Subpathotypes of Avian Pathogenic Escherichia coli (APEC) Exist as Defined by their Syndromes and Virulence Traits
Victor Gonçalves Maturana1, Fernanda de Pace1, Camila Carlos2, Mathias Mistretta Pires3, Tatiana Amabile de Campos1, 4, Gerson Nakazato1, 5, Eliana Guedes Stheling1, 6, Catherine M Logue7, Lisa K Nolan8, Wanderley Dias da Silveira1, *
1 Department of Genetics, Evolution and Bioagentes, Biology Institute, Campinas State University-UNICAMP, Campinas, SP, Brazil
2 Molecular Biology and Genetic Engineering Center, Campinas State University-UNICAMP, Campinas, SP, Brazil. Centro de Biologia Molecular e Engenharia Genética, - UNICAMP, Campinas
3 Department of Ecology, Biology Institute, São Paulo State University-USP, São Paulo, SP, Brazil. Ecology Post-Grad Program, USP, São Paulo, SP. Brazil
4 Genetics and Biochemistry Institute, UFU, Uberlândia, MG, Brazil
5 Department of Microbiology, UEL, Londrina, PR, Brazil
6 Department of Toxicological and Bromatologic Clinical Analyses, USP, Ribeirão Preto, SP, Brazil
7 Departmente of Veterinary and Microbiological Sciences, North Dakota State University, Fargo. ND 58108, USA
8 College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
Avian pathogenic Escherichia coli (APEC) strains cause different types of systemic extraintestinal infections in poultry, collectively termed colibacillosis, which can cause significant economic losses in the poultry industry. To date, there have been no descriptions of genes or characteristics that allow for the classification of avian strains pathotypes responsible for causing specific diseases in their hosts. In this study we aimed to characterize avian E. coli strains representing 4 groups, including one of commensal strains (AFEC – Avian Fecal Escherichia coli) and 3 groups of APEC strains, where each group is responsible for causing a different disease syndrome in their respective hosts (septicemia, omphalitis and swollen head syndrome). We chose to examine several biological characteristics of these strains including: adhesion to eukaryotic cells, pathogenicity levels according to the lethal dose (50%) assay, phylogenetic group and virulence gene profiles. The comparison of strains based on these genotypic and phenotypic traits, using multivariate statisticals tools and complex networks, allowed us to infer information about the population structure of the studied groups. Our results indicate that APEC strains do not constitute a unique homogeneous group, but rather a structured set of subgroups, where each one is associated with a specific infectious syndrome which can possibly be used to define pathotypes or subpathotypes within APEC strains. These results offer new possibilities with which to study the genes responsible for various pathogenetic processes within APEC strains, and for vaccine development. It may be important to consider these subgroups when developing a vaccine in an effort for obtain cross protection, which has not yet been successfully accomplished when working with APEC strains.
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* Address correspondence to this author at the Department of Genetics, Evolution and Bioagents, CP 6109, Institute of Biology, Campinas State University, CEP 13083-875, Brazil; Tel: (055-19-35216268); Fax: (055-19- 35216185); E-mail: email@example.com