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Valat C, Haenni M, Arnaout Y, Drapeau A, Hirchaud E, Touzain F, Boyer T, Delannoy S, Vorimore F, Fach P, Madec JY. F74 plasmids are major vectors of virulence genes in bovine NTEC2. Lett Appl Microbiol 2022; 75:355-362. [PMID: 35509148 DOI: 10.1111/lam.13733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/08/2022] [Accepted: 04/29/2022] [Indexed: 11/28/2022]
Abstract
Necrotoxigenic Escherichia coli 2 (NTEC2) are defined as E. coli producing the toxin known as cytotoxic necrotizing factor 2 (CNF2), a potent toxin primarily found in bovine but also in humans. NTEC2 are mostly associated with bovine, and cnf2 is known to be carried by pVir-like plasmids. In this study, we looked for NTEC2 in a collection of E. coli collected between 2011 and 2018 in French bovine. Thirty-two isolates, collected from both sick (n=19) and healthy (n=13) animals, were identified and characterized using whole-genome sequencing. One F74 plasmid of this bacterial collection was long-read sequenced: its size was 138 121 bp and it carried the cnf2, F17cA-eG, cdtB, iutA, iucC, and ompP virulence factors (VFs), but no resistance gene. A large variety of genetic backgrounds was observed, but all cnf2-carrying plasmids belonged to the IncF family, and most of them (78.1%) were of the F74 group. Similar F74 plasmids were also reported from bovine in the United Kingdom and USA, as identified in the publically available databases. Consequently, these F74 plasmids, which are widely disseminated among E. coli from cattle in the French territory, are vectors of virulence determinants that largely went unnoticed until now.
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Affiliation(s)
- Charlotte Valat
- Unité Antibiorésistance et Virulence Bactériennes, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
| | - Marisa Haenni
- Unité Antibiorésistance et Virulence Bactériennes, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
| | - Youssef Arnaout
- Unité Antibiorésistance et Virulence Bactériennes, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
| | - Antoine Drapeau
- Unité Antibiorésistance et Virulence Bactériennes, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
| | - Edouard Hirchaud
- Unité Génétique Virale et Biosécurité, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
| | - Fabrice Touzain
- Unité Génétique Virale et Biosécurité, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
| | - Théophile Boyer
- Unité Epidémiologie et appui à la surveillance, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
| | - Sabine Delannoy
- Unité COLiPATH / Plateforme d'identification et de typage des agents pathogènes (IdentyPath) du laboratoire de sécurité des aliments, Agence Nationale de Sécurité Sanitaire (ANSES), Maisons-Alfort, France
| | - Fabien Vorimore
- Unité COLiPATH / Plateforme d'identification et de typage des agents pathogènes (IdentyPath) du laboratoire de sécurité des aliments, Agence Nationale de Sécurité Sanitaire (ANSES), Maisons-Alfort, France
| | - Patrick Fach
- Unité COLiPATH / Plateforme d'identification et de typage des agents pathogènes (IdentyPath) du laboratoire de sécurité des aliments, Agence Nationale de Sécurité Sanitaire (ANSES), Maisons-Alfort, France
| | - Jean-Yves Madec
- Unité Antibiorésistance et Virulence Bactériennes, Agence Nationale de Sécurité Sanitaire (ANSES) - Université de Lyon, Lyon, France
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Sun M, Gao X, Zhao K, Ma J, Yao H, Pan Z. Insight Into the Virulence Related Secretion Systems, Fimbriae, and Toxins in O2:K1 Escherichia coli Isolated From Bovine Mastitis. Front Vet Sci 2021; 8:622725. [PMID: 33644149 PMCID: PMC7904677 DOI: 10.3389/fvets.2021.622725] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/05/2021] [Indexed: 11/13/2022] Open
Abstract
Mastitis remains a major infection of dairy cows and an important issue for the dairy farmers, and Escherichia coli (E. coli) bovine mastitis is a disease of significant economic importance in the dairy industry. Our study identified six isolates belong to phylogroup B2 from 69 bovine mastitis E. coli strains. Except for one serotype O1 strain, all group B2 isolates were identified into serotype O2 and showed significantly higher mortality in the mouse infection than other phylogroups' strains. Genomic analyses and further tests were performed to examine the role of secretion systems, fimbriae, and toxins during the systemic infection of O2:K1 strain BCE049. Two integral T6SS loci and three predicted effectors clusters were found to assemble the functional T6SS complex and deliver diverse toxic effectors to modulate bacterial virulence in the mouse infection model. A total of four T4SS loci were harbored in the BCE049 genome, three of them are encoded in different plasmids, respectively, whereas the last one locates within the bacterial chromosome at FQU84_16715 to FQU84_16760, and was significantly involved in the bacterial pathogenicity. Numerous predicted pilus biosynthesis gene loci were found in the BCE049 genome, whereas most of them lost long fragments encoding key genes for the pili assembly. Unexpectedly, a type IV pilus gene locus locating at FQU84_01405 to FQU84_01335 in the plasmid 2, was found to be required for the full virulence of mastitis strain BCE049. It should be noted that a genetic neighborhood inserted with diverse genes is encoded by the plasmid 1, which harbors three prominent toxins including β-hemolysin, cytotoxic necrotizing factor 2 and cytolethal distending toxin type III. Consequent studies verified that these toxins significantly contributed to the bacterial pathogenicity. These findings provide a molecular blueprint for understanding the underlying mechanisms employed by the bovine mastitis E. coli to colonize in host and cause systemic infection.
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Affiliation(s)
- Min Sun
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xing Gao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
| | - Kejie Zhao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
| | - Jiale Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
| | - Zihao Pan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
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