Hemolytic properties of exosubstance of serovar 5 Listeria monocytogenes compared with beta toxin of Staphylococcus aureus.

Hemolytic exosubstance of serovar 5 Listeria monocytogenes, tested in native and pre-purified forms, produced identical interactions with exosubstances of certain bacterial species to those of Staphylococcus aureus beta toxin on agars with ovine, rabbit, human and equine erythrocytes. In the same way like the staphylococcal beta toxin, it enhanced hemolysis of other L. monocytogenes serovars, though only slightly and after a longer time of incubation. With the hemolysin of Corynebacterium pyogenes it produced a characteristic sickle-shape hemolysis on sheep blood agars. The listerial exosubstance observed had a direct hemolytic effect on sheep, rabbit, human and horse erythrocytes in both agar and tube tests. In addition to the direct hemolysis in tube tests it produced the hot-cold type hemolysis in titres considerably exceeding those of direct action on sheep erythrocytes. The staphylococcal beta toxin macroscopically altered only sheep erythrocytes, with which it produced hot-cold hemolysis in tube tests, and gave no visible reaction with other erythrocytes used either in agar or tube tests. A comparison of both exosubstances showed that their hemolytic activity was strongly enhanced by the exosubstance of Rhodococcus equi on sheep, rabbit and human blood agars, though only the hemolysin of serovar 5 L. monocytogenes had its hemolysis enhanced on horse erythrocytes also.