<unk> s (preferably known as pathogenicity<unk> s or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following: * colonization of a niche in the host (this includes movement towards and attachment to host cells) * immunoevasion, evasion of the host's immune response * immunosuppression, inhibition of the host's immune response (this includes leukocidin-mediated cell death) * entry into and exit out of cells (if the pathogen is an intracellular one) * obtain nutrition from the host Specific pathogens possess a wide array of<unk> s. Some are chromosomally encoded and intrinsic to the bacteria (e.g. capsules and endotoxin), whereas others are obtained from mobile genetic elements like plasmids and bacteriophages (e.g. some exotoxins).<unk> s encoded on mobile genetic elements spread through horizontal gene transfer, and can convert harmless bacteria into dangerous pathogens. Bacteria like Escherichia coli O157:H7 gain the majority of their<unk>  from mobile genetic elements. Gram-negative bacteria secrete a variety of<unk> s at host-pathogen interface, via membrane vesicle trafficking as bacterial outer membrane vesicles for invasion, nutrition and other cell-cell communications. It has been found that many pathogens have converged on similar<unk> s to battle against eukaryotic host defenses. These obtained bacterial<unk> s have two different routes used to help them survive and grow: * The<unk> s are used to assist and promote colonization of the host. These<unk> s include adhesins, invasins, and antiphagocytic<unk> s. * The<unk> s, including toxins, hemolysins and proteases, bring damage to the host.
Virulence factor
Bacterial adhesin
Microbial toxin
Protective factor
Insect toxin
Neurotoxin
Polysaccharide peptide
Host factor