Molecular characterization of the virulence of classic atypical Enteropathogenic Escherichia coli (aEPEC) strains

• Grant number: 11/18911-4
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2011
• End date: November 30, 2013
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: Isabel Cristina Affonso Scaletsky
• Grantee: Isabel Cristina Affonso Scaletsky
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

The term atypical enteropathogenic Escherichia coli (atypical EPEC) is used to define E. coli strains that not have the EAF plasmid and do not produce Shiga toxin. Like typical EPEC and enterohemorhagic E. coli (EHEC) strains, atypical EPEC produce the attaching and effacing (A/E) lesion encoded by the LEE pathogenicity island. Atypical EPEC strains may belong to serotypes of the classical EPEC (classical serotypes). The classical serotypes are genetically related to EHEC O157:H7. Recently, we showed that a subgroup of atypical EPEC strains producing the localized adherence pattern (LAL) pattern were statistically associated with diarrhea. In addition, most of these strains presented high-molecular-mass plasmid bands compatible with EAF plasmid. Previous study showed that some of these strains have the abilities to form biofilm on abiotic surfaces. Autotransporter proteins (AT) including AIDA-I, Ag43 and TibA, are associated with virulence functions such as adhesion, invasion and biofilm formation. Recently, novel AT proteins including Cah, Eha, EhB e EhaD, have been implicated in the formation of microcolonies and biofilm of EHEC O157:H7. The aims of this work are to (i) analysis the virulence traits of atypical EPEC strains belonging to classical EPEC serogroups (O26, O55, O111, O114, O119, O125, O127, O128 e O142); and (ii) evaluate the presence of AT proteins and their association with LAL pattern and biofilm formation. (AU)