Phenotypic and virulence traits of Escherichia coli and Salmonella strains isolated from vegetables and fruits from India

AimsThe present study was designed to assess the phenotypic traits and virulence determinants of vegetable-/fruit-origin Escherichia coli and Salmonella strains. Methods and ResultsA total of 520 fresh vegetables/fruits samples were analysed for the presence of E.coli, including Shiga toxin-producing E.coli (STEC), and Salmonella. The vegetable-/fruit-origin E.coli and Salmonella strains were further assessed for antimicrobial resistance, biofilm formation, extracellular matrix production and invitro invasion/intracellular survivability assays. A total of 73 E.coli, including four STEC, and 26 Salmonella strains were recovered from vegetables/fruits in the present study. Most of the E.coli and Salmonella isolates were able to form biofilm with higher production of cellulose/curli-fimbriae. Furthermore, more resistance was observed in E.coli isolates (616%) than in Salmonella isolates (385%) against tested antimicrobials. Additionally, invasion/intracellular survival results showed that majority of the E.coli and Salmonella isolates were able to efficiently invade/replicate intracellularly in the human epithelial cells. ConclusionsOur results demonstrate that vegetable-/fruit-origin E.coli and Salmonella significantly exhibited distinct phenotypic/virulence traits which could be linked to their plant-associated lifestyle with food safety issues. Significance and Impact of the StudyThe present study provides valuable baseline information that E.coli and Salmonella may use plants as an alternative host with significant clinical importance.