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Full-Text Articles in Veterinary Preventive Medicine, Epidemiology, and Public Health
Failure Of The Congo Red Dye Uptake Test To Discriminate Between Virulent And Avirulent Avian Escherichia Coli, Kathy R. Spears, Richard E. Wooley, John Brown, Lisa K. Nolan
Failure Of The Congo Red Dye Uptake Test To Discriminate Between Virulent And Avirulent Avian Escherichia Coli, Kathy R. Spears, Richard E. Wooley, John Brown, Lisa K. Nolan
Lisa K. Nolan
Twenty avian Escherichia coli isolates from normal and diseased chickens were compared by use of three virulence tests. These tests included the uptake of Congo red dye, an embryo lethality test, and a quantitative microtiter complement resistance test. A direct correlation was seen between the results of the complement resistance test and the embryo lethality test. The results of the Congo red test did not correlate with the two other tests.
Relationship Of Complement Resistance And Selected Virulence Factors In Pathogenic Avian Escherichia Coli, Richard E. Wooley, Kathy R. Spears, John Brown, Lisa K. Nolan, Oscar J. Fletcher
Relationship Of Complement Resistance And Selected Virulence Factors In Pathogenic Avian Escherichia Coli, Richard E. Wooley, Kathy R. Spears, John Brown, Lisa K. Nolan, Oscar J. Fletcher
Lisa K. Nolan
Complement resistance, antibiotic resistance profiles, and virulence profiles of 80 Escherichia coli isolates from the intestines of normal chickens (40 isolates) and chickens diagnosed as having colisepticemia (40 isolates) were compared. Differences were observed between the two groups for antibiotic resistance, siderophore production, presence of type 1 pili, complement resistance, motility, and size of plasmids. The systemic isolates were more likely to have siderophores and type 1 pili, and to be complement-resistant and motile than were the intestinal isolates. No differences between the two groups were observed for colicin production. Further comparison of the 10 most complement-resistant isolates from the …
Characteristics Of Conjugative R-Plasmids From Pathogenic Avian Escherichia Coli, Richard E. Wooley, Kathy R. Spears, Lisa K. Nolan, John Brown, Mark A. Dekich
Characteristics Of Conjugative R-Plasmids From Pathogenic Avian Escherichia Coli, Richard E. Wooley, Kathy R. Spears, Lisa K. Nolan, John Brown, Mark A. Dekich
Lisa K. Nolan
Three of four virulent avian Escherichia coli isolates transferred a single large molecular-weight R-plasmid to two recipient E. coli strains. Antibiotic resistances transferred included streptomycin (two isolates) and streptomycin-tetracycline-sulfa (one isolate). Production of colicin and siderophores, complement resistance, and embryo lethality present in the virulent isolates were not transferred to recipient organisms. From the results, it appears that the R-plasmids of these virulent avian E. coli are not associated with virulence.
Comparison Of A Complement Resistance Test, A Chicken Embryo Lethality Test, And The Chicken Lethality Test For Determining Virulence Of Avian Escherichia Coli, Lisa K. Nolan, Richard E. Wooley, John Brown, Kathy R. Spears, H. W. Dickerson, Mark Dekich
Comparison Of A Complement Resistance Test, A Chicken Embryo Lethality Test, And The Chicken Lethality Test For Determining Virulence Of Avian Escherichia Coli, Lisa K. Nolan, Richard E. Wooley, John Brown, Kathy R. Spears, H. W. Dickerson, Mark Dekich
Lisa K. Nolan
Results with four pathogenic avian Escherichia coli isolates and one avirulent isolate in a complement resistance test, a chicken lethality test, and a chicken embryo lethality test were compared. Results of the complement resistance test with these isolates were highly correlated to results of the chicken lethality test of virulence. The chicken embryo test yielded results that were of a medium positive correlation with the chicken lethality results. The results of the complement resistance and chicken embryo lethality tests were highly correlated.
Transposon Mutagenesis Used To Study The Role Of Complement Resistance In The Virulence Of An Avian Escherichia Coli Isolate, Lisa K. Nolan, Richard E. Wooley, Richard K. Cooper
Transposon Mutagenesis Used To Study The Role Of Complement Resistance In The Virulence Of An Avian Escherichia Coli Isolate, Lisa K. Nolan, Richard E. Wooley, Richard K. Cooper
Lisa K. Nolan
The role of complement resistance in the virulence of an avian Escherichia coli isolate was examined with transposon mutagenesis. A suicide plasmid containing a kanamycin-encoding mini-transposon was used to transform a virulent complement-resistant avian E. coli isolate. A less resistant mutant was identified that contained a transposon insertion in a plasmid and in the chromosome. This loss of complement resistance was associated with a drop in virulence in an embryo assay. No other phenotypic changes were detected in the mutant. These results suggest that complement resistance is associated with the virulence of this organism.