Effect of DMPEI coating against biofilm formation on PVC catheter surface.

Urinary tract infections (UTIs) are a significant cause of morbidity in healthcare systems and are prominently associated with applying urethral catheters, particularly in surgeries. Polyvinyl chloride (PVC) is extensively utilized in the fabrication of catheters. Biofilms, complex polymeric constructions, provide a protective milieu for cell multiplication and the enhancement of antibiotic resistance. Strategies to counteract biofilm development on medical apparatuses' surfaces incorporate antimicrobial agents such as N,N-dodecyl, and methyl polyethylenimine (DMPEI). This research endeavored to characterize the morphology of PVC and PVC-DMPEI surfaces utilizing Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) and to gauge hydrophobicity through contact angle measurements. Employing Escherichia coli, Staphylococcus aureus, and Candida albicans in adhesion assays enabled the assessment of DMPEI's efficacy in preventing microbial adherence to PVC. Butanol successfully solubilized 2 mg.mL-1 DMPEI without altering the PVC structure. SEM results substantiated the formation of a DMPEI layer on the PVC surface, which led to decreased surface roughness, as validated by AFM, and increased hydrophilicity, as demonstrated by contact angle evaluations. E. coli, S. aureus, and C. albicans exhibited significant adhesion reduction, 89.3%, 94.3%, and 86.6% on PVC-DMPEI surfaces. SEM visualizations confirmed reduced cellular colonization on PVC-DMPEI and highlighted considerable morphological modifications in E. coli. Consequently, DMPEI films effectively minimize the adhesion of E. coli, S. aureus, and C. albicans on PVC surfaces. DMPEI, with its potential as a protective coating for innovative medical devices, promises to inhibit biofilm adherence effectively.

Impact of DMPEI on Biofilm Adhesion on Latex Urinary Catheter.

BACKGROUND: Microorganisms can migrate from the external environment to the patient's organism through the insertion of catheters. Despite being indispensable medical device, the catheter surface can be colonized by microorganisms and become a starting point for biofilm formation. Therefore, new technologies are being developed in order to modify surfaces to prevent the adhesion and survival of microorganisms. Patents with the use of DMPEI have been filed. OBJECTIVE: In the present work, we coated latex catheter surfaces with 2 mg mL-1 DMPEI in different solvents, evaluated the wettability of the surface and the anti- biofilm activity of the coated catheter against Escherichia coli, Staphylococcus aureus, and Candida albicans. METHODS: We coated the inner and outer catheter surfaces with 2 mg mL-1 of DMPEI solubilized in butanol, dimethylformamide, and cyclohexanone and the surfaces were analyzed visually. Contact angle measurement allowed the analysis of the wettability of the surfaces. The CFU mL-1 count evaluated E. coli, S. aureus, and C. albicans adhesion onto the control and treated surfaces. RESULTS: The contact angle decreased from 50.48º to 46.93º on the inner surface and from 55.83º to 50.91º on the outer surface of latex catheters coated with DMPEI. The catheter coated with DMPEI showed anti-biofilm activity of 83%, 88%, and 93% on the inner surface and 100%, 92%, and 86% on the outer surface for E. coli, S. aureus, and C. albicans, respectively. CONCLUSION: Latex catheter coated with DMPEI efficiently impaired the biofilm formation both on the outer and inner surfaces, showing a potential antimicrobial activity along with a high anti-biofilm activity for medical devices.

Cocoa Pulp as Alternative Food Matrix for Probiotic Delivery.

BACKGROUND: For screening probiotic strains with viability and stability in non-dairy foods for health benefits, we revised all patents relating to probiotics in food. OBJECTIVE: Screening of potential probiotics from Brazilian Minas artisanal cheese and verify their survival in frozen Brazilian cocoa pulp. METHODS: Isolation and identification of the strains. The potential probiotic characterization involved gastric juice and bile resistance, antibiotic and antimicrobial activity, hydrophobicity, autoaggregation, coaggregation and adhesion assay in HT-29 cells. Organoleptic, viability and stability of probiotic strain in frozen cocoa pulp were evaluated. RESULTS: Fourteen strains of Lactobacillus plantarum (9), Weissella paramesenteroides (3), Lactobacillus fermentum (1), and Leuconostoc mesenteroides (1) were obtained. Most of the strains were resistant to simulated gastric acidity and bile salts. Almost all strains were sensitive to the antibiotics tested, except to ciprofloxacin and vancomycin. About 47% of the strains are potential producers of bacteriocins. High hydrophobicity was observed for four strains. Autoaggregation ranged from 8.3-72.6% and the coaggregation capacity from 5.2-60.2%. All of the assessed strains presented more than 90% of adhesion to HT-29 intestinal cells. The percentage of Salmonella inhibition in HT-29 cells ranged from 4.7-31.1%. No changes in color, aroma, and pH were observed in cocoa pulps after storage at -20 °C for 90 days. CONCLUSION: Wild strains of acid lactic bacteria from cheese proved to be viable and stable in frozen Brazilian cocoa pulp. This work showed a promising application of L. plantarum isolated strains to be used with frozen cocoa pulp matrix in probiotics food industry.

Expression and Biochemical Characterization of a Yersinia intermedia Phytase Expressed in Escherichia coli.

BACKGROUND: Phytases are enzymes capable of degrading phytic acid and used in animal feed supplementation in order to improve digestibility through the release of minerals such as phosphorus. OBJECTIVE: The main goal of this study was to express and characterize a Yersinia intermedia phytase expressed in Escherichia coli cells. METHODS: The Y. intermedia phytase gene was synthesized and overexpressed in Escherichia coli cells. The phytase recombinante (rPHY) was purified to homogeneity using a Ni-NTA column. The biochemical and biophysical properties of the rPHY were measured in order to fully characterize the recombinant enzyme. The following patents database were consulted: Espacenet, USPTO, LATIPAT, Patent Scope, WIPO and Google Patents. RESULTS: The results showed that the rPHY is active at 37-40ºC and presented an optimal pH and temperature of 8.0 and 40°C, respectively. The phytase rPHY was activated by Cu2+ ion and showed resistance to trypsin and pepsin, retaining 55% of the activity at the ratio of 0.02. Furthermore, the dissociation constant (Kd = 1.1150 ± 0.0087 mM), as estimated by a fluorescence binding assay, suggests a medium affinity of the enzyme with the substrate. CONCLUSION: The results of this article can be considered as innovative and for this reason, they were protected by Intellectual Property Law in Brazil. Take together, the biochemical properties of the rPHY could be useful in future for its industrial application of this enzyme as an additive in the monogastric feed.

Primary Structure of a Trypsin Inhibitor (Copaifera langsdorffii Trypsin Inhibitor-1) Obtained from C. langsdorffii Seeds.

In this study, the aim was to determine the complete sequence of the Copaifera langsdorffii trypsin inhibitor (CTI)-1 using 2-dimensional (2D)-PAGE, matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF), and quadrupole time-of-flight (QTOF) spectrometry. Spots A (CTI-1) and F (CTI-2) were submitted to enzymatic digestions with trypsin, SV8, and clostripain. The accurate mass of the peptide obtained from each digest was determined by mass spectrometry (MS) using MALDI-TOF. The most abundant peptides were purified and sequenced in a liquid chromatograph connected to an electrospray ionization-QTOF MS. When the purified trypsin inhibitor was submitted to 2D electrophoresis, different spots were observed, suggesting that the protein is composed of 2 subunits with microheterogeneity. Isoelectric points of 8.0, 8.5, and 9.0 were determined for the 11 kDa subunit and of 4.7, 4.6, and 4.3 for the 9 kDa subunit. The primary structure of CTI-1, determined from the mass of the peptide of the enzymatic digestions and the sequence obtained by MS, indicated 180 shared amino acid residues and a high degree of similarity with other Kunitz (KTI)-type inhibitors. The peptide also contained an Arg residue at the reactive site position. Its 3-dimensional structure revealed that this is because the structural discrepancies do not affect the canonical conformation of the reactive loop of the peptide. Results demonstrate that a detailed investigation of the structural particularities of CTI-1 could provide a better understanding of the mechanism of action of these proteins, as well as clarify its biologic function in the seeds. CTI-1 belongs to the KTI family and is composed of 2 polypeptide chains and only 1 disulfide bridge.