Modified 'nurse' culture technique for accelerating the growth of atypical Aeromonas salmonicida on blood agar

A modified technique for accelerating the growth of atypical Aeromonas salmonicida, the causative agent of furunculosis disease in salmonids, is described. The method was modified from the technique first described by Evelyn et al. (1989) in which a 'nurse' culture of Renibacterium salmoninarum was used to accelerate the growth of R. salmoninarum in samples on LDM2 culture media plates. In the present procedure, the 'nurse' organism is a stock culture of Staphylococcus aureus, a heavy suspension of which is streaked onto the middle of a blood agar culture plate. Growth of the nurse culture occurs rapidly and modifies conditions in the culture plate such that atypical A. salmonicida shows satellitism by accelerated growth close to the S. aureus streak.