TABLE 1.

Virulence factors encoded by chromosomal Shigella PAIs

PAIGene(s)Biochemical activityVirulence function(s)Reference(s)
SHI-1sigAImmunoglobulin A-like cytopathic proteaseIntestinal fluid accumulation, cytopathic toxin5
picSerine protease, mucinaseMucus permeabilization, serum resistance, hemagglutination105
set1A, set1BEnterotoxin ShET1Intestinal fluid accumulation, development of watery diarrhea70, 71
SHI-2iucA to iucD, iutASiderophore (aerobactin) production and transportIron acquisition177, 182, 322
shiDUnknownColicin I and colicin V immunity
shiAUnknownDownregulation of inflammation by suppression of T-cell signaling116, 117
SHI-3iucA to iucD, iutAAerobactin production and transportIron acquisition (found only in S. boydii)227
SHI-OgtrA, gtrB, gtrVModification of O antigens, serotype conversionEvasion of host immune response113, 115
SRLfecA to fecE, fecI, fecRFerric dicitrate uptakeIron acquisition154, 314
tetA to tetD, tetREfflux systemTetracycline resistance
catAcetyltransferaseChloramphenicol resistance
oxa-1β-LactamaseAmpicillin resistance
aadA1AdenylyltransferaseStreptomycin resistance