?ová K. and Vargová M.

ABSTRACT

Milk and milk products are important global dietary products, consumed by more than 6 billion people worldwide. Despite the increasing level of zoohygienic provision of dairy farming, inflammation of the mammary gland - mastitis is still one of the main health problems. The aim of study was examination of the udder health with detection of contagious and environmental pathogens causing mastitis in 940 ewes from four dairy herds localized in east of Slovakia. Particularly, in isolated Staphylococci were determined the presence of selected virulence factors such as formation of hemolysis, gelatinase, biofilm, hydrolyze DNA, and resistance to antibiotics with detection of methicillin resistance gene – mecA. The results of the study indicate that, in addition to the major udder pathogens (S. aureus, S. uberis, and S. agalactiae) causing mastitis, non-aureus Staphylococci (NAS) is a major risk to ewes. NAS, such as S. chromogenes, S. warneri, and S. xylosus isolated from infected ewes with clinical and chronic mastitis, had the highest representation of virulence factors in comparison to less virulent strains. In addition, isolates of S. aureus and NAS showed 44.2% resistance to one or more antimicrobial classes from mastitic milk samples. The 22 isolates (25.6% of all isolated staphylococci) from ewes in which phenotypic resistance was confirmed to β-lactam antimicrobials were tested by PCR for methicillin resistance with the detection of the mecA gene. We can conclude that despite the increased resistance to β-lactam antimicrobials, the presence of the mecA gene was not confirmed in the tested staphylococci.

Keywords: sheep, milking, mastitis, PCR, resistance.