The rule of thumb I use to divide a plant is to end up with at least 3 healthy bulbs in each piece. So I would not divide that plant

There does seem to be some problem with the plant in general. I would expect those older bulbs to still have leaves. It’s hard to tell from the photo but the pot appears to be too small. The way the roots are it looks like it was removed from a pot and placed in another a little too high and no new medium?

Sunken brown/black spots I would say are bacterial, but could be culture and nutrition.

As I recommend in another thread, the St. Augustine Orchid Society has excellent info and pictures on leaf spots. Another great resource is the American Orchid Society web site. They have a catalog of webinars free to the public. They do a monthly Greenhouse Chat that covers a wide range of topics lots of info.

Thank you James! I will not dived now.

If it's bacterial are my other plants in danger?

I wouldn’t worry about separating it, fungus and bacteria are everywhere. Don’t share water or cutting utensils with other plants.

Thank you!

Polina.

It looks dehydrated to me. It may need to be watered more frequently. It has new growth so that's a good sign!

Thank you!