I recruit for (among others) IH here in Italy,and most of their schools will accept any kind of Tesol qualification...Celta or not.Of course if it is something completely unheard of they may think twice,but there are plenty of other Tesol qualifications that are accepted..Trinity or SIT for example......
British Council here will rarely recruit anyone at that level......Delta or equivalent is required in almost all cases.Again,any recognised equivalent to Delta is accepted.Most schools want specific experience,and they want to interview you and know what kind of person you are......