Lactobacillus species produce lactic acid as their single or major metabolic end product from glucose fermentation

Taxonomy
Family: Lactobacillaceae

Natural habitats
They are widely distributed in the environment
They belong to the normal flora of the intestine, urogenital tract and mouth.

Clinical significance
Despite the reputation of lactobacilli as beneficial organisms, they can be involved in serious infections, especially in immunocompromised individuals.

Lactobacilli are particularly associated with advanced dental caries, where they are considered a secondary colonizer because of their preference for low-pH habitats, but probaply play a role in exacerbating existing lesions.

The clinical infections most commonly caused by lactobacilli are bacteremia and endocarditis, with an associated relatively high mortality rate, with the mouth, the primary route of entry to the bloodstream.