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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #400556
Research Project: Developing Agronomically and Environmentally Beneficial Management Practices to Increase the Sustainability and Safety of Animal Manure Utilization

Location: Food Animal Environmental Systems Research

Title: Core genome sequencing analysis of E. coli O157:H7 unravelling genetic relatedness among strains from cattle, beef and humans in Bishoftu, Ethiopia

Author
item GUTEMA, FANTA - University Of Iowa
item DE ZUTTER, LIEVEN - Ghent University
item PIÉRARD, DENIS - Vrije Universiteit Brussel
item HINCKEL, BRUNO - Vrije Universiteit Brussel
item IMAMURA, HIDEO - Vrije Universiteit Brussel
item RASSCHAERT, GEERTRU - Flanders Research Institute For Agriculture
item ABDI, RETA - Long Island University
item Agga, Getahun
item CROMBÉ, FLORENCE - Vrije Universiteit Brussel

Submitted to: Microbiology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2023
Publication Date: 1/25/2023
Citation: Gutema, F.D., De Zutter, L., Piérard, D., Hinckel, B., Imamura, H., Rasschaert, G., Abdi, R.D., Agga, G.E., Crombé, F. 2023. Core genome sequencing analysis of E. coli O157:H7 unravelling genetic relatedness among strains from cattle, beef and humans in Bishoftu, Ethiopia. Microbiology Research. 14(1):148-160. https://doi.org/10.3390/microbiolres14010013.
DOI: https://doi.org/10.3390/microbiolres14010013

Interpretive Summary: Escherichia coli O157 is a known strain of bacteria that produces a Shiga toxin that causes foodborne diarrheal and other more life-threatening infections in humans throughout the world. Cattle are the principal reservoirs and consumption of beef and beef products is the primary route for human infections. To explore the potential of cattle-to-human transmission through beef, 44 E. coli O157 isolates previously isolated from cattle at slaughterhouses, beef at retail markets, and human patients at a local hospital in Ethiopia were genetically characterized by sequencing their entire genome through a method commonly called whole-genome sequencing. The isolates formed six groups each consisting of closely related isolates. Genetically linked isolates were observed in the isolates obtained from cattle feces and/or hides, beef carcasses at slaughterhouse, beef at retail markets and human stools over a time frame of 20 months. Majority of the isolates carried genes that enable them to cause diseases in humans. All strains carried a gene that codes for a protein pump which transports many toxic substances, including antibiotics, out of the bacterial cells. This pumping mechanism enables the bacteria to survive both in the host and the environment. The results indicated that genetically linked E. coli O157:H7 isolates circulate in cattle and human populations with the possibility of cattle-to-human transmission through beef.

Technical Abstract: E. coli O157:H7 is a known Shiga toxin-producing Escherichia coli (STEC), causing foodborne disease globally. Cattle are the main reservoir and consumption of beef and beef products contaminated with E. coli O157:H7 is an important source of STEC infections in humans. To emphasize the cattle-to-human transmission through the consumption of contaminated beef in Bishoftu, Ethiopia, whole-genome sequencing (WGS) was performed on E. coli O157 strains isolated from three sources (cattle, beef, and humans). Forty-four E. coli O157:H7 isolates originating from 23 cattle rectal contents, three cattle hides, five beef carcasses, seven beef cuts at retail shops, and six human stools in Bishoftu between June 2017 and May 2019 were included. This study identified six clusters of closely related E. coli O157:H7 isolates based on core genome multilocus sequence typing (cgMLST) by targeting 2,513 loci. A genetic linkage was observed among the isolate genomes from the cattle rectal contents, cattle hides, beef carcasses at slaughterhouses, beef at retail shops, and human stool within a time frame of 20 months. All the strains carried practically the same repertoire of virulence genes except for the stx2 gene, which was present in all but eight of the closely related isolates. All the strains carried the mdfA gene, encoding for the MdfA multi-drug efflux pump. CgMLST analysis revealed genetically linked E. coli O157:H7 isolates circulating in the area, with a potential transmission from cattle to humans through the consumption of contaminated beef and beef products.