Purpose: This study aimed at investigating the presence of STEC in organic vegetables in the area of Sao Paulo City, Brazil, characterizing the virulence factors stx1, stx2, eae and ehx as well as identifying the serotype.
Methods: A total of 200 samples of organic vegetables (leafy green), obtained from three organic producers located in the area of Sao Paulo City, SP, Brazil, were analyzed for the presence of STEC strains. Tryptic Soy Broth supplemented with vancomycin (8mg/l), cefixim (50µg/l) and potassium telurite (2.5mg/l) was used in the pre enrichment step (incubation at 37°C/24 h), followed by plating onto Sorbitol-MacConkey (SMAC) and CHROMagar STEC (CHROM) incubated at 37°C/24 h. Presumptive colonies were confirmed by biochemical tests and submitted to PCR targeting stx1, stx2, eae and ehx virulence genes.
Results: Among the 200 organic vegetable samples analyzed for STEC strains, 29 were positive for E. coli, but none of them showed the virulence genes studied.
Significance: Our findings show that STEC strains were not detected in any organic vegetable sample, indicating a low risk of infection due the consumption of these fresh produce in Sao Paulo, Brazil. However, more research is required with a larger number of samples, since this is, most likely, the first study to investigate STEC in vegetables reported in Brazil.
Acknowledgement: CNPq