Has anyone heard of a bitch losing a litter because of this organism?
If so has she ever gone on to produce a viable litter?

Just heard of a tragic case.

Did it come from the dogs sheath ?

We dont know, it may have in the first mating but this was a second litter, different dog....same results despite extensive antibiotic treatment.

Don't know what this is but to save my heartbreak I'd have her spayed. Was she swabbed for nasties before hand? Has a swab been taken from both to be cultured?

Yes she was swabbed and treated the first time, swabbed again before mating and yet it happened again.
The owner is not going to mate her again as she is a carrier of this organism ( perfectly healthy otherwise) but she couldnt find anyone else whose bitch had suffered this fate.

She asked me if I knew and if anyone had trouble with other bitches in the household.
No one seems to know.

Only known it happen with the dog swabs....