Lortie L A, Dubreuil J D, Harel J
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada.
J Clin Microbiol. 1991 Mar;29(3):656-9. doi: 10.1128/jcm.29.3.656-659.1991.
Two of 49 cytolethal distending toxin-producing strains of Escherichia coli isolated from human stools contained the gene coding for heat-stable enterotoxin b (STb), as detected by a colony hybridization assay. The STb gene was found to be on a 70-kb plasmid also coding for heat-labile enterotoxin (pLT-I). Restriction endonuclease analysis showed the STb gene from human isolates to be similar to the STb gene found in porcine strains. Moreover, by enzymatic amplification based on oligonucleotide primers designed from a porcine STb sequence, the expected portion of the STb gene was amplified for the human E. coli strains. The STb enterotoxin from these strains was bioactive in rat jejunal loops and was detected with an enzyme-linked immunosorbent assay by using polyclonal antiserum raised against purified porcine STb toxin.
通过菌落杂交试验检测发现，从人类粪便中分离出的49株产细胞致死膨胀毒素的大肠杆菌中有两株含有编码热稳定肠毒素b（STb）的基因。发现STb基因位于一个70kb的质粒上，该质粒也编码不耐热肠毒素（pLT-I）。限制性内切酶分析表明，来自人类分离株的STb基因与猪源菌株中发现的STb基因相似。此外，根据从猪STb序列设计的寡核苷酸引物进行酶促扩增，对人类大肠杆菌菌株扩增出了STb基因的预期片段。这些菌株产生的STb肠毒素在大鼠空肠肠袢中具有生物活性，并且使用针对纯化猪STb毒素产生的多克隆抗血清通过酶联免疫吸附测定法检测到了该毒素。
