Is lack of susceptible recipients in the intestinal environment the limiting factor for transduction of Shiga toxin-encoding phages?
OBJECTIVE
To determine whether a Shiga toxin 2 (Stx2)-encoding phage from Escherichia coli O157:H7 could be transmitted to commensal E. coli in a ruminant host without adding a specific recipient strain.


RESULTS
Sheep were inoculated with an E. coli O157:H7 strain containing an Stx2-encoding bacteriophage (Phi3538) in which a chloramphenicol-resistant gene, cat, is inserted into stx(2). A total of 149 faecal samples were sampled and analysed for detection and quantification of E. coli O157:H7 and presumptive transductants. Phage Phi3538 (Deltastx(2)::cat) was demonstrated to be transduced to an ovine E. coli O175:H16 at one occasion.


CONCLUSIONS
The study demonstrates an in vivo transduction in sheep from an E. coli O157:H7 strain to an ovine E. coli O175:H16. A functional Stx2-encoding phage was incorporated into the host's DNA.


CONCLUSIONS
This is the first in vivo stx phage transduction study reported in which a recipient strain was not fed to the test animals. We suggest that the access to susceptible hosts is one main limiting factor for transduction to occur in the intestine.
Sekse
C
C
Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway.
Solheim
H
H
Urdahl
A M
AM
Wasteson
Y
Y
D000818:Animals; D001435:Bacteriophages / Q000235:genetics*; D015169:Colony Count, Microbial; D004197:Disease Reservoirs; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000517:prevention & control*; D019453:Escherichia coli O157 / Q000302:isolation & purification / Q000821:virology*; D005243:Feces / Q000382:microbiology; D007267:Injections; D023421:Models, Animal; D012417:Rumen / Q000821:virology*; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control*; D022641:Shiga Toxin 2 / Q000235:genetics*; D014161:Transduction, Genetic / Q000379:methods
D022641:Shiga Toxin 2