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ARS Home » Southeast Area » Mississippi State, Mississippi » Poultry Research » Research » Publications at this Location » Publication #409089
Research Project: Intervention Strategies to Mitigate Avian Escherichia coli Infections and Antimicrobial Resistance in the Poultry Environment

Location: Poultry Research

Title: Evaluating the effects of virulence genotype, swarming motility, and multi-locus sequence types of Escherichia coli of layer chicken through an embryo lethality assay

Author
item OVI, FOZOL - Mississippi State University
item ZHANG, LI - Mississippi State University
item JIA, LINAN - Mississippi State University
item Collins Elliott, Katie
item SUKUMARAN, ANURAJ - Mississippi State University
item COSBY, DOUGLAS - Southern Poultry Research, Inc
item WILSON, DAN - Wilson Veterinary Co
item TONY, ARICK - Mississippi State University
item RAMACHANDRAN, RESHMA - Mississippi State University
item Evans, Jeffrey - Jeff
item POUDEL, ISHAB - Mississippi State University
item ADHIKARI, PRATIMA - Mississippi State University

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Disease remains a constant threat to our food production system impacting both availability and cost. Collibacillosis is a broad term describing a wide range of Escherichia coli-associated diseases in poultry and this infection is one of the most common bacterial diseases affecting poultry. Interestingly, not all E. coli strains result in poultry diseases, but the factors which cause disease are not fully understood. To aid in the identification of disease-associated factors, E. coli isolates were obtained from poultry and investigated for the presence of genes thought to be associated with colibacillosis. The physical mobility of the isolates was also determined and measured against the isolate’s association with disease. An embryo model was developed and implemented to assess the pathogenicity of the isolates and results demonstrated that motility and the presence of certain genes impacted the isolates’ ability to cause disease.

Technical Abstract: To determine the effects of virulence genotype (VG), swarming motility (SM), and Multi-locus sequence types (MLST) of E. coli on layer chicken’s embryos between the 12th -18th days of incubation. We collected 58 E. coli isolates from commercial hens and colibacillosis cases, then classified them as avirulent, moderately-virulent, virulent-healthy, and virulent-colibacillosis categories by the presence of 5 virulence-associated genes (iroN, ompT, hlyF, iutA, and iss). These isolates were further classified as non-motile, motile, or hyper-motile by SM assay. We selected 29 of these isolates for embryo lethality assay (ELA) and determined their MLST. Each isolate was inoculated into 15 eggs through the allantoic cavity. We found the avirulent isolates reduced the relative embryo weight compared to virulent-colibacillosis and moderately-virulent isolates (37.49 vs. 41.51 and 40.34%, P=0.03). Amidst the moderately-virulent and virulent-colibacillosis categories, embryo lethality decreased when isolates were non-motile. Yolk retention was unaffected by virulence categories, motility, or MLST. Interaction between VG and SM substantially influenced the ELA of E. coli isolates. We recommend incorporating swarming motility as a sub-factor while estimating the effect of virulence-associated genes of E. coli through ELA. Maternal antibodies in the yolk could be effective against E. coli regardless of their VG, SM, and MLST.