The following link can give you some advice on common causes of front loader washer odors and some preventive measures you can take to keep them from coming back:http://www.fixya.com/support/r3608512-getting_rid_front_loader_mildew_odor
The most common causes of persistent odors comes from not leaving the door OPEN between washes. The manufacturer recommends this to allow the wash tub to air out and to prevent mold and mildew from forming.
NOTE: Residual water in the drain lines and pump reservoir is NORMAL. Leaving the door open will NOT make this water evaporate, but will allow constant air flow to prevent it from becoming stagnant.
A common secondary cause comes from debris becoming trapped in the rubber door bellow and/or drain pump. It is recommended that you pull back the rubber folds in the door bellow (gray rubber seal) and check for dirt, debris or small articles of clothing that may have become trapped there. Socks are a common thing that become trapped, and if left for a long period of time, become stagnant. The drain pump reservoir is another common place for things to collect and become stagnant.
If you need to check the drain pump, the following link explains how:http://www.fixya.com/support/r3574284-checking_the_drain_pump_on_a_front_loade
You can use use a 50/50 mix of bleach and water to clean the door bellow thoroughly with a scrubbing pad to get rid of mold and mildew. Use the green kitchen type scrub pads as they are not as abrasive. Do not use steel wool. If the mold becomes permiated in the rubber and will not come off, you will need to replace the bellow to get rid of it. The following link explains how:
Replacement parts (if required) can be purchased from any of the following websites:
Prices vary between sites, so shop and compare. The first three sites listed also have helpful exploded view parts illustrations to assist you with locating and properly identifying the parts you may need.
All these are preventive measures that can drastically prevent odors, mold and mildew. Read through the advice given and post back and let me kow if you require additional assistance. I hope you find this information helpful.