Impact of Changes in Sugar Exudate Created by Biological Damage to Tomato Plants on the Persistence of Escherichia coli O157:H7

Abstract

The survival of enteric pathogens on vegetable leaves improves due to presence of phytopathogens. Phytopathogen damage alters the microenvironment on the leaf surface. The objective of this study was to identify differences in sugar concentrations in tomato leaves damaged by biotropic plant pathogens and determine if these differences affect Escherichia coli O157:H7 survival. E. coli O157:H7 survived better on tomato plants damaged by Xanthomonas campestris than on healthy plants (P = 0.012). The most common sugars and sugar alcohols in the damaged leaf exudate were glucose, fructose, inositol, and sucrose. The abundance of sucrose and inositol differed between the healthy and infected plants (P < 0.05). In this study, it was found that phytopathogen damaged plants increased sugar availability on the leaf surface for E. coli O157:H7 to proliferate. Keeping plants free from biological damage can limit the amount of leaching of sugars that could allow human pathogens to proliferate. There is the possibility of increasing food safety of vegetable products by limiting phytopathogenic damage to plants.

Contribution of the Salmonella enterica KdgR Regulon to Persistence of the Pathogen in Vegetable Soft Rots

“…In fact, supermarket surveys established that human pathogens are significantly more likely to be found in produce affected by bacterial soft rot than in lesions caused by mechanical damage or fungal pathogens (9). Follow-up laboratory studies supported conclusions of supermarket surveys and demonstrated that within soft rots, S. enterica and E. coli reach cell numbers that are 10 to 1,000 times higher than those in intact plants (7,(10)(11)(12)(13). The effects of phytobacteria on human pathogens occupying the same niche are significant not only in the magnitude of their growth increase but also in the breadth of physiological adaptation to the cohabitation.…”

“…Salmonella appears to be able to repurpose the strategies it uses to obtain nutrients in the intestine in order to gain 1,2-propanediol and ethanolamine from soft rots (12). Nevertheless, mechanisms by which these enteric pathogens take advantage of the presence of phytopathogens only now are beginning to be understood (7,12,38).…”

“…Interactions of pathogens with native host-associated microbiota are complex, and their mechanisms only now are beginning to be understood (7,11,12,(36)(37)(38)(39)). Salmonella appears to be able to repurpose the strategies it uses to obtain nutrients in the intestine in order to gain 1,2-propanediol and ethanolamine from soft rots (12).…”

“…Recent studies suggest that the persistence of human enteric pathogens, such as Salmonella and pathogenic Escherichia coli, in plants, soil, and water represent an important component of their life cycle outside the animal host (4,5). The ability of human pathogens, such as pathogenic E. coli and nontyphoidal strains of Salmonella enterica, to persist in the environment is determined, to a great extent, by their interactions with native microbial communities (3,4,(6)(7)(8). In fact, supermarket surveys established that human pathogens are significantly more likely to be found in produce affected by bacterial soft rot than in lesions caused by mechanical damage or fungal pathogens (9).…”

Survival of Enteric Pathogens During Butterhead Lettuce Growth: Crop Stage, Leaf Age, and Irrigation

“…Irrigation water is considered a potentially important introduction route, and several studies have shown its potential for the transmission of enteric pathogens to lettuce plants. However, most of these studies were conducted either under laboratory or controlled conditions in growth chambers (Brandl and Mandrell, 2002;Solomon et al, 2003;Aruscavage et al, 2008;Aruscavage et al, 2010;Brandl and Amundson, 2008;Zhang et al, 2009;Erickson et al, 2010a) or field experiments (Barker-Reid et al, 2009;Erickson et al, 2010b;Harapas et al, 2010;Wood et al, 2010;Fonseca et al, 2011). Few studies have compared both types of experimental setups.…”