Hi Héctor,
ENTUR uses OpenTripPlanner 2 with NeTEx (Nordic Profile). Not sure how close the Italian feeds are to the Nordic profile.
Regarding Public-transport-enabler, I assume it will not support NeTEx/Siri directly but only routing services which might use these formats.
Regarding PTE's OTP support, I'm not up-to-date. Our former initiative stalled.
Best regards,
Holger