The virulence factor ychO has a pleiotropic action in an Avian Pathogenic Escherichia coli (APEC) strain

Author(s)

Pilatti, Livia ^[1] ; de Paiva, Jacqueline Boldrin ^[1] ; Galvao Rojas, Thais Cabrera ^[1] ; Leite, Janaina Luisa ^[1] ; Conceicao, Rogerio Arcuri ^[1] ; Nakazato, Gerson ^[2] ; da Silveira, Wanderley Dias ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Biol, Dept Genet Evolut & Bioagents, POB 6109, BR-13083970 Campinas, SP - Brazil

^[2] State Univ Londrina UEL, Ctr Biol Sci, Dept Microbiol, Londrina, Parana - Brazil

• Document type: Journal article
• Source: BMC Microbiology; v. 16, MAR 10 2016.
• Web of Science Citations: 5

Abstract

Background: Avian pathogenic Escherichia coli strains cause extraintestinal diseases in birds, leading to substantial economic losses to the poultry industry worldwide. Bacteria that invade cells can overcome the host humoral immune response, resulting in a higher pathogenicity potential. Invasins are members of a large family of outer membrane proteins that allow pathogen invasion into host cells by interacting with specific receptors on the cell surface. Results: An in silico analysis of the genome of a septicemic APEC strain (SEPT362) demonstrated the presence of a putative invasin homologous to the ychO gene from E. coli str. K-12 substr. MG1655. In vitro and in vivo assays comparing a mutant strain carrying a null mutation of this gene, a complemented strain, and its counterpart wildtype strain showed that ychO plays a role in the pathogenicity of APEC strain SEPT362. In vitro assays demonstrated that the mutant strain exhibited significant decreases in bacterial adhesiveness and invasiveness in chicken cells and biofilm formation. In vivo assay indicated a decrease in pathogenicity of the mutant strain. Moreover, transcriptome analysis demonstrated that the ychO deletion affected the expression of 426 genes. Among the altered genes, 93.66 % were downregulated in the mutant, including membrane proteins and metabolism genes. Conclusion: The results led us to propose that gene ychO contributes to the pathogenicity of APEC strain SEPT362 influencing, in a pleiotropic manner, many biological characteristics, such as adhesion and invasion of in vitro cultured cells, biofilm formation and motility, which could be due to the possible membrane location of this protein. All of these results suggest that the absence of gene ychO would influence the virulence of the APEC strain herein studied. (AU)

• FAPESP's process: 12/04391-1 - Mutation in AI-2 Quorum Sensing system and analyses of gene expression in an Avian Pathogenic Escherichia coli (APEC) strain
• Grantee: Livia Pilatti Mendes da Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/09655-7 - In vivo analyses of genic expression and mutation in quorum sensing gene AI-2 of an avian Pathogenic Escherichia coli strain
• Grantee: Wanderley Dias da Silveira
• Support Opportunities: Regular Research Grants