Definitely 2, maybe 3 in Vietnam.
CHC operate 155 out of Den Helder (Netherlands), Bristow operate them out of Norwich (UK). Both haven't had them very long, but plenty of experience of the type from the 6 in Nigeria (Bristow) and CHC have lots of 365 experience. Dancopter (Denmark) have 2, also gas & oil.
Premiair (UK) are always looking for corporate pilots, 155 being one of their types.
An Indian company bought a couple last year, don't know much about them though.