Biofouling最新文献

Staphylococcus aureus is a high-priority pathogen requiring novel antimicrobial strategies. Thymoquinone (TQ), a bioactive compound from Nigella sativa, exhibits antimicrobial and antibiofilm properties, but its precise mechanisms remain unclear. This study evaluated free and nano-encapsulated TQ against multidrug-resistant S. aureus isolates. Nano-encapsulation enhanced biofilm penetration, with TQ significantly reducing extracellular DNA (eDNA) at sub-MIC levels without affecting initial adhesion, exopolysaccharides, or enzymatic virulence. Comparative analysis with vancomycin, ciprofloxacin, and azithromycin confirmed TQ's potent antibiofilm activity. Notably, TQ downregulated crtN, essential for staphyloxanthin biosynthesis, and msaB, a key biofilm and stress response regulator. However, at MIC and super-MIC levels, TQ paradoxically increased staphyloxanthin, suggesting a concentration-dependent oxidative stress response. We propose that TQ disrupts biofilm integrity by modulating the msaABCR operon. These findings highlight nano-TQ's therapeutic potential for biofilm-associated infections and underscore the role of natural compounds in combating multidrug-resistant pathogens.

Bacterial biofilms significantly contribute to persistent infections and the emergence of drug resistance of Staphylococcus aureus. Integrating conventional antibiotics with antibiofilm agents represents a promising strategy for combating biofilm-associated infections. This study systematically investigated the antibiofilm activity and underlying mechanisms of butenolide (BU) against methicillin-resistant S. aureus (MRSA), with a focus on the synergistic effects between BU and vancomycin (VAN). BU exhibited dual antibiofilm activities by efficiently preventing biofilm formation and eradicating established biofilms. Phenotypic characterisation revealed that 200 μg/mL of BU suppressed extracellular DNA production and autoaggregation of MRSA, leading to a significant reduction in biofilm thickness, biovolume, and coverage by up to 30%, 98%, and 96%, respectively. Transcriptome and quantitative-PCR analyses showed that BU treatment downregulated the expression of genes involved in energy metabolism. Notably, BU exhibited promising synergistic and additive effects with VAN in eradicating pre-formed biofilms, achieving synergy or additivity in five out of six S. aureus clinical strains tested, with a minimal fractional inhibitory concentration index as low as 0.375. These results highlight the potential of BU as an effective antibiofilm agent for preventing S. aureus-related infections.

Biofilm formation is a critical factor in uropathogenic Klebsiella pneumoniae, enabling colonization in the urinary tract and contributing to biofilm-mediated antibiotic resistance. This study evaluates the anti-biofilm and antimicrobial properties of the nitrofurantoin-rutin (Ntf-Rut) combination against a strong biofilm-forming clinical isolate, K. pneumoniae SLMK002, screened from Klebsiella spp. (n = 15) causing urinary tract infections (UTI). The findings showed Ntf-Rut combination significantly inhibited biofilm mass by 81%, with a 74% reduction in extracellular polymeric substances (EPS). Colony Forming Unit (CFU) enumeration analysis revealed higher cell death in mature biofilm, with CFU reduced from 9 ± 1 × 10⁶ to 2 ± 1 × 10⁶. Further, flow cytometry results prove that the combination induces cell membrane damage. In conclusion, the findings depict that the Ntf-Rut combination effectively reduces and inhibits the biofilm of K. pneumoniae SLMK002.

This study investigated the effects of arginine, with/without sodium fluoride (NaF), on mature oral microcosm biofilms and enamel calcium loss (ECL). Saliva-derived biofilms grown on bovine enamel for three days were subsequently assigned to their respective test groups and cultured until day seven (n = 9/group). Biofilm parameters and ECL were assessed. Reductions in the number of lactobacilli were observed with arginine at 2.5%/8% concentrations, with/without NaF, while 8% arginine, with/without NaF, reduced the number of all microorganism groups. The addition of 8% arginine and combinations of arginine with NaF reduced biofilm vitality. While all treatments resulted in a reduction of α-EPS, 8% arginine showed the most pronounced effect, being the only treatment to decrease β-EPS compared to the control. Reductions in ECL were achieved by 8% arginine, with/without NaF, 2.5% with NaF, and NaF, compared with the negative control (untreated biofilms). These findings demonstrated that arginine and NaF increased antibiofilm activity against mature biofilms, reducing ECL.

Salty environments are susceptible to biological contamination by halotolerant microorganisms, by the phenotypic adaptation of microbial populations through the induction of survival mechanisms such as stress response pathways, and biofilm formation. Thus, this study aimed to investigate the bio-contamination risks posed by Pseudomonas aeruginosa and Escherichia coli in salted environments. The adhesion of the strains to glass and the surface energies were monitored in an aqueous medium at varying concentrations of sodium chloride (NaCl) (0%, 3%, 6%, 13%, 26%). Bacterial adhesion was observed by the optical microscopy, and the surface energies were estimated using the contact angle method. Surface energy measurements showed that NaCl was able to increase the electron donor (γ^-) and acceptor (γ⁺) characters, and the hydrophobicity (ΔG_iwi) of the bacterial surfaces at 3%. At 6%, 13%, and 26%, bacterial surfaces gradually regained their normal hydrophobicity. Similarly, the hydrophobicity of the glass surface increased and even reversed at 26%. The adhesion images showed an agglutination of the bacterial cells of both strains at 3% and 6%. However, at 6%, 13% and 26%, the adhesion becomes more dispersed and lighter. In brief, these findings suggest that NaCl may contribute to the enhancement of contamination in salted environments. Consequently, this raises concerns regarding the potential for bio-contamination in salty foods.

This systematic review explores the relationship between the oral microbiome in edentulous patients and cardiovascular diseases (CVD). A search was conducted across databases PubMed, Scopus, Web of Science, Embase, and gray literature sources. The review followed PRISMA and AMSTAR guidelines. After removing duplicates, the articles were evaluated by titles and abstracts, and 21 were selected for full-text review, with 9 ultimately included in the final analysis. Oral dysbiosis, linked to systemic conditions like obesity, diabetes, and CVD, is common in inflammatory oral diseases such as periodontitis and denture stomatitis, disrupting original oral microbiota. This imbalance may lead to transient bacteremia and systemic inflammation, contributing to CVD development. Tooth loss reduces salivary microbiome diversity, and denture use in CVD patients is linked to decreased life expectancy compared to dentate individuals. The findings suggest tooth loss, denture use, and oral microbiota dysbiosis are unconventional risk factors for CVD progression.

Mycobacterium abscessus is resistant to traditional anti-TB medications and most currently available antibiotics, its strong biofilm formation may contribute to the resistance and make the situation even worse. In this study, Scutellaria baicalensis extract significantly inhibited the planktonic growth as well as the biofilm formation of M. abscessus. Baicalein, the principal active element in S. baicalensis extract, inhibited the biofilm formation instead of the planktonic growth and reduced extracellular matrix lipids in M. abscessus biofilm. The synergistic effects of baicalein in combination with clinical drugs were investigated, the baicalein effectively restored the susceptibility of M. abscessus to the investigated drugs in the biofilm growth. The transcriptome analysis revealed that 98 genes were upregulated and 19 genes were downregulated after baicalein treatment, genes involved in the fatty acid synthesis pathway were validated by RT-qPCR. Therefore, the extract of S. baicalensis and its monomer baicalein might serve as potential innovative adjuvant agents for the prevention and treatment of M. abscessus biofilm formation in chronic infections.

Helicobacter pylori is associated with gastric disorders, and the increase in bacterial resistance has sparked interest in the search for new antimicrobial compounds. The current study investigated the effect of the silver metal complex [Ag(phen)(PETSC)](NO₃)∙HCl∙2H₂O (phen = 1,10-phenanthroline; PETSC = 2-formylpyridine-N(4)-ethyl-thiosemicarbazone), termed the Compound against H. pylori. The antibacterial activity exhibited a minimum inhibitory concentration of 6.25 μg/mL. The checkerboard titration method assessed the combination of the Compound with amoxicillin and tetracycline, which presented antagonistic and indifferent effects, respectively. Time Kill kinetics were bactericidal after 12 h of treatment. Biofilm inhibition results showed antibacterial activity and bacterial morphological changes were observed by scanning electron microscopy. In vitro, cytotoxicity in normal gastric cells showed IC₅₀ of 0.6733 μg/mL. The alternative in vivo test using Galleria mellonella showed acute toxicity at a dose of 150 mg/kg. Therefore, technological strategies can be an alternative to overcome the cytotoxicity since the Compound has a bactericidal effect against H. pylori.

This study evaluated the effectiveness of natamycin (NAT) on multispecies yeast biofilms isolated from ultrafiltration membranes in an apple juice processing industry. Biofilms were developed on stainless steel surfaces using 12° Brix apple juice under static (SC) and laminar flow (LF) conditions. NAT (0.01 mM) was applied from the beginning of the adhesion stage (NAT T0) and on 24-h-preformed biofilms (NAT T24). NAT T0 significantly reduced attachment and biofilm formation by ∼4-log₁₀ units after 48 h, while NAT T24 achieved reductions of 1.83 and 0.79-log₁₀ units in SC and LF, respectively. The overall reduction in total cell count was significantly more pronounced and consistent under SC. This highlights the importance of preventing initial adhesion for controlling biofilm development. Additionally, these findings underscore the importance of evaluating antimicrobial agents in dynamic flow conditions that closely mimic real-world applications.

Biofilm formation was investigated in a maize rot-causing pathogen, Fusarium verticillioides. This work revealed that in vitro cultures produce structured, adherent communities with a dense extracellular matrix (ECM) surrounding hyphae that makes up the biomass of a matured biofilm. Pellicle containing exopolysaccharide had a hydrodynamic diameter of 4.19 nm and a low viscosity (0.022 dl/g). The exopolysaccharide was composed of amino sugars and unordered, facilitating stability through complexation with the anionic eDNA. Biofilm formation varied over different pH and temperature values, emphasising its role in promoting adaption, survival, and persistence in F. verticillioides, potentially contributing to its pathogenicity in maize. Collectively, the results provide valuable insights into biofilm structure and stress resistance in this fungus, and will serve as a foundation for future studies incorporating in planta infection systems.