Serum resistance and virulence of Escherichia coli isolated from turkeys.
Twenty-five strains of Escherichia coli isolated from turkeys were characterized for their serum resistance and virulence. An in vitro bactericidal assay was used to determine the serum resistance of E coli. Virulence was determined by survival time after IV inoculation of each strain into 3-week-old turkeys. Serum-resistant E coli strains were generally found to be virulent for turkeys, whereas serum-sensitive E coli strains were avirulent. Of the 25 strains, 18 strains were placed in the 2 categories of serum-resistant/virulent and serum-sensitive/avirulent. Five strains were serum-resistant and avirulent, and 2 strains were serum-sensitive and virulent. Serum resistance appears to be an important determinant of virulence for E coli in turkeys; however, the requirement for other virulence factors, in addition to serum resistance, was suggested by the finding that 5 serum-resistant strains were avirulent in turkeys.
Ellis
M G
MG
Department of Animal Science, Iowa State University, Ames 50011.
Arp
L H
LH
Lamont
S J
SJ
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000276:immunology / Q000662:veterinary; D010403:Penicillin Resistance; D010587:Phagocytosis; D011201:Poultry Diseases / Q000276:immunology; D012703:Serotyping / Q000662:veterinary; D014422:Turkeys / Q000276:immunology / Q000382:microbiology*; D014774:Virulence
D000907:Antibodies, Bacterial