Hi, I'm having the similar problem (there is only /dev/cu.Bluetooth*, the /dev/cu.usbserial* has gone! There used to be a /dev/cu.usbserial* few weeks ago. It just suddenly disappeared).
I'm on Mac OS El Capitian 10.11.3.
The Edison is powered on (with an adaptor). I have connected the serial port (the corner micro usb port, with the switch in the middle pointing to the serial ports) to the mac USB port.
Again, the serial port used to work fine (e.g. screen -L /dev/cu.usbserial* used to be there). Somehow it just disappered. Strange.
Has anyone got similar problem and managed to fixed it? And how?