Lecithinase reaction of XXXX strains of different origin on Baird-Parker medium.

@entity1 @entity291 @entity794
@entity794 produces one or more enzymes with lipolytic activity, but differences between strains have been reported (Owens and John 1975; O'Toole 1987; Rollof et al. 1987). The biological and biochemical properties of these enzymes have been investigated and results were recently reviewed (K  tting et al. 1984). Baird-Parker medium (Baird-Parker 1962) is a selective medium commonly used for the isolation of Staph. aureus. The presence of egg yolk in this medium permits the detection of two reactions due to lipolytic activity of staphylococci: (1) Lecithinase reaction, a zone of precipitate in the medium surrounding the colonies; and (2) Lipase reaction or 'pearly layer', an iridescent film in and immediately surrounding colonies, visible by reflected light (iridescent sheen or 'oil in water'). In this study, @entity1 and @entity291 strains, previously biotyped according to the scheme of Devriese et al. (1984), were compared for production of a zone of precipitation, lecithinase reaction, on Baird-Parker medium. @entity291 and @entity1 strains of Staph. aureus were compared for production of the egg yolk reaction (lecithinase reaction) on Baird-Parker medium and the results were related to their biotypes and site of origin of the sample. @entity1 strains and strains biotyped as @entity1 biotypes had higher percentage of positive results than @entity291 isolates and/or biotypes. However, all strains isolated from body sites of heifers produced a positive reaction regardless of the biotype.
