Virulence factor affecting bacterial dissemination and survival within the host (PubMed:2403529). Has magnesium-dependent catalytic activity toward sphingomyelin (SM) and acyl- and alkyl-lysophosphatidylcholine (LPC), but not toward sphingosylphosphorylcholine (SPC) and phosphatidylcholine (PC) (PubMed:2403529, PubMed:14732720). Lysophosphatidic acid (LPA), assumed to result from LPC hydrolysis, evokes pathophysiological responses after LPA receptor internalization (PubMed:14732720). Shows hemolytic activity (PubMed:2403529). a sphingomyelin + H2O = an N-acylsphing-4-enine 1-phosphate + choline + H(+) 1-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine + H2O = 1-(9Z-octadecenoyl)-sn-glycero-3-phosphate + choline + H(+) 1-O-hexadecyl-sn-glycero-3-phosphocholine + H2O = 1-O-hexadecyl-sn-glycero-3-phosphate + choline + H(+) Belongs to the sphingomyelinase D/phospholipase D family.