It depends. Many members say the MTS shell is too hard for loaches to eat, while others say they eat them fine. The loach will most likely eat the shrimp. The best way to rid a tank of MTS is through a tank cleaning and manual removal. MTS thrive in organic rich substrate. Tanks that are overfed, not cleaned frequently, or just plain old (organic material works its way into the substrate) are prone to large numbers of MTS.
If you want to lower the number I'd remove all your plants and shrimp, remove all your gravel and give the tank and gravel a good thorough washing in either used tank water or fresh dechlorinated water. This will remove most of the organics that your MTS are living on. Cleaning out your filter is also a good step, though I wouldn't do both at the same time for fear of upsetting the biological filter.
A much easier way is if you have access to a diatom filter. I'd still remove the shrimp and most of the plants but you can just shoot it around the tank, kick up all the gunk, and then replace the shrimp and plants. You will be shocked at how much debris is in a seemingly clean tank!