1887

Abstract

SUMMARY: A mixture of two phages, B44/1 and B44/2, protected calves against a potentially lethal oral infection with an O9: K30,99 enteropathogenic strain of , called B44, when given before, but not after, the onset of diarrhoea; a mixture in which phage B44/3 was replaced by phage B44/3 was effective after the onset of diarrhoea. Calves that responded to phage treatment had much lower numbers of B44 in their alimentary tract than untreated calves. Usually, high numbers of phage B44/1 and rather lower numbers of phage B44/2 or B44/3 were present in the alimentary tract of these animals. At death, most calves that had not responded to treatment with phages B44/1 and B44/2 had high numbers of mutants of B44 resistant to phage B44/1 in their small intestine. Phage-treated calves that survived infection continued to excrete phage in their faeces, at least until the numbers of B44 also excreted were low. The phages survived longer than B44 in faecal samples taken from phage-treated calves and exposed to the atmosphere in an unheated animal house. Calves inoculated orally with faecal samples from phage-treated calves that contained sufficient B44 to cause a lethal infection remained healthy.

A mixture of two phages, P433/1 and P433/2, and phage P433/1 alone cured diarrhoea in piglets caused by an O20:K101,987P strain of called P433. The numbers of the infecting bacteria and phages in the alimentary tract of the piglets resembled those in the calves. Another phage given to lambs 8 h after they were infected with an O8:K85,99 enteropathogenic strain of , called S13, reduced the numbers of these organisms in the alimentary tract and had an ameliorating effect on the course of the disease. No phage-resistant mutants of S13 were isolated from the lambs. The only mutants of B44 and P433 that emerged in the calves and piglets were K30 or K101 and resistant to phage B44/1 or P433/1 respectively; those tested were much less virulent than their parent strains.

Loading

Article metrics loading...

/content/journal/micro/10.1099/00221287-129-8-2659
1983-08-01
2020-01-21
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/micro/10.1099/00221287-129-8-2659
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error