Willshaw G A, Smith H R, McConnell M M, Barclay E A, Krnjulac J, Rowe B
Infect Immun. 1982 Sep;37(3):858-68. doi: 10.1128/iai.37.3.858-868.1982.
Plasmids coding for colonization factor antigen I (CFA/I) and heat-stable enterotoxin (ST) were identified in 10 strains of human enterotoxigenic Escherichia coli. The strains, which belonged to serogroups O63, O114, O128, and O153, were isolated in Bangladesh, Latin America, Spain, and South Africa. Two strains produced heat-labile enterotoxin in addition to ST. CFA/I-ST plasmids were mobilized from two O128 strains into E. coli K-12 with the R factor R1-19K-. Like the prototype CFA/I-ST plasmid NTP113, mobilized previously from an E. coli O78 strain into K-12, these two plasmids were non-autotransferring. All 10 CFA/I-ST plasmids were incompatible with NTP113 and had molecular weights ranging from 59 X 10(6) to 72 X 10(6). The molecular properties of seven of these plasmids were compared with those of six CFA/I-ST plasmids previously mobilized from O78 strains from Ethiopia, South Africa, and Bangladesh and with those of one plasmid coding for CFA/I, ST and heat-labile enterotoxin from a South African strain of serogroup O63. Digestion with the restriction endonuclease HindIII showed that several plasmids had very similar fragment patterns and two were identical. Generally, a larger proportion of HindIII fragments were of common size in digests of plasmids identified in strains from related geographical areas, regardless of serogroup. However, all except one plasmid shared five or six HindIII fragments of the same size, one of which had been shown previously to be involved in CFA/I production. There was at least 90% DNA homology between CFA/I-ST plasmids with a molecular weight of about 58 X 10(6) from O78 strains from different sources. Most of the DNA sequences of these plasmids were present in a larger CFA/I-ST plasmid (72 X 10(6) from an O128 strain. The results of genetic and molecular studies suggest that CFA/I and ST production is determined by very similar plasmids in different serogroups of human enterotoxigenic E. coli from several sources.
在10株人肠产毒性大肠杆菌中鉴定出编码定居因子抗原I（CFA/I）和热稳定肠毒素（ST）的质粒。这些菌株分别属于O63、O114、O128和O153血清群，是在孟加拉国、拉丁美洲、西班牙和南非分离得到的。其中两株除产生ST外，还产生不耐热肠毒素。CFA/I-ST质粒从两株O128菌株转移至带有R因子R1-19K-的大肠杆菌K-12中。与先前从一株大肠杆菌O78菌株转移至K-12中的原型CFA/I-ST质粒NTP113一样，这两种质粒均不能自动转移。所有10种CFA/I-ST质粒均与NTP113不相容，分子量范围为59×10⁶至72×10⁶。将其中7种质粒的分子特性与先前从埃塞俄比亚、南非和孟加拉国的O78菌株转移得到的6种CFA/I-ST质粒以及一种来自南非O63血清群菌株的编码CFA/I、ST和不耐热肠毒素的质粒进行了比较。用限制性内切酶HindIII消化显示，几种质粒具有非常相似的片段模式，其中两种完全相同。一般来说，无论血清群如何，在来自相关地理区域的菌株中鉴定出的质粒消化物中，较大比例的HindIII片段大小相同。然而，除一种质粒外，所有质粒都共有五六个大小相同的HindIII片段，其中一个片段先前已被证明与CFA/I的产生有关。来自不同来源的O78菌株的分子量约为58×10⁶的CFA/I-ST质粒之间至少有90%的DNA同源性。这些质粒的大多数DNA序列存在于一个更大的CFA/I-ST质粒（来自一株O128菌株，分子量为72×10⁶）中。遗传和分子研究结果表明，在来自多个来源的人肠产毒性大肠杆菌的不同血清群中，CFA/I和ST的产生由非常相似的质粒决定。
