Transcriptomic response of Escherichia coli O157 isolates on meat: Comparison between a typical Australian isolate from cattle and a pathogenic clinical isolate

Summary The development of effective natural antibacterial agents is important due to the insecurity of synthetic antimicrobial agents and consumer preferences. In this study, kojic acid (KA) and tea polyphenols (TP) were found to exhibit synergistic inhibitory effect against Escherichia coli O157:H7 with a fractional inhibitory concentration index of 0.25. KA combined with TP at 25% of their minimum inhibitory concentrations (MICs) completely inactivated E. coli O157:H7 within 4 h. Subsequently, propidium iodide uptake tests, genomic DNA interaction analysis, molecular docking, field emission scanning electron microscopy and biofilm formation assay were conducted to understand the synergistic antibacterial mechanism of KA‐TP. The results demonstrated that KA‐TP attacked the cell membrane cooperatively, thus disturbing membrane integrity and cell structure, and KA could bind to the genomic DNA to affect the biofilm formation of E. coli O157:H7. Moreover, the contamination of E. coli O157:H7 on raw salmon fillets was eliminated to varying degrees after soaking treatments with KA and/or TP for 30 min. The depuration effect was further enhanced when KA combined with TP, and more than 2‐log reduction of E. coli O157:H7 was obtained under the treatment of KA‐TP at 2 MIC, suggesting that KA‐TP may serve as a natural compound disinfectant for ready‐to‐eat aquatic products.

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“…(2020) and King et al . (2019). Briefly, the salmons were washed thoroughly and preliminary disinfected with ethanol.…”

Section: Methodsmentioning

confidence: 99%

Kojic acid and tea polyphenols inactivate Escherichia coli O157:H7 in vitro and on salmon fillets by inflicting damage on cell membrane and binding to genomic DNA

Wang

Fang

et al. 2021

Int J of Food Sci Tech

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“…They identified several genes that were differentially expressed between HUS-producing STEC (higher level) and non-HUS STEC, including nleB. A number of factors have been postulated to account for differential expression between isolates, including differences in DNA sequence, in the number of gene copies and in specific transcriptional regulators (de Gouw et al, 2014;Roberfroid et al, 2016;King et al, 2019).…”

Section: Resultsmentioning

confidence: 99%

Differential expression of the virulence gene nleB among Shiga toxin-producing Escherichia coli strains

Cadona

Burgán

González

et al. 2020

Heliyon

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Shiga toxin-producing Escherichia coli (STEC) is a zoonotic foodborne pathogen associated with hemolytic uremic syndrome (HUS) that vary in their ability to cause disease in humans. STEC represents a serious problem for public health and Argentina is the country with the highest HUS incidence worldwide. Non-LEE effector (nle) genes, present on pathogenicity islands (PAIs), encode translocated substrates of the type III secretion system (T3SS), which could have an important role in STEC virulence. Particularly, nleB is one of the main effector genes proposed as a virulence marker that is involved in the action of T3SS during the STEC infection. NleB inhibits the inflammatory response of the host cell allowing the bacteria to persist in the first stage of the infection. In order to identify the potential risk of STEC strains for public health, the aim of this study was to evaluate and compare basal nleB transcription of 24 STEC strains belonging to 10 serotypes isolated from cattle, food and patients. The results showed differences in nleB transcription among strains. Some non-O157:H7 strains presented transcription levels above the control, an O157:H7 HUS-producing strain. On the other hand, no significant differences were found in basal transcription levels associated with origin or serotype but differences were found between HUS and non-HUS strains. These differences in nleB transcription may be of importance in STEC pathogenesis and could help to differentiate high and low virulence STEC strains.

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“…E. coli O157:H7 strongly tolerates many food-related environmental stresses, such as acid stress, low temperatures, osmotic stress, and poor nutrition [3]. Any food and beverage that may contact animal feces is a potential source of E. coli O157:H7 outbreaks that significantly contaminate beef [4,5]. Thus, many researchers are currently trying to find antimicrobials to control E. coli O157:H7 and other pathogens.…”

Section: Introductionmentioning

confidence: 99%

Antibacterial mechanism of kojic acid and tea polyphenols against Escherichia coli O157:H7 through transcriptomic analysis

Lin¹,

Wang²,

Li³

et al. 2024

Food Science and Human Wellness

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Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans. The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E. coli O157:H7 than using either alone. This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level. The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E. coli O157:H7 found that acid resistance systems in kojic acid were activated, and the cell membrane and genomic DNA were destructed in the cells, resulting in "oxygen starvation". The oxidative stress response triggered by tea polyphenols was inhibited both sulfur uptake and the synthesis of ATP, which affected the bacteria's life metabolic process. Interestingly, we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA, respiration, tricarboxylic acid cycle. The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E. coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.

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Transcriptomic response of Escherichia coli O157 isolates on meat: Comparison between a typical Australian isolate from cattle and a pathogenic clinical isolate

Cited by 7 publications

References 86 publications

Kojic acid and tea polyphenols inactivate Escherichia coli O157:H7 in vitro and on salmon fillets by inflicting damage on cell membrane and binding to genomic DNA

Kojic acid and tea polyphenols inactivate Escherichia coli O157:H7 in vitro and on salmon fillets by inflicting damage on cell membrane and binding to genomic DNA

Differential expression of the virulence gene nleB among Shiga toxin-producing Escherichia coli strains

Antibacterial mechanism of kojic acid and tea polyphenols against Escherichia coli O157:H7 through transcriptomic analysis

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