Plasmids Coding for Colonization Factor Antigens I and II, Heat-Labile Enterotoxin, and Heat-Stable Enterotoxin A2 in Escherichia coli
ARMED FORCES RESEARCH INST OF MEDICAL SCIENCES APO SAN FRANCISCO 96346
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Colonization factor antigens I and II CFAI and CFAII are important in the pathogenesis of diarrhea in human caused by some enterotoxigenic Escherichia coli ETEC. Plasmid DNA from 16 CFAI and five CFAII ETEC were examined by Southern blot analysis with enterotoxin gene probes, and compared with plasmid DNA from derivatives of these ETEC that had lost the ability to produce these colonization factors. Among 16 CFAI ETEC strains, loss of CFAI was accompanied by the loss of a plasmid of between 34 and 68 megadaltons Mdal coding for ST-A2 in twelve strains, with the loss of a 60 Mdal plasmids coding LT and ST-A2 in one strain, or with deletions of a segment of DNA encoding for ST-A2 in three strains. Among five CFAII ETEC strains, loss of CFAII was associated with the loss of a plasmid of 75 Mdal coding for LT and ST-A2 in three strains, the loss of genes coding for LT and ST-A2 from a 68 Mdal plasmid in one strain, or with no discernible loss of a plasmid or DNA sequences coding for enterotoxins in the remaining strain. The loss of CFAI and CFAII production was associated with the loss of DNA sequences encoding for ST-A2 in 20 of 21 ETEC examined.
- Medicine and Medical Research