Analysis of virulence genes in Escherichia coli isolated from grated cheese

Food Science and Technology (Campinas)

Rodrigo Prado Martins²  Luciano Nakazato¹  Valéria Dutra¹  Domingos Da Silva Leite¹ 

[1] ,Universidade Federal de Mato Grosso Departamento de Ciências Básicas e Produção Animal

关键词: Escherichia coli;    virulence genes;    grated cheese;    Cuiabá - MT;    Escherichia coli;    genes de virulência;    queijo ralado;    Cuiabá - MT;   

DOI  :  10.1590/S0101-20612011000100014

来源: SciELO

【 摘 要 】

This research aimed to verify the presence of virulence genes in strains of Escherichia coli isolated from grated cheese sold in farmers' markets of Cuiabá-MT, Brazil. Forty samples of this food were submitted for microbiological analysis and 22 (55%) tested positive for E. coli. Next, 64 strains of E. coli were isolated from the positive samples and screened by the polymerase chain reaction (PCR) for the presence of the genes encoding the following virulence factors: stx1 and stx2 (verotoxin types 1 and 2), eae (intimin), lt1 (heat-labile toxin type 1), st1 (heat-stable toxin type 1), cnf1 and cnf2 (cytotoxic necrozing factor types 1 and 2), and cdtB (cytolethal distending toxin). All the isolates were negative for the genes stx1, stx2, eae, lt1, st1, cnf1, and cdtB, and five strains (7.81%) were positive for cnf2. A low prevalence of E. coli positive for virulence factors associated with the pathogenesis of diarrhoea was observed in this study. However, the presence of CNF-2 producing strains and the possibility of occurrence and scattering of other virulence factors that were not surveyed in the work indicate the risk related to the consumption of grated cheese from farmers' markets.

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