Department of Veterinary Microbiology and Biotechnology, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animal Sciences, Bikaner-334001 (Rajasthan)
Online published on 19 December, 2013.
Mastitis is one of the most common global diseases of dairy cattle causing severe economical losses to dairy industry. Among several etiological agents Staphyococcus aureus is regarded as the most common pathogen responsible for causing all forms of mastitis which are difficult to be treated because of certain reasons associated with this organism. Haemolysins produced by S. aureus have been considered true virulent factors in causation of the disease and typing and titration of these haemolysins may well be an indicator of pathogenicity of these organisms. In the present investigation S. aureus were obtained from milk samples collected from H.F. crosses and Rathi cattle of various parities and from different localities in Bikaner (Rajastyhan). The organisms were characterised for the type and titre of the toxins produced using rabbit, cattle and horse erythrocytes for alpha (α), beta (β), and delta (δ) toxins, respectively. In the present investigation all the isolates produced α and β toxins but not δ. The titre of α-toxin from H-F isolates ranged between 1:40 and 1:1280, whereas for Rathi isolates it ranged between 1:160 and 1:2560. The titre of β-toxin was much less than that of α-toxin for isolates both from H-F and Rathi cattle which was between 1:5 and 1:30, and between 1:5 and 1:60 for isolates from H-F and Rathi cattle, respectively. Most of the isolates produced higher titres of α-toxin.
