usb drives disconnecting

My wifes late 2010 macbook pro has been having a serious issue with ejecting just about any usb drive connected. Shes a graphic designer and is constantly plugging and unplugging portable drives and mini flash drives, but always sure to properly eject them before pulling them. Recently (and becoming more and more frequent), the drives with just disconnect on its own and will give the warning that the drive was not properly ejected. it then immediately tries to mount again and disconnectes again. this happen no matter which drive or flash unit we use on either usb port. every drive she has had problems with works perfectly fine with no eject problems on my 2011 macbook pro, so that rules out bad cables or drives. We've also tried usb hubs and zapping the pram, but with no success. as of 5 mins ago, i just tried to connect a usb microSD adapter with a 8gb microSD card inside and it ejected in less than 30 secs and goes on an endless loop of mounting and improperly ejecting. the same usb is now in my macbook pro and is fine as i write this.

if anyone has had this issue or knows what the problem may be, please enlighten us. im leaning more towards the ports are shot....but ive been know to be wrong. any help is appreciated. thanks in advance.