Foodborne Pathogenic Bacteria Research Articles

Investigating enzyme kinetics and fluorescence sensing strategy of CRISPR/Cas12a for foodborne pathogenic bacteria

Foodborne pathogenic bacteria are widespread in various foods, whose cross-contamination and re-contamination are critical influences on food safety. Rapid, accurate, and sensitive detection of foodborne pathogenic bacteria remains a topic of concern. CRISPR/Cas12a can recognize double-stranded DNA directly, showing great potential in nucleic acid detection. However, few studies have investigated the cleavage properties of CRISPR/Cas12a. In this study, the trans-cleavage properties of LbCas12a and AsCas12a were investigated to construct the detection methods for foodborne pathogenic bacteria. The highly sensitive fluorescent strategies for foodborne pathogens were constructed by analyzing the cleavage rates and properties of substrates at different substrate concentrations. Cas12a was activated in the presence of foodborne pathogenic target sequence was present, resulting in the cleavage of a single-stranded reporter ssDNA co-labelled by fluorescein quencher and fluorescein. The sensitivity and specificity of the Cas12a fluorescent strategy was investigated with Salmonella and Staphylococcus aureus as examples. The results showed that AsCas12a was slightly more capable of trans-cleavage than LbCas12a. The detection limits of AsCas12a for Salmonella and Staphylococcus aureus were 24.9 CFU mL−1 and 1.50 CFU mL−1, respectively. In all the seven bacteria, Staphylococcus aureus and Salmonella were accurately discriminated. The study provided a basis for constructing and improving the CRISPR/Cas12a fluorescence strategies. The AsCas12a-based detection strategy is expected to be a promising method for field detection.

Double phage displayed peptides co-targeting-based biosensor with signal enhancement activity for colorimetric detection of Staphylococcus aureus

The development of simple, fast, sensitive, and specific strategies for the detection of foodborne pathogenic bacteria is crucial for ensuring food safety and promoting human health. Currently, detection methods for Staphylococcus aureus still suffer from issues such as low specificity and low sensitivity. To address this problem, we proposed a sensitivity enhancement strategy based on double phage-displayed peptides (PDPs) co-targeting. Firstly, we screened two PDPs and analyzed their binding mechanisms through fluorescent localization, pull-down assay, and molecular docking. The two PDPs target S. aureus by binding to specific proteins on its outer membrane. Based on this phenomenon, a convenient and sensitive double PDPs colorimetric biosensor was developed. Double thiol-modified phage-displayed peptides (PDP-SH) enhance the aggregation of gold nanoparticles (AuNPs), whereas the specific interaction between the double PDPs and bacteria inhibits the aggregation of AuNPs, resulting in an increased visible color change before and after the addition of bacteria. This one-step colorimetric approach displayed a high sensitivity of 2.35 CFU/mL and a wide detection range from 10–2 × 108 CFU/mL. The combination with smartphone-based image analysis improved the portability of this method. This strategy achieves the straightforward, highly sensitive and portable detection of pathogenic bacteria.

Rapid, on-site and yes-or-no detection of Salmonella typhimurium in foods using Argonaute-enabled assay

Early detection and control of foodborne diseases are crucial for ensuring food safety and consumer health. Therefore, there is a need for faster and more sensitive detection methods. We developed a rapid, portable and visible lateral flow biosensor (LFB) for foodborne pathogenic bacteria detection powered by a Pyrococcus furiosus Argonaute nuclease (PfAgo), named as PfAgo-LFB. LAMP (Loop-mediated isothermal amplification) was used to amplify the target nucleic acid. By using PfAgo as the “lighting up” technology, we can overcome the limitations of false-positive results and lack of effective endpoint monitoring in LAMP, greatly enhancing its applicability. It turned out that PfAgo-LFB was able to provide yes-or-no (positive or negative) results with a limit of detection (LOD) as low as 1 CFU/mL for S. typhimurium and the detection range was between 100 to 108 CFU/mL. It was able to secure a sample-to-answer test for contaminated food samples in less than 45 min and demonstrated satisfactory selectivity. In summary, we designed a PfAgo-LFB that rendered a novel, rapid, accurate, easy-to-deploy, on-site and yes or no detection of S. typhimurium, which could be generalized for building a “one-for-all” biosensing platform.

7,10-Dihydroxy-8(E)-octadecenoic Acid Displays a Fungicidal Activity against Malassezia furfur.

Microbial conversion of some natural unsaturated fatty acids can produce polyhydroxy fatty acids, giving them new properties, such as higher viscosity and reactivity. Pseudomonas aeruginosa has been intensively studied to produce a novel 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) from oleic acid and natural vegetable oils containing oleic acid. Recently, the antibacterial activities of DOD against food-borne pathogenic bacteria were reported; however, the action of such antibacterial properties against eucaryotic cells remains poorly known. In this study, we determined the antifungal activities of DOD against Malassezia furfur KCCM 12679 quantitatively and qualitatively. The antifungal activity of DOD against M. furfur KCCM 12679 was approximately five times higher than that of ketoconazole, a commercial antifungal agent. The MIC 90 value of DOD against M. furfur KCCM 12679 was 50 µg/mL. In addition, we confirmed that the antifungal property of DOD was exerted through fungicidal activity.

Dual functionalized copper nanoparticles for thermoplastics with improved processing and mechanical properties and superior antibacterial performance.

The utilization of metal nanoparticles for antibacterial thermoplastic composites has the potential to enhance the safety of human and animal life by mitigating the spread and transmission of foodborne pathogenic bacteria. The dispersion, antioxidant and antimicrobial activities of metal nanoparticles directly affect the application performance of the composites. This study focused on achieving amine-carboxyl co-modified copper nanoparticles (Cu-AC) with excellent antioxidant properties and monodispersity through in situ grafting of amine and carboxyl groups onto the surface of copper nanoparticles via ligand interaction. Polyacrylic acid's extended carbon chain structure was utilized to improve its dispersion and antioxidant properties, and its antibacterial properties were synergistically enhanced using secondary amines. It was found that Cu-AC possesses high antibacterial properties, with a minimum inhibition concentration of 0.156 mg mL-1. Antibacterial masterbatches and their composites (polypropylene/Cu) manufactured by melt blending of polypropylene and Cu-AC exhibited excellent antibacterial rates of up to 90% and 99% at 300 ppm and 700 ppm Cu-AC, respectively. Additionally, Cu-AC bolstered the thermal degradation, processing and mechanical properties of polypropylene. The successful implementation of this product substantiates the potential applications of polypropylene/Cu composite materials across diverse industries.

اختبار التأثير التثبيطي لمركب Tricin ضد بعض البكتريا التي تنتقل عن طريق الاغذية وتقدير المعامل الفينولي له

The inhibitory effect of the hot aqueous extract of commercial jasmine rice bran (HAE) and the purified tricin compound on the growth of some food-borne pathogenic bacteria (Escherichia coli, E. coli O157:H7, Salmonella typhimurium, Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella spp, Staphylococcus aureus, Bacillus cereus and Bacillus subtilis) and compared with phenol coefficient using several dilutions of water: purified tricin (70:1, 90:1, 1:100, 1:120 and 1:150). and water: purified tricin (70:1, 90:1 and 1:100),at the same concentration, sterilized with microbial filters .Tricin purified showed higher efficiency then the aqueous extract HAE against growth of gram-positive and negative bacteria. The highest significant inhibition activity of purified Tricin compound was at P≤0.05 effect against B. subtilis , B. cereus and S. aureus with inhibitory diameter of 29, 27.5 and 27.5 mm respectively. White the aqueous extract HAE had loupe effectiveness than it against the same bacteria with a diameter of inhibition7,8.5 and 10.5 mm respectively After incubation at 37°C for 24 h, the last reading was the highest inhibition activity of the extract HAE. As for the results of the susceptibility of tricin as an antiseptic towards Gram-negative bacteria S. typhi and Gram-positive S. aureus compared to phenol using several dilutions of each, high dilutions had a clear inhibition in the growth of S. aureus and S. typhi bacterial isolates, especially when compared with phenol when The higher dilution (1:100) showed bacterial growth, while we did not find growth for these isolates at the same dilution coefficient of tricin for periods (5, 10, and 15) min After incubation at 37°C for 48 h. S. typhi was less sensitive than S. aureus towards phenol and tricin.

Antibacterial activity of Amomum tsaoko essential oil and its interaction with Staphylococcus aureus

Amomum tsaoko is a medicinal and edible plant mainly distributed in southwest China and Southeast Asia. This study investigated the antibacterial activity of Amomum tsaoko essential oil (AEO) against typical foodborne pathogenic bacteria and the interaction of AEO with Staphylococcus aureus. The results showed that AEO exhibited excellent antibacterial activity against foodborne pathogenic bacteria, with the most performance against S. aureus, with MIC and MBC values of 0.20 mg/mL and 0.39 mg/mL, respectively. In addition, the effects of AEO on S. aureus might include affecting cell membrane permeability, integrity, bacterial energy, and respiratory metabolism. Furthermore, the (E)-dec-2-enal in AEO was considered a vital antibacterial component. Overall, AEO presented positive antibacterial properties, suggesting that AEO can be served as a potential inhibitor against S. aureus and contribute to the application of AEO in food preservation.

Discussion of “Inactivation of foodborne pathogenic and spoilage bacteria by single and dual wavelength UV-LEDs: Synergistic effect and pulsed operation” [Food Control 125 (2021) 107999

This paper clarifies the ambiguity in the assessment of the synergy of dual wavelength UV-LEDs disinfection.

Prevalence of Campylobacter spp., Salmonella spp., and Listeria monocytogenes, and Population Levels of Food Safety Indicator Microorganisms in Retail Raw Chicken Meat and Ready-To-Eat Fresh Leafy Greens Salads Sold in Greece.

The presence of microbial pathogens in foods compromises their safety resulting in foodborne illnesses, public health disorders, product recalls, and economic losses. In this work, 60 samples of chilled raw chicken meat and 40 samples of packaged ready-to-eat (RTE) fresh leafy greens salads, sold in Greek retail stores (butchers and supermarkets), were analyzed for the presence of three important foodborne pathogenic bacteria, i.e., Campylobacter spp., Salmonella spp., and Listeria monocytogenes, following the detection protocols of the International Organization for Standardization (ISO). In parallel, the total aerobic plate count (APC), Enterobacteriaceae, total coliforms, Escherichia coli, and staphylococci were also enumerated as hygiene (safety) indicator organisms. When present, representative typical colonies for each pathogen were biochemically verified, following the ISO guidelines. At the same time, all the Campylobacter isolates from chicken (n = 120) were identified to the species level and further phylogenetically discriminated through multiplex and repetitive sequence-based (rep) polymerase chain reaction (PCR) methods, respectively. Concerning raw chicken, Campylobacter spp. were recovered from 54 samples (90.0%) and Salmonella spp. were recovered from 9 samples (15.0%), while L. monocytogenes was present in 35 samples (58.3%). No Campylobacter was recovered from salads, and Salmonella was present in only one sample (2.5%), while three salads were found to be contaminated with L. monocytogenes (7.5%). The 65% of the Campylobacter chicken isolates belonged to C. jejuni, whereas the rest, 35%, belonged to C. coli. Alarmingly, APC was equal to or above 106 CFU/g in 53.3% and 95.0% of chicken and salad samples, respectively, while the populations of some of the other safety indicators were in some cases also high. In sum, this study unravels high occurrence percentages for some pathogenic and food safety indicator microorganisms in raw chicken meat and RTE fresh leafy greens salads sold in Greek retail, highlighting the need for more extensive microbiological control throughout the food production chain (from the farm/field to the market).

Multi-aptamer-mediated hairpin allosteric and aptamer-assisted CRISPR system for detection of S. pneumoniae and S. aureus.

A novel nucleic acid aptamer nanoprobes-mediated hairpin allosteric and aptamer-assisted CRISPR system for detection of Streptococcus pneumoniae and Staphylococcus aureus is presented.In this fluorescence assay system, utilizing the hairpin allosteric effect caused by the aptamer binding to the target bacteria, the detection of S. pneumoniae is first achieved through changes in fluorescence due to FRET. Subsequently, aCas12a protein mixture is added to detect S. aureus. The amplified output signal is triggered by two methods to ensure the sensitivity of the method: the synergistic FRET effect is achieved by the assembly of multi-aptamer through the conjugation of streptavidin-biotin, and the trans-cleavage function of CRISPR/Cas 12a. Under the optimized conditions, the proposed hairpin allosteric aptasensor could achieve high sensitivity (a detection limit of 135cfu/mL) and broad-concentration quantification (dynamic range of 103-107cfu/mL) of S. pneumoniae. The aptamer-assisted CRISPR system for S. aureus detection showed good linearity (R2 = 0.996) in the concentration range 102-108cfu/mL, with a detection limit of 39cfu/mL. No cross-reactivity with other foodborne pathogenic bacteria was observed in both systems. Taking only 55min, this method of multiple pathogen detection proved to be promising.

Detection of Vibrio parahaemolyticus Based on Magnetic and Upconversion Nanoparticles Combined with Aptamers.

Vibrio parahaemolyticus is a halophilic and heat-labile gram-negative bacterium and is the most prevalent foodborne bacterium in seafood. In order to develop a rapid and sensitive method for detecting the foodborne pathogenic bacterium Vibrio parahaemolyticus, an aptamer-modified magnetic nanoparticle and an aptamer-modified upconversion nanoparticle were synthesised and used as a capture probe and a signal probe, respectively. The aptamer-modified magnetic nanoparticle, V. parahaemolyticus cell, and aptamer-modified upconversion nanoparticle formed a sandwich-like complex, which was rapidly separated from a complex matrix using a magnetic force, and the bacterial concentration was determined by fluorescence intensity analysis. The results showed that the fluorescence intensity signal correlated positively with the concentration of V. parahaemolyticus in the range of 3.2 × 102 to 3.2 × 105 CFU/mL, with a linear equation of y = 296.40x - 217.67 and a correlation coefficient of R2 = 0.9610. The detection limit of the developed method was 4.4 CFU/mL. There was no cross-reactivity with other tested foodborne pathogens. This method is highly specific and sensitive for the detection of V. parahaemolyticus, and can achieve the qualitative detection of this bacterium in a complex matrix.

Electrospun Cactus Mucilage/Poly(vinyl alcohol) Nanofibers as a Novel Wall Material for Dill Seed Essential Oil (Anethum graveolens L.) Encapsulation: Release and Antibacterial Activities.

This study aimed to create long-lasting carriers by producing electrospun nanofibers loaded with dill seed (Anethum graveolens L.) essential oil (DSEO), using cactus mucilage (CM) and poly(vinyl alcohol) (PVA). Continuous and uniform electrospun nanofibers with a diameter of 158 ± 18 to 230 ± 26 nm were successfully made from the CM/PVA blend solution and the CM/PVA/DSEO emulsion. Atomic force microscopy topographic images revealed that the electrospun nanofibers had a tubular morphology. The thermogravimetric curves of DSEO, CM, pure PVA, and electrospun nanofibers demonstrate that the polymers used and the essential oil have effective chemical interactions. The water contact angle results suggest that the manufactured nanofibers are hydrophilic. CM/PVA consistently achieves a remarkable encapsulation efficiency of 100% DSEO. The electrospun nanofibers enabled the controlled release of free and encapsulated DSEO, resulting in sustained long-term release. The agar disk diffusion technique was used to study the antimicrobial activity of electrospun nanofibers and nanofibers containing DSEO against Gram-positive and Gram-negative bacteria. With a minimum inhibitory concentration of 2.5 mg/mL and a minimum bactericidal concentration of 5 mg/mL, electrospun nanofibers containing DSEO demonstrated bacteriostatic and bactericidal activities against foodborne pathogenic bacteria (Staphylococcus aureus and Pseudomonas aeruginosa). The DSEO-loaded electrospun nanofibers derived from carbohydrates show promise as an active interior coating for use in biomedical and food packaging applications.

Antimicrobial potential of lactic acid bacteria against food spoilage and foodborne pathogenic bacteria

Antimicrobial potential of lactic acid bacteria against food spoilage and foodborne pathogenic bacteria

An Account of Hygienic Practices and Street Food Safety Around the Medical Colleges of Kolkata, India

The safety of street food is an important aspect in the field of nutrition security. A cross sectional study was conducted among street food vendors around the medical colleges of Kolkata selected by simple random sampling. Data were collected by interviewing the selected food vendors with the predesigned schedule and observation. Microbiological analyses of food samples selected randomly from seventy five vendors were carried out. Food vendors unwilling or abstaining from the interview could not be selected in this current study. None of the food vendors used head cap or apron or hand gloves during preparation or selling of foods. Only 25.33% of food vendors covered the foods after preparation. Most of the vendors were cleaning their serving utensils in stagnant water of bucket. The continuous re-use of same stagnant water for washing non-disposable utensils led to deposition of food materials on them and this increased the chance of chemical and microbial contamination as well as enhanced the food borne intoxication. Half of the food samples were contaminated with the organisms causing Food Borne Diseases. Significant relationship was found between various hygienic practices and presence of probable food borne pathogenic bacteria. Approximately 81% of the food vendors did not have clean nails and nor did they use gloves for food service resulting in increased chances of microbial contamination in the foods. Also, the amount of food vendors using the leftover food of previous day was 44% meaning a significant decrease in food quality due to mixing of leftover foods. So, the hygienic practices of the food vendors around the medical colleges of Kolkata were very poor and foods served were contaminated.

Dual extracellular mycofabrication of cobalt and zinc nano metal oxides mediated by mycelial-cell free filtrate of Aspergillus sojae: Characterization and assessment of antibacterial activity

Foodborne pathogenic bacteria cause a wide range of infectious diseases that pose a serious threat to human health worldwide with significant social and economic consequences. Nano metal oxides have attracted paramount attention owing to their remarkable antimicrobial potency. Microbial synthesis of metal oxide nanoparticles has gained prominence due to cost-effectiveness, biocompatibility, and environmental friendliness. This study reports extracellular mycosynthesis of two nano metal oxides mediated by Aspergillus sojae mycelial cell-free filtrate (MCFF). A. sojae MCFF was reacted with cobalt chloride hexahydrate and zinc nitrate hexahydrate for the preparation of Co3O4 NPs and ZnO NPs, respectively. After reacting with each metal salt, A. sojae MCFF changed from transparent to greyish-brown and white-milky suspensions, indicating the mycosynthesis of Co3O4 NPs and ZnO NPs, respectively. Physicochemical and morphological properties of the two nano metal oxides were determined using various characterization techniques, involving XRD, FTIR, EDX, DLS, zeta potential analysis, XPS, and electron microscopy. The two nano metal oxides exhibited antibacterial potency against three foodborne pathogens. Co3O4 NPs had zones of inhibition (ZOI) of 19.33 ± 0.58, 20.67 ± 0.58, and 22.67 ± 0.58 mm against Escherichia coli (ATCC 43889), Salmonella enterica Serovar Typhimurium (ATCC 43174), and Staphylococcus aureus (ATCC 12600), respectively. Whereas ZnO NPs had ZOI of 15.67 ± 0.58, 15.67 ± 0.58, and 14.33 ± 0.58 mm against the three foodborne pathogens, respectively. The intact morphological structures of the bacterial cells collapsed following exposure to A. sojae-mediated Co3O4 NPs and ZnO NPs, with some cells having irregular, twisted, and rough surfaces. The current study concluded that A. sojae mycelia acted as potential biological entity for the biosynthesis of Co3O4 NPs and ZnO NPs. A. sojae-derived Co3O4 NPs and ZnO NPs can be potential candidates for use as antimicrobial nano metal oxides in food and pharmaceutical industries.

A gas-driven capillary based on the synergy of the catalytic and photothermal effect of PB@Au for Salmonella typhimurium detection

Rapid detection method for Salmonella typhimurium is vital to prevent the spread of food-borne diseases. In this work, a gas-driven capillary detection method was established to achieve sensitive and rapid detection of Salmonella typhimurium using the catalytic and photothermal synergy of Prussian blue-nanogold (PB@Au) nanomaterials. The immuno-PB@Au probe attached to the capillary by specific identification of target bacteria catalyzed the H2O2 under laser irradiation, driving the H2O2 liquid column to move (ΔL) by producing gas, and achieving the quantitative detection of Salmonella typhimurium. After detailed optimization of the critical performance parameters of the gas-driven capillary assay, the limit of detection (LOD) after laser irradiation and being catalyzed by PB@Au was calculated to be 37 CFU mL−1 through the determination of different concentrations of target bacteria. Furthermore, the detection performances of the gas-driven capillary method were evaluated in detail, and the recoveries ranging from 92.9 ± 4.7 % to 107.7 ± 4.1 % were achieved using the spiked actual samples with complex matrices, indicating that the established rapid assay can offer promising strategies for the monitoring and controlling of food-borne pathogenic bacteria.

Illicium verum L. (Star Anise) Essential Oil: GC/MS Profile, Molecular Docking Study, In Silico ADME Profiling, Quorum Sensing, and Biofilm-Inhibiting Effect on Foodborne Bacteria

Illicium verum, or star anise, has many uses ranging from culinary to religious. It has been used in the food industry since ancient times. The main purpose of this study was to determine the chemical composition, antibacterial, antibiofilm, and anti-quorum sensing activities of the essential oil (EO) obtained via hydro-distillation of the aerial parts of Illicium verum. Twenty-four components were identified representing 92.55% of the analyzed essential oil. (E)-anethole (83.68%), limonene (3.19%), and α-pinene (0.71%) were the main constituents of I. verum EO. The results show that the obtained EO was effective against eight bacterial strains to different degrees. Concerning the antibiofilm activity, trans-anethole was more effective against biofilm formation than the essential oil when tested using sub-inhibitory concentrations. The results of anti-swarming activity tested against P. aeruginosa PAO1 revealed that I. verum EO possesses more potent inhibitory effects on the swarming behavior of PAO1 when compared to trans-anethole, with the percentage reaching 38% at a concentration of 100 µg/mL. The ADME profiling of the identified phytocompounds confirmed their important pharmacokinetic and drug-likeness properties. The in silico study using a molecular docking approach revealed a high binding score between the identified compounds with known target enzymes involved in antibacterial and anti-quorum sensing (QS) activities. Overall, the obtained results suggest I. verum EO to be a potentially good antimicrobial agent to prevent food contamination with foodborne pathogenic bacteria.

Profiling toxin genes and antibiotic resistance in Bacillus cereus isolated from pre-launch spacecraft.

Characterization of the microbiomes of pre-launch spacecraft in spacecraft assembly facilities is an important step in keeping crews healthy during journeys that can last several hundred days in small artificial environments in space. Bacillus cereus, a foodborne pathogenic bacterium, has the potential to be a significant source of food contamination in such environments. This bacterium is a spore-forming bacteria that resists different antimicrobial treatments in cleanrooms where spacecraft are assembled. This study evaluated 41 B. cereus isolates from four pre-launch spacecraft in spacecraft assembly facilities for their toxin gene profile and antibiotic resistance. Four enterotoxin genes (hlbC, cytK, nheA, and entFM) and two emetic toxin genes (ces and CER) were targeted for chromosomal DNA and plasmid DNA. Results showed 31.7, 7.3, 85, and 41.5% of isolates contained hblC, cytK, nheA, and entFM, respectively, in chromosomal or plasmid DNA. Overall, 37 isolates (90.2%) showed at least one enterotoxin gene. The emetic toxin gene, ces, was detected in the plasmid DNA of three isolates (7.3%). The antibiotic resistance of isolates was evaluated by the Kirby-Bauer disk diffusion procedure. All the isolates exhibited 100% susceptibility to gentamicin, 97% were susceptible to clindamycin, and 95% to chloramphenicol, imipenem, tetracycline, and vancomycin. The overall susceptibility average is 51%. However, 98% of the isolates were resistant to β-lactam antibiotics, 97.5% were resistant to sulfamethoxazole/trimethoprim, and 80% were resistant to rifampin. This study provides important information on B. cereus isolates from spacecraft assembly facilities for use in microbial monitoring programs of spacecraft.

Electrochemical biosensing for E.coli detection based on triple helix DNA inhibition of CRISPR/Cas12a cleavage activity

BackgroundEscherichia coli (E.coli) is both a commensal and a foodborne pathogenic bacterium in the human gastrointestinal tract, posing significant potential risks to human health and food safety. However, one of the major challenges in E.coli detection lies in the preparation and storage of antibodies. In traditional detection methods, antibodies are indispensable, but their instability often leads to experimental complexity and increased false positives. This underscores the need for new technologies and novel sensors. Therefore, the development of a simple and sensitive method for analyzing E.coli would make significant contributions to human health and food safety. ResultsWe constructed an electrochemical biosensor based on triple-helical DNA and entropy-driven amplification reaction (EDC) to inhibit the cleavage activity of Cas12a, enabling high-specificity detection of E.coli. Replacing antibodies with nucleic acid aptamers (Apt) as recognition elements, we utilized the triple-helical DNA generated by the binding of DNA2 and DNA5/DNA6 double-helical DNA through the entropy-driven amplification reaction to inhibit the collateral cleavage activity of clustered regularly interspaced short palindromic repeats gene editing system (CRISPR) and its associated proteins (Cas). By converting E.coli into electrical signals and recording signal changes in the form of square wave voltammetry (SWV), rapid detection of E.coli was achieved. Optimization of experimental conditions and data detection under the optimal conditions provided high sensitivity, low detection limits, and high specificity. SignificanceWith a minimal detection limit of 5.02 CFU/mL and a linear range of 1 × 102 - 1 × 107 CFU/mL, the suggested approach was successfully verified to analyze E.coli at various concentrations. Additionally, after examining E.coli samples from pure water and pure milk, the recoveries ranged between 95.76 and 101.20%, demonstrating the method's applicability. Additionally, it provides a feasible research direction for the detection of pathogenic bacteria causing other diseases using the CRISPR/Cas gene editing system.

Freshwater plastispheres as a vector for foodborne bacteria and viruses.

There is growing evidence that plastic particles can accumulate microorganisms that are pathogenic to humans or animals. In the current study, the composition of the plastispheres that accumulated on polypropylene (PP), polyvinyl chloride (PVC), and high-density polyethylene (HDPE) pieces submerged in a river in the southeast Norway was characterized by 16S rRNA amplicon sequencing. Seasonal and geographical effects on the bacterial composition of the plastisphere were identified, in addition to the detection of potential foodborne pathogenic bacteria and viruses as part of the plastisphere. The diversity and taxonomic composition of the plastispheres were influenced by the number of weeks in the river, the season, and the location. The bacterial diversity differed significantly in the plastisphere from June and September, with a generally higher diversity in June. Also, the community composition of the plastisphere was significantly influenced by the geographical location, while the type of plastic had less impact. Plastics submerged in river water assembled a variety of microorganisms including potentially pathogenic bacteria and viruses (noro- and adenovirus) detected by qPCR. Cultivation methods detected viable bacteria such as Escherichia coli and Listeria monocytogenes. The results highlight the need for additional research on the risk of contaminating food with plastic particles colonized with human pathogens through irrigation water.