That's a drag. IDK
I have seen several reports on iboats, whaler, and sea-ray sites. One fellow (microbiologist from UC Davis) claimed its a a Strep bacteria that likes the white vinyl. Doesn't sound like marine quality vinyl. I'd see if your upholstery guy or his supplier can make it right.
Another guy claimed oxy-10 acne remover killed/it cleaned it... otherwise put a couple of pink ribbons around there to show solidarity with the fight against breast cancer
