Is the lyme spirochete (borrelia) the only infectious cause of raynaud's? if not, what are some other infections that cause this?

Not likely: Raynaud's is either primary or secondary.Primary raynaud's means there is no known reason for it (idiopathic)and that it is not part of a more severe autoimmune disease such as lupus or scleroderma.Likely there's a genetic link since this can run in families. Secondary raynaud's is a more severe form that is part of an autoimmune disease.It's not well documented that any infections cause raynaud's.

Possibly Bartonella: Interesting question. No one knows for sure but it seems likely to me that bartonella may also cause raynaud's, but most with bartonella infection also have lyme ; bartonella is even harder to diagnose than lyme. There may be other microbes not yet known to cause it. If someone has raynaud's ; standard lyme tests are negative they may well still have lyme disease- see http://bit.Ly/1aaqjgc.