Table 1.
Intestinal environmental cues utilized by virulence gene regulation of pathogens.
| Related-Pathway | |||||||
|---|---|---|---|---|---|---|---|
| Stimulus | Putative Site | Pathogen | Regulator | Virulence gene | Pathological meanings | Ref. | |
| Physico-chemical sensing | pH | stomach | EPEC | GadX |
gadA↑ ler↓ |
Adaptation to acidic environment -Resistance to acid↑ -Virulence factors↓ |
22 |
| Bicarbonate | duodenum-colon | C. rodentium | AraC/XylS-like proteins (RegA) |
adcA↑ kfcC↑ |
Increased chance to find niches -Motility (fimbriae)↑ -Carbon metabolism↑ |
25 | |
| Osmolarity | ileum | S. typhimurium | EnvZ/OmpR-TviA |
flhC↓ viaB↑ |
Adaptation to host tissue -Vi capsule↑ -Motility↓ |
32 | |
| Oxygen | colon | S. flexneri | FNR | T3SS↑ | Entry to the niche -Invasion ability↑ |
34 | |
| Metabolic sensing | Bile | duodenum- | V. cholerae | ToxT |
flrA↑ ctxAB, tcpA ↓ |
Increased chance to find niches -Motility (fimbriae)↑ -Cholera toxin↓ |
36 |
| SCFAs | ileum | S. typhimurium | BarA-SirA | hilA↑ | Entry to the niches (cells) -Invasion ability↑ |
42 | |
| Fucose | colon | EHEC | FusKR | LEE↓ | Prevention of Energy expenditure -Repression of virulence genes ↓ |
47 | |
| Mechano sensing |
Attachment Shear stress |
colon | C. rodentium | GrlA | LEE↑ | Entry to the niches -Invasion ability↑ |
49 |
| Viscosity | colon | V. cholerae | flagella |
ctxAB↑ tcpA ↑ |
Increased chance to find niches -Invasion ability↑ |
52 | |
| Quorum sensing | Cell density | ileum | S. aureus | AgrA/AgrC |
hla↑ spa↓ |
Adaptation to host tissue -Endosomal escape↑ -Surface proteins↓ |
54 |
| - | Unknown | unknown | S. typhimurium | unknown | TTSS-1↑↓ | Stabilization of cooperative virulence -Bistable virulence expression |
57 |