The Endophytic Lifestyle of Escherichia coli O157:H7: Quantification and Internal Localization in Roots

Abstract

The foodborne pathogen Escherichia coli O157:H7 is increasingly associated with fresh produce (fruit and vegetables). Bacterial colonization of fresh produce plants can occur to high levels on the external tissue but bacteria have also been detected within plant tissue. However, questions remain about the extent of internalization, its molecular basis, and internal location of the bacteria. We have determined the extent of internalization of E. coli O157:H7 in live spinach and lettuce plants and used high-resolution microscopy to examine colony formation in roots and pathways to internalization. E. coli O157:H7 was found within internal tissue of both produce species. Colonization occurred within the apoplast between plant cells. Furthermore, colonies were detected inside the cell wall of epidermal and cortical cells of spinach and Nicotiana benthamiana roots. Internal colonization of epidermal cells resembled that of the phytopathogen Pectobacterium atrosepticum on potato. In contrast, only sporadic cells of the laboratory strain of E. coli K-12 were found on spinach, with no internal bacteria evident. The data extend previous findings that internal colonization of plants appears to be limited to a specific group of plant-interacting bacteria, including E. coli O157:H7, and demonstrates its ability to invade the cells of living plants.

Escherichia coli Common Pilus (ECP) Targets Arabinosyl Residues in Plant Cell Walls to Mediate Adhesion to Fresh Produce Plants

“…Both ECP variants from E. coli isolates Sakai and IHE3034 demonstrated enhanced adherence to spinach root polysaccharides compared with leaves, which supports previous findings of increased colonization in the roots (69). Furthermore, higher levels of ECP-mediated adherence of E. coli O157:H7 occurred in spinach compared with lettuce, which may be a result of the (49).…”

Robust cropping systems to tackle pests under climate change. A review

“…Once within the fruits, the pathogen can multiply to high densities (Gu et al 2011;Noel et al 2010). A recent study demonstrated that Escherichia coli can internally colonize both leaves and roots of lettuce and spinach (Wright et al 2013). Lastly, human norovirus and norovirus surrogates (Murine norovirus and Tulane virus) are also reported to colonize spinach stem and leaves (Hirneisen and Kniel 2013).…”

Interacciones entre Escherichia coli O157:H7 y Plantas Comestibles. ¿Se han Desarrollado Mecanismos de Internalización Bacteriana?

“…Several studies have pointed to flies , arthropods, birds, wild mammals and reptiles (Wright et al, 2013) as other major sources of pathogen transmission. It has been shown that if fresh produce is grown near livestock, these vectors can easily carry faecal contaminants to plants (Doyle and Erickson, 2012;Fletcher et al, 2013;Wasala et al, 2013).…”

“…Thus, the environments in which food products are produced, processed and transported can all cause cross-contamination. Some of the most common sources of microbial contamination of fresh produce are related to contaminated irrigation water (Cooley et al, 2007;Wright et al, 2013) and the use of improperly treated or contaminated manure Olaimat and Holley, 2012).…”

“…De esta manera, el ambiente en el cual los alimentos se producen, procesan y transportan puede causar contaminación cruzada. Las fuentes más comunes de contaminación microbiológica en hortalizas frescas son el agua de riego contaminada (Cooley et al, 2007;Wright et al, 2013) y el uso de abono a base de estiércol no tratado adecuadamente Olaimat and Holley, 2012).…”