Biofouling最新文献

Candida and Staphylococcus species are responsible for hospital-acquired infections, forming resilient biofilms. This study evaluated the impact of biocides on the biofilm matrix components of Candida parapsilosis and Staphylococcus aureus in monospecies and mixed biofilms. Proteins, carbohydrates, and extracellular DNA (eDNA) were quantified using the Bradford reagent, phenol-sulfuric acid, and silica column extraction with spectrophotometric readings at 260 and 280 nm. Biofilms were treated with 0.5% chlorhexidine (CLX) and 0.55% ortho-phthalaldehyde (OPA) for 3 and 10 min, respectively. Results showed a significant protein increase (8.6 ± 4.94 µg/mL for C. parapsilosis and 17.25 ± 1.86 µg/mL for S. aureus) after CLX and OPA exposure, especially in isolates 935 M, 936 C, and S. aureus biofilms (p < 0.01). Carbohydrates significantly decreased (p < 0.0001), with CLX generally more effective than OPA. eDNA levels increased across all samples. These findings suggest that CLX and OPA alter biofilm matrix composition, facilitating antimicrobial efficacy.

This study aimed to investigate the antibiofilm activity of Aleppo pine essential oil (APEO); hydrolytic enzyme mixtures or their combination in two sequential washing steps against C. sakazakii on plastic and stainless steel surfaces. The minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of APEO against C. sakazakii strains were 500-1,000 µg/ml, and 1,000-4,000 µg/ml, respectively. Further, APEO showed antibiofilm activity where 4 × MIC APEO at 25 °C for 30 min reduced C. sakazakii cells by 1.8 and 1.6 log CFU/coupon on plastic and stainless steel, respectively. Similarly, both enzyme mixtures reduced the C. sakazakii cells attached to both surfaces by 1.7-2.2 log CFU/coupon. However, the two-step sequential cleaning regime with enzyme mixture of 10% protease, 5% α-amylase, and 1% lipase at 50 °C for 30 min followed by 4 × MIC APEO for 30 min reduced C. sakazakii biofilm on both surfaces by 4.4-4.5 log CFU/coupon compared to the control.

This study evaluated the antibiofilm activity of caffeine against Listeria monocytogenes and Escherichia coli within grape and apple juice matrices. Caffeine, a purine alkaloid recognized for its antimicrobial properties, was tested at the minimum inhibitory concentration (MIC) against planktonic and sessile cells. MIC values were established at 9.37 mM for E. coli and 37.5 mM for L. monocytogenes. Biofilm formation was evaluated through crystal violet staining, both when bacterial cells were exposed to caffeine during the initial stages of biofilm development (co-treatment) and after the biofilm had been established (post-treatment). The extracellular polymeric substances (EPS) produced within the biofilms were quantitatively measured. Bacterial viability was assessed by time-kill kinetics assays and further visualized by scanning electron microscopy (SEM). Caffeine treatment significantly inhibited biofilm formation by 98.1% for E. coli and 98.7% for L. monocytogenes, and by 98.8 and 99.0%, in co-treatment and post-treatment, respectively. No consistent correlation was observed between EPS quantity and biofilm inhibition. SEM analysis confirmed caffeine-induced structural disruption of the biofilm matrix and damage to bacterial cell integrity. This investigation introduces a novel application of caffeine as an anti-biofilm agent in unpreserved fruit juice systems and demonstrates, for the first time, its efficacy against foodborne pathogens.

The isolation of non-aureus Staphylococcus (NAS) from the milk of both healthy cows and cows with mastitis has been frequently reported. However, there are few in-depth studies regarding their virulence profile and the ability of these microorganisms to form biofilms. Therefore, this research aimed to evaluate the biofilm formation capacity of NAS isolates from Brazilian milk. In this work, 309 NAS isolates were subjected to the Congo Red Agar (CRA) phenotypic test. Next, genotypic characterization was carried out by screening the bap, icaA, icaD, and MSCRAMMs genes: bbp, cna, ebps, eno, fib, fnbA, fnbB, clfA and clfB. Finally, ten isolates that presented the highest frequency of the genes analysed were selected to evaluate their ability to form biofilm on stainless-steel discs. t The number of cells (log10 CFU/cm²) in the biofilms was assessed at three time periods (24 h, 48 h, and 72 h) at a temperature of 25 °C. 35 NAS (11.32%) produced biofilms in the CRA test. Genotypic analysis showed the eno (38.5%) and bap (27.5%) genes were the most prevalent. In the analysis of biofilm formation on stainless steel, the factor 'growth time' had no significant effect on cell numbers. All selected isolates formed biofilm on stainless steel, and cell numbers were estimated to be in the 5.94 to 9.10 log10 CFU/m² range. These results provide evidence that NAS isolated from milk may represent a risk to human and animal health since they carry several virulence genes and demonstrate the ability to form biofilms.

Candida species and Staphylococcus aureus coexist in nosocomial infections. These interkingdom interactions are associated with oral biofilm formation, leading to various oral diseases. This study elucidated the interkingdom interactions of these microorganisms, particularly their aggregation and biofilm formation, in three different media. Candida auris, Candida albicans, Candida lusitaniae, Candida dubliniensis, Candida parapsilosis, Candida glabrata and S. aureus were used in this study. Aggregation assays were conducted to determine planktonic interaction, and biofilm assays were performed to investigate intra- and interkingdom interactions in a static biofilm environment. Most Candida spp. exhibited a high auto-aggregation percentage in brain heart infusion broth supplemented with yeast extract (BHIYE). In addition, co-culture biofilm with S. aureus significantly reduced the total cell counts of Candida spp. compared to mono-culture (p < 0.05). In conclusion, co-aggregation, biofilm biomass and total cell count were species- and growth medium-dependent, and S. aureus interacted antagonistically with Candida spp.

Cyanobacteria biomass sources have the potential to contribute to the replacement of fossil fuels and to the reduction in global warming by sustainable conversion of atmospheric CO₂ into biofuels and high-value chemicals. Cyanobacteria cultivation in photobioreactors (PBRs) results in biofouling on their transparent inner walls, which reduces photosynthetic efficiency and productivity. While cyanobacteria biofouling in PBRs is recognized as a significant operating challenge, this review draws attention to the lack of studies on antifouling strategies for PBRs involving cyanobacteria and discusses several areas related to cyanobacteria fouling mechanisms on PBR materials, which require further investigation. These include an in-depth analysis of conditioning films, the role of pili and EPS in gliding and adhesion, potential revisions to existing theoretical models for predicting adhesion, and material properties that affect cyanobacteria adhesion. We use knowledge from marine, medical, and industrial biofouling management to help identify strategies to combat cyanobacteria fouling in PBRs, and we review the applicability of various bioinspired physical and chemical strategies, as well as genetic engineering approaches to prevent cyanobacteria biofilm formation in PBRs.

The aim of this study was to analyse how the properties of reference-resistant bacterial strains and textiles affect the transmission of bacteria, the antibacterial potential of detergents and disinfectants and how this can be implemented in low-temperature washing. Bacterial cells were characterised by a hydrophobicity test, and textiles were characterised by roughness and surface energy. Transmission and suspension tests were then carried out, followed by an evaluation of the wash. The results show that cotton has the highest roughness, polyester is the most hydrophobic and MRSA (methicillin-resistant Staphylococcus aureus) is the most hydrophobic bacterium. It was observed that resistant bacteria can be transmitted to a considerable extent via household textiles. The suspension test showed that the 0.5% European Colourfastness Establishment (ECE) reference detergent did not achieve a sufficient reduction (>5 log colony forming units - CFU) for any of the strains tested, whereas the addition of 3% hydrogen peroxide or 4% quaternary ammonium silicone compound did so for all of them. Washing at 60 °C reduced the textile contamination sufficiently (>4 log CFU) for all strains tested, while the criteria for cross-contamination and wash water were not met (<1.1 CFU/mL). However, the addition of disinfectants to the detergent at 30 °C met all hygiene requirements with the complete elimination of all tested bacteria on all textiles. Washing home textiles contaminated with resistant bacteria at low temperatures was only possible if a disinfectant was added. Otherwise, textiles can be an important vehicle for the transmission of resistant bacteria in domestic facilities.

Burkholderia pseudomallei biofilms are resistant to antibiotics and immune responses, leading to persistent infections. This study aimed to investigate the metabolic profiles of B. pseudomallei in biofilms and the extracellular polymeric substances (EPS) produced during grown in LB or MVBM medium using Nuclear Magnetic Resonance (NMR) spectroscopy to identify key metabolites. The results revealed similar biofilm metabolites in both media. However, betaine was detected in LB, but not in the case of MVBM. Acetate was significantly higher in MVBM compared to that of LB. Pathway analysis revealed that betaine-producing B. pseudomallei biofilm in LB was associated with metabolism of glycine, serine, and threonine, while acetate in MVBM was associated with metabolism of taurine and hypotaurine, phosphonate and phosphinate, and glycolysis/gluconeogenesis. The NMR analysis of EPS disclosed shared metabolites including dimethylsulfide, 1-methyluric acid and oxypurinol. This study provides the first extensive investigation into B. pseudomallei biofilm and EPS metabolites, identifying pathways that offer potential targets for combating B. pseudomallei biofilm-associated infections.

Pseudomonas aeruginosa is an opportunistic pathogen able to form biofilms, contributing to its virulence. With the increasing use of sweeteners in various foods, understanding their influence on bacterial behavior is critical. This study investigated the virulence of P. aeruginosa PAO1 exposed to sweeteners (erythritol, stevia, fructose, coconut sugar, cane sugar, demerara). Sweeteners didn't affect growth rates. Erythritol stimulated biofilm (100 µg/mL, 159.98% formation), while 10 µg/mL of coconut sugar, cane sugar, and demerara promoted lower levels (∼70% formation). Erythritol stimulated exopolysaccharides production but reduced biofilm eDNA. Stevia, fructose, and coconut sugar increased the expression of lasI, lasR, rhlI, rhlR, pqsA, mvfR, and pvdF. HPLC analysis confirmed sucrose as the major sugar in demerara, coconut and cane sugar. Erythritol stimulated biofilm and some virulence genes expression, while other sweeteners' effects varied. Cane sugar was a biofilm inhibitor with a limited gene expression effect. The sweeteners' impact on microorganisms is diverse and should be further investigated.

Strategies focusing on natural compounds and nanotechnology have been explored to overcome the limitations of conventional therapies in managing Candida infections. In this context, metal nanoparticles, both non-functionalised and combined with gallic acid, may offer a promising alternative. This study investigated the effects of gold nanoparticles non-functionalised (AuNp) and associated with gallic acid (AuNpGA) against planktonic cells and biofilms of Nakaseomyces glabratus, Pichia kudriavzevii, Candida parapsilosis, and Candida tropicalis. Both AuNp and AuNpGA inhibited the growth of all strains at 1.56 µg/mL and exhibited fungicidal effects at concentrations ranging from 1.56 to 3.12 µg/mL. The time-kill curve revealed that AuNpGA and AuNp completely inhibited the viability of all strains in planktonic cultures at 8 and 24 h, respectively, exhibiting greater antifungal activity compared to fluconazole. Treatment with AuNp increased ROS production against N. glabratus and P. kudriavzevii. Oxidative stress was enhanced against all strains after treatment with AuNpGA, and exposure to this compound reduced ergosterol levels of P. kudriavzevii and C. parapsilosis. Furthermore, AuNpGA and AuNp significantly decreased the viability of all Candida biofilms at 7.8 and 15.6 µg/mL, respectively. In summary, both gold nanoparticles exhibited activity against planktonic cells and biofilms, suggesting their potential as agents for treating Candida infections.