Biofouling最新文献

To reveal the responsible microorganisms of microbiologically-influenced-corrosion (MIC), using 16S rRNA and ITS sequencing techniques, we investigated the bacterial and fungal communities in rust layer and seawater. Results show that the corrosion-related genera of Erythrobacter, norank_f__Rhodothermaceae, and Acinetobacter bacteria, as well as Aspergillus fungi, were overrepresented in the rust layer, along with the Pseudoalteromonas and Marinobacterium bacteria in seawater, and Ramlibacter, Aquimarina, and Williamsia bacteria were first detected in the rust layer. SourceTracker analysis revealed that approximately 23.08% of bacteria and 21.48% of fungi originated from seawater. Stochastic processes governed the rust layer and seawater microbial communities, and network analysis showed coexistence and interaction among bacterial and fungal communities. These results indicate that the composition of microbial communities in the rust layer was influenced by the marine environmental microbial communities, which can provide basic data support for the control of MIC in marine-related projects.

The traditional medicinal value of Curcuma longa (turmeric) and its potential relevance in modern healthcare suggests that traditional remedies and natural products can provide valuable solutions to contemporary challenges, such as combating biofilms and antibiotic-resistant pathogens, potentially offering new strategies for addressing health and safety issues in the fields of food and medicine. This study assessed the antibiofilm and antibacterial characterization of Curcuma longa rhizome extract against antibiotic-resistant foodborne pathogens. Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier-transform infrared (FTIR) analysis were determined to check for the compounds, functional groups, and constituents of the plant extract. In-vitro antibiofilm and antibacterial bioassay of the extract were determined using standard bacteriological procedures. Potential mechanisms of the plant extract were also studied using standard biological methods. The important chemical constituents from the GC-MS extract of C. longa are arturmerone, cinnamyl angelate, tumerone, γ-atlantone, atlantone, α-atlantone, γ-atlantone and curlone. The FTIR analysis of the extract comprises alkyl halides, bromoalkanes, alkanes, ethylene molecules, arenes, amines, alcohols, sulfones, carboxylic acids and their derivatives, aromatic compounds, and phenols. The MIC of C. longa crude extract ranges from ethanol extract (0.03125 - 0.5 mg/mL) and acetone extract (0.0625 - 0.5 mg/mL). The MBC range is as follows: ethanol extract (0.125 - 1 mg/mL), acetone extract (0.125 - 1 mg/mL). The time-kill kinetics showed significant cell reduction with time. The bacterial isolates' nucleic acids and protein leakage were consistent with increased extract concentration and time. There was a reduction in the biofilm cell on the shrimp surface and EPS with increased concentration and time. C. longa exerted significant anti-biofilm activity by removing existing biofilms, disrupting cell connections, and decreasing cells in biofilms. These findings can aid food protection from microbial contamination and prevent biofilms-related infections.

Both Candida albicans and Issatchenkia orientalis have been isolated from different types of infections over the years. They have the ability to form communities of microorganisms known as biofilms. It has been demonstrated that the medium employed in studies may affect the biofilm development. The aim of this study was to investigate the arrangement of dual-species biofilms of C. albicans and I. orientalis cultivated on either RPMI-1640 or Sabouraud Dextrose Broth (SDB), as well as the inhibitory effect of Voriconazole (VRC). For the experiments performed, ATCC strains were used, and yeast-mixed suspensions were inoculated in 96-well plates with either RPMI-1640 or SDB, in the presence or absence of VRC. The results were observed by counting the number of CFU obtained from scraping off the biofilms produced and plating the content on CHROMagar Candida medium. It was observed that for all conditions tested the medium chosen affected the arrangement of dual-species biofilms: when RPMI-1640 was used, there was a prevalence of C. albicans, while the opposite was noted when SDB was used. It could be suggested that the medium and environment could regulate interactions between both yeast species, including the response to different antifungal drugs.

Reactive chlorine species (RCS) like sodium hypochlorite (NaOCl) are potent oxidizing agents and widely used biocides in surface disinfection, water treatment, and biofilm elimination. Moreover, RCS are also produced by the human immune system to kill invading pathogens. However, bacteria have developed mechanisms to survive the damage caused by RCS. Using the comprehensive Pseudomonas aeruginosa PA14 transposon mutant library in a genetic screen, we identified a total of 28 P. aeruginosa PA14 mutants whose biofilms showed increased susceptibility to NaOCl in comparison to PA14 WT biofilms. Of these, ten PA14 mutants with a disrupted apaH, PA0793, acsA, PA1506, PA1547, PA3728, yajC, queA, PA3869, or PA14_32840 gene presented a 4-fold increase in NaOCl susceptibility compared to wild-type biofilms. While none of these mutants showed a defect in biofilm formation or attenuated susceptibility of biofilms toward the oxidant hydrogen peroxide (H₂O₂), all but PA14_32840 also exhibited a 2-4-fold increase in susceptibility toward the antibiotic ciprofloxacin. Further analyses revealed attenuated levels of intracellular ROS and catalase activity only for the apaH and PA1547 mutant, providing insights into the oxidative stress response in P. aeruginosa biofilms. The findings of this paper highlight the complexity of biofilm resistance and the intricate interplay between different mechanisms to survive oxidative stress. Understanding resistance strategies adopted by biofilms is crucial for developing more effective ways to fight resistant bacteria, ultimately contributing to better management of bacterial growth and resistance in clinical and environmental settings.

Candida albicans invasive candidiasis is considered a global health problem. In such cases, biofilm formation on implanted devices represents a therapeutic challenge and the presence of metabolically inactive persistent cells (PCs) in these communities increases their tolerance to fungicidal drugs. This study investigated the influence of amoxicillin, AMX; cefepime, CEF; gentamicin, GEN; amikacin, AMK; vancomycin, VAN; and ciprofloxacin, CIP; on the production of PCs in biofilms of C. albicans bloodstream isolates. 48 h-mature biofilms (n = 6) grown in RPMI-1640 supplemented with antibiotics were treated with 100 μg ml^-1 amphotericin B and then evaluated for PCs. Biofilms grown in the presence of antibiotics produced more PCs, up to 10×, when exposed to AMX and CIP; 5 × to CEF; and 6 × to GEN and VAN. The results indicate that antibiotics can modulate PC production in C. albicans biofilms. This scenario may have clinical repercussions in immunocompromised patients under broad-spectrum antibiotic therapy.

Although Streptococcus pyogenes and Candida albicans may colonize tonsillar tissues, the interaction between them in mixed biofilms has been poorly explored. This study established an interkingdom biofilm model of S. pyogenes and C. albicans and verified the dose-response validation of antimicrobials. Biofilms were formed on microplates, in the presence or absence of a conditioning layer of human saliva, using Brain Heart Infusion (BHI) broth or artificial saliva (AS) as a culture medium, and with variations in the microorganism inoculation sequence. Biofilms grown in AS showed higher mass than those grown in BHI broth, and an opposite trend was observed for metabolism. The number of S. pyogenes colonies was lower in AS. Amoxicillin and nystatin showed dose-dependent effects. The inoculation of the two species at the same time, without prior exposure to saliva, and using BHI broth would be the model of choice for future studies assessing the effects of antimicrobials on dual S. pyogenes/C. albicans biofilms.

This case study aimed to isolate and identify methanogenic bacteria from landfill soil, mud, and leachate samples to assess their role in anaerobic digestion and biogas production. Anaerobic digestion involves the breakdown of organic matter by a diverse group of bacteria under oxygen-free conditions, resulting in the production of methane and carbon dioxide. The collected samples from the landfill were cultured in a modified mineral salt medium (MSM). Microscopic observations revealed distinct coccus and bacillus morphologies of the isolated methanogenic bacteria. Gas production experiments and substrate utilization studies identified two types of methanogens. Methanosarcina sp., which utilized acetate and methanol for methane production, and Methanobacterium sp., utilizing hydrogen and carbon dioxide, as well as acetate. Scanning electron microscope (SEM) analysis confirmed the different morphotypes of the isolated methanogens. The study findings demonstrated the presence of diverse methanogens in the landfill environment, contributing to anaerobic digestion and biogas production.

To improve the durability of the photobioreactor antibiofouling surface for microalgal cultivation, a series of photoreactive poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) were successfully synthesized and used to modify ethylene-vinyl acetate (EVA) films by a surface coating and UV light grafting method. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy analysis (XPS) and fluorescence microscopy results indicated that PTFEMA were fixed successfully onto the EVA film surface through a covalent bond. During the microalgal adhesion assay, the number of EVA-PTFEMA film-adhered microalgae was 41.4% lower than that of the EVA film. Moreover, the number of microalgae attached to the EVA-PTFEMA film decreased by 61.7% after cleaning, while that of EVA film decreased by only 49.1%. It was found that the contact angle of EVA-PTFEMA film surface increased, and remained stable when immersed in acid and alkali solution for up to 90 days.HIGHLIGHTSDurable photobioreactor antibiofouling surfaces for microalgal cultivation were prepared successfully.The contact angle of antibiofouling coating surface remained stable in acid and base environment for 90 days.The attached microalgae on antibiofouling surface decreased 41.4% than those of unmodified surface.The attached microalgae on antibiofouling surface could be cleaned by 61.7% through changing the flow velocity of microalgal suspension.

Candida auris is a multidrug-resistant yeast that has seen a worrying increase during the COVID-19 pandemic. Give7/n this, new therapeutic options, such as controlled-release nanomaterials, may be promising in combating the infection. Therefore, this study aimed to develop amphotericin B (AmB) and micafungin (MICA)-loaded nanoemulsions (NEMA) and evaluated against biofilms of C. auris. Nanoemulsions (NEs) were characterized and determined minimum inhibitory concentration MIC₉₀, checkerboard and anti-biofilm. NEMA presented a size of 53.7 and 81.4 nm for DLS and NTA, respectively, with good stability and spherical morphology. MICAmB incorporated efficiency was 88.4 and 99.3%, respectively. The release results show that AmB and MICA obtained a release of 100 and 63.4%, respectively. MICAmB and NEMA showed MIC90 values of 0.015 and 0.031 ug/mL, respectively and synergism. NEMA showed greater metabolic inhibition and morphological changes in mature biofilms. This drugs combination and co-encapsulation proved to be a promising therapy against C. auris biofilms.