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1.
BMC Vet Res ; 20(1): 192, 2024 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-38734600

RESUMEN

BACKGROUND: Natural antimicrobial agents such as nisin were used to control the growth of foodborne pathogens in dairy products. The current study aimed to examine the inhibitory effect of pure nisin and nisin nanoparticles (nisin NPs) against methicillin resistant Staphylococcus aureus (MRSA) and E.coli O157:H7 during the manufacturing and storage of yoghurt. Nisin NPs were prepared using new, natural, and safe nano-precipitation method by acetic acid. The prepared NPs were characterized using zeta-sizer and transmission electron microscopy (TEM). In addition, the cytotoxicity of nisin NPs on vero cells was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The minimum inhibitory concentrations (MICs) of nisin and its nanoparticles were determined using agar well-diffusion method. Further, fresh buffalo's milk was inoculated with MRSA or E.coli O157:H7 (1 × 106 CFU/ml) with the addition of either nisin or nisin NPs, and then the inoculated milk was used for yoghurt making. The organoleptic properties, pH and bacterial load of the obtained yoghurt were evaluated during storage in comparison to control group. RESULTS: The obtained results showed a strong antibacterial activity of nisin NPs (0.125 mg/mL) against MRSA and E.coli O157:H7 in comparison with control and pure nisin groups. Notably, complete eradication of MRSA and E.coli O157:H7 was observed in yoghurt formulated with nisin NPs after 24 h and 5th day of storage, respectively. The shelf life of yoghurt inoculated with nisin nanoparticles was extended than those manufactured without addition of such nanoparticles. CONCLUSIONS: Overall, the present study indicated that the addition of nisin NPs during processing of yoghurt could be a useful tool for food preservation against MRSA and E.coli O157:H7 in dairy industry.


Asunto(s)
Antibacterianos , Escherichia coli O157 , Staphylococcus aureus Resistente a Meticilina , Pruebas de Sensibilidad Microbiana , Nanopartículas , Nisina , Yogur , Nisina/farmacología , Nisina/química , Yogur/microbiología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Escherichia coli O157/efectos de los fármacos , Nanopartículas/química , Animales , Antibacterianos/farmacología , Antibacterianos/química , Conservantes de Alimentos/farmacología , Células Vero , Microbiología de Alimentos , Chlorocebus aethiops , Conservación de Alimentos/métodos
2.
MMWR Morb Mortal Wkly Rep ; 73(18): 411-416, 2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38722798

RESUMEN

During July-September 2023, an outbreak of Shiga toxin-producing Escherichia coli O157:H7 illness among children in city A, Utah, caused 13 confirmed illnesses; seven patients were hospitalized, including two with hemolytic uremic syndrome. Local, state, and federal public health partners investigating the outbreak linked the illnesses to untreated, pressurized, municipal irrigation water (UPMIW) exposure in city A; 12 of 13 ill children reported playing in or drinking UPMIW. Clinical isolates were genetically highly related to one another and to environmental isolates from multiple locations within city A's UPMIW system. Microbial source tracking, a method to indicate possible contamination sources, identified birds and ruminants as potential sources of fecal contamination of UPMIW. Public health and city A officials issued multiple press releases regarding the outbreak reminding residents that UPMIW is not intended for drinking or recreation. Public education and UPMIW management and operations interventions, including assessing and mitigating potential contamination sources, covering UPMIW sources and reservoirs, indicating UPMIW lines and spigots with a designated color, and providing conspicuous signage to communicate risk and intended use might help prevent future UPMIW-associated illnesses.


Asunto(s)
Brotes de Enfermedades , Infecciones por Escherichia coli , Escherichia coli O157 , Humanos , Utah/epidemiología , Preescolar , Escherichia coli O157/aislamiento & purificación , Niño , Femenino , Masculino , Infecciones por Escherichia coli/epidemiología , Lactante , Adolescente , Riego Agrícola , Microbiología del Agua , Escherichia coli Shiga-Toxigénica/aislamiento & purificación
3.
Commun Biol ; 7(1): 535, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38710842

RESUMEN

Escherichia coli O157 can cause foodborne outbreaks, with infection leading to severe disease such as hemolytic-uremic syndrome. Although phage-based detection methods for E. coli O157 are being explored, research on their specificity with clinical isolates is lacking. Here, we describe an in vitro assembly-based synthesis of vB_Eco4M-7, an O157 antigen-specific phage with a 68-kb genome, and its use as a proof of concept for E. coli O157 detection. Linking the detection tag to the C-terminus of the tail fiber protein, gp27 produces the greatest detection sensitivity of the 20 insertions sites tested. The constructed phage detects all 53 diverse clinical isolates of E. coli O157, clearly distinguishing them from 35 clinical isolates of non-O157 Shiga toxin-producing E. coli. Our efficient phage synthesis methods can be applied to other pathogenic bacteria for a variety of applications, including phage-based detection and phage therapy.


Asunto(s)
Escherichia coli O157 , Escherichia coli O157/virología , Escherichia coli O157/genética , Escherichia coli O157/aislamiento & purificación , Humanos , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/diagnóstico , Bacteriófagos/genética , Bacteriófagos/aislamiento & purificación , Colifagos/genética , Colifagos/aislamiento & purificación , Sensibilidad y Especificidad , Genoma Viral
4.
Carbohydr Polym ; 337: 122160, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38710575

RESUMEN

Sterilisation technologies are essential to eliminate foodborne pathogens from food contact surfaces. However, most of the current sterilisation methods involve high energy and chemical consumption. In this study, a photodynamic inactivation coating featuring excellent antibacterial activity was prepared by dispersing curcumin as a plant-based photosensitiser in a chitosan solution. The coating generated abundant reactive oxygen species (ROS) after light irradiation at 420 nm, which eradicated ≥99.999 % of Escherichia coli O157:H7. It was also found that ROS damaged the cell membrane, leading to the leakage of cell contents and cell shrinkage on the basis of chitosan. In addition, the production of ROS first excited the bacterial antioxidant defence system resulting in the increase of peroxidase (POD) and superoxide dismutase (SOD). ROS levels exceed its capacity, causing damage to the defence system and further oxidative decomposition of large molecules, such as DNA and proteins, eventually leading to the death of E. coli O157:H7. We also found the curcumin/chitosan coating could effectively remove E. coli O157:H7 biofilms by oxidative of extracellular polysaccharides and proteins. All the contributors made the chitosan/curcumin coating an efficient detergent comparable with HClO.


Asunto(s)
Antibacterianos , Biopelículas , Quitosano , Curcumina , Escherichia coli O157 , Fármacos Fotosensibilizantes , Especies Reactivas de Oxígeno , Quitosano/química , Quitosano/farmacología , Curcumina/farmacología , Curcumina/química , Escherichia coli O157/efectos de los fármacos , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/química , Antibacterianos/farmacología , Antibacterianos/química , Especies Reactivas de Oxígeno/metabolismo , Biopelículas/efectos de los fármacos , Microbiología de Alimentos , Luz
5.
Food Microbiol ; 121: 104516, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38637078

RESUMEN

Oxidation-reduction potential (ORP) is commonly used as a rapid measurement of the antimicrobial potential of free chlorine during industrial fresh produce washing. The current study tested the hypothesis that ORP can act as a "single variable" measurement of bacterial (vegetative and endospores) inactivation effectiveness with free chlorine irrespective of the water pH value. This situation has on occasion been assumed but never confirmed nor disproven. Chlorine-dosed pH 6.5 and 8.5 phosphate buffer solutions were inoculated with Escherichia coli (E. coli), Listeria innocua (L. innocua), or Bacillus subtilis (B. subtilis) endospores. ORP, free chlorine (FC), and log reduction were monitored after 5 s (for E. coli and L. innocua) and up to 30 min (for B. subtilis spores) of disinfection. Logistic and exponential models were developed to describe how bacteria reduction varied as a function of ORP at different pH levels. Validation tests were performed in phosphate buffered pH 6.5 and 8.5 cabbage wash water periodically dosed with FC, cabbage extract and a cocktail of Escherichia coli O157:H7 (E. coli O157:H7) and Listeria monocytogenes (L. monocytogenes). The built logistic and exponential models confirmed that at equal ORP values, the inactivation of the surrogate strains was not consistent across pH 6.5 and pH 8.5, with higher reductions at higher pH. This is the opposite of the well-known free chlorine-controlled bacterial inactivation, where the antibacterial effect is higher at lower pH. The validation test results indicated that in the cabbage wash water, the relationship between disinfection efficiency and ORP was consistent with the oxidant demand free systems. The study suggests that ORP cannot serve as a reliable single variable measurement to predict bacterial disinfection in buffered systems. When using ORP to monitor and control the antibacterial effectiveness of the chlorinated wash water, it is crucial to take into account (and control) the pH.


Asunto(s)
Escherichia coli O157 , Listeria monocytogenes , Listeria , Desinfección/métodos , Cloro/farmacología , Cloro/análisis , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Oxidantes , Recuento de Colonia Microbiana , Manipulación de Alimentos/métodos , Cloruros , Oxidación-Reducción , Agua/química , Antibacterianos , Concentración de Iones de Hidrógeno , Fosfatos
6.
Food Microbiol ; 121: 104526, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38637088

RESUMEN

Korean style kimchi contaminated with Shiga toxin-producing Escherichia coli (STEC) O157:H7 was the cause of an outbreak in Canada from December 2021 to January 2022. To determine if this STEC O157:H7 has greater potential for survival in kimchi than other STEC, the outbreak strain and six other STEC strains (O26:H11, O91:H21, O103:H2, O121:H19, and two O157:H7) were inoculated individually at 6 to 6.5 log CFU/g into commercially sourced kimchi and incubation at 4 °C. At intervals of seven days inoculated and control kimchi was plated onto MacConkey agar to enumerate lactose utilising bacteria. The colony counts were interpreted as enumerating the inoculated STEC, since no colonies were observed on MacConkey agar plated with uninoculated kimchi. Over eight weeks of incubation the pH was stable at 4.10 to 4.05 and the STEC strains declined by 0.7-1.0 log, with a median reduction of 0.9 log. The linear rate of reduction of kimchi outbreak STEC O157:H7 was -0.4 log per 30 days (Slope Uncertainty 0.05), which was not significantly different from the other O157 and nonO157 STEC strains (P = 0.091). These results indicate that the outbreak was not due to the presence of strain better adapted to survival in kimchi than other STEC, and that STEC can persist in refrigerated Korean style kimchi with a minimal decline over the shelf-life of the product.


Asunto(s)
Escherichia coli O157 , Proteínas de Escherichia coli , Alimentos Fermentados , Escherichia coli Shiga-Toxigénica , Agar , Escherichia coli O157/genética , Escherichia coli Shiga-Toxigénica/genética , Medios de Cultivo , República de Corea
7.
J Inorg Biochem ; 256: 112575, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38678912

RESUMEN

Escherichia coli O157:H7 possesses an 8-gene cluster (chu genes) that contains genes involved in heme transport and processing from the human host. Among the chu genes, four encode cytoplasmic proteins (ChuS, ChuX, ChuY and ChuW). ChuX was previously shown to be a heme binding protein and to assist ChuW in heme degradation under anaerobic conditions. The purpose of this work was to investigate if ChuX works in concert with ChuS, which is a protein able to degrade heme by a non-canonical mechanism and release the iron from the porphyrin under aerobic conditions using hydrogen peroxide as the oxidant. We showed that when the heme-bound ChuX and apo-ChuS protein are mixed, heme is efficiently transferred from ChuX to ChuS. Heme-bound ChuX displayed a peroxidase activity with ABTS and H2O2 but not heme-bound ChuS, which is an efficient test to determine the protein to which heme is bound in the ChuS-ChuX complex. We found that ChuX protects heme from chemical oxidation and that it has no heme degradation activity by itself. Unexpectedly, we found that ChuX inhibits heme degradation by ChuS and stops the reaction at an early intermediate. We determined using surface plasmon resonance that ChuX interacts with ChuS and that it forms a relatively stable complex. These results indicate that ChuX in addition to its heme transfer activity is a regulator of ChuS activity, a function that was not described before for any of the heme carrier protein that delivers heme to heme degradation enzymes.


Asunto(s)
Escherichia coli O157 , Proteínas de Escherichia coli , Proteínas de Unión al Hemo , Hemo , Hemo/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Escherichia coli O157/metabolismo , Escherichia coli O157/genética , Proteínas de Unión al Hemo/metabolismo , Peróxido de Hidrógeno/metabolismo , Hemoproteínas/metabolismo , Hemoproteínas/genética , Oxidación-Reducción
8.
ACS Infect Dis ; 10(5): 1644-1653, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38602317

RESUMEN

This study describes the synthesis of amino-functionalized carbon nanoparticles derived from biopolymer chitosan using green synthesis and its application toward ultrasensitive electrochemical immunosensor of highly virulent Escherichia coli O157:H7 (E. coli O157:H7). The inherent advantage of high surface-to-volume ratio and enhanced rate transfer kinetics of nanoparticles is leveraged to push the limit of detection (LOD), without compromising on the selectivity. The prepared carbon nanoparticles were systematically characterized by employing CO2-thermal programmed desorption (CO2-TPD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-visible), and transmission electron microscopy (TEM). The estimated limit of detection of 0.74 CFU/mL and a sensitivity of 5.7 ((ΔRct/Rct)/(CFU/mL))/cm2 in the electrochemical impedance spectroscopy (EIS) affirm the utility of the sensor. The proposed biosensor displayed remarkable selectivity against interfering species, making it well suited for real-time applications. Moreover, the chitosan-derived semiconducting amino-functionalized carbon shows excellent sensitivity in a comparative analysis compared to highly conducting amine-functionalized carbon synthesized via chemical modification, demonstrating its vast potential as an E. coli sensor.


Asunto(s)
Técnicas Biosensibles , Carbono , Quitosano , Espectroscopía Dieléctrica , Escherichia coli O157 , Escherichia coli O157/aislamiento & purificación , Técnicas Biosensibles/métodos , Carbono/química , Quitosano/química , Nanopartículas/química , Límite de Detección , Tecnología Química Verde
9.
Nano Lett ; 24(20): 5993-6001, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38655913

RESUMEN

Bimetallic hollow structures have attracted much attention due to their unique properties, but they still face the problems of nonuniform alloys and excessive etching leading to structural collapse. Here, uniform bimetallic hollow nanospheres are constructed by pore engineering and then highly loaded with hemin (Hemin@MOF). Interestingly, in the presence of polydopamine (PDA), the competitive coordination between anionic polymer (γ-PGA) and dimethylimidazole does not lead to the collapse of the external framework but self-assembly into a hollow structure. By constructing the Hemin@MOF immune platform and using E. coli O157:H7 as the detection object, we find that the visual detection limits can reach 10, 3, and 3 CFU/mL in colorimetric, photothermal, and catalytic modes, which is 4 orders of magnitude lower than the traditional gold standard. This study provides a new idea for the morphological modification of the metal-organic skeleton and multifunctional immunochromatography detection.


Asunto(s)
Hemina , Indoles , Inmunoensayo/métodos , Inmunoensayo/instrumentación , Hemina/química , Indoles/química , Polímeros/química , Escherichia coli O157 , Estructuras Metalorgánicas/química , Nanosferas/química , Límite de Detección
10.
Environ Pollut ; 350: 123988, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38648967

RESUMEN

Outbreaks of Escherichia coli (E. coli) O157:H7 in farms are often triggered by heavy rains and flooding. Most cells die with the decreasing of soil moisture, while few cells enter a dormant state and then resuscitate after rewetting. The resistance of dormant cells to stress has been extensively studied, whereas the molecular mechanisms of the cross-resistance development of the resuscitated cells are poorly known. We performed a comparative proteomic analysis on O157:H7 before and after undergoing soil dry-wet alternation. A differential expression of 820 proteins was identified in resuscitated cells compared to exponential-phase cells, as determined by proteomics analysis. The GO and KEGG pathway enrichment analyses revealed that up-regulated proteins were associated with oxidative phosphorylation, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), aminoacyl-tRNA biosynthesis, ribosome activity, and transmembrane transporters, indicating increased energy production and protein synthesis in resuscitated O157:H7. Moreover, proteins related to acid, osmotic, heat, oxidative, antibiotic stress and horizontal gene transfer efficiency were up-regulated, suggesting a potential improvement in stress resistance. Subsequent validation experiments demonstrated that the survival rates of the resuscitated cells were 476.54 and 7786.34 times higher than the exponential-phase cells, with pH levels of 1.5 and 2.5, respectively. Similarly, resuscitated cells showed higher survival rates under osmotic stress, with 7.5%, 15%, and 30% NaCl resulting in survival rates that were 460.58, 1974.55, and 3475.31 times higher. Resuscitated cells also exhibited increased resistance to heat stress, with survival rates 69.64 and 139.72 times higher at 55 °C and 90 °C, respectively. Furthermore, the horizontal gene transfer (HGT) efficiency of resuscitated cells was significantly higher (153.12-fold) compared to exponential phase cells. This study provides new insights into bacteria behavior under changing soil moisture and this may explain O157:H7 outbreaks following rainfall and flooding, as the dry-wet cycle promotes stress cross-resistance development.


Asunto(s)
Escherichia coli O157 , Microbiología del Suelo , Suelo , Escherichia coli O157/fisiología , Suelo/química , Estrés Fisiológico , Proteómica
11.
Nutrients ; 16(8)2024 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-38674854

RESUMEN

Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is a commonly encountered foodborne pathogen that can cause hemorrhagic enteritis and lead to hemolytic uremic syndrome (HUS) in severe cases. Bifidobacterium is a beneficial bacterium that naturally exists in the human gut and plays a vital role in maintaining a healthy balance in the gut microbiota. This study investigated the protective effects of B. longum K5 in a mouse model of EHEC O157:H7 infection. The results indicated that pretreatment with B. longum K5 mitigated the clinical symptoms of EHEC O157:H7 infection and attenuated the increase in myeloperoxidase (MPO) activity in the colon of the mice. In comparison to the model group, elevated serum D-lactic acid concentrations and diamine oxidase (DAO) levels were prevented in the K5-EHEC group of mice. The reduced mRNA expression of tight junction proteins (ZO-1, Occludin, and Claudin-1) and mucin MUC2, as well as the elevated expression of virulence factors Stx1A and Stx2A, was alleviated in the colon of both the K5-PBS and K5-EHEC groups. Additionally, the increase in the inflammatory cytokine levels of TNF-α and IL-1ß was inhibited and the production of IL-4 and IL-10 was promoted in the K5-EHEC group compared with the model group. B. longum K5 significantly prevented the reduction in the abundance and diversity of mouse gut microorganisms induced by EHEC O157:H7 infection, including blocking the decrease in the relative abundance of Roseburia, Lactobacillus, and Oscillibacter. Meanwhile, the intervention with B. longum K5 promoted the production of acetic acid and butyric acid in the gut. This study provides insights into the use of B. longum K5 for developing probiotic formulations to prevent intestinal diseases caused by pathogenic bacterial infections.


Asunto(s)
Bifidobacterium longum , Colon , Infecciones por Escherichia coli , Escherichia coli O157 , Microbioma Gastrointestinal , Probióticos , Animales , Ratones , Probióticos/farmacología , Infecciones por Escherichia coli/prevención & control , Infecciones por Escherichia coli/microbiología , Colon/microbiología , Colon/metabolismo , Modelos Animales de Enfermedad , Mucina 2/metabolismo , Citocinas/metabolismo , Peroxidasa/metabolismo , Amina Oxidasa (conteniendo Cobre)/metabolismo
12.
Biosens Bioelectron ; 257: 116338, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38677017

RESUMEN

Foodborne pathogens have a substantial bearing on food safety and environmental health. The development of automated, portable and compact devices is essential for the on-site and rapid point-of-care testing (POCT) of bacteria. Here, this work developed a micro-automated microfluidic device for detecting bacteria, such as Escherichia coli (E. coli) O157:H7, using a seashell-like microfluidic chip (SMC) as an analysis and mixing platform. The automated device integrates a colorimetric/fluorescent system for the metabolism of copper (Cu2+) by E. coli affecting o-phenylenediamine (OPD) for concentration analysis. A smartphone was used to read the RGB data of the chip reaction reservoir to detect colorimetric and fluorescence patterns in the concentration range of 102-106 CFU mL-1. The automated device overcomes the low efficiency and tedious steps of traditional detection and enables high-precision automated detection that can be applied to POCT in the field, providing an ideal solution for broadening the application of E. coli detection.


Asunto(s)
Técnicas Biosensibles , Colorimetría , Cobre , Diseño de Equipo , Escherichia coli O157 , Microbiología de Alimentos , Dispositivos Laboratorio en un Chip , Pruebas en el Punto de Atención , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Escherichia coli O157/aislamiento & purificación , Humanos , Colorimetría/instrumentación , Cobre/química , Teléfono Inteligente/instrumentación , Enfermedades Transmitidas por los Alimentos/microbiología , Fenilendiaminas/química , Infecciones por Escherichia coli/microbiología , Contaminación de Alimentos/análisis
13.
Food Res Int ; 184: 114252, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38609230

RESUMEN

Leafy green surface microbiology studies often experience significant variations in results due to the heterogeneous nature of leaf surfaces. To provide a precise and controllable substitute, we microfabricated double-sided artificial leafy green phylloplanes using polydimethylsiloxane (PDMS) with a vinyl-terminated polyethylene glycol chain-based hydrophobicity modifier (PDMS-PEG) to modify PDMS hydrophobicity. We further tested the properties and applications of these artificial leaves, by examining the function of epicuticular wax, growth and survival of E. coli O157:H7 87-23 on the surface, and removal of attached E. coli cells via sanitation. The double-sided PDMS-PDMS-PEG leaves well-replicated their natural counterparts in macroscopic and microscopic structure, hydrophobicity, and E. coli O157:H7 87-23 attachment. After depositing natural epicuticular wax onto artificial leaves, the leaf surface wetting ability decreased, while E. coli O157:H7 87-23 surface retention increased. The artificial leaves supplied with lettuce lysate or bacterial growth media supported E. coli O157:H7 87-23 growth and survival similarly to those on natural leaves. In the sanitation test, the artificial lettuce leaves also displayed patterns similar to those of natural leaves regarding sanitizer efficiency. Overall, this study showcased the microfabrication and applications of double-sided PDMS-PDMS-PEG leaves as a replicable and controllable platform for future leafy green food safety studies.


Asunto(s)
Dimetilpolisiloxanos , Escherichia coli O157 , Medios de Cultivo , Inocuidad de los Alimentos , Lactuca
14.
Mikrochim Acta ; 191(5): 237, 2024 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-38570419

RESUMEN

An ultra-sensitive fluorescent biosensor based on CDs/QDs@ZIF-8 and microfluidic fluidized bed was developed for rapid and ultra-sensitive detection of multiple target bacteria. The zeolitic imidazolate frameworks (ZIF-8) act as the carrier to encapsulate three kinds of fluorescence signal molecules from the CDs/QDs@ZIF-8 signal amplification system. Besides, three kinds of target pathogenic bacteria were automatically, continuously, and circularly captured by the magnetic nanoparticles (MNPs) in the microfluidic fluidized bed. The neutral Na2EDTA solution was the first time reported to not only dissolve the ZIF-8 frameworks from the MNPs-bacteria-CDs/QDs@ZIF-8 sandwich complexes, but also release the CDs/QDs from sandwich complexes with no loss of fluorescence signal. Due to the advantages of signal amplification and automated sample pretreatment, the proposed fluorescent biosensor can simultaneously detect Escherichia coli O157:H7, Salmonella paratyphi A, and Salmonella paratyphi B as low as 101 CFU/mL within 1.5 h, respectively. The mean recovery in spiked milk samples can reach 99.18%, verifying the applicability of this biosensor in detecting multiple bacteria in real samples.


Asunto(s)
Técnicas Biosensibles , Escherichia coli O157 , Puntos Cuánticos , Zeolitas , Microfluídica , Colorantes
15.
Microbiol Res ; 284: 127711, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38636240

RESUMEN

Microbial ferroptosis has been proved to combat drug-resistant pathogens, but whether this pattern can be applied to the prevention and control of Escherichia coli remains to be further explored. In this study, ferrous gluconate (FeGlu) showed remarkable efficacy in killing E. coli MG1655 with a mortality rate exceeding 99.9%, as well as enterotoxigenic E. coli H10407 (ETEC H10407) and enterohemorrhagic E. coli O157:H7 (EHEC O157:H7). Bacteria death was instigated by the infiltration of Fe2+, accompanied by a burst of intracellular reactive oxygen species (ROS) and lipid peroxidation. Notably, mitigating lipid peroxidation failed to alleviate death of E. coli. Further findings confirmed that FeGlu induced DNA damage, and ΔrecA mutant showed more sensitive, implicating that DNA damage was involved in the death of E. coli. The direct interaction of Fe2+ with DNA was demonstrated by fluorescent staining, gel electrophoresis, and circular dichroism (CD). Moreover, proteomic analysis unveiled 50 differentially expressed proteins (DEPs), including 18 significantly down-regulated proteins and 32 significantly up-regulated proteins. Among them, the down-regulation of SOS-responsive transcriptional suppressor LexA indicated DNA damage induced severely by FeGlu. Furthermore, FeGlu influenced pathways such as fatty acid metabolism (FadB, FadE), iron-sulfur cluster assembly (IscA, IscU, YadR), iron binding, and DNA-binding transcription, along with α-linolenic acid metabolism, fatty acid degradation, and pyruvate metabolism. These pathways were related to FeGlu stress, including lipid peroxidation and DNA damage. In summary, FeGlu facilitated ferroptosis in E. coli through mechanisms involving lipid peroxidation and DNA damage, which presents a new strategy for the development of innovative antimicrobial strategies targeting E. coli infections.


Asunto(s)
Daño del ADN , Escherichia coli , Ferroptosis , Compuestos Ferrosos , Peroxidación de Lípido , Especies Reactivas de Oxígeno , Ferroptosis/efectos de los fármacos , Daño del ADN/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/metabolismo , Compuestos Ferrosos/metabolismo , Compuestos Ferrosos/farmacología , Especies Reactivas de Oxígeno/metabolismo , Antibacterianos/farmacología , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Proteómica , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/genética , Escherichia coli O157/metabolismo
16.
J Food Prot ; 87(4): 100258, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38428462

RESUMEN

The objective of this study was to compare preharvest monitoring strategies by evaluating three different sampling methods in the lairage area to determine pathogen recovery for each sampling method and incoming pathogen prevalence from the cattle to inform in-plant decision making. Samples were gathered over a 5-month period, from February to June 2022, at a harvesting and processing facility located in Eastern Nebraska. Sampling methods included (i) fecal pats, (ii) boot swabs, and (iii) MicroTally swab. A total of 329 samples were collected over the study period (fecal pats: n = 105, boot swabs: n = 104, and MicroTally swabs: n = 120). Specific media combinations, an incubation temperature of 42°C, and incubation timepoints (18-24 h) were utilized for each matrix and the prevalence of Salmonella, Escherichia coli O157:H7, and six non-O157 Shiga-toxin producing E. coli (STEC) was evaluated using the BAX system Real-Time PCR assay. Overall, results from the study concluded that boot swabs were an effective sampling method for pathogen detection in the cattle lairage area. Boot swabs (97.1%) were statistically more likely to detect for Salmonella (p < 0.05) when compared to fecal pats (67.6%) and MicroTally swab (77.5%) methods. For E. coli O157:H7 and STEC - O26, O121, O45, and O103 prevalence, boot swabs were significantly better at detecting for these pathogens (p < 0.05) than MicroTally swabs (OR = 3.16 - 11.95) and a comparable sampling method to fecal pats (OR = 0.93 - 2.01, p > 0.05). Lastly, all three sampling methods detected a very low prevalence for E. coli O111 and O145; therefore, no further analysis was conducted. The boot swab sampling method was strongly favored because they require little training to implement, are inexpensive, and they do not require much sampling labor; therefore, would be a simple and effective sampling method to implement within the industry to evaluate pathogen prevalence preharvest.


Asunto(s)
Infecciones por Escherichia coli , Escherichia coli O157 , Proteínas de Escherichia coli , Escherichia coli Shiga-Toxigénica , Bovinos , Animales , Infecciones por Escherichia coli/veterinaria , Heces , Salmonella , Microbiología de Alimentos
17.
ACS Appl Bio Mater ; 7(4): 2367-2377, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38497627

RESUMEN

Ensuring food safety is paramount for the food industry and global health concerns. In this study, we have developed a method for the detection of prevalent foodborne pathogenic bacteria, including Escherichia coli, Salmonella spp., Listeria spp., Shigella spp., Campylobacter spp., Clostridium spp., and Vibrio spp., utilizing antibody-aptamer arrays. To enhance the fluorescence signals on the microarray, the mesoporous silica nanoparticles (MSNs) conjugated with fluorescein, streptavidin, and seven detection antibodies-biotin were employed, forming fluorescein doped mesoporous silica nanoparticles conjugated with detection antibodies (MSNs-Flu-SA-Abs) complexes. The array pattern was designed for easy readability and enabled the simultaneous detection of all seven foodborne pathogens, referred to as the 7FP-biochip. Following the optimization of MSNs-Flu-SA-Abs complexes attachment and enhancement of the detection signal in fluorescent immunoassays, a high level of sensitivity was achieved. The detection limits for the seven pathogens in both buffer and food samples were 102 CFU/mL through visual screening, with fluorescent intensity quantification achieving levels as low as 20-34 CFU/g were achieved on the antibody-aptamer arrays. Our antibody-aptamer array offers several advantages, including significantly reduced nonspecific binding with no cross-reaction between bacteria. Importantly, our platform detection exhibited no cross-reactivity among the tested bacteria in this study. The multiplex detection of foodborne pathogens in canned tuna samples with spiked bacteria was successfully demonstrated in real food measurements. In conclusion, our study presents a promising method for detecting multiple foodborne pathogens simultaneously. With its high sensitivity and specificity, the developed antibody-aptamer array holds great potential for enhancing food safety and public health.


Asunto(s)
Escherichia coli O157 , Nanopartículas , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Bacterias , Fluoresceínas , Tecnología
18.
Analyst ; 149(8): 2436-2444, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38498083

RESUMEN

Paper-based electrochemical sensors have the characteristics of flexibility, biocompatibility, environmental protection, low cost, wide availability, and hydropathy, which make them very suitable for the development and application of biological detection. This work proposes electrospun cellulose acetate nanofiber (CA NF)-decorated paper-based screen-printed (PBSP) electrode electrochemical sensors. The CA NFs were directly collected on the PBSP electrode through an electrospinning technique at an optimized voltage of 16 kV for 10 min. The sensor was functionalized with different bio-sensitive materials for detecting different targets, and its sensing capability was evaluated by CV, DPV, and chronoamperometry methods. The test results demonstrated that the CA NFs enhanced the detection sensitivity of the PBSP electrode, and the sensor showed good stability, repeatability, and specificity (p < 0.01, N = 3). The electrochemical sensing of the CA NF-decorated PBSP electrode exhibited a short detection duration of ∼5-7 min and detection ranges of 1 nmol mL-1-100 µmol mL-1, 100 fg mL-1-10 µg mL-1, and 1.5 × 102-106 CFU mL-1 and limits of detection of 0.71 nmol mL-1, 89.1 fg mL-1, and 30 CFU mL-1 for glucose, Ag85B protein, and E. coli O157:H7, respectively. These CA NF-decorated PBSP sensors can be used as a general electrochemical tool to detect, for example, organic substances, proteins, and bacteria, which are expected to achieve point-of-care testing of pathogenic microorganisms and have wide application prospects in biomedicine, clinical diagnosis, environmental monitoring, and food safety.


Asunto(s)
Técnicas Biosensibles , Celulosa/análogos & derivados , Escherichia coli O157 , Nanofibras , Nanofibras/química , Celulosa/química , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos
19.
Int J Biol Macromol ; 264(Pt 1): 130533, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38428782

RESUMEN

In this work, silver­bismuth oxide encapsulated 1,3,5-triazine-bis(4-methylbenzenesulfonyl)-hydrazone functionalized chitosan (SBO/FCS) nanocomposite was synthesized by a simple hydrothermal method. The amine (-NH2) group was functionalized by the addition of cyanuric acid chloride followed by 4-methylbenzenesulfonol hydrazide. The SBO/FCS has been characterized by FT-IR, X-ray diffraction, XPS, HR-SEM, HR-TEM, AFM, and thermogravimetry (TGA). Under the optimum conditions, the SBO/FCS sensor showed brilliant electrochemical accomplishment for the sensing of glucose and H2O2 by a limit of detection (LOD) of 0.057 µM and 0.006 µM. It also showed linearity for glucose 0.008-4.848 mM and for H2O2 of 0.01-6.848 mM. Similarly, the sensor exhibited a low sensitivity to glucose (32 µA mM-1 cm-2) and a good sensitivity to H2O2 (295 µA mM-1 cm-2). In addition, that the prepared electrode could be used to sense the glucose and H2O2 levels in real samples such as blood serum and HeLa cell lines. The screen printed electrode (SPE) immunosensor could sense the E. coli O157:H7 concurrently and quantitatively with a linear range of 1.0 × 101-1.0 × 109 CFU mL-1 and a LOD of 4 CFU mL-1. Likewise, the immunosensor efficiently detect spiked E. coli O157:H7 in milk, chicken, and pork samples, with recoveries ranging from 89.70 to 104.72 %, demonstrating that the immunosensor was accurate and reliable.


Asunto(s)
Técnicas Biosensibles , Bismuto , Quitosano , Escherichia coli O157 , Nanocompuestos , Humanos , Peróxido de Hidrógeno/química , Plata , Glucosa , Técnicas Biosensibles/métodos , Hidrazonas , Espectroscopía Infrarroja por Transformada de Fourier , Células HeLa , Inmunoensayo/métodos , Nanocompuestos/química
20.
Int J Food Microbiol ; 416: 110665, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38457887

RESUMEN

Romaine lettuce in the U.S. is primarily grown in California or Arizona and either processed near the growing regions (source processing) or transported long distance for processing in facilities serving distant markets (forward processing). Recurring outbreaks of Escherichia coli O157:H7 implicating romaine lettuce in recent years, which sometimes exhibited patterns of case clustering in Northeast and Midwest, have raised industry concerns over the potential impact of forward processing on romaine lettuce food safety and quality. In this study, freshly harvested romaine lettuce from a commercial field destined for both forward and source processing channels was tracked from farm to processing facility in two separate trials. Whole-head romaine lettuce and packaged fresh-cut products were collected from both forward and source facilities for microbiological and product quality analyses. High-throughput amplicon sequencing targeting16S rRNA gene was performed to describe shifts in lettuce microbiota. Total aerobic bacteria and coliform counts on whole-head lettuce and on fresh-cut lettuce at different storage times were significantly (p < 0.05) higher for those from the forward processing facility than those from the source processing facility. Microbiota on whole-head lettuce and on fresh-cut lettuce showed differential shifting after lettuce being subjected to source or forward processing, and after product storage. Consistent with the length of pre-processing delays between harvest and processing, the lettuce quality scores of source-processed romaine lettuce, especially at late stages of 2-week storage, was significantly higher than of forward-processed product (p < 0.05).


Asunto(s)
Escherichia coli O157 , Microbiota , Microbiología de Alimentos , Lactuca , Escherichia coli O157/genética , Inocuidad de los Alimentos , Recuento de Colonia Microbiana , Manipulación de Alimentos , Contaminación de Alimentos/análisis
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