The presence of antibiotic resistance genes (ARGs), disinfectant resistance genes (DRGs), and pathogens in animal food processing environments (FAPE) poses a significant risk to human health. ...However, knowledge of the contamination and risk profiles of a typical commercial pig slaughterhouse with periodic disinfectant applications is limited. By creating the overall metagenomics-based behavior and risk profiles of ARGs, DRGs, and microbiomes in a nine-section pig slaughterhouse, an important FAPE in China. A total of 454 ARGs and 84 DRGs were detected in the slaughterhouse with resistance genes for aminoglycosides and quaternary ammonium compounds, respectively. The entire slaughtering chain is a hotspot for pathogens, including 83 human pathogenic bacteria (HPB), with 47 core HPB. In addition, 68 high-risk ARGs were significantly correlated with 55 HPB, 30 of which were recognized as potential bacteria co-resistant to antibiotics and disinfectants, confirm a three-fold risk of ARGs, DRGs, and pathogens prevailing throughout the chain. Pre-slaughter pig house (PSPH) was the major risk source for ARGs, DRGs, and HPB. Moreover, 75 Escherichia coli and 47 Proteus mirabilis isolates showed sensitivity to potassium monopersulfate and sodium hypochlorite, suggesting that slaughterhouses should use such related disinfectants. By using whole genome multi-locus sequence typing and single nucleotide polymorphism analyses, genetically closely related bacteria were identified across distinct slaughter sections, suggesting bacterial transmission across the slaughter chain. Overall, this study underscores the critical role of the PSPH section as a major source of HPB, ARGs, and DRGs contamination in commercial pig slaughterhouses. Moreover, it highlights the importance of addressing clonal transmission and cross-contamination of antibiotic- and disinfectant-resistant bacteria within and between slaughter sections. These issues are primarily attributed to the microbial load carried by animals before slaughter, carcass handling, and content exposure during visceral treatment. Our findings provide valuable insights for One Health-oriented slaughterhouse management practices.
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•Integral health risks of ARGs, DRGs, and HPBs in pig slaughtering chains were identified.•The PSPH section is a major source of contamination for HPBs, ARGs, and DRGs.•Metagenomics revealed some HPBs as supercarriers of ARGs or DRGs at high risk.•Clonal transmission and cross-contamination of co-resistant bacteria were shown.
•Lactic acid bacteria (LAB) exhibited inhibition against E. coli and S. Typhimurium.•L. acidophilus was selected as model for optimization of cane molasses-based medium.•A cell dry weight of 3.63 g/L ...of L. acidophilus was achieved in optimized medium.
The overuse of antibiotics in livestock farming has led to the emergence of antibiotic resistance, which poses a significant threat to human health. Probiotics have gained increasing popularity as an alternative to antibiotics, prompting the exploration of cost-effective fermentation substrates for large-scale production.
This work aimed to investigate the antimicrobial effect of probiotics lactic acid bacteria (LAB) against various pathogenic bacterial strains (e.g. S. Typhimurium O66, S. Typhimurium S251, E. coli O78:K80 and E. coli O157:H7). A total of 28 bacterial isolates were obtained from fermented food sources, in conjunction with 12 identified LAB strains, were screened for antimicrobial activity using microdilution broth method. The chosen probiotic strain, Lactobacillus acidophilus, was subsequently cultivated in a medium formulated with cane molasses to assess its suitability for probiotic production.
The results demonstrated that most LAB strains inhibited S. Typhimurium and E. coli by over 90 %. In the optimized cane molasses-based medium containing 16.02 % (v/v) molasses, 10 g/L (w/v) yeast extract with pH of 6.6, a cell dry weight (CDW) of 3.63 g/L of L. acidophilus was achieved. Therefore, cane molasses emerged as a promising alternative carbon source for LAB biomass production, offering the potential to reduce production costs while minimizing waste generation.
Rapid and reliable detection of pathogenic bacteria at the early stage represents a highly topical research area for food safety and public health. Although culture based method is the gold standard ...method for bacteria detection, recent techniques have promoted the development of alternative methods, such as surface enhanced Raman scattering (SERS). SERS provides additional advantages of high speed, simultaneous detection and characterization, multiplex analysis, and comparatively low cost. However, conventional SERS methods for bacteria detection are facing limitations of low sensitivity, susceptible to matrix interference, and poor accuracy. In recent years, specific detection of pathogenic bacteria with dual recognition based SERS methods has attracted increasing attentions. These methods include two steps recognition of target bacteria, and integrate the functions of target separation and detection. Considering their merits of excellent specificity, ultrahigh sensitivity, multiplex detection capability, and potential for on-site applications, these methods are promising alternatives for rapid and reliable detection of pathogenic bacteria. Herein, this review aims to summarize the recent advances in dual recognition based SERS methods for specific detection of pathogenic bacteria. Their advantages and limitations are discussed, and further perspectives are tentatively given. This review provides new insights into the application of SERS as a reliable tool for pathogenic bacteria detection.
This review summarized the recent advances in specific detection of pathogenic bacteria using surface enhanced Raman scattering. Display omitted
•Dual recognition based SERS methods are highly specific and sensitive for bacteria detection.•Recent advances in dual recognition based SERS methods for pathogenic bacteria detection were summarized.•This review provides new insights into the application of SERS in bacteria detection.
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Antibiotic pollution has been a serious global public health concern in recent years, photodynamic inactivation is one of the most promising and innovative methods for antibacterial ...applications that avoids antibiotic abuse and minimizes risks of antibiotic resistance. However, limited by the weak interaction between the photosensitizers and Gram-negative bacteria, the effect of photodynamic inactivation cannot be fully exerted. Herein, photosensitizer chlorin e6-loaded polyethyleneimine-based micelle was constructed. The synergy of electrostatic and hydrophobic interactions between the nanoparticles and the bacterial surface promoted the anchoring of nanoparticles onto the bacteria, resulting in enhanced photoinactivation activities on Gram-negative bacteria. As expected, an eminent antibacterial effect was also observed on the Gram-positive bacteria Staphylococcus aureus. The cellular uptake results showed that photosensitizer was firmly anchored to the bacterial cell surface of Escherichia coli or Staphylococcus aureus by the introduction of branched polyethylenimine-containing nanoparticles. The light-triggered generation of reactive oxygen species, mainly singlet oxygen, from the membrane-bound nanoparticles caused irreversible damage to the bacterial outer membrane, achieving enhanced bactericidal efficiency than free photosensitizer. The study would provide an efficient and promising antimicrobial alternative to prevent overuse of antibiotics and have enormous potential for human healthcare and the environment remediation.
•Hedgehog-inspired magnetic nanoparticles (HMN) was fabricated for DNA extraction.•HMN possessed a high-surface-area due to the distinct burr-like structure of hedgehog.•HMN-based solid-phase ...microextraction (MSPE) could capture DNA of pathogenic bacteria.•HMN-based MSPE linked qPCR was successfully used in the detection of pathogenic bacteria.
Efficient separation of deoxyribonucleic acid (DNA) through magnetic nanoparticles (MN) is a widely used biotechnology. Hedgehog-inspired MNs (HMN) possess a high-surface-area due to the distinct burr-like structure of hedgehog, but there is no report about the usage of HMN for DNA extraction. Herein, to improve the selection of MN and illustrate the performance of HMN for DNA separation, HMN and silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2) were fabricated and compared for the high-efficient separation of pathogenic bacteria of DNA. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical Gram-negative and Gram-positive bacteria and are selected as model pathogenic bacteria. To enhance the extraction efficiency of two kinds of MNs, various parameters, including pretreatment, lysis, binding and elution conditions, have been optimized in detail. In most separation experiments, the DNA yield of HMN was higher than that of Fe3O4@SiO2. Therefore, a HMN-based magnetic solid-phase microextraction (MSPE) and quantitative real-time PCR (qPCR) were integrated and used to detect pathogenic bacteria in real samples. Interestingly, the HMN-based MSPE combined qPCR strategy exhibited high sensitivity with a limit of detection of 2.0 × 101 CFU mL−1 for E. coli and 4.0 × 101 CFU mL−1 for S. aureus in orange juice, and 2.8 × 102 CFU mL−1 for E. coli and 1.1 × 102 CFU mL−1 for S. aureus in milk, respectively. The performance of the proposed strategy was significantly better than that of commercial kit. This work could prove that the novel HMN could be applicable for the efficient separation of DNA from complex biological samples.
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•Fluorescent Probes for the cell walls of pathogenic bacteria have been reviewed.•The function of the bacterial cell wall was discussed.•The composition and dynamic behavior of ...bacterial cell walls are discussed.•The cell wall components are used to classify the recognized objects.
Contamination of pathogenic bacteria seriously threatens human health and safety, and the types and pathogenicity of bacteria are closely related to cell walls. Fluorescent probes can perform specific and sensitive detection of bacterial cells, and make an important contribution to the diagnosis of bacterial diseases and the development of antibiotics. In this review, we summarized the latest developments in integrating identification elements targeting bacterial cell walls with different chromogenic elements (small molecule fluorophores, conjugated polymers, and fluorescent nanomaterials) to detect and sense pathogenic bacteria. We hope this review paper can provide ideas for the design of new pathogen detection probes with better performance.
Microplastics pollution in marine environments is concerning. Microplastics persist and accumulate in various sections of the ocean where they present opportunity for micropollutant accumulation and ...microbial colonisation. Even though biofilm formation on plastics was first reported in the 1970's, it is only in recent years were plastic associated biofilms have gained research attention. Plastic surfaces pose a problem as they are a niche ready for colonisation by diverse biofilm assemblages, composed of specific bacterial communities and putative pathogens prone to acquiring ARGs and resistance in the biofilm. However, the nature of antibiotic resistance on aquatic plastic debris is not yet fully understood and remains a concern. Given the inevitable increase of plastic production and waste generation, microplastics released into the environment may prove to be problematic. This review explores microplastic waste in the ocean and possible concerns that may arise from the presence of microplastics in conjunction with favourable conditions for the development and dispersal of antibiotic resistance in the ocean and food web.
•Microplastics fibres and fragments are commonly found polluting the world's ocean.•Microplastics biofilm assemblages are different from free-living communities.•Microplastics serve as a pathway for dispersal of drug resistant bacteria.•Microplastics allow for enrichment and dispersal of antibiotic resistance genes.•A need exist for regulatory frameworks addressing microplastics in aquatic ecosystems.
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•DNAzymes can be used for the detection and diagnosis of pathogenic bacteria.•DNAzymes can be used to detect pathogenic bacteria in food and environments.•DNAzymes have potential ...applications in molecules detection.•RNA-cleaving DNAzymes as a molecular beacon have great advantages in fabrication of sensors.
Pathogenic bacteria contamination can cause many problems, such as infections in humans and animals and environmental pollution. Early prevention and detection of pathogenic bacteria outbreaks is crucial to managing these problems. Some traditional detection methods such as cell culturing and polymerase chain reaction (PCR) are time-consuming, labor-intensive, insensitive, and inconvenient for detection. Therefore, simple and efficient pathogenic bacteria detection methods involving DNAzymes signaling mechanisms have been reported, including fluorescence and color detection. DNAzymes are divided into cases as a molecular recognition element (RNA-cleaving DNAzyme) and as a reporter element (peroxidase mimicking DNAzyme), which have proven compatible with isothermal amplification technology for pathogenic bacteria detection. In this review, we summarize the current methods of detecting pathogenic bacteria based on various DNAzyme sensors. We include the design principles, working mechanisms, and detection applications of these sensors and discuss the experimental and theoretical bases for their application in the diagnosis and prevention of diseases caused by pathogenic bacteria.
Wastewater-based epidemiology (WBE) is a powerful tool for early warning of infectious disease outbreaks. Hence, a rapid and portable pathogen monitoring system is urgent needed for on-site ...detection. In this work, we first reported synthesis of an artificial modulated wide-spectrum bacteria capture nanoparticle (Arg-CSP@UiO@Fe3O4). Arginine-modified phosphorylated chitosan (Arg-CSP) coating could provide strongly positive charged guanidinium group for pathogen interaction by electrostatic attraction, and UiO-66-NH2 layer could help Arg-CSP graft onto Fe3O4 magnetic particles. The capture efficiency of Arg-CSP@UiO@Fe3O4 reached 92.2 % and 97.3 % for Escherichia coli (E.coli) and Staphylococcus epidermidis (S.epidermidis)within 40 min, in 10 mL sample. To prevent pathogen degradation in sewage, a portable nucleic acid extraction-free method was also developed. UiO-66-NH2 could disintegrate in buffer with high concentration of PO43− for bacterium desorption, and then nucleic acid of the bacteria was released by heating. The DNA template concentration obtained by this method was 779.28 times higher than that of the direct thermal lysis product and 8.63 times higher than that of the commercial kit. Afterwards, multiple detection of bacteria was realized by loop-mediated isothermal amplification (LAMP). Artificial regulated pathogen desorption could prevent non-specific adsorption of nucleic acid by nanoparticles. The detection limit of Arg-CSP@UiO@Fe3O4-LAMP method was 80 cfu/mL for E.coli and 300 cfu/mL for S.epidermidis. The accuracy and reliability of the method was validated by spiked sewage samples. In conclusion, this bio-monitoring system was able to detect multiple bacteria in environment conveniently and have good potential to become an alternative solution for rapid on-site pathogen detection.
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•The magnetic separation and detection of bacteria in 10 mL sewage was achieved.•We achieved controllable release of bacteria by binging Arg-CSP with UiO-66-NH2.•The system achieved extraction-free amplification of bacterial nucleic acids.
