Dermicidin is a beta-defensin made my sweat glands and is secreated into sweat. It has an antimicrobial effect against organisms like E.coli, Staphlococcus aureus and Candida albicans.
it is 99% water, sodium chloride, and trace amounts of wastes, lactic acid, and vitamin C.
Yes, sweat itself is mostly sterile and odorless. However, when it comes into contact with bacteria on the skin's surface, the bacteria can metabolize the sweat and produce odorous compounds.