Shiga-like toxin production and attaching effacing activity of Escherichia coli associated with calf diarrhea.
Four hundred twenty-nine isolates of Escherichia coli from calves were tested for the production of HeLa cell cytotoxin(s). Isolates that produced enough cytotoxin to be detected in culture supernatants of iron-depleted broth were considered to produce increased amounts of cytotoxins. Isolates also were tested for homology with a DNA probe for a gene that encodes localized adherence of human enteropathogenic E coli. Four isolates produced increased amounts of cytotoxin that was neutralized by Shiga antitoxin (toxin designated as Shiga-like toxin-I [SLT-I]). A 5th isolate produced increased amounts of cytotoxin (SLT+) that was not neutralized by the Shiga antitoxin, but was neutralized by antitoxin against a variant of SLT (toxin designated as SLT-II). None of the isolates hybridized with the probe for the localized adherence gene. Three of the SLT+ isolates belonged to human enteropathogenic E coli serogroups O26 and O111. All 5 of the SLT+ isolates were from calves with diarrhea, but none of the 5 SLT+ isolates contained genes for classic heat-labile or heat-stable enterotoxins, for K99 fimbriae, or for invasiveness; neither did any of them adhere to HeLa cells in culture. Three of the 5 SLT+ isolates had attaching and effacing activities when inoculated into ligated intestinal loops of rabbits. One of the isolates with attaching and effacing activity in rabbits was originally isolated from a calf with lesions characteristic of those produced by attaching effacing E coli (AEEC). Calves inoculated with this SLT+ AEEC isolate developed focal colonic lesions characteristic of those produced by AEEC, but did not develop diarrhea.(ABSTRACT TRUNCATED AT 250 WORDS)
Mainil
J G
JG
Duchesnes
C J
CJ
Whipp
S C
SC
Marques
L R
LR
O'Brien
A D
AD
Casey
T A
TA
Moon
H W
HW
D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D003603:Cytotoxins / Q000096:biosynthesis*; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004926:Escherichia coli / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000662:veterinary*; D006367:HeLa Cells; D006801:Humans; D011817:Rabbits; D022603:Shiga Toxins; D012760:Shigella
D001427:Bacterial Toxins; D003603:Cytotoxins; D022603:Shiga Toxins