Assay of Staphylococcal -Haemolysin with Fish Erythrocytes

Abstract
Suspensions of erythrocytes from certain marine fish (cod, saithe, haddock and mackerel) were 4-16 times more sensitive than human or horse erythrocytes to staphylococcal .delta.-hemolysin. Cod erythrocytes were lysed rapidly by .delta.-hemolysin and the titers of hemolysin were independent of the temperatures at which the tests were incubated, over the range 0-37.degree. C. Fish erythrocytes were not lysed by purified .alpha.- and .beta.-hemolysins and no synergistic action was found between .beta.- and .delta.-hemolysins. In blood agar-overlay plates, the zones of lysis that developed in cod blood agar were larger and clearer than those that developed in human or horse blood agar.