That depends on the backpacking hostel! Is it clean? Most backpacking hostels don't maintain the place very well and it can be quite smelly and disgusting. I stayed in a place where fifteen or so people slept in one room and the smell was nauseating. If the sheets are not clean then you might catch some disease or the other so make sure you take your own sheets. The toilets are another problem and you must make sure that they are clean before you use them. A uni sex hostel may not be such a good idea if you are worried about cleanliness.