The genus Lactobacillus contains a number of phenotypically and genotypically diverse species.  Lactobacilli are Gram-positive, nonsporulating rods that produce lactic acid as their primary byproduct of carbohydrate metabolism.  Some species of Lactobacillus are utilized by the food industry for their ability to ferment foods, and others are recognized for their proposed probiotic benefits.  Some species of lactobacilli are natural inhabitants of the gastrointestinal tract, skin, and vagina of humans and other mammals.