You can't travel from the Czech Republic with a one country pass for Italy, but you can buy a normal ticket from the Czech Republic to the Italian border and then use the one country pass for Italy.

It is probably not worth buying a global pass only to travel from the Czech Republic to the Italian border.

Thank you so much. 
I would also like to ask if you would recommend me a website to buy a ticket from the Czech Republic to Italy, as our Czech Railways will not allow me to buy a ticket that crosses the Czech border.  
Best Regards 

Valentýna Vavřičková 

Thats nonsense-Ive done that ,many times on cd.cz.

BUT you have to clearly state to what station, not just ´granitsa´.

You can also try bahn.com, as this is german rails, but then you may have to split in 2 sectors. f.e. to/fro München. But as you did not clearly state to where and how (f.e. overnight od Prahy do INnsbruck, then smeny), its hard to say. Or-if you are Prazske or Brnenske-simply go to CD in HN-they can arrange it all for you and also sell the passes right there-on paper.

Depending on how you want to go and/or save money or use fastest-there may be many ways to cut the nr of koruny to spend

For In IT it also depends no how close these cities are from another and if you want to use hi-speed frecce or normal treni/vlakove.

Okay, this helped me a lot. Thank you so much. 
Valy