Bacteriodes fragilis

Bacteroides fragilis is a bacterium that normally inhabits the human intestinal tract. While it typically causes no issues when confined to the gut, it can lead to abscesses if it enters the body through an injury. The bacterial capsule stimulates the body to wall off the bacteria, forming an abscess to limit their spread. Bacteroides species are among the bacteria that can cause disease in humans, specifically abscesses.1

Coliform bacteria, on the other hand, are rod-shaped microorganisms found in the intestinal tracts of animals and are widespread in the environment. They serve as indicators of water quality, signaling potential fecal contamination. While coliform bacteria themselves usually don't cause illness, their presence suggests the possibility of contamination by disease-causing organisms.2