SUMMARY: A genetic factor (designated Ent) responsible for enterotoxin production in six of 51 enterotoxigenic strains of Escherichia coli of porcine origin could be transmitted to other strains of E. coli and to Salmonella typhimurium and S. choleraesuis by conjugation in mixed culture. A high proportion of organisms of the recipient strains in these cultures was found to have accepted Ent, which was probably a plasmid. The possession of Ent by an organism was a stable characteristic; no organisms were found to have lost it during either laboratory cultivation, acriflavine treatment, or residence in the alimentary tract of pigs and mice. Ent could be transmitted independently of F, R, Hly and K88 factors; the transfer factor responsible for its transmission closely resembled F and the transfer factors of fi + R factors and Hly. Ent+ organisms could not be differentiated from Ent− ones, morphologically, culturally or antigenically. The oral administration of enterotoxin-containing bacteria-free culture fluid of an Ent+ strain of E. coli had no apparent ill effect on pigs, piglets and calves; neither did the fluid influence skin permeability. The transmission of Ent to S. typhimurium and S. choleraesuis did not affect their pathogenicity. Three of four piglets given Ent+E. coli organisms developed diarrhoea; three given Ent− organisms of the same strain did not.
CraigJ. P.1965; A permeability factor found in cholera stools and culture filtrates and its neutralisation by convalescent cholera sera.. Nature, Lond 207:614
DeS. N.,
ChatterjeD. N.1953; An experimental study of the mechanism of action of Vibrio cholerae on the intestinal mucous membrane.. J. Path. Bact 66:559
ØrskovI.,
rskovF.1966; Episome-carried surface antigen K88 of Escherichia coli. 1. Transmission of the determinant of the K88 antigen and influence on the transfer of chromosomal markers.. J. Bact 91:69
SmithH. Williams.
1966; The incidence of infective drug resistance in strains of Escherichia coli isolated from diseased human beings and domestic animals.. J. Hyg., Camb 60:301
SmithH. Williams,
HallsS.1967a; The transmissible nature of the genetic factor in Escherichia coli that controls haemolysin production.. J. gen. Microbiol 47:153
SmithH. Williams,
HallsS.1967b; Observations by the ligated intestinal segment and oral inoculation methods on Escherichia coli infections in pigs, calves, lambs and rabbits.. J. Path. Bact 93:499
SmithH. Williams,
JonesJ. E. T.1967; Observations on experimental oral infection with Salmonella dublin in calves and Salmonella cholerae-suis in pigs.. J. Path. Bact 93:141
WatanabeT.,
NishidaH.,
OgataC.,
AraiT.,
SatoS.1964; Episome-mediated transfer of drug resistance in Enterobacteriaceae. VII. Two types of naturally-occurring R. factors.. J. Bact 88:716