Phospholipids and Fatty Acids Affect the Colonization of Urological Catheters by Proteus mirabilis

Proteus mirabilis-mediated CAUTIs are usually initiated by the adherence of bacteria to a urinary catheter surface. In this paper, three isolates of different origin and exhibiting different adhesion abilities were investigated in search of any changes in lipidome components which might contribute to P. mirabilis adhesion to catheters. Using GC-MS and LC-MS/MS techniques, 21 fatty acids and 27 phospholipids were identified in the examined cells. The comparison of the profiles of phospholipids and fatty acids obtained for catheter-attached cells and planktonic cells of the pathogens indicated C11:0 and PE 37:2 levels as values which could be related to P. mirabilis adhesion to a catheter, as well as cis C16:1, PE 32:0, PE 33:0, PE 38:2, PG 33:1, PG 34:0, PE 30:1, PE 32:1 and PG 30:2 levels as values which could be associated with cell hydrophobicity. Based on DiBAC4 (3) fluorescence intensity and an affinity to p-xylene, it was found that the inner membrane depolarization, as well as strong cell-surface hydrophobicity, were important for P. mirabilis adhesion to a silicone catheter. A generalized polarization of Laurdan showed lower values for P. mirabilis cells attached to the catheter surface than for planktonic cells, suggesting lower packing density of membrane components of the adherent cells compared with tightly packed, stiffened membranes of the planktonic cells. Taken together, these data indicate that high surface hydrophobicity, fluidization and depolarization of P. mirabilis cell membranes enable colonization of a silicone urinary catheter surface.

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 devices, the catheter surface can be colonized by mi-croorganisms 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: 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 surface with 2 mg mL-1 of DMPEI solubilized in butanol, dime-thylformamide, and cyclohexanone and were analyzed visually. Contact angle measurement allowed the analysis of the wettability of the surfaces. The CFU mL-1 counting 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 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 in the outer and inner surfaces showing a potential antimicrobial with high anti-biofilm activity for medical devices.

Prevention of urinary infection through the incorporation of silver–ricinoleic acid–polystyrene nanoparticles on the catheter surface

Nosocominal infections associated with biofilm formation on urinary catheters cause serious complications. The aim of this study was to investigate the feasibility of the polyurethane (PU) catheter modified with tetracycline hydrochloride (TCH) attached Ag nanoparticles embedded PolyRicinoleic acid-Polystyrene Nanoparticles (PU-TCH-AgNPs-PRici-PS NPs) and the influence on antimicrobial and antibiofilm activity of urinary catheters infected by Escherichia coli and Staphylococcus aureus. For this purpose, AgNPs embedded PRici graft PS graft copolymers (AgNPs-PRici-g-PS) were synthesized via free radical polymerization and characterized by FTIR, HNMR and DSC. AgNPs-PRici-PS NPs were prepared and optimized by the different parameters and the optimized size of nanoparticle was found as about 150 ± 1 nm. The characterization of the nanoparticles and the morphological evaluation were carried out by FTIR and SEM. Short term stability of nanoparticles was realised at 4°C for 30 days. In vitro release profiles of TCH and Ag NPs were also investigated. The formation of biofilm on PU modified TCH-Ag NPs-PRici-PS NPs, was evaluated and the biocompatibility test of the nanoparticles was realized via the mouse fibroblast (L929) and mouse urinary bladder cells (G/G An1). This is the first time that TCH-AgNPs-PRici-PS NPs used in the modification of PU catheter demonstrated high antimicrobial and antibiofilm activities against the urinary tract infection.

Evaluation of the antithrombogenicity of poly-2-methoxyethylacrylate-coated catheters

Background and objectives: The blood compatibility of indwelling intravascular catheters is facilitated by the use of antithrombogenic materials. Heparin has typically been used for this purpose; however, since heparin-coated catheters are considered combination products, difficulties meeting the relevant Food and Drug Administration safety recommendations have disrupted commercialization. Other issues include coating durability and the occurrence of heparin-induced thrombocytopenia. Polymer coatings are a potential alternative; however, polymer antithrombogenicity in circulating human blood has yet to be demonstrated. The present study aimed to establish the ex vivo antithrombogenicity of a poly-2-methoxyethylacrylate (PMEA) polymer coating applied to a central venous catheter using an artificial human blood circulation system. Methods: The present study used an artificial human blood circulation system to conduct an ex vivo evaluation of the antithrombogenicity of poly-2-methoxyethylacrylate (PMEA)-coated catheters. Human blood samples obtained from volunteer donors were loaded into a circulation system fitted with either a PMEA-coated or uncoated catheter. After 3-h, the catheter was removed and examined using scanning electron microscopy. Protein adsorption on the catheter surface was investigated by shredding the catheter that had contacted the blood inside the circulation system and immersing the pieces in 1 mL of 0.5 N NaOH for 2 days. The amount of protein in the 0.5 N NaOH was determined according to the Lowry method. Results: Adherent fibrin, which forms a sheath on the catheter surface, was observed on uncoated, but not PMEA-coated catheters. Furthermore, the amount of protein adsorption was significantly less with PMEA-coated than uncoated catheters ( p = 0.043). Conclusions: The present findings demonstrated the antithrombogenicity of PMEA-coated catheters in circulating human blood.

Anti-biofilm Fe3O4@C18-[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate Derivative Core-shell Nanocoatings

The derivatives 5,7-dimethyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (1) and 7-methyl-5-phenyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (2) were fully characterized by single-crystal X-ray diffraction. Their supramolecular structure is built through both π–π stacking and C=S–π interactions for both compounds. The embedment of the tested compounds into Fe3O4@C18 core-shell nanocoatings increased the protection degree against Candida albicans biofilms on the catheter surface, suggesting that these bioactive nanocoatings could be further developed as non-cytotoxic strategies for fighting biofilm-associated fungal infections.

A comparative study of the identification frequency and composition of bacteria isolated from catheter and urine in urologic patients: A single-center descriptive study

This study aimed to compare the identification frequency and composition of bacteria isolated from catheter and urine in urologic patients. Methods: Ninety patients with urethral catheters were involved in the study. Urinary and catheter cultures were taken simultaneously from each patient and cultured on MacConkey's agar. Urine culture and sensitivity were performed for all samples in pre- and postoperative periods. Swab culture and sensitivity from the surface of intraluminal urethral catheters were performed for all cases in the post-operative period. Results: The median indwelling period of the catheters was 8 days (range 3 to 21). The overall positive rate of catheter culture was significantly greater than that of urine culture, even in subjects without a recent antibacterial agent history. Urine cultures and catheter cultures did not match each other completely. The percentage of patients who had the same bacterial species isolated from both specimens increased in a time-dependent manner. Conclusions: Not all species of bacteria colonizing the intraluminal surface of the urethral catheter were detected as urinary bacteria. Bacterial colonization on the intraluminal catheter surface could precede the emergence of bacteriuria.

The Efficacy of Umbelliferone, Arbutin, and N-Acetylcysteine to Prevent Microbial Colonization and Biofilm Development on Urinary Catheter Surface: Results from a Preliminary Study

We evaluated, in a preliminary study, the efficacy of umbelliferone, arbutin, and N-acetylcysteine to inhibit biofilm formation on urinary catheter. We used 20 urinary catheters: 5 catheters were incubated withEnterococcus faecalis(control group); 5 catheters were incubated withE. faecalisin presence of umbelliferone (150 mg), arbutin (60 mg), and N-acetylcysteine (150 mg) (group 1); 5 catheters were incubated withE. faecalisin presence of umbelliferone (150 mg), arbutin (60 mg), and N-acetylcysteine (400 mg) (group 2); and 5 catheters were incubated withE. faecalisin presence of umbelliferone (300 mg), arbutin (60 mg), and N-acetylcysteine (150 mg) (group 3). After 72 hours, planktonic microbial growth and microorganisms on catheter surface were assessed. In the control group, we found a planktonic load of ≥105 CFU/mL in the inoculation medium and retrieved 3.69 × 106 CFU/cm from the sessile cells adherent to the catheter surface. A significantly lower amount in planktonic (p<0.001) and sessile (p=0.004) bacterial load was found in group 3, showing <100 CFU/mL and 0.12 × 106 CFU/cm in the incubation medium and on the catheter surface, respectively. In groups 1 and 2, 1.67 × 106 CFU/cm and 1.77 × 106 CFU/cm were found on catheter surface. Our results document that umbelliferone, arbutin, and N-acetylcysteine are able to reduceE. faecalisbiofilm development on the surface of urinary catheters.