Comparison of Several Challenge Models for Studies in Avian Colibacillosis

Abstract

In previous studies, the embryo lethality assay (ELA) discriminated between virulent and avirulent avian Escherichia coli isolates, and also proved to be highly correlated with mortality and morbidity results of the intravenous (IV) challenge model. In the current study, the same 20 avian E. coli isolates were used in subcutaneous (subQ) and intratracheal (IT) chicken challenge models in order to determine whether the results from the prior ELA challenges and/or the IV challenge model correlate with these models. The correlation observed between the two previous ELA trials and the combined mortality/morbidity percentages of the subQ challenge model were r = 0.792, P > 0.0001 for the first ELA trial and r = 0.738, P = 0.0002 for the second ELA trial. The IV challenge results were more highly correlated with the subQ challenge results (mortality/morbidity comparison, r = 0.894, P < 0.0001). The IV challenge mortality results were slightly correlated (r = 0.4810, P=0.0319) with the IT challenge results. Several of the isolates differed in their ability to produce mortality and/or morbidity with the different challenge models. The mortality/morbidity results of the IV and subQ challenges and the mortality results of the ELA were all positively correlated with the ability of an E. coli isolate to produce Colicin V (ColV) (r = 0.7131, P = 0.0004). The IT mortality results were slightly correlated with the production of ColV (r = 0.455, P = 0.049). The IT challenge results were only slightly correlated with resulting IV mortality and ColV production. Previous results indicate that the ELA correlates extremely well with the IV challenge model. The current study demonstrates that ELA also correlates well with the subQ challenge model. Overall, the conclusion of this study is that the ELA, IV, and subQ challenge models similarly demonstrate the ability to discriminate between virulent and avirulent avian E. coli isolates.

Isolation and characterization of virulent bacteriophages against Escherichia coli serogroups O1, O2, and O78

“…Avian colibacillosis, a disease caused by a group of bacteria called avian pathogenic Escherichia coli (APEC) in chickens, turkeys, and other avian species, is an infectious disease that often causes severe mortality and subsequently results in economic losses to the poultry industry (Dho-Moulin and Fairbrother, 1999;Gibbs et al, 2004). The disease is associated with a complete set of syndromes including septicemia, airsaculitis, pericarditis, and swollen head syndrome (Cheville and Arp, 1978;Rodriguez-Siek et al, 2005).…”

Acquisition of Avian PathogenicEscherichia coliPlasmids by a CommensalE. coliIsolate Enhances Its Abilities To Kill Chicken Embryos, Grow in Human Urine, and Colonize the Murine Kidney

“…The models used included a chicken embryo lethality assay, chosen because its results have been shown to positively correlate with an isolate's ability to cause lethality in 3-week old chickens (32) and morbidity and mortality in subcutaneous and intravenous chicken challenge models (12). Also, lethality to chicken embryos is a common characteristic of E. coli causing extraintestinal infections in humans (30).…”

Effect of heparan sulfate and gold nanoparticles on muscle development during embryogenesis

“…It has a rapid rate of growth and its embryonic development is described in detail. 21 The embryo is independent from the mother, 22 it is highly sensitive to harmful factors, 23 and it has been used as a suitable model for cancer therapy research, 24 the determination of bacterial invasiveness, 25 and new drug delivery systems development. 26 Analysis of the present results led to the conclusion that administration of nano-Au, HS, and nano-Au+HS did not negatively affect the growth and development of chicken embryos.…”