Echeverria P, Seriwatana J, Taylor D N, Changchawalit S, Smyth C J, Twohig J, Rowe B
Infect Immun. 1986 Feb;51(2):626-30. doi: 10.1128/iai.51.2.626-630.1986.
Colonization factor antigens I and II (CFA/I and CFA/II) are important in the pathogenesis of diarrhea in humans caused by some enterotoxigenic Escherichia coli (ETEC). Plasmid DNA from 16 CFA/I+ and five CFA/II+ ETEC were examined by Southern blot analysis with enterotoxin gene probes and were compared with plasmid DNA from derivatives of the same ETEC that had lost the ability to produce these colonization factors. Among the 16 CFA/I+ ETEC strains, the loss of CFA/I was accompanied by the loss of a plasmid of between 34 and 68 megadaltons (MDa) coding for heat-stable enterotoxin A2 (ST-A2) in 12 strains, by the loss of a 60-MDa plasmid coding for heat-labile enterotoxin (LT) and ST-A2 in one strain, or by deletions of a segment of DNA encoding for ST-A2 in three strains. Among five CFA/II+ ETEC strains, the loss of CFA/II was associated with the loss of a plasmid of 75 MDa coding for LT and ST-A2 in three strains, with the loss of genes coding for LT and ST-A2 from a 68-MDa 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 CFA/I and CFA/II production was associated with the loss of DNA sequences encoding for ST-A2 in 20 of 21 ETEC examined.
定居因子抗原I和II（CFA/I和CFA/II）在某些产肠毒素大肠杆菌（ETEC）引起的人类腹泻发病机制中起重要作用。用肠毒素基因探针通过Southern印迹分析检测了16株CFA/I+和5株CFA/II+ ETEC的质粒DNA，并与同一ETEC中失去产生这些定居因子能力的衍生物的质粒DNA进行了比较。在16株CFA/I+ ETEC菌株中，12株CFA/I的丧失伴随着编码热稳定肠毒素A2（ST-A2）的34至68兆道尔顿（MDa）质粒的丧失，1株伴随着编码不耐热肠毒素（LT）和ST-A2的60-MDa质粒的丧失，3株伴随着编码ST-A2的一段DNA的缺失。在5株CFA/II+ ETEC菌株中，3株CFA/II的丧失与编码LT和ST-A2的75 MDa质粒的丧失有关，1株与68-MDa质粒中编码LT和ST-A2的基因丧失有关，其余1株未观察到编码肠毒素的质粒或DNA序列有明显丧失。在所检测的21株ETEC中，20株CFA/I和CFA/II产生的丧失与编码ST-A2的DNA序列的丧失有关。
