Phal: Black spots with yellow on leaves

[TracyLee9]

Does anyone know if I need to be concerned about these black on yellow markings? Firstly, along the leaf crease in the middle and then towards the base on the edge. I bought this orchid form the nursery 2 weeks ago, but only noticed the markings now (and only because I had some drama on a subsequent new orchid that made me really inspect my existing orchids – see Transport disaster post if interested, eek!!). I reckon these markings were there when I bought it.

I’ve been reading up on other black spot posts and it sounds like maybe this is a bacteria/fungus, but I’m not sure, hence writing this post. If it is a bacteria, looks like I’ve caught it early…but now what? Cut it, spray it, wait first to see if it spreads? And how does it spread? Do I keep it separate from my other orchids? Can I transfer it from one orchid to another just by touching it and then touching other orchids?