Enterobacter aerogenes is a facultative anaerobe. It is found in the human gastrointestinal tract but does not generally cause disease in healthy individuals. It ferments both glucose and lactose as a carbon source. Since it produces hydrogen gas, it may be of commercial interest. At present, however, there is a greater concern that it is resistant to many antibiotics. Because of this resistance, it is frequently found in hospitals, where it infects weakened patients together with other pathogens.