Using a P-channel mosfet instead of a PNP
if the line is high when it is non-active(instead of floating) you should be able to remove the pullup and leave the 3k and have it work without modification.

When the P Channel has it's gate high it should be in cutoff, as you would want. When the gate goes low you can expect it to saturate, allowing full conduction through the mosfet like a short. MOSFETs are slower, you want to make sure you have one that has a switching frequency that is relatively close to the rate they suggest, but you should have no issues with this, the USB control will not be toggled at an extremely high rate(>10MHz).

The 3k resistor you have in series you can leave to avoid you pulling too much current when changing states, but it will probably work better if you reduce that a significant amount. 

You want to make sure that the change in Voltage your output pin must drive divided by your resistance is less than the maximum current you pin can drive. This will protect your circuit without slowing the drive time of the MOSFET. The MOSFET is effectively a capacitance, so you can think of the capacitance with the resistance causing a delay to your signal (4 tau or 5 tau, depending on philosophy).