Group D streptococcus is the sort of streptococcus that normally lives in our GI system (bowels, gall bladder etc) It does not normally cause invasive/aggressive infection but can cause a problem in people (adults and babies) who have had surgery to the bowel/gall bladder, or who have lots of intravenous lines in them etc; as some very poorly or premature babies sometimes do.

In other words, it is not intrinsically dangerous, but can cause a problem it gets into the bloodstream in those who are already poorly – especially it is resistant to some of the commonly – used antibiotics.

It also does not normally cause necrotising fasciitis, though it might be there in a mixture of bugs – say in a surgical wound.