Targeting microbial biofilms: current and prospective therapeutic strategies

A novel MIR imaging approach for precise detection of S. epidermidis biofilms in seconds

The impact of microbial biofilm growth poses a threat to both human health and the performance of industrial systems, manifesting as a global crisis with noteworthy economic implications for modern society. Exploring new methods and alternative approaches for the detection of biofilm signatures are imperative for developing optimized and cost-effective strategies that can help to identify early-stage biofilm formation. Clinical diagnostic technologies are constantly looking for more affordable, practical and faster methods of prevention and detection of chronic infections in periprosthetic joint infections (PJIs), which are often characterized by biofilm formation on implant surfaces. Staphylococcus epidermidis (SE) is especially known for its strong biofilm production and is considered a leading cause of biomaterial-associated infections, including PJIs. Implant-associated infections are severe and difficult to treat, therefore it is crucial to continue identifying bacterial biomarkers that contribute to its structural stability and attachment to implant surfaces. This study presents a pioneering approach for fast spectral detection of biofilm formation with a novel mid-infrared (MIR) scanning system. To highlight the advantages of our MIR system, we performed a comparative analysis with measurements from a commercially available Fourier-transform infrared (FTIR) scanner. We have assessed SE biofilms grown for 3 days comparing the processing times between a commercially available infrared (IR) scanning system (∼8 h/cm2), and our innovative scanning approach with rapid self-built MIR detection, achieving a reduction in scanning time to seconds. K-means clustering analysis identified pronounced differences in distribution of clusters, representing a significant variation between biofilm producing (RP62A) and non-biofilm producing (ATCC 12228) bacterial strains. The distribution serves as a critical tool for identifying biofilm phenotypes, particularly where poly-N-acetylglucosamine (PNAG), a key constituent of extracellular polymeric substances (EPS) in S. epidermidis, represents the dominant mass fraction in the samples analyzed by our infrared (IR) scanning systems. In addition to faster processing times, our novel MIR system demonstrated significantly higher sensitivity compared to FTIR, enabling clear differentiation between the chemical signatures of biofilm and planktonic strains. The corresponding novel approach integrates advanced data analytics with a newly designed rapid MIR prototype, enabling optimized and swift detection of biofilm signatures. These signatures, now recognized as critical targets in diagnosing complex infections, provide an alternative to traditional microbial detection methods in clinical diagnostics.

Janus PEGylated CuS-engineered Lactobacillus casei combats biofilm infections via metabolic interference and innate immunomodulation

Bacterial implant-associated infections predominantly contribute to the failure of prosthesis implantation. The local biofilm microenvironment (BME), characterized by its hyperacidic condition and high hydrogen peroxide (H2O2) level, inhibits the host's immune response, thereby facilitating recurrent infections. Here, a Janus PEGylated CuS nanoparticle (CuPen) armed engineered Lactobacillus casei (L. casei) denoted as LC@CuPen, is proposed to interfere with bacterial metabolism and arouse macrophage antibiofilm function. Once LC@CuPen reached the BME, NIR irradiation-activated mild heat damages L. casei and biofilm structure. Meanwhile, the BME-responsive LC@CuPen can catalyze local H2O2 to produce toxic •OH, whereas in normal tissues, the effect of •OH production is greatly reduced due to the higher pH and lower H2O2 concentration. The released bacteriocin from damaged L. casei can destroy the bacterial membrane to enhance the penetration of •OH into damaged biofilm. Excessive •OH interferes with normal bacterial metabolism, resulting in reduced resistance of bacteria to heat stress. Finally, under the action of mild heat treatment, the bacterial biofilm lysed and died. Furthermore, the pathogen-associated molecular patterns (PAMPs) in LC@CuPen can induce M1 polarization of macrophages through NF-κB pathway and promote the release of inflammatory factors. Inflammatory factors enhance the migration of macrophages to the site of infection and phagocytose bacteria, thereby inhibiting the recurrence of infection. Generally, this engineered L. casei program presents a novel perspective for the treatment of bacterial implant-associated infections and serves as a valuable reference for future clinical applications of engineered probiotics.

In-vitro and in-silico antibacterial and antibiofilm activities of an aromatic heterocyclic metabolite from a novel halo-thermophilic Streptomyces sp. strain CBN-1 against bacteria causing nosocomial infections

BACKGROUND

Multidrug-resistant and biofilm-forming pathogens have become a global health challenge, contributing to persistent and hard-to-treat infections. The objective of this study was to characterize an active metabolite produced by a novel halo-thermophilic Streptomyces sp. CBN-1 that exhibits potent antibacterial and antibiofilm activities using a combined in-silico and experimental approach.

METHODS & RESULTS

In this study, a halo-thermophilic Streptomyces sp. CBN-1 strain was selected for its ability to grow in 10% NaCl at 40 °C. This strain was identified using phenotypic characterizations and 16S rRNA gene sequence analysis as Streptomyces rochei NRRL B-2410 with 99.15% similarity. An active metabolite, CBNa-1, was extracted using n-butanol solvent from ISP2 broth medium and purified by HPLC. Structural characterization using electrospray ionization mass spectrometry and NMR spectroscopy identified CBNa-1 as an aromatic heterocyclic compound regulated by non-ribosomal peptide synthetase (NRPS) and type II polyketide synthase (PKS) genes. It exhibited potent activity with minimum inhibitory concentrations (MIC) ranging from 4 to 5 µg/mL and minimum biofilm inhibitory concentrations (MBIC50%) at ½ MIC. Additionally, in-silico docking analyses showed that CBNa-1 had stronger binding affinities from - 8.7 to -8.1 kcal/mol with isoleucyl-tRNA synthetase, glucosamine-6-phosphate synthase, penicillin-binding protein 1a, type II DNA topoisomerases, and quorum sensing compared to antibiotics (-5.7 to -7.9 kcal/mol). Furthermore, molecular dynamic (MD) simulation showed the stability of the protein-ligand complex under physiological conditions.

CONCLUSION

This study reports the first identification of CBNa-1, a metabolite from prokaryotic cells, with potent antibacterial and anti-biofilm properties to combat nosocomial infections caused by MDR pathogens, including bacteria resistant to third-generation cephalosporins.

Rationale design, synthesis and antimicrobial activity of benzimidazole-pyridinecarbonitrile conjugates: Insights into ROS-induced oxidative damage and molecular dynamics simulations

A new series of Benzimidazole pyridinecarbonitrile scaffolds 4a-r have been designed and synthesized through a regioselective Michael addition interaction between 2-acetyl N-propyne-benzimidazole (1) and ylidenemalononitrile (2), facilitated by a freshly prepared sodium methoxide solution. All synthesized derivatives were assessed for their antimicrobial potential on S. aureus (Gram-positive), P. aeruginosa (Gram-negative), as well as C.albicans (unicellular fungal). Derivatives 4a, 4c, 4f, 4l, 4m and 4q showed promising antimicrobial properties against all the tested MDR pathogens. In particular, compounds 4c, 4f, 4l, and 4m demonstrated brilliant inhibitory activity on C.albicans with MIC = 10 μg/mL each, a 4-fold increase compared to Amphotericin B (MIC = 40 μg/mL). While compound 4a presented MIC = 10 μg/mL compared with ciprofloxacin (MIC = 20 μg/mL) against MRSA, the MIC recorded by 4c and 4f against P. aeruginosa was 20 μg/mL, which equals that of ciprofloxacin. Bacterial lipid peroxidation (LPO) and antibiofilm activity and evaluation of reactive oxygen species (ROS) induced by the most potent derivatives were evaluated, revealing that derivatives 4f and 4m demonstrated the best behavior among the tested compounds. Furthermore, molecular docking and molecular dynamics (MD) simulations validated the stability of compound 4f within the catalytic binding pocket of the DNA gyrase receptor. The molecules were geometrically optimized using DFT with the B3LYP 6-21 basis set, and their electronic properties were analyzed. The study also encompassed ADME predictions and drug-likeness assessments for the new compounds.

Modified casein-stabilized amorphous calcium phosphate nanoparticles prevent dental caries by inhibiting the growth of Streptococcus mutans and promoting the remineralization of tooth enamel

Dental caries, a prevalent oral disease, is caused by acid- producing plaque microorganisms-notably Streptococcus mutans (S. mutans)-which drive enamel demineralization. Current prevention strategies, such as fluoride and chlorhexidine, primarily target planktonic bacteria but exhibit limited efficacy against biofilms and neglect enamel remineralization, thereby reducing their therapeutic efficacy. To address these limitations, we developed dual-functional nanoparticles (AXCP NPs) that can eradicate S. mutans biofilm and promote enamel remineralization. The amphiphilic polymer Arg-XOS-CPP (AXC) was synthesized by covalently conjugating oligosaccharide carbonyl groups to the amino residues of L-arginine and casein. Self-assembly of AXC with calcium and phosphate ions yielded hybrid nanoparticles (AXCP NPs). Experimental results indicated that AXCP NPs had no effect on the viability of HaCaT cells. Under acidic conditions, protonation of arginine triggered a surface charge reversal from negative to positive, enabling targeted binding to negatively charged biofilms. As expected, AXCP NPs exhibited potent anti-S. mutans activity (MIC: 640 μg/mL) and remarkable biofilm eradication efficacy (>80 % clearance). In vitro release and remineralization assays demonstrated that AXCP NPs continuously released calcium and phosphorus ions, regulating the mineralization process and effectively restoring enamel functionality. Furthermore, in mice caries model, localized application of AXCP NPs significantly suppressed biofilm accumulation on tooth surface and restored mineral density in demineralized enamel, inhibiting caries progression.

Decoy EPS layers for trapping and killing bacteria

Here we report a novel strategy using bacterial extracellular polymeric substances (EPS) as decoys to enhance bacterial adhesion and contact-based antimicrobial activity. EPS extracted from Staphylococcus aureus and Bacillus subtilis was used to coat wafers as a conditioning layer to alter surface properties and facilitate bacterial aggregation. Results show that EPS downregulates quorum sensing-related genes (agr and atl in Staphylococcus aureus by 80.5 % and 86.6 %, respectively; fliC in Escherichia coli by ~58.3 %), suggesting that EPS facilitates energy-efficient adhesion independent of quorum sensing signals. Loading antibiotics (erythromycin, linezolid, levofloxacin) into the EPS layer further enhances adhesion and contact killing. Especially, the surfaces loaded with a levofloxacin concentration of 2 μg/mL exhibit a significant antimicrobial effect. For Staphylococcus aureus, the antimicrobial rate reaches 83.66 % after 4 h incubation but drops to 39.9 % after 8 h incubation. In contract, Escherichia coli exhibits greater sensitivity, with antibacterial activity increasing to 92.97 % after 8 h incubation. Laser confocal microscopy characterization further reveals that the antibiotic-loaded EPS surfaces possess remarkable contact bacteria-killing activity. Our results show the promising recruiting-killing efficacy of the antibiotics-loaded EPS against bacteria, which would give insight into exploring new antibacterial strategies for enhanced contact-antibacterial performances.

Multi-enzymatic biomimetic cerium-based MOFs mediated precision chemodynamic synergistic antibacteria and tissue repair for MRSA-infected wounds

Antibiotic-resistant pathogens represent a significant global public health challenge, particularly in refractory infections associated with biofilms. Urgent development of innovative, safe, and therapeutically adaptive strategies to combat these resistant biofilms is essential. We present a novel biomimetic antibacterial system inspired by the multifunctional enzymatic properties of cerium-based metal-organic frameworks. This system utilizes the inherent oxidase and peroxidase activities of a nanozyme to generate reactive oxygen species (ROS) for bacterial eradication, while its phosphate-ester hydrolase activity disrupts bacterial genetic material and energy metabolism. By the reversible covalent binding between boronic acid groups and cis-diol groups on bacterial surfaces, combined with abundant cerium catalytic sites from the porous structure and the potent antibacterial effects of sanguinarine, we enhance targeted antibacterial activity. This system effectively penetrates extracellular polymeric substances (EPS) and demonstrates precise regulation of ROS, allowing for localized delivery of ROS and sanguinarine for biofilm eradication. Transcriptomic analyses indicate that this approach disrupts the cellular environment, impairs energy metabolism, inhibits bacterial attachment to EPS, and promotes biofilm dispersion by modulating drug resistance-related genes. In vivo experiments confirm that this nanocatalyst composite effectively treats biofilm-induced wounds with efficacy comparable to vancomycin, presenting a promising solution for managing chronic infections caused by antibiotic-resistant biofilms.

Therapeutic potential of celastrol in bacterial infections: Current research advancements and future perspectives

Drug-resistant bacterial infections and their associated inflammatory diseases constitute a deadly threat to global health. Celastrol is one of the main effective components extracted from the traditional Chinese medicine Tripterygium wilfordii Hook.F (TWHF). An increasing number of researchers have been focusing on the pharmacological properties of celastrol in the context of bacterial infection and associated inflammatory complications. This paper presents a comprehensive review of the pharmacological activity and mechanisms of celastrol in the treatment of bacterial infectious diseases. Celastrol has been demonstrated to possess a range of antibacterial, anti-biofilm, anti-virulence and synergistic antibacterial properties with antibiotics, mediated through diverse molecular mechanisms. Several potential targets of celastrol, such as Δ1-Pyrroline-5-Carboxylate Dehydrogenase (P5CDH), Filamenting temperature-sensitive mutant Z (FtsZ), and GdpP, have been identified. By acting on these proteins, celastrol can disrupt bacterial structure (e.g., cell walls and membranes), inhibit macromolecular synthesis (protein, RNA, and DNA), and interfere with metabolic pathways. Furthermore, celastrol exerts dual immunomodulatory effects against bacterial infections through the coordinated regulation of host-pathogen interactions: by suppressing critical bacterial virulence factors staphyloxanthin (STX) and chemotaxis inhibitory protein of S. aureus (CHIPS) to counteract immune evasion mechanisms, while simultaneously activating nuclear respiratory factor 1 (Nrf1), nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK), and various signaling pathways of host immune cells to attenuate infection-induced hyperinflammatory responses and immunocyte-derived tissue damage. Finally, a review and discussion of the therapeutic potential of celastrol is presented, with particular attention to its future development as an effective therapeutic agent for treating diseases associated with bacterial infections.

Essential Oils for Biofilm Control: Mechanisms, Synergies, and Translational Challenges in the Era of Antimicrobial Resistance

Biofilms, structured microbial consortia embedded in self-produced extracellular matrices, pose significant challenges across the medical, industrial, and environmental sectors due to their resistance to antimicrobial therapies and ability to evade the immune system. Their resilience is driven by multifaceted mechanisms, including matrix-mediated drug sequestration, metabolic dormancy, and quorum sensing (QS)-regulated virulence, which collectively sustain persistent infections and contribute to the amplification of antimicrobial resistance (AMR). This review critically examines the potential of plant-derived essential oils (EOs) as innovative agents for biofilm control. EOs exhibit broad-spectrum antibiofilm activity through multi-target mechanisms, including disrupting initial microbial adhesion, degrading extracellular polymeric substances (EPSs), suppressing QS pathways, and compromising membrane integrity. Their ability to act synergistically with conventional antimicrobials at sub-inhibitory concentrations enhances therapeutic efficacy while reducing the selection pressure for resistance. Despite their potential, EO applications face technical challenges, such as compositional variability due to botanical sources, formulation stability issues, and difficulties in standardization for large-scale production. Clinical translation is further complicated by biofilm stage- and strain-dependent efficacy, insufficient in vivo validation of therapeutic outcomes, and potential cytotoxicity at higher doses. These limitations underscore the need for optimized delivery systems, such as nanoencapsulation, to enhance bioavailability and mitigate adverse effects. Future strategies should include combinatorial approaches with antibiotics or EPS-degrading enzymes, advanced formulation technologies, and standardized protocols to bridge laboratory findings to clinical practice. By addressing these challenges, EOs hold transformative potential to mitigate biofilm-associated AMR, offering sustainable, multi-target alternatives for infection management and biofilm prevention in diverse contexts.

Nanomedicines as disruptors or inhibitors of biofilms: Opportunities in addressing antimicrobial resistance

The problem of antimicrobial resistance (AMR) has caused global concern due to its great threat to human health. Evidences are emerging for a critical role of biofilms, one of the natural protective mechanisms developed by bacteria during growth, in resisting commonly used clinical antibiotics. Advances in nanomedicines with tunable physicochemical properties and unique anti-biofilm mechanisms provide opportunities for solving AMR risks more effectively. In this review, we summarize the five "A" stages (adhesion, amplification, alienation, aging and allocation) of biofilm formation and mechanisms through which they protect the internal bacteria. Aimed at the characteristics of biofilms, we emphasize the design "THAT" principles (targeting, hacking, adhering and transport) of nanomedicines in their interactions with biofilms and internal bacteria. Furthermore, recent progresses in multimodal antibacterial nanomedicines, including biofilms disruption and bactericidal activity, and the types of currently available antibiofilm nanomedicines contained organic and inorganic nanomedicines are outlined and highlighted their potential applications in the development of preclinical research. Last but not least, we offer a perspective for the effectiveness of nanomedicines designed to address AMR and challenges associated with their clinical translation.

ZBP1 synchronized with periodontopathogenesis as the essential pattern recognition receptor

BACKGROUND

Periodontitis is a chronic inflammatory disease impacting quality of life. Understanding its pathogenesis is key to developing effective treatments. This study aimed to identify key pattern recognition receptors (PRRs) involved in periodontitis and elucidate their roles in disease progression.

METHODS

Periodontal tissues from healthy individuals and those with periodontitis were analyzed using RNA-sequencing, quantitative real-time PCR(qRT-PCR), and immunohistochemical analysis. Paired tissues collected before and after non-surgical treatment were analyzed via 4D-microDIA proteomics and Western blot.

RESULTS

RNA-sequencing showed significantly higher expression of Z-DNA binding protein 1(ZBP1) and absent in melanoma 2(AIM2) in periodontitis tissues compared to healthy controls, confirmed by qRT-PCR. Post-treatment proteomics indicated significant downregulation of ZBP1, with a non-significant trend for AIM2. Immunohistochemical staining localized ZBP1 to the middle and superficial layers of the gingival epithelium and around deep pockets in periodontitis, while AIM2 was detected in the junctional epithelium and extended throughout the pocket epithelium in periodontitis.

CONCLUSIONS

ZBP1 is highlighted as a key PRR in periodontitis, with significant regulatory potential. AIM2 may play a secondary role. Their distinct spatial distributions suggest involvement in specific microenvironments within periodontal tissues, mediating responses to microbial and inflammatory challenges. ZBP1 may be a critical receptor initiating periodontitis.

Bioinspired programmed antibiofilm strategies for accelerated wound healing via spatiotemporally controlled enzyme nanoreactors

Biofilms, protected by their dense, self-produced matrix, pose a significant clinical challenge due to their antibiotic resistance, leading to persistent infections and delayed wound healing, particularly in diabetic patients. Tailored to the biofilm life cycle, a double-layered nanoreactor was developed for rapid and complete antibiofilm therapy. The inner layer, cross-linked with poly(allylamine hydrochloride) (PAH)/phosphate, dimeric indocyanine green (dICG), and bromothymol blue (BTB), shields glucose oxidase (GOx) and β-glucanase (β-DEX) from unfavorable environment. The outer layer is coated with bacteria-targeted gold nanozymes (AuNEs). The healing of biofilm-infected diabetic wounds progresses three spatiotemporal stages activated by light irradiation and pH changes. Initially, the photothermal effect of dICG triggers nitric oxide (NO)-mediated biofilm dispersion and lowers the wound pH via a GOx/AuNEs cascade reaction. The resulting acidic environment then induces nanoreactor disassembly, releasing β-DEX to degrade the biofilm matrix and facilitate deeper penetration. Finally, AuNEs specifically recognize and eliminate planktonic bacteria, further disrupting the biofilms and accelerating wound healing by generating reactive oxygen species (ROS) and more toxic reactive nitrogen species (RNS). The wound status can be monitored in real-time using BTB's colorimetric pH analysis for visual feedback on treatment progress. This multifunctional design offers a programmed antibiofilm strategy for dynamic wound management.

Pseudomonas aeruginosa biofilm: treatment strategies to combat infection

Pseudomonas aeruginosa is an opportunistic human pathogenic bacterium that is a common cause of both acute and chronic infections. Multidrug-resistant P. aeruginosa poses a significant challenge to antibiotics and therapeutic approaches due to its pathogenicity, virulence, and biofilm-forming ability mediated by quorum sensing. Understanding the pathogenic mechanisms is essential for developing potential drug targets. In this regard, strategies aimed at combating the targeted inhibition of virulence, quorum sensing pathways, secretion systems, biofilm-associated two-component systems, and signalling system regulators (such as c-di-GMP) associated with biofilm formation are critical. Several new antimicrobial agents have been developed using these strategies, including antimicrobial peptides, bacteriophages, nanoantibiotics, photodynamics, and natural products, which are considered promising therapeutic tools. In this review, we address the concept of biofilms, their regulation, and recent treatment strategies to target P. aeruginosa, a clinically significant pathogen known for biofilm formation.

Competitive dynamics and balance between Streptococcus mutans and commensal streptococci in oral microecology

Dental caries, as a biofilm-related disease, is closely linked to dysbiosis in microbial ecology within dental biofilms. Beyond its impact on oral health, bacteria within the oral cavity pose systemic health risks by potentially entering the bloodstream, thereby increasing susceptibility to bacterial endocarditis, among other related diseases. Streptococcus mutans, a principal cariogenic bacterium, possesses virulence factors crucial to the pathogenesis of dental caries. Its ability to adhere to tooth surfaces, produce glucans for biofilm formation, and metabolize sugars into lactic acid contributes to enamel demineralization and the initiation of carious lesions. Its aciduricity and ability to produce bacteriocins enable a competitive advantage, allowing it to thrive in acidic environments and dominate in changing oral microenvironments. In contrast, commensal streptococci, such as Streptococcus sanguinis, Streptococcus gordonii, and Streptococcus salivarius, act as primary colonizers and compete with S. mutans for adherence sites and nutrients during biofilm formation. This competition involves the production of alkali, peroxides, and antibacterial substances, thereby inhibiting S. mutans growth and maintaining microbial balance. This dynamic interaction influences the balance of oral microbiota, with disruptions leading to shifts in microbial composition that are marked by rapid increases in S. mutans abundance, contributing to the onset of dental caries. Thus, understanding the dynamic interactions between commensal and pathogenic bacteria in oral microecology is important for developing effective strategies to promote oral health and prevent dental caries. This review highlights the roles and competitive interactions of commensal bacteria and S. mutans in oral microecology, emphasizing the importance of maintaining oral microbial balance for health, and discusses the pathological implications of perturbations in this balance.

Chitosan nanoparticles loaded with epigallocatechin-3-gallate: synthesis, characterisation, and effects against Streptococcus mutans biofilm

This study evaluated the effects of chitosan nanoparticles loaded with epigallocatechin-3-gallate (EGCG) against Streptococcus mutans biofilm. EGCG-loaded chitosan (Nchi + EGCG) nanoparticles and Chitosan (Nchi) nanoparticles were prepared by ion gelation process and characterised regarding particle size, polydispersion index, zeta potential, and accelerated stability. S mutans biofilms were treated twice daily with NaCl 0.9% (negative control), Nchi, Nchi + EGCG, and chlorhexidine (CHX) 0.12% (positive control). After 67 h, the biofilms were evaluated for acidogenesis, bacterial viability and dry weight. Biofilm morphology and structure were analysed by scanning electron microscopy. The nanoformulations presented medium to short-term stability, size of 500 nm, and polydispersion index around 0.400. Treatments affected cell morphology and biofilm structure. However, no effects on microbial viability, biofilm dry weight, and acidogenesis were observed. Thus, the nanoformulations disassembled the biofilm matrix without affecting microbial viability, which makes them promising candidates for the development of dental caries preventive and therapeutic agents.

A Self-Assembled Nanoreactor for Realizing Antibacterial Photodynamic/Gas Therapy and Promoting Wound Healing

Among various treatments employed to solve the global problem of bacterial infection, photodynamic therapy (PDT) is recognized as a method with great potential to inactivate a wide range of bacteria without the development of drug resistance. However, many commonly used photosensitizers (PSs) have the disadvantages of poor water-solubility and potential toxicity, which limits their clinical application. Additionally, nitric oxide (NO) has unique advantages in antibacterial treatments due to its small molecular weight. Herein, protoporphyrin IX (PpIX), L-arginine (L-Arg), and glycol chitosan (GC) are used to construct a self-assembled cationic Arg-GC-PpIX nanoreactor for efficient bacterial inactivation under white light illumination. The Arg-GC-PpIX nanoreactor with excellent water dispersity and stability can rapidly bind to bacteria through electrostatic interaction and produce local singlet oxygen (1O2)/NO under light irradiation, leading to a high antibacterial efficiency toward both Gram-negative and Gram-positive bacteria. Besides, these NPs also possess a desirable antibiofilm ability. Finally, Arg-GC-PpIX@Gel which is obtained through loading Arg-GC-PpIX into the sodium alginate (SA)/Ca2+ hydrogel shows a satisfactory ability to promote infected wound healing when combined with white light irradiation. Therefore, the rationally designed Arg-GC-PpIX nanoreactor with light-triggered 1O2/NO release is a promising antibacterial agent for achieving effective PDT/NO gas therapy.

Novel two-stage expansion of Streptococcus mutans biofilm supports EPS-targeted prevention strategies for early childhood caries

Early childhood caries (ECC) affects nearly half of preschool children worldwide and characterized by rapid progression across multiple teeth. While Streptococcus mutans (S. mutans) is a keystone species in dental caries, its process for rapid biofilm expansion remains unclear. Using an air-solid interface model simulating the oral environment, we uncovered a novel expansion for S. mutans biofilms. Our findings reveal that S. mutans employs a distinct two-step expansion strategy. Through osmotic pressure, extracellular polymeric substances (EPS) spread and transport bacterial clusters to new sites. Subsequently, the hydroxyapatite surface enables new colony formation. Hydroxyapatite's acid-neutralization properties appear critical for bacterial growth and colonization. Despite successful EPS spreading, environments without hydroxyapatite failed to support new colony formation. These results reveal the unique pattern of rapid ECC progression in sugar-rich environments and establish EPS as a promising therapeutic target, advancing understanding of cariogenic biofilm behavior and preventative strategies for ECC prevention.

Silver Nanoparticles Functionalized with Polymeric Substances to Reduce the Growth of Planktonic and Biofilm Opportunistic Pathogens

The global rise in antimicrobial resistance, particularly among ESKAPE pathogens, has intensified the demand for alternative therapeutic strategies. Silver nanoparticles (AgNPs) have exhibited broad-spectrum antimicrobial activity and represent a promising approach to combat multidrug-resistant infections. This study aimed to synthesize and functionalize AgNPs using various polymeric agents-ethylene glycol (EG), polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and their combinations-and to evaluate their antimicrobial and antibiofilm efficacy against clinically relevant bacterial strains. AgNPs were synthesized via chemical reduction and functionalized as Ag@EG, Ag@PEG, Ag@EG/PVP, and Ag@PEG/PVP. A total of 68 clinical isolates-including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa-were tested. Antimicrobial susceptibility was assessed using disc diffusion and broth microdilution assays, while antibiofilm activity was evaluated via the crystal violet method. Among all tested formulations, Ag@EG/PVP exhibited the highest antimicrobial and antibiofilm activity, with notably low minimum inhibitory concentrations (MIC50) and minimum biofilm eradication concentrations (MBEC50) for Ps. aeruginosa and K. pneumoniae. In contrast, AgNPs functionalized with PEG or EG alone showed limited efficacy. Biofilm-forming isolates, particularly Staphylococcus spp., required higher concentrations for inhibition. These results highlight the critical role of functionalization in modulating the antimicrobial properties of AgNPs, with Ag@EG/PVP demonstrating potent activity against both planktonic and biofilm-associated multidrug-resistant bacteria. Overall, this study supports further developing AgNPs-based formulations as adjuncts or alternatives to conventional antibiotics, particularly for managing biofilm-related infections. Future research should focus on formulation optimization, safety assessment, and translational potential.

Design and Synthesis of Triazole-Based p-tert-Butylcalix[4]Arene Conjugates and Evaluation of Their Antimicrobial, Antibiofilm, and Anti-Quorum-Sensing Activities

Macrocyclic calix[n]arenes have many applications, with diverse structures that can easily be functionalized either on upper or lower rims, mostly to impart solubility and improve biological activities. In this study, triazole-based p-tert-butylcalix[4]arene conjugates (AT10a and AT10b) and their p-tert-butylphenol analogs (AT10b and AT11b) were synthesized in good yields and characterized using 13C NMR and 1H NMR experiments. The compounds were evaluated for their antimicrobial (AM) activity against Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes), Gram-negative bacteria (Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa), and fungi (Candida albicans, Candida tropicalis), and minimal/minimum inhibitory concentration (MIC) values varied from 19 to 2500 µg/mL. The AM activities of the compounds were good against most of the strains, with S. aureus, L. monocytogenes, and C. albicans being the most susceptible. The compounds inhibited violacein synthesis in Chromobacterium violaceum CV12472 and MIC and sub-MIC concentrations. AT10a and AT11a all showed 100% inhibition at MIC and 1/2 MIC concentrations, whereas compound AT10b and compound AT11b had 85.1% ± 2.1% and 90.7% ± 1.2% inhibitions at 1/2 MIC. The compounds inhibited quorum sensing (QS) against C. violaceum CV026 at MIC and 1/2 MIC, with AT11a being the most active with inhibition diameters of 18.50 ± 0.75 mm (MIC) and 11.50 ± 0.47 mm (1/2 MIC). QS inhibition indicates that the compounds could disrupt communication and coordinated behavior in bacteria. The compounds inhibited swarming and swimming motilities against P. aeruginosa PA01 at MIC and sub-MIC concentrations, implying that they can reduce spread of bacteria and cross-infections through surface colonization. The compounds showed concentration-dependent biofilm inhibition against a range of pathogenic bacteria at MIC and sub-MIC. S. aureus, L. monocytogenes, and S. typhi biofilms were most susceptible to the compounds compared to the others. Inhibition of biofilm is an indication of possible eradication of resistance in bacteria. The results suggest that triazole-based calixarene derivatives are suitable scaffolds for the development of good AMs, which could quench cell-to-cell signaling and attenuate virulence factors in bacteria.

Halogen anion modulated metal-organic frameworks with enhanced nanozyme activities for bacterial biofilm disruption

There is an urgent need to develop new nanozymes with enhanced catalytic activities to combat bacterial infections, which have become increasingly challenging due to the misuse of antibiotics and the difficulties of new antibiotic discovery. Here, we employed a new strategy against bacterial biofilms by introducing halide anions to modulate the crystal facets of ZIF-L metal-organic frameworks (MOFs) and then loading chloroquine to form Ch@ZIF-L. The modulation of crystal facets significantly enhanced the oxidase activities of ZIF-L, which can be significantly changed by modulation of its crystal facets, with the hexagonal ZIF-L (ZIF-L-H-Cl) structure showing the highest oxidase activity. At pH 6.0, over 80% of chloroquine was released from Ch@ZIF-L-H-Cl within 8 hours, altering the DNA conformation of bacterial biofilms and disrupting the extracellular polymeric substances (EPSs). The generation of singlet oxygen catalyzed by ZIF-L-H-Cl can effectively kill bacteria at the infected wound site. The composite nanozyme of Ch@ZIF-L-H-Cl, when treated at 100 μg mL-1, exhibited no adverse effects on normal cell growth or hemolysis. Our in vivo experiments demonstrated an 85% reduction of the wound area by day 8 and a rapid recovery of body weight in mice with wounds infected with Staphylococcus aureus (S. aureus) biofilms. Furthermore, substantial reductions in bacterial counts were observed in both wounds and blood samples in the mice, highlighting the great potential of Ch@ZIF-L-H-Cl in combating bacterial biofilm infections.

Enhanced Interfacial Electric Field of an S-Scheme Heterojunction by an Ultrasonication-Triggered Piezoelectric Effect for Sonocatalytic Therapy of Bacterial Infections

Sonodynamic therapy indicates advantages in combating antibiotics-resistant bacteria and deep tissue infections, but challenges remain in the less efficient charge transfer and reactive oxygen species (ROS) generation of sonosensitizers. Herein, an effective bactericidal strategy is developed through enhancing the interfacial electric field (IEF) of S-scheme heterojunctions by an ultrasonication-triggered piezoelectric effect. Hollow barium titanate (hBT) nanoparticles (NPs) were prepared through template etching, followed by in situ assembly of tetrakis (4-carboxyphenyl)porphyrin (TCPP) with Zn2+ to obtain hBT@ZnTCPP. Both experimental and theoretical evidences support the notion that an IEF is generared from ZnTCPP to hBT. Compared to metalloporphyrins with Fe3+, Mn3+, Cu2+ and Ni2+, the stronger reduction of ZnTCPP induced by elevation of the orbital energy level of porphyrins after Zn2+ coordination leads to formation of S-scheme heterojunctions. The ultrasonication-activated polarization field enhances IEF and boosts energy band bending of hBT@ZnTCPP to promote electron-hole separations and ROS generations. Planktonic methicillin-resistant Staphylococcus aureus and their derived biofilms are completely destroyed within 5 min under ultrasonication through up-regulating genes of glucose catabolism and ion transportation and down-regulating genes of ribosomal synthesis and transmembrane transporter. Thus, this study demonstrates molecular-level modulation of energy levels for S-scheme heterojunction formation to achieve efficient sonocatalytic therapy of bacterial infections.

Convenient Synthesis of β-C-Acyl Glycosides and its Application in the Synthesis of Scleropentaside A, Scleropentaside B and the Derivatives of Dapagliflozin

C-Glycosides are a common feature in numerous bioactive natural compounds and play a crucial role as mimics of O/N-glycosides. Our process for synthesizing β-C-acyl glycosides involves a reductive cross-coupling of protected glycosyl bromides with the corresponding carboxylic acid, followed by base-assisted deprotection and isomerization. This method is compatible with diverse glycosyl donors, including disaccharides. Consequently, we achieved the total synthesis of the natural products scleropentaside A and scleropentaside B with exceptional efficiency. These β-C-acyl glycosides can be readily transformed into novel forms of C-glycosides capable of disrupting signaling pathways linked to various pathological conditions, such as diabetes.

Linalool as a potential agent for inhibiting Escherichia coli biofilm formation and exopolysaccharide production

Escherichia coli (E. coli) is one of the most common pathogens causing endometritis in dairy cows. The presence of genes encoding extended-spectrum β-lactamase (ESBL) and biofilm formation are important factors contributing to bacterial resistance, which poses a significant challenge to the treatment of endometritis in dairy cows. Essential oils containing linalool have been shown to improve the cure rate of bovine endometritis, but whether linalool can inhibit E. coli biofilm has not yet been reported. We proposed to ascertain the linalool implications on the development of E. coli biofilm and its extracellular polysaccharides, as well as to assess the impacts of linalool on E. coli in both planktonic and biofilm states. We discovered that the minimum biofilm inhibitory concentrations (MBICs) of linalool against E. coli were twice as high as the minimum inhibitory concentrations. Linalool exhibited a strong bactericidal effect on clinical E. coli strain producing ESBL and forming strong biofilm, regardless of whether they were in a planktonic or biofilm condition. Linalool suppressed the biofilm development in a way that was dependent on the dosage, with an MBIC 4 µL/mL. This was verified by the use of crystal violet test and scanning electron microscopy. Moreover, the CCK-8 assay and confocal laser scanning microscopy (CLSM) manifested significant reductions in live bacteria within the biofilm. The concentrations of extracellular polymeric compounds in the E. coli biofilm were also reduced. Furthermore, CLSM and RT-qPCR analysis confirmed that linalool (2 µL/mL) significantly suppressed exopolysaccharide (EPS) and the pgaABCD gene expression, regulating an essential exopolysaccharide expression in biofilm formation. These findings revealed that linalool effectively suppressed viable bacteria, EPS production, and E. coli biofilm formation, providing a theoretical foundation for alternative antibiotic therapy in endometritis in dairy cows and as a potential agent for preventing E. coli biofilm-related infections.

Oral-gut microbiome interactions in advanced cirrhosis: characterisation of pathogenic enterotypes and salivatypes, virulence factors and antimicrobial resistance

BACKGROUND & AIMS

Cirrhosis complications are often triggered by bacterial infections with multidrug-resistant organisms. Alterations in the gut and oral microbiome in decompensated cirrhosis (DC) influence clinical outcomes. We interrogated: (i) gut and oral microbiome community structures, (ii) virulence factors (VFs) and antimicrobial resistance genes (ARGs) and (iii) oral-gut microbial overlap in patients with differing cirrhosis severity.

METHODS

Fifteen healthy controls (HCs), as well as 26 patients with stable cirrhosis (SC), 46 with DC, 14 with acute-on-chronic liver failure (ACLF) and 14 with severe infection without cirrhosis participated. Metagenomic sequencing was undertaken on paired saliva and faecal samples. 'Salivatypes' and 'enterotypes' based on genera clustering were assessed against cirrhosis severity and clinical parameters. VFs and ARGs were evaluated in oral and gut niches, and distinct resistotypes identified.

RESULTS

Salivatypes and enterotypes revealed a greater proportion of pathobionts with concomitant reduction in autochthonous genera with increasing cirrhosis severity and hyperammonaemia. Increasing overlap between oral and gut microbiome communities was observed in DC and ACLF vs. SC and HCs, independent of antimicrobial, beta-blocker and gastric acid-suppressing therapies. Two distinct gut microbiome clusters harboured genes encoding for the PTS (phosphoenolpyruvate:sugar phosphotransferase system) and other VFs in DC and ACLF. Substantial ARGs (oral: 1,218 and gut: 672) were detected (575 common to both sites). The cirrhosis resistome was distinct, with three oral and four gut resistotypes identified, respectively.

CONCLUSIONS

The degree of oral-gut microbial community overlap, frequency of VFs and ARGs all increase significantly with cirrhosis severity, with progressive dominance of pathobionts and loss of commensals. Despite similar antimicrobial exposure, patients with DC and ACLF have reduced microbial richness compared to patients with severe infection without cirrhosis, supporting the additive pathobiological effect of cirrhosis.

IMPACT AND IMPLICATIONS

This research underscores the crucial role of microbiome alterations in the progression of cirrhosis in an era of escalating multidrug resistant infections, highlighting the association and potential impact of increased oral-gut microbial overlap, virulence factors, and antimicrobial resistance genes on clinical outcomes. These findings are particularly significant for patients with decompensated cirrhosis and acute-on-chronic liver failure, as they reveal the intricate relationship between microbiome alterations and cirrhosis complications. This is relevant in the context of multidrug-resistant organisms and reduced oral-gut microbial diversity that exacerbate cirrhosis severity, drive hepatic decompensation and complicate treatment. For practical applications, these insights could guide the development of targeted microbiome-based therapeutics and personalised antimicrobial regimens for patients with cirrhosis to mitigate infectious complications and improve clinical outcomes.

Ultrasound-assisted preparation of shikonin-loaded emulsions for the treatment of bacterial infections

Bacteria can encapsulate themselves in a self-generated matrix of hydrated extracellular polymeric substances such as polysaccharides, proteins, and nucleic acids, thereby forming bacterial biofilm infections. These biofilms are drug resistant and will diminish the efficacy of antimicrobial agents, rendering treatment of such infections challenging. Herein, an innovative strategy is proposed to synergistically degrade bacterial biofilms and eradicate the entrapped bacteria through integrating α-amylase (α-Amy), shikonin (SK) and epigallocatechin gallate (EGCG) within an emulsion. The natural protein α-Amy is deployed to enzymatically hydrolyze the polysaccharide of biofilms. Due to the amphipilic properties of α-Amy and the cross-linking capability of EGCG, the formed α-Amy/SK@EGCG emulsion possess high stability. SK was encapsulated within the emulsion through ultrasound-assisted assembly, targeting to treat bacterial infection after biofilm degradation. In vitro and in vivo experiments demonstrate that the polyphenol-protein stabilized emulsion loaded with antibacterial SK achieves profound penetration into the biofilms due to the extracellular polysaccharide hydrolysis mediated by α-Amy. As a result, the α-Amy/SK@EGCG emulsion can significantly alleviate inflammation symptoms and accelerate the healing process of biofilm-infected wounds. This study provides a promising therapeutic strategy for the development of novel materials aimed for the enhanced treatment of bacterial biofilm infections.

Enhanced antibacterial and antibiofilm activities of quaternized ultra-highly deacetylated chitosan against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacterial infections pose a severe threat to global public health and present significant challenges in the treatment of bacterial keratitis. The escalation of antimicrobial resistance (AMR) underscores the urgent need for alternative therapeutic strategies. In this study, we report the homogeneous synthesis of quaternized ultra-highly deacetylated chitosan (QUDCS) using a sequential acid-base combination approach. The optimized QUDCS-2 exhibits broad-spectrum antibacterial activity through a membrane-disruption mechanism driven by electrostatic, hydrogen bonding, and hydrophobic interactions, while maintaining low cytotoxicity and high selectivity. Compared to less deacetylated counterparts, QUDCS-2 demonstrates superior stability in enzyme-rich environments and effectively inhibits and eradicates mature biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Furthermore, QUDCS-2 exhibits a remarkable ability to prevent the development of antimicrobial resistance. In a mouse keratitis model, QUDCS-2 shows excellent biocompatibility and significant antibacterial efficacy, providing strong support for its potential as a long-term, effective antimicrobial agent.

A macrophage-like biomimetic nanoparticle with high-efficiency biofilm disruption and innate immunity activation for implant-related infection therapy

The innate immune system's inactivation and microbial biofilm-induced antibiotic resistance are the main causes of implant-associated infections (IAIs), which frequently result in implant surgical failure. Refractory recolonization is the consequence of standard therapies that are unable to consistently suppress escaping planktonic bacteria from biofilm, thereby enabling IAIs to thrive. Here, we specifically designed a macrophage-like biomimetic nanoparticle (F/R@PM) for a biofilm microenvironment (BME), which was fabricated by coating the cell membrane derived from macrophage onto poly (lactic-co-glycolic acid) (PLGA) namoparticles (NPs) loaded with FOT (NO donor) and R837 (TLR7 agonist). After injecting F/R@PM into mice with implant-associated infections, it was able to selectively target macrophages through macrophage membrane proteins on its surface and effectively release FOT and R837. Then, FOT that spreads outside the cell could react with glutathione (GSH) in the BEM to rapidly produce a large amount of NO inside biofilms to destroy the biofilm and kill bacteria. At the same time, R837 would encourage macrophages to scavenge planktonic bacteria that had escaped biofilm disintegration through improved phagocytosis. Overall, this work shows that NO treatment and immunotherapy together have promising potential for the long-term and efficient control and eradication of IAIs.

Quercetin Exhibits Broad-Spectrum Antibiofilm and Antiquorum Sensing Activities Against Gram-Negative Bacteria: In Vitro and In Silico Investigation Targeting Antimicrobial Therapy

Quercetin (QC), a flavonoid abundant in fruits and vegetables, has garnered attention for its potential therapeutic properties. In this study, we investigated the antibiofilm and antiquorum sensing (QS) activities of QC against Gram-negative bacteria both in vitro and in silico. The findings of this study demonstrate MIC values of 125 μg/mL for Chromobacterium violaceum, 250 μg/mL for Pseudomonas aeruginosa, and 500 μg/mL for Serratia marcescens, indicating its antibacterial potential abilities. QS-mediated production of violacein and prodigiosin was significantly inhibited in a dose-dependent manner at sub-MIC concentrations. Additionally, a dose-dependent reduction in the virulence factors of P. aeruginosa, including production of pyocyanin, pyoverdine, and rhamnolipid, was noted with QC. Biofilm formation decreased by 66.40%, 59.28%, and 63.70% at the highest sub-MIC for C. violaceum, P. aeruginosa, and S. marcescens, respectively. Furthermore, swimming motility and exopolysaccharide (EPS) production were also reduced in the presence of QC. Additionally, molecular docking and molecular dynamics simulations elucidate the binding interactions between QC and key molecular targets (LasI, LasR, PilY1, LasA, PilT, CviR, CviR', PqsR, RhlR, and PigG) involved in biofilm formation and QS pathways. Our results indicated that the antibiofilm and anti-QS sensing activities of QC may be attributed to its ability to interfere with critical signaling molecules and regulatory proteins. Overall, this study highlights QC as a promising natural compound for combating biofilm-associated infections caused by Gram-negative bacteria. The multifaceted antimicrobial mechanisms of QC underscore its potential as a therapeutic agent for the treatment of biofilm-related infections, providing the way for further exploration, and development of QC-based strategies in antimicrobial therapy.

Large-scale biosynthetic analysis of human microbiomes reveals diverse protective ribosomal peptides

The human microbiome produces diverse metabolites that influence host health, yet the chemical landscape of ribosomally synthesized and post-translationally modified peptides (RiPPs)-a versatile class of bioactive compounds-remains underexplored. Here, we conduct a large-scale biosynthetic analysis of 306,481 microbial genomes from human-associated microbiomes, uncovering a broad array of yet-to-be-discovered RiPPs. These RiPPs are distributed across various body sites but show a specific enrichment in the gut and oral microbiome. Big data omics analysis reveals that numerous RiPP families are inversely related to various diseases, suggesting their potential protective effects on health. For a proof of principle study, we apply the synthetic-bioinformatic natural product (syn-BNP) approach to RiPPs and chemically synthesize nine autoinducing peptides (AIPs) for in vitro and ex vivo assay. Our findings reveal that five AIPs effectively inhibit the biofilm formation of disease-associated pathogens. Furthermore, when ex vivo testing gut microbiota from mice with inflammatory bowel disease, we observe that two AIPs can regulate the microbial community and reduce harmful species. These findings highlight the vast potential of human microbial RiPPs in regulating microbial communities and maintaining human health, emphasizing their potential for therapeutic development.

Bacterial cell wall-specific nanomedicine for the elimination of Staphylococcus aureus and Pseudomonas aeruginosa through electron-mechanical intervention

Personalized synergistic antibacterial agents against diverse bacterial strains are receiving increasing attention in combating antimicrobial resistance. However, the current research has been struggling to strike a balance between strain specificity and broad-spectrum bactericidal activity. Here, we propose a bacterial cell wall-specific antibacterial strategy based on an in situ engineered nanocomposite consisting of carbon substrate and decorated TiOx dots, termed TiOx@C. The fiber-like carbon substrate of TiOx@C is able to penetrate the bacterial membrane of Pseudomonas aeruginosa (P. aeruginosa), but not that of Staphylococcus aureus (S. aureus) due to its thicker bacterial wall, thus achieving bacterial wall specificity. Furthermore, a series of experiments demonstrate the specific electro-mechanical co-sterilization effect of TiOx@C. On the one hand, TiOx@C can disrupt the electron transport chain and block the energy supply of S. aureus. On the other hand, TiOx@C capable of destroying the membrane structure of P. aeruginosa could cause severe mechanical damage to P. aeruginosa as well as inducing oxidative stress and protein leakage. In vivo experiments demonstrate the efficacy of TiOx@C in eliminating 97% of bacteria in wounds and promoting wound healing in wound-infected female mice. Overall, such a bacterial cell wall-specific nanomedicine presents a promising strategy for non-antibiotic treatments for bacterial diseases.

Dual-responsive polydopamine-embellished Zn-MOFs enabling synergistic photothermal and antibacterial metal ion therapy for oral biofilm eradication

Oral biofilms are associated with various oral diseases causing pain and discomfort, and pose a severe threat to general health. Conventional surgical debridement and antibacterial therapy often yield unsatisfactory outcomes because they either fail to fully and painlessly eliminate biofilms or increase the risk of bacterial resistance. In this study, we synthesized polydopamine-embellished Zn-MOFs (ZIF-8@PDA NPs), which can degrade under mildly acidic conditions to release Zn2+. These nanoparticles also convert near-infrared light energy into heat, thereby enabling synergistic photothermal and antibacterial metal ion therapy for oral biofilm eradication. Our findings reveal that therapy with ZIF-8@PDA NPs, when exposed to near-infrared radiation, demonstrates exceptional antibacterial efficacy and is highly effective in eradicating oral biofilms both in vitro and ex vivo. Furthermore, we used an in vivo rodent tooth biofilm model to demonstrate the suppression of dental caries. This work presents a promising solution for preventing and suppressing dental caries as well as other treating diseases linked to oral biofilm infections.

Echinacoside reduces intracellular c-di-GMP levels and potentiates tobramycin activity against Pseudomonas aeruginosa biofilm aggregates

Cyclic diguanylate (c-di-GMP) is a central biofilm regulator in Pseudomonas aeruginosa, where increased intracellular levels promote biofilm formation and antibiotic tolerance. Targeting the c-di-GMP network may be a promising anti-biofilm approach, but most strategies studied so far aimed at eliminating surface-attached biofilms, while in vivo P. aeruginosa biofilms often occur as suspended aggregates. Here, the expression profile of c-di-GMP metabolism-related genes was analysed among 32 P. aeruginosa strains grown as aggregates in synthetic cystic fibrosis sputum. The diguanylate cyclase SiaD proved essential for auto-aggregation under in vivo-like conditions. Virtual screening predicted a high binding affinity of echinacoside towards the active site of SiaD. Echinacoside reduced c-di-GMP levels and aggregate sizes and potentiated tobramycin activity against aggregates in >80% of strains tested. This synergism was also observed in P. aeruginosa-infected 3-D alveolar epithelial cells and murine lungs, demonstrating echinacoside's potential as an adjunctive therapy for recalcitrant P. aeruginosa infections.

Advancing Nanotechnology: Targeting Biofilm-Forming Bacteria with Antimicrobial Peptides

Nanotechnology offers innovative solutions for addressing the challenges posed by biofilm-forming bacteria, which are highly resistant to conventional antimicrobial therapies. This review explores the integration of pharmaceutical nanotechnology with antimicrobial peptides (AMPs) to enhance the treatment of biofilm-related infections. The use of various nanoparticle systems-including inorganic/metallic, polymeric, lipid-based, and dendrimer nanostructures-provides promising avenues for improving drug delivery, targeting, and biofilm disruption. These nanocarriers facilitate the penetration of biofilms, down-regulate biofilm-associated genes, such as ALS1, ALS3, EFG1, and HWP1, and inhibit bacterial defense mechanisms through membrane disruption, reactive oxygen species generation, and intracellular targeting. Furthermore, nanoparticle formulations such as NZ2114-NPs demonstrate enhanced efficacy by reducing biofilm bacterial counts by several orders of magnitude. This review highlights the potential of combining nanotechnology with AMPs to create novel, targeted therapeutic approaches for combatting biofilm-related infections and overcoming the limitations of traditional antimicrobial treatments.

Targeted elimination of cariogenic Streptococcus mutans biofilms via Cu,Fe-doped chitosan nanozyme

Human dental caries is an intractable biofilm-associated disease caused by the symbiotic cariogenic bacteria, but how to target effectively eliminate cariogenic bacterial and their biofilms without affecting normal bacteria still remains great challenges. To address this issue, we reported Cu,Fe-doped chitosan-based nanozyme (i.e. CS@Cu,Fe) that exhibits well peroxidase-like activity at acidic environment of caries, and kill S. mutans and S. sanguinis without impacting the normal S. oralis. The synergistic interaction between Cu and Fe could effectively enhance the efficiency of electron transfer, promoting the production of hydroxyl radicals (·OH) and superoxide radical (·O2-) to selectively destroy the biofilm of S. mutans. Compared to curcumin and hexadecyl trimethyl ammonium bromide (CTAB) (control), the chitosan on the surface of CS@Cu,Fe not only showed the synergistic antibacterial activity, but also enabled the selectively eradication of S. mutans biofilm without affecting S. sanguinis and S. oralis biofilms. Furthermore, CS@Cu,Fe also exhibited excellent selective anti-symbiotic caries bacteria and targeted anti-biofilm properties to hybrid biofilm model of these co-existing bacteria under the same oral environment. Therefore, the CS@Cu,Fe nanozyme not only has potential for the treatment of dental biofilms, but also can offer new insights for the design of highly selective antibacterial and antibiofilm nanozyme.

Sodium dichloroisocyanurate: a promising candidate for the disinfection of resilient drain biofilm

Background

Biofilms are complex multicellular communities of microorganisms embedded within a protective matrix which confers resistance to various antimicrobials, including biocides. Biofilms can cause a range of human diseases and are responsible for 1.7 million hospital-acquired infections in the US annually, providing an economic burden of $11.5 billion in treatment costs. Biofilm contained within drain and plumbing systems may contain pathogenic viruses and bacteria which pose a significant risk to patient safety within healthcare environments.

Aim

The aim of this study was to determine if three hospital-grade disinfectants (sodium dichloroisocyanurate, peracetic acid and sodium hypochlorite) were capable of killing microorganisms within biofilm, and thus, determining their potential as candidates for drain biofilm disinfection.

Methods

Pseudomonas aeruginosa biofilms were cultivated using the CDC biofilm reactor, a standardised method for determining disinfectant efficacy against biofilm within the United States of America. Each disinfectant was tested using a one-minute contact time, using the highest concentration available on the product label.

Findings

The sodium dichloroisocyanurate product was successful in killing biofilm microorganisms, resulting in a log reduction of ≥ 8.70. Peracetic acid reduced biofilm by 3.82 log10 units, followed by sodium hypochlorite, which produced a reduction of 3.78 log10 units.

Conclusions

The use of a highly effective disinfectant with proven biofilm efficacy can help ensure patient safety and reduce infection levels. Drains and plumbing systems provide a reservoir for potential pathogens and biofilm; thus, drain disinfection is critical in reducing the instance of hospital-acquired infections. Sodium dichloroisocyanurate may provide a reliable solution for drain applications and subsequently, patient wellbeing and safety.

Recent Development of Nanozymes for Combating Bacterial Drug Resistance: A Review

The World Health Organization has warned that without effective action, deaths from drug-resistant bacteria can exceed 10 million annually, making it the leading cause of death. Conventional antibiotics are becoming less effective due to rapid bacterial drug resistance and slowed new antibiotic development, necessitating new strategies. Recently, materials with catalytic/enzymatic properties, known as nanozymes, have been developed, inspired by natural enzymes essential for bacterial eradication. Unlike recent literature reviews that broadly cover nanozyme design and biomedical applications, this review focuses on the latest advancements in nanozymes for combating bacterial drug resistance, emphasizing their design, structural characteristics, applications in combination therapy, and future prospects. This approach aims to promote nanozyme development for combating bacterial drug resistance, especially towards clinical translation.

Nanozyme-Shelled Microcapsules for Targeting Biofilm Infections in Confined Spaces

Bacterial infections in irregular and branched confinements pose significant therapeutic challenges. Despite their high antimicrobial efficacy, enzyme-mimicking nanoparticles (nanozymes) face difficulties in achieving localized catalysis at distant infection sites within confined spaces. Incorporating nanozymes into microrobots enables the delivery of catalytic agents to hard-to-reach areas, but poor nanoparticle dispersibility and distribution during fabrication hinder their catalytic performance. To address these challenges, a nanozyme-shelled microrobotic platform is introduced using magnetic microcapsules with collective and adaptive mobility for automated navigation and localized catalysis within complex confinements. Using double emulsions produced from microfluidics as templates, iron oxide and silica nanoparticles are assembled into 100-µm microcapsules, which self-organize into multi-unit, millimeter-size assemblies under rotating magnetic fields. These microcapsules exhibit high peroxidase-like activity, efficiently catalyzing hydrogen peroxide to generate reactive oxygen species (ROS). Notably, microcapsule assemblies display remarkable collective navigation within arched and branched confinements, reaching the targeted apical regions of the tooth canal with high accuracy. Furthermore, these nanozyme-shelled microrobots perform rapid catalysis in situ and effectively kill biofilms on contact via ROS generation, enabling localized antibiofilm action. This study demonstrates a facile method of integrating nanozymes onto a versatile microrobotic platform to address current needs for targeted therapeutic catalysis in complex and confined microenvironments.

Nanotherapies Based on ROS Regulation in Oral Diseases

Oral diseases rank among the most prevalent clinical conditions globally, typically involving detrimental factors such as infection, inflammation, and injury in their occurrence, development, and outcomes. The concentration of reactive oxygen species (ROS) within cells has been demonstrated as a pivotal player in modulating these intricate pathological processes, exerting significant roles in restoring oral functionality and maintaining tissue structural integrity. Due to their enzyme-like catalytic properties, unique composition, and intelligent design, ROS-based nanomaterials have garnered considerable attention in oral nanomedicine. Such nanomaterials have the capacity to influence the spatiotemporal dynamics of ROS within biological systems, guiding the evolution of intra-ROS to facilitate therapeutic interventions. This paper reviews the latest advancements in the design, functional customization, and oral medical applications of ROS-based nanomaterials. Through the analysis of the components and designs of various novel nanozymes and ROS-based nanoplatforms responsive to different stimuli dimensions, it elaborates on their impacts on the dynamic behavior of intra-ROS and their potential regulatory mechanisms within the body. Furthermore, it discusses the prospects and strategies of nanotherapies based on ROS scavenging and generation in oral diseases, offering alternative insights for the design and development of nanomaterials for treating ROS-related conditions.

Synergistic anti-biofilm strategy based on essential oils and its application in the food industry

The microbial biofilm can induce a variety of food safety problems, and cause huge economic losses. Essential oils (EOs) not only have broad-spectrum antibacterial activity but also have a good ability to inhibit biofilm. However, the addition dose of EOs in practical application usually exceeds their flavor threshold, resulting in the appearance of undesired flavor. Therefore, synergistic antimicrobial may be a potential strategy to improve the antibacterial activity of EOs and to reduce their dosage. This paper focuses on the analysis of the synergistic anti-biofilm strategies based on EOs. Based on these, the action mechanism of EOs against biofilm and other commonly used anti-biofilm strategies in the food industry are summarized. The anti-biofilm mechanism of EOs is mainly related to inhibiting the synthesis of extracellular polysaccharides and proteins, destroying biofilm structure, inhibiting the metabolic activity of biofilm, inhibiting quorum sensing (QS) and regulating the formation of biofilm and the expression of toxicity-related genes. At present, the commonly used anti-biofilm strategies in the food industry mainly include physical strategies, chemical strategies and biological strategies, among which the combined application of different strategies is the future development trend. In particular, the synergistic anti-biofilm strategy based on EOs has shown great application value in the food industry. To sum up, some new information in this paper will give guidance and provide more reference for the development of efficient biofilm regulation strategies in future.

Microbiome modulation of implant-related infection by a novel miniaturized pulsed electromagnetic field device

Dental implant-related infections, which lack effective therapeutic strategies, are considered the primary cause for treatment failure. Pulsed electromagnetic field (PEMF) technology has been introduced as a safe and effective modality for enhancing biological responses. However, the PEMF effect on modulating microbial diversity has not been explored. Thus, we tested a miniaturized PEMF biomedical device as a healing component for dental implants. PEMF activation did not alter the chemical composition, surface roughness, wettability, and electrochemical performance. PEMF effectively controlled chronic in vitro polymicrobial microbial accumulation. The in vivo study where devices were inserted in the patients' oral cavities and 16S RNA sequencing analysis evidenced a fivefold or more reduction in 23 bacterial species for PEMF group and the absence of some species for this group, including pathogens associated with implant-related infections. PEMF altered bacterial interactions and promoted specific bacterial pathways. PEMF has emerged as an effective strategy for controlling implant-related infections.

Enhancing antibiotic therapy through comprehensive pharmacokinetic/pharmacodynamic principles

Antibiotic therapy relies on understanding both pharmacokinetics (PK) and pharmacodynamics (PD), which respectively address drug absorption, distribution, and elimination, and the relationship between drug concentration and antimicrobial efficacy. This review synthesizes decades of research, drawing from in-vitro studies, in-vivo models, and clinical observations, to elucidate the temporal dynamics of antibiotic activity. We explore how these dynamics, including concentration-effect relationships and post antibiotic effects, inform the classification of antibiotics based on their PD profiles. Additionally, we discuss the pivotal role of PK/PD principles in determining optimal dosage regimens. By providing a comprehensive overview of PK/PD principles in antibiotic therapy, this review aims to enhance understanding and improve treatment outcomes in clinical practice.

In Situ Application of Berberine-Loaded Liposomes on the Treatment of Osteomyelitis

Osteomyelitis is a major challenge in global healthcare, as it requires the simultaneous management of bone defects and bacterial infections, which poses considerable difficulties for orthopedic clinicians. In this study, we developed berberine liposome-modified bone cement specifically aimed at treating osteomyelitis induced by Staphylococcus aureus. We characterized the physical properties of this modified bone cement, conducted in vitro antibacterial assays to evaluate its efficacy in eradicating Staphylococcus aureus biofilm, established an in vivo rat model of osteomyelitis, and performed histopathological assessments alongside micro-CT analysis of bone parameters. The results indicated that the berberine liposome-modified bone cement exhibited favorable biodegradability and sustained-release characteristics, with a drug release rate of more than 90% within 14 days, while effectively eliminating bacterial biofilm with a biofilm eradication rate of up to 80% and facilitating bone repair with a bone volume fraction of 80%. This innovative treatment demonstrated both safety and efficacy in addressing tibial osteomyelitis in rats, thereby offering novel insights and methodologies for clinical interventions against osteomyelitis.

Graveyard effects of antimicrobial nanostructured titanium over prolonged exposure to drug resistant bacteria and fungi

Innovations in nanostructured surfaces have found a practical place in the medical area with use in implant materials for post-operative infection prevention. These textured surfaces should be dual purpose: (1) bactericidal on contact and (2) resistant to biofilm formation over prolonged periods. Here, hydrothermally etched titanium surfaces were tested against two highly antimicrobial resistant microbial species, methicillin-resistant Staphylococcus aureus and Candida albicans. Two surface types - unmodified titanium and nanostructured titanium - were incubated in a suspension of each microbial strain for 1 day and 7 days. Surface topography and cross-sectional information of the microbial cells adhered to the surfaces, along with biomass volume and live/dead rate, showed that while nanostructured titanium was able to kill microbes after 1 day of exposure, after 7 days, the rate of death becomes negligible when compared to the unmodified titanium. This suggests that as biofilms mature on a nanostructured surface, the cells that have lysed conceal the nanostructures and prime the surface for planktonic cells to adhere, decreasing the possibility of structure-induced lysis. Synchrotron macro-attenuated total reflection Fourier transform infrared (macro ATR-FTIR) micro-spectroscopy was used to elucidate the biochemical changes occurring following exposure to differing surface texture and incubation duration, providing further understanding into the effects of surface morphology on the biochemical molecules (lipids, proteins and polysaccharides) in an evolving and growing microbial colony.

Drug delivery systems loaded with plant-derived natural products for dental caries prevention and treatment

Dental caries, driven by dysbiosis in oral flora and acid accumulation, pose a significant threat to oral health. Traditional methods of managing dental biofilms using broad-spectrum antimicrobials and fluoride face limitations such as microbial resistance. Natural products, with their antimicrobial properties, present a promising solution for managing dental caries, yet their clinical application faces significant challenges, including low bioavailability, variable efficacy, and patient resistance due to sensory properties. Advanced drug delivery systems (DDSs) are emerging to address these limitations by enhancing the delivery and effectiveness of natural products. These systems, such as nanoparticles and micelles, aim to enhance drug solubility, stability, and targeted release, leading to increased therapeutic efficacy and decreased side effects. Furthermore, innovative approaches like pH-responsive nanoparticles offer controlled release triggered by the acidic environment of carious lesions. Despite these technological advancements, further validation is necessary for the clinical application of these DDSs.

The anti-biofilm effect of α-amylase/glycopolymer-decorated gold nanorods

The continuous evolution of bacteria and the formation of biofilm have exacerbated resistance issues, highlighting the urgent need for new antibacterial materials. In this study, L-fucose was polymerized to synthesize thiolated poly(2-(L-fucose) ethyl methacrylate) (PFEMA-SH), which was subsequently co-modified with α-amylase onto gold nanorods (GNR) to prepare the antibacterial nanoparticle composite, GNR-Amy-PFEMA (G-A-P). These nanomaterials exhibit both photothermal and enzymatic properties, enabling G-A-P to effectively sterilize and disperse biofilm. Under near-infrared light irradiation, the temperature of G-A-P composite increases significantly, leading to bacterial cell damage and biofilm disruption. The G-A-P composite demonstrated nearly 100 % eradication of planktonic bacteria after 5 min of irradiation and achieved a 70.9 % reduction in mature biofilm biomass, with a 3.37-log decrease in the number of bacteria within the biofilm. These composites display strong antimicrobial activity and hold great potential for the removal of Pseudomonas aeruginosa biofilm. Furthermore, the ability of G-A-P to reduce biofilm formation without the use of traditional antibiotics suggests that it may offer an antibiotic-free alternative for managing biofilm-related infections.

Antibacterial and antibiofilm efficacy of quercetin against Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus associated with ICU infections

Infections caused by multidrug-resistant pathogens, particularly in ICU settings, pose significant health risks globally. Pseudomonas aeruginosa (PA) and methicillin-resistant Staphylococcus aureus (MRSA) are prominent nosocomial pathogens among the ESKAPE group, known for their resistance mechanisms such as biofilm formation and quorum sensing. Quercetin, a flavonoid found in fruits and vegetables, exhibits diverse pharmacological properties, including antimicrobial activity. This study evaluated quercetin's efficacy against PA and MRSA through in vitro and in vivo experiments. Minimum Inhibitory Concentration (MIC) assays showed MIC values of 158 µg mL-1 for PA and 176 µg mL-1 for MRSA. Quercetin inhibited PA's swarming motility at concentrations as low as 39.5 µg mL-1 and reduced MRSA viability in serum by up to 79%. Quercetin treatment significantly reduced biofilm formation by both pathogens, with Pseudomonas aeruginosa showing biomass reductions of 23% at 1/4 MIC (39.5 µg mL-1) and 48% at 1/2 MIC, while methicillin-resistant Staphylococcus aureus exhibited reductions of 27% at 1/4 MIC and 53% at 1/2 MIC compared to the control. High-content fluorescence imaging demonstrated quercetin's ability to disrupt biofilm structure and viability. Moreover, quercetin suppressed EPS production and protease activity in both PA and MRSA, alongside downregulating virulence-related genes involved in quorum sensing and toxin production. In vivo studies using Caenorhabditis elegans confirmed quercetin's ability to reduce bacterial adherence and colonization. These findings underscore quercetin's potential as a therapeutic agent against multidrug-resistant pathogens in ICU settings, warranting further exploration for clinical applications.

ZnO‐CuS/F127 Hydrogels with Multienzyme Properties for Implant‐Related Infection Therapy by Inhibiting Bacterial Arginine Biosynthesis and Promoting Tissue Repair

Implant‐related infections are characterized by the formation of bacterial biofilms. Current treatments have various drawbacks. Nanozymes with enzyme‐like activity can produce highly toxic substances to kill bacteria and remove biofilms without inducing drug resistance. However, it is difficult for current monometallic nanozymes to function well in complex biofilm environments. Therefore, the development of multimetallic nanozymes with efficient multienzyme activities is crucial. In the present study, bimetallic nanozyme, ZnO‐CuS nanoflowers with peroxidase (POD), glutathione oxidase (GSH‐Px), and catalase (CAT) activity are successfully synthesized via calcination and loaded into F127 hydrogels for the treatment of implant‐related infections. The ability of ZnO‐CuS nanoflowers to bind bacteria is key for efficient antimicrobial activity. In addition, ZnO‐CuS nanoflowers with H2O2 disrupt the metabolism of MRSA, including arginine synthesis, nucleotide excision repair, energy metabolism, and protein synthesis. ZnO‐CuS/F127 hydrogel in combination with H2O2 has been demonstrated to be effective in clearing biofilm infection and facilitating the switch of M1 macrophages to M2‐repairative phenotype macrophages for the treatment of implant infections in mice. Furthermore, ZnO‐CuS/F127 hydrogels have favorable biosafety, and their toxicity is negligible. ZnO‐CuS/F127 hydrogel has provided a promising biomedical strategy for the healing of implant‐related infections, highlighting the potential of bimetallic nanozymes for clinical applications.

Warm and humid environment induces gut microbiota dysbiosis and bacterial translocation leading to inflammatory state and promotes proliferation and biofilm formation of certain bacteria, potentially causing sticky stool

BACKGROUND AND AIMS OF THE STUDY

Fluctuations in environmental temperature and humidity significantly affect human physiology and disease manifestation. In the Lingnan region of China, high summer temperatures and humidity often cause symptoms like diminished appetite, sticky tongue coating, sticky stool, unsatisfactory defecation, lethargy, and joint heaviness. These are referred to as "Dampness Syndrome" in Traditional Chinese Medicine (TCM). Thick and greasy tongue fur and sticky feces are characteristic symptoms of "Dampness Syndrome" and serve as crucial diagnostic indicators in TCM for assessing health conditions. However, the specific mechanisms that lead to these symptoms, such as sticky feces and thick and greasy tongue fur, have not been fully elucidated. Understanding these external symptoms is essential, as they reflect internal health status. Warm, humid environments favor microorganism growth, potentially disrupting gut microbiota and bacterial translocation, which could induce an immune-inflammatory response. The primary objective of this study is to explore the potential significant role of immune response products in influencing the proliferation and biofilm formation of gut microbiota, which may subsequently lead to changes in fecal characteristics.

METHODS

In this study, mice were exposed to a controlled warm and humid environment (25 ± 3 °C with 95% humidity) for 16 days to simulate conditions associated with "Dampness Syndrome." After this period, Huoxiang Zhengqi Water, a traditional remedy, has been administrated for four days. On the one hand saliva and tongue coating samples were also taken from human subjects with "Dampness Syndrome" for microorganism culturing and to assess biofilm formation, on the other hand the co-culture products of a macrophage cell line RAW264.7 and Candida albicans and the effect of tumor necrosis factor-α (TNF-α) were evaluated for their impact on the proliferation and biofilm-forming abilities of different bacterial strains.

RESULTS

Compared to a control group, the treatment group exhibited significant changes in gut microbiota, including increased biofilm formation, which was mitigated by Huoxiang Zhengqi Water. In the model group, fungal translocation was observed, potentially triggering an inflammatory response. Intraperitoneal injections of various bacterial strains in mice reproduced the sticky stool characteristics. Both mice and human subjects with "Dampness Syndrome" displayed elevated serum levels of inflammatory cytokines TNF-α and interleukin-17 A (IL-17A). Interestingly, Saliva samples from individuals with "Dampness Syndrome" showed elevated TNF-α levels, accompanied by thick and greasy tongue fur. Culturing samples from the tongue coating of individuals in the "Dampness Syndrome" group revealed an increased biofilm formation capability. C. albicans co-cultured with RAW264.7 cells increased TNF-α secretion, and the supernatant promoted pathogenic bacterial proliferation and biofilm formation. TNF-α specifically enhanced biofilm formation in microorganism like C. albicans and Staphylococcus aureus, with minimal effect on beneficial bacteria like Lacticaseibacillus paracasei and Lactiplantibacillus plantarum in the tested conditions.

CONCLUSIONS

These findings provided new insights into the biological mechanisms of 'Dampness Syndrome' and support the therapeutic role of Huoxiang Zhengqi Water in treating symptoms associated with microbial dysbiosis and inflammation. Additionally, they indicate that TNF-α seems to have selective effects in promoting the proliferation and biofilm formation of different microbial species.

Phagocytosis by macrophages decreases the radiance of bioluminescent Staphylococcus aureus

BACKGROUND

In vivo evaluations of the antimicrobial efficacy of biomaterials often use bioluminescent imaging modalities based on bioluminescent bacteria to allow follow-up in single animals. Bioluminescence production by bacteria is dependent on their metabolic activity. It is well known that several factors can influence the metabolism of bacteria, such as the use of antimicrobials and changes in bacterial growth phase. However, little is known about the influence of intracellular residence of bacteria on bioluminescence. For example, Staphylococcus aureus can survive in the peri-implant tissue and is known to survive intracellularly in macrophages.

RESULTS

In this study, we evaluated the bioluminescent radiance of S. aureus upon phagocytosis by macrophages. We showed that S. aureus reduced its bioluminescence upon phagocytosis by macrophages compared to S. aureus in a single culture. Simultaneously, bacterial numbers as measured by colony-forming units remained constant over time. S. aureus was released extracellularly as a result of macrophage cell death. Following this release, the bacteria increased their bioluminescence again. Replenishment of fresh macrophages showed an immediate increase in bioluminescence. Moreover, the addition of fresh macrophages showed a diminished decrease in bioluminescence at 24 h of coculture, but this effect did not last.

CONCLUSION

Together, this study demonstrates that phagocytosis by macrophages decreases bioluminescence of S. aureus, which is an important factor to consider when using bioluminescent imaging to study the infection process in an in vivo model.

Biofilm formation comparison of Vibrio parahaemolyticus on stainless steel and polypropylene while minimizing environmental impacts and transfer to grouper fish fillets

This study investigated the influence of food contact surface materials on the biofilm formation of Vibrio parahaemolyticus while attempting to minimize the impact of environmental factors. The response surface methodology (RSM), incorporating three controlled environmental factors (temperature, pH, and salinity), was employed to determine the optimal conditions for biofilm formation on stainless steel (SS) and polypropylene (PP) coupons. The RSM results demonstrated that pH was highly influential. After minimizing the impacts of environmental factors, initially V. parahaemolyticus adhered more rapidly on PP than SS. To adhere to SS, V. parahaemolyticus formed extra exopolysaccharide (EPS) and exhibited clustered stacking. Both PP and SS exhibited hydrophilic properties, but SS was more hydrophilic than PP. Finally, this study observed a higher transfer rate of biofilms from PP to fish fillets than from SS to fish fillets. The present findings suggest that the food industry should consider the material of food processing surfaces to prevent V. parahaemolyticus biofilm formation and thus to enhance food safety.