A Multistate Outbreak of Escherichia coli O157:H7 Infections Associated With Consumption of Mesclun Lettuce

Hilborn, Elizabeth D.; Mermin, Jonathan; Mshar, P.; Hadler, James L.; Voetsch, Andrew C.; Wojtkunski, C; Swartz, Margaret; Mshar, Roger; Lambert-Fair, Mary Ann; Farrar, Jeffrey A.; Glynn, M. Kathleen; Slutsker, Laurence

doi:10.1001/archinte.159.15.1758

Cited by 317 publications

(174 citation statements)

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“…Indirect routes of transmission may, however, be more significant in India, where most of the population does not eat beef for religious reasons. Possibly in areas like this, STEC transmission could occur through exposure to vegetables, fruits, or drinking water contaminated by bovine feces or through direct contact with feces of infected persons (14)(15)(16)(17). Only non-O157 STEC strains were isolated from human cases.…”

Section: Discussionmentioning

confidence: 99%

“…Principally, STEC is transmitted through the consumption of contaminated foods such as raw or undercooked ground meat products and raw milk (13). Although cattle are the primary known reservoirs of STEC, humans may acquire STEC infections from other sources, possibly vegetables (14), fruit juice (15), or contaminated drinking water (16), or through direct contact with feces of infected persons (17).…”

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confidence: 99%

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Prevalence and Genetic Profiling of Virulence Determinants of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolated from Cattle, Beef, and Humans, Calcutta, India

Khan

Yamasaki

Sato

et al. 2002

Emerg. Infect. Dis.

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We investigated the prevalence of Shiga toxin-producing Escherichia coli (STEC) in hospitalized diarrhea patients in Calcutta, India, as well as in healthy domestic cattle and raw beef samples collected from the city's abattoir. Multiplex polymerase chain reaction using primers specific for stx1 and stx2 detected STEC in 18% of cow stool samples, 50% of raw beef samples, and 1.4% and 0.6% of bloody and watery stool samples, respectively, from hospitalized diarrhea patients. Various virulence genes in the STEC isolates indicated that stx1 allele predominated. Plasmid-borne markers, namely, hlyA, katP, espP, and etpD, were also identified. Bead enzyme-linked immunosorbent assay and Vero cell assay were performed to detect and evaluate the cytotoxic effect of the Shiga toxins produced by the strains. STEC is not an important cause of diarrhea in India; however, its presence in domestic cattle and beef samples suggests that this enteropathogen may become a major public health problem in the future.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Prevalence and Genetic Profiling of Virulence Determinants of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolated from Cattle, Beef, and Humans, Calcutta, India

Khan

Yamasaki

Sato

et al. 2002

Emerg. Infect. Dis.

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“…EHEC often resides in bovine reservoirs and is transmitted via many food vehicles including cooked meat, such as hamburger (4) and salami (5), and raw vegetables, such as lettuce (6,7) and spinach (8). In North America, E. coli O157:H7 is the most common EHEC serotype contributing to Ͼ75,000 human infections (9) and 17 outbreaks (3) per year.…”

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confidence: 99%

Variation in virulence among clades of Escherichia coli O157:H7 associated with disease outbreaks

Manning

Motiwala

Springman

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

406

612

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Escherichia coli O157:H7, a toxin-producing food and waterborne bacterial pathogen, has been linked to large outbreaks of gastrointestinal illness for more than two decades. E. coli O157 causes a wide range of clinical illness that varies by outbreak, although factors that contribute to variation in disease severity are poorly understood. Several recent outbreaks involving O157 contamination of fresh produce (e.g., spinach) were associated with more severe disease, as defined by higher hemolytic uremic syndrome and hospitalization frequencies, suggesting that increased virulence has evolved. To test this hypothesis, we developed a system that detects SNPs in 96 loci and applied it to >500 E. coli O157 clinical strains. Phylogenetic analyses identified 39 SNP genotypes that differ at 20% of SNP loci and are separated into nine distinct clades. Differences were observed between clades in the frequency and distribution of Shiga toxin genes and in the type of clinical disease reported. Patients with hemolytic uremic syndrome were significantly more likely to be infected with clade 8 strains, which have increased in frequency over the past 5 years. Genome sequencing of a spinach outbreak strain, a member of clade 8, also revealed substantial genomic differences. These findings suggest that an emergent subpopulation of the clade 8 lineage has acquired critical factors that contribute to more severe disease. The ability to detect and rapidly genotype O157 strains belonging to such lineages is important and will have a significant impact on both disease diagnosis and treatment guidelines.pathogens ͉ polymorphisms ͉ population genetics E nterohemorrhagic Escherichia coli (EHEC) includes a diverse population of Shiga toxin-producing E. coli that causes outbreaks of food and waterborne disease (1-3). EHEC often resides in bovine reservoirs and is transmitted via many food vehicles including cooked meat, such as hamburger (4) and salami (5), and raw vegetables, such as lettuce (6, 7) and spinach (8). In North America, E. coli O157:H7 is the most common EHEC serotype contributing to Ͼ75,000 human infections (9) and 17 outbreaks (3) per year.It is not clear why outbreaks of EHEC O157 vary dramatically in the severity of illness and the frequency of the most serious complication, hemolytic uremic syndrome (HUS) (10-12). The 1993 outbreak in western North America (4) and the large 1996 outbreak in Japan (13) had low rates of hospitalization and HUS (14, 15), whereas the 2006 North American spinach outbreak (8) had high rates of both hospitalization (Ͼ50%) and HUS (Ͼ10%). One hypothesis is that outbreak strains differ in virulence as a result of variation in the presence and expression of different Shiga toxin (Stx) gene combinations (16)(17)(18)(19).To assess the genetic diversity and variability in virulence among E. coli O157 strains, we developed a real-time PCR system for identifying synonymous and nonsynonymous mutations as SNPs (20-23). Although molecular subtyping methods, such as pulsedfield gel electrophoresis (PFGE), ...

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“…Proximity of animal production to fresh produce fields has often been associated with foodborne outbreaks. Pathogens can be transferred to the fresh produce within a mixed animal/produce farm (Hilborn et al, 1999;Mshar et al, 1997) and at a wider scale after transport by water (Soderstrom et al, 2008) or wild life (Jay et al, 2007). Safety of fresh produce is presumably easier to control in areas with no, or little, animal production, although areas free of contamination from livestock reservoirs may be difficult to define.…”

Section: Farm Animals and Produce Safety Issuesmentioning

confidence: 99%

Agrifood systems and the microbial safety of fresh produce: Trade-offs in the wake of increased sustainability

Nguyen-Thé

Bardin²,

Bérard

et al. 2016

Science of The Total Environment

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(2016). Agrifood systems and the microbial safety of fresh produce: trade-offs in the wake of increased sustainability.Science of the Total Environment, 562, 751-759. H I G H L I G H T S• Measures taken to improve safety were assessed for their impact on sustainability.• Fresh produce safety improvements may come at the expense of sustainability.• Environment, food security and human health constituted the three domains of sustainability.• Measures to improve safety should be adapted to each agrifood system. Fresh produce has been a growing cause of food borne outbreaks world-wide prompting the need for safer production practices. Yet fresh produce agrifood systems are diverse and under constraints for more sustainability. We analyze how measures taken to guarantee safety interact with other objectives for sustainability, in light of the diversity of fresh produce agrifood systems. The review is based on the publications at the interface between fresh produce safety and sustainability, with sustainability defined by low environmental impacts, food and nutrition security and healthy life. The paths for more sustainable fresh produce are diverse. They include an increased use of ecosystem services to e.g. favor predators of pests, or to reduce impact of floods, to reduce soil erosion, or to purify run-off waters. In contrast, they also include production systems isolated from the environment. From a socio-economical view, sustainability may imply maintaining small tenures with a higher risk of pathogen contamination. We analyzed the consequences for produce safety by focusing on risks of contamination by water, soil, environment and live stocks. Climate change may increase the constraints and recent knowledge on interactions between produce and human pathogens may bring new solutions. Existing technologies may suffice to resolve some conflicts between ensuring safety of fresh produce and moving towards more sustainability. However, socio-economic constraints of some agri-food systems may prevent their implementation. In addition, current strategies to preserve produce safety are not adapted to systems relying on ecological principles and knowledge is lacking to develop the new risk management approaches that would be needed. G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o

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A Multistate Outbreak of Escherichia coli O157:H7 Infections Associated With Consumption of Mesclun Lettuce

Cited by 317 publications

References 31 publications

Prevalence and Genetic Profiling of Virulence Determinants of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolated from Cattle, Beef, and Humans, Calcutta, India

Prevalence and Genetic Profiling of Virulence Determinants of Non-O157 Shiga Toxin-ProducingEscherichia coliIsolated from Cattle, Beef, and Humans, Calcutta, India

Variation in virulence among clades of Escherichia coli O157:H7 associated with disease outbreaks

Agrifood systems and the microbial safety of fresh produce: Trade-offs in the wake of increased sustainability

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