The effect of oxidative stress on gene expression of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and non-O157 serotypes

Mei, Gui-Ying; Tang, Joshua; Carey, Christine; Bach, Susan; Kostrzynska, Magdalena

doi:10.1016/j.ijfoodmicro.2015.07.029

Cited by 26 publications

(31 citation statements)

References 79 publications

(79 reference statements)

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“…Low cinnamon oil concentrations, especially 0.5ϫ MIC, however, increased the oxidative stress response gene expression, which is consistent with a previous report showing that 2 h of cinnamaldehyde (200 mg/liter) exposure caused oxidative stress responses in E. coli O157:H7 (64). Oxidative stress plays a positive role in stx 2 gene expression (65). An induced oxidative stress response together with QS after a 0.5ϫ MIC treatment may contribute to the increased stx 2 expression and Stx2 production.…”

Section: Discussionsupporting

confidence: 92%

Cinnamon Oil Inhibits Shiga Toxin Type 2 Phage Induction and Shiga Toxin Type 2 Production in Escherichia coli O157:H7

Sheng

Rasco

Zhu

2016

Appl Environ Microbiol

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This study evaluated the inhibitory effect of cinnamon oil against Escherichia coli O157:H7 Shiga toxin (Stx) production and further explored the underlying mechanisms. The MIC and minimum bactericidal concentration (MBC) of cinnamon oil against E. coli O157:H7 were 0.025% and 0.05% (vol/vol), respectively. Cinnamon oil significantly reduced Stx2 production and the stx 2 mRNA expression that is associated with diminished Vero cell cytotoxicity. Consistently, induction of the Stx-converting phage where the stx 2 gene is located, along with the total number of phages, decreased proportionally to cinnamon oil concentration. In line with decreased Stx2 phage induction, cinnamon oil at 0.75؋ and 1.0؋ MIC eliminated RecA, a key mediator of SOS response, polynucleotide phosphorylase (PNPase), and poly(A) polymerase (PAP I), which positively regulate Stx-converting phages, contributing to reduced Stx-converting phage induction and Stx production. Furthermore, cinnamon oil at 0.75؋ and 1.0؋ MIC strongly inhibited the qseBC and luxS expression associated with decreased AI-2 production, a universal quorum sensing signaling molecule. However, the expression of oxidative stress response genes oxyR, soxR, and rpoS was increased in response to cinnamon oil at 0.25؋ or 0.5؋ MIC, which may contribute to stunted bacterial growth and reduced Stx2 phage induction and Stx2 production due to the inhibitory effect of OxyR on prophage activation. Collectively, cinnamon oil inhibits Stx2 production and Stx2 phage induction in E. coli O157:H7 in multiple ways. IMPORTANCEThis study reports the inhibitory effect of cinnamon oil on Shiga toxin 2 phage induction and Shiga toxin 2 production. Subinhibitory concentrations (concentrations below the MIC) of cinnamon oil reduced Stx2 production, stx 2 mRNA expression, and cytotoxicity on Vero cells. Subinhibitory concentrations of cinnamon oil also dramatically reduced both the Stx2 phage and total phage induction in E. coli O157:H7, which may be due to the suppression of RNA polyadenylation enzyme PNPase at 0.25؋ to 1.0؋ MIC and the downregulation of bacterial SOS response key regulator RecA and RNA polyadenylation enzyme PAP I at 0.75؋ or 1.0؋ MIC. Cinnamon oil at higher levels (0.75؋ and 1.0؋ MIC) eliminated quorum sensing and oxidative stress. Therefore, cinnamon oil has potential applications as a therapeutic to control E. coli O157:H7 infection through inhibition of bacterial growth and virulence factors. E scherichia coli O157:H7 is an important foodborne pathogen that is associated with hemorrhagic colitis, hemolytic-uremic syndrome (HUS), and death (1). More than 63,000 cases of foodborne illness are estimated to be caused by E. coli O157:H7 annually in the United States (2). Outbreaks have been associated with ground beef, ready-to-eat salad, cheese, apple juice, and other foods (3-6).Shiga toxin (Stx) is a major virulence factor of E. coli O157:H7. Its production in the gastrointestinal tract in conjunction with other virulence factors induces hemorrhagic colitis, and its entry...

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Section: Discussionsupporting

confidence: 92%

Cinnamon Oil Inhibits Shiga Toxin Type 2 Phage Induction and Shiga Toxin Type 2 Production in Escherichia coli O157:H7

Sheng

Rasco

Zhu

2016

Appl Environ Microbiol

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“…E. coli O157:H7 (EDL933) was isolated from raw hamburger meat linked to an outbreak of HC. Further details regarding these strains have been published previously (Mei et al, 2015). E. coli O157:H7 (EDL933) possesses genes encoding Stx1 and Stx2, intimin gene ( eae ) and flagellin gene ( fliC ).…”

Section: Methodsmentioning

confidence: 99%

“…Each 25-μL reaction contained 1 μL of reverse-transcribed cDNA, 12.5 μL of Power SYBR ® Green PCR Master Mix, 0.25 U AmpErase ® Uracil N -Glycosylase (UNG; Applied Biosystems), 2.0 μM of each primer and 6.25 μL nuclease-free water. All primers used in the study were previously described (Mei et al, 2015). Amplification and detection were carried out on a MX3500 ® Multiplex Quantitative PCR System (Stratagene, La Jolla, CA, USA) with an initial temperature of 50°C for 2 min.…”

Section: Methodsmentioning

confidence: 99%

“…No template control and No RT were included for each assay and no Ct values were obtained for all negative controls after 40 cycles of PCR (data not shown). Several well-known candidate reference genes including 16S rRNA, tufA/B , mdh , pyrC , gatB , recA , serC , frr , rpsU , udp , mdoG , rpoA , and arcA were tested for expression stability as previously described (Mei et al, 2015). Only 16S rRNA gene expression was stable in all VTEC strains on lettuce under experimental conditions.…”

Section: Methodsmentioning

confidence: 99%

“…To date, several studies have been conducted on the gene expression in pure culture of E. coli O157:H7 under oxidative stress (Wang et al, 2009; Allen and Griffiths, 2012; Mei et al, 2015). In addition, using H 2 O 2 as a sanitizer on fresh produce to reduce E. coli O157:H7 was investigated (Sapers et al, 2000; Huang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Changes in Gene Transcription Induced by Hydrogen Peroxide Treatment of Verotoxin-Producing Escherichia coli O157:H7 and Non-O157 Serotypes on Romaine Lettuce

et al. 2017

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Disease outbreaks of verotoxin-producing Escherichia coli (VTEC) O157:H7 and non-O157 serotypes associated with leafy green vegetables are becoming a growing concern. A better understanding of the behavior of VTEC, particularly non-O157 serotypes, on lettuce under stress conditions is necessary for designing more effective control strategies. Hydrogen peroxide (H2O2) can be used as a sanitizer to reduce the microbial load in leafy green vegetables, particularly in fresh produce destined for the organic market. In this study, we tested the hypothesis that H2O2 treatment of contaminated lettuce affects in the same manner transcription of stress-associated and virulence genes in VTEC strains representing O157 and non-O157 serotypes. Six VTEC isolates representing serotypes O26:H11, O103:H2, O104:H4, O111:NM, O145:NM, and O157:H7 were included in this study. The results indicate that 50 mM H2O2 caused a population reduction of 2.4–2.8 log10 (compared to non-treated control samples) in all six VTEC strains present on romaine lettuce. Following the treatment, the transcription of genes related to oxidative stress (oxyR and sodA), general stress (uspA and rpoS), starvation (phoA), acid stress (gadA, gadB, and gadW), and virulence (stx1A, stx2A, and fliC) were dramatically downregulated in all six VTEC serotypes (P ≤ 0.05) compared to not treated control samples. Therefore, VTEC O157:H7 and non-O157 serotypes on lettuce showed similar survival rates and gene transcription profiles in response to 50 mM H2O2 treatment. Thus, the results derived from this study provide a basic understanding of the influence of H2O2 treatment on the survival and virulence of VTEC O157:H7 and non-O157 serotypes on lettuce.

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The Influence of Lactobacillus spp. Secondary Metabolites Isolated from Immature Egyptian Honey on Human Pathogens, Transcription of Virulence Genes and Lung Cancer

Elsayed,

Nour,

Hamed

et al. 2024

Indian J Microbiol

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This work aimed to isolate, and identify Lactic Acid Bacteria LAB from Egyptian immature citrus honey, and characterize their secondary metabolites, as well as determine the antibacterial activities and transcription of virulence genes (stx1, stx2, and eae) influenced by these bacterial secondary metabolites. From twenty hives, twenty immature citrus bee honey samples were taken. Traditional cultural and biochemical testing were used, followed by molecular confirmation. Further, LAB isolates' antibacterial and cytotoxic properties were investigated. 16S rRNA gene sequencing were assessed and, two lactic acid bacterial isolates were identified as Lactobacillus acidophilus Ch2 and Levilactobacillus brevis Ch1. Both isolates have good antagonistic action against clinical pathogens, with Levilactobacillus brevis Ch1 exhibiting the best antibacterial activity against all indicator pathogens examined. When compared to untreated cancer cells, the isolates demonstrated significant cytotoxic activity. Ch1 and Ch2 cell viability percentages were 39.5% and 18.76%, respectively. Furthermore, when exposed to Levilactobacillus brevis Ch1 metabolites, Shiga-producing Escherichia coli (STEC) virulence gene expression was suppressed. To identify bacterial secondary metabolites, a high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF) approach was developed. Twenty-seven metabolites from diverse chemical classes were discovered in the crude extracts with antibacterial and anticancer characteristics. This is the first thorough investigation on the metabolic profile of LAB isolated from immature Egyptian honey and the findings suggested that isolates or their secondary metabolites could be used in the food sector as medicinal alternatives or as a biocontrol agent.

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The effect of oxidative stress on gene expression of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and non-O157 serotypes

Cited by 26 publications

References 79 publications

Cinnamon Oil Inhibits Shiga Toxin Type 2 Phage Induction and Shiga Toxin Type 2 Production in Escherichia coli O157:H7

Cinnamon Oil Inhibits Shiga Toxin Type 2 Phage Induction and Shiga Toxin Type 2 Production in Escherichia coli O157:H7

Changes in Gene Transcription Induced by Hydrogen Peroxide Treatment of Verotoxin-Producing Escherichia coli O157:H7 and Non-O157 Serotypes on Romaine Lettuce

The Influence of Lactobacillus spp. Secondary Metabolites Isolated from Immature Egyptian Honey on Human Pathogens, Transcription of Virulence Genes and Lung Cancer

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