Bacterial infection pathways aim to capture molecular mechanisms of human bacterial diseases related to bacterial adhesion to and invasion of human host cells and tissues, toxigenicity (interaction of bacterially-produced toxins with the human host), and evasion of the host's immune defense.

Bacterial infection pathways currently include some metabolic processes mediated by intracellular Mycobacterium tuberculosis, the actions of clostridial, anthrax, and diphtheria toxins, and the entry of Listeria monocytogenes into human cells.

Clostridial toxins are produced by anaerobic spore-forming gram-positive bacilli of the genus Clostridium. Clostridium tetani causes tetanus, Clostridium botulinum causes botulism, Clostridium perfringens causes gas gangrene, and Clostridium difficile causes pseudomembranous colitis. The anthrax toxin is produced by the aerobic spore-forming gram-positive bacilli of the species Bacillus anthracis. The diphtheria toxin is produced by aerobic nonspore-forming gram-positive bacilli of the species Corynebacterium diphtheriae infected with the bacterial virus corynephage beta. Enterobacterial toxins are produced by pathogenic strains of Enterobacteriaceae, aerobic gram-negative bacilli that are part of normal intestinal flora, such as Escherichia coli.

Mycobacterium tuberculosis bacteria are acid-fast, aerobic, nonspore-forming bacilli that cause tuberculosis, a wide-spread disease that usually affects the lungs.

Listeria monocytogenes bacteria are aerobic nonspore-forming gram-positive bacilli that cause listeriosis.