Both streaked strains and supernatants of the LLO- L.
monocytogenes mutant strain were always nonhemolytic on
BHIA and CAB with or without PT. On the other hand,
streaked cells and supernatants of L. monocytogenes mutant
strains affected either in PI-PLC or in lecithinase production
displayed clear zones of hemolysis which were enhanced in
the presence of PT.
The cholesterol-treated supernatants of L. ivanovii did not
display the inner halo of complete hemolysis. Without PT,
the external ring of incomplete hemolysis on BHIA and CAB
was of a size similar to that of the nontreated supernatants.
Nevertheless, the zone of incomplete hemolysis was
strongly inhibited in both media when PT was added.