Fasano A, Kay B A, Russell R G, Maneval D R, Levin M M
Department of Medicine, University of Maryland School of Medicine, Baltimore 21201.
Infect Immun. 1990 Nov;58(11):3717-23. doi: 10.1128/iai.58.11.3717-3723.1990.
It has long been suspected that besides their ability to invade enterocytes, enteroinvasive Escherichia coli (EIEC) strains have the ability to elaborate an enterotoxin. We tested 35 EIEC strains for cytotoxins and 9 (1 per serogroup) for enterotoxins. All 35 strains exhibited low levels of Vero cell cytotoxins that are immunologically and genetically distinct from Shiga-like toxin I or II of enterohemorrhagic E. coli. Sterile supernatants and cell lysates of two EIEC strains were tested in rabbit ileal loops, and both stimulated moderate fluid accumulation (circa 0.5 ml/cm) without tissue damage; secretory activity was confirmed in Ussing chambers, where these two strains and the seven others tested significantly increased short circuit current without altering tissue conductance. Curing the 140-MDa invasiveness plasmid from an EIEC strain did not diminish enterotoxin production. Culture in minimal Fe2+ medium is necessary to detect expression of the enterotoxin which is circa 68 to 80 kDa in size and is distinct from the EIEC cytotoxin.
长期以来，人们一直怀疑除了具有侵袭肠上皮细胞的能力外，肠侵袭性大肠杆菌（EIEC）菌株还具有产生肠毒素的能力。我们检测了35株EIEC菌株的细胞毒素，并检测了9株（每个血清群1株）的肠毒素。所有35株菌株均表现出低水平的Vero细胞细胞毒素，这些细胞毒素在免疫和基因上与肠出血性大肠杆菌的志贺样毒素I或II不同。对两株EIEC菌株的无菌上清液和细胞裂解物进行了兔回肠袢试验，两者均刺激了适度的液体蓄积（约0.5 ml/cm），且无组织损伤；在尤斯灌流小室中证实了其分泌活性，在该小室中，这两株菌株以及另外七株受试菌株显著增加了短路电流，而未改变组织电导。从一株EIEC菌株中去除140-MDa侵袭性质粒并不会减少肠毒素的产生。在最低限度的Fe2+培养基中培养对于检测肠毒素的表达是必要的，该肠毒素大小约为68至80 kDa，与EIEC细胞毒素不同。
