Abstract
Escherichia coli is a major causative agent of environmental bovine mastitis and this disease causes significant economic losses for the dairy industry. There is still debate in the literature as to whether mammary pathogenic E. coli (MPEC) is indeed a unique E. coli pathotype, or whether this infection is merely an opportunistic infection caused by any E. coli isolate being displaced from the bovine gastrointestinal tract to the environment and, then, into the udder. In this study, we conducted a thorough genomic analysis of 113 novel MPEC isolates from clinical mastitis cases and 100 bovine commensal E. coli isolates. A phylogenomic analysis indicated that MPEC and commensal E. coli isolates formed clades based on common sequence types and O antigens, but did not cluster based on mammary pathogenicity. A comparative genomic analysis of MPEC and commensal isolates led to the identification of nine genes that were part of either the core or the soft-core MPEC genome, but were not found in any bovine commensal isolates. These apparent MPEC marker genes were genes involved with nutrient intake and metabolism [adeQ, adenine permease; nifJ, pyruvate-flavodoxin oxidoreductase; and yhjX, putative major facilitator superfamily (MFS)-type transporter], included fitness and virulence factors commonly seen in uropathogenic E. coli (pqqL, zinc metallopeptidase, and fdeC, intimin-like adhesin, respectively), and putative proteins [yfiE, uncharacterized helix-turn-helix-type transcriptional activator; ygjI, putative inner membrane transporter; and ygjJ, putative periplasmic protein]. Further characterization of these highly conserved MPEC genes may be critical to understanding the pathobiology of MPEC.
Highlights
Bovine mastitis – inflammation of bovine udder usually caused by a bacterial infection – is a costly disease in the dairy industry [1], and results in annual losses of $665 million (CAD) [£386 million, 1 CAD=£0.58] for the Canadian dairy industry [2], $2 billion (USD) [£1.4 billion, 1 USD=£0.71] for the American dairy industry [3] and £168 million for the British dairy industry [4]
The nine genes are associated with nutrient intake, metabolism and fitness; in addition, we have identified that a few virulence factors common to uropathogenic E. coli are found in mammary pathogenic E. coli (MPEC), but are absent from commensal bovine E. coli
A phylogenomic tree that illustrates the phylogenomic relatedness of the 113 MPEC and 100 bovine commensal E. coli isolates examined in this study was created by comparing core-genomeSNPs across the entire genome of each isolate (Fig. 1)
Summary
Bovine mastitis – inflammation of bovine udder usually caused by a bacterial infection – is a costly disease in the dairy industry [1], and results in annual losses of $665 million (CAD) [£386 million, 1 CAD=£0.58] for the Canadian dairy industry [2], $2 billion (USD) [£1.4 billion, 1 USD=£0.71] for the American dairy industry [3] and £168 million for the British dairy industry [4]. The aetiological agents of bovine mastitis can be categorized as either contagious or environmental pathogens. Contagious bovine mastitis is commonly caused by Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis and Corynebacterium bovis, which are transmitted from infected to uninfected cows via milking equipment, direct contact or vectors like farm workers. Environmental mastitis pathogens originate from the farm environment, such as pasture, stable or bedding material.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
