Reduced Crystalline Biofilm Formation on Superhydrophobic Silicone Urinary Catheter Materials.

Crystalline biofilm formation in indwelling urinary catheters is a serious health problem as it creates a barrier for antibacterial coatings. This emphasizes the failure of antibacterial coatings that do not have a mechanism to reduce crystal deposition on catheter surfaces. In this study, trifluoropropyl spray-coated polydimethylsiloxane (TFP-PDMS) has been employed as an antibiofilm forming surface without any antibacterial agent. Here, TFP was coated on half-cured PDMS using the spray coating technique to obtain a durable superhydrophobic coating for a minimum five cycles of different sterilization methods. The crystalline biofilm-forming ability of Proteus mirabilis in artificial urine, under static and flow conditions, was assessed on a TFP-PDMS surface. In comparison to the commercially available silver-coated latex and silicone catheter surfaces, TFP-PDMS displayed reduced bacterial attachment over 14 days. Moreover, the elemental analysis determined by atomic absorption spectroscopy and energy-dispersive X-ray analysis revealed that the enhanced antibiofilm forming ability of TFP-PDMS was due to the self-cleaning activity of the surface. We believe that this modified surface will significantly reduce biofilm formation in indwelling urinary catheters and further warrant future clinical studies.

Effect of natural curcuminoids-intercalated layered double hydroxide nanohybrid against Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis: A bactericidal, antibiofilm, and mechanistic study.

The study aimed to determine the antibacterial/antibiofilm effect and mechanism of interaction of curcuminoids-intercalated Mg/Al layered double hydroxide (curcuminoids-LDH) against three different bacteria. Antimicrobial effect of curcuminoids-LDH nanohybrid was investigated against P. aeruginosa, S. aureus, and E. faecalis (for both standard strains and clinical isolates), using agar well diffusion method. Minimum inhibitory concentrations (MIC) of planktonic bacteria were determined using the broth microdilution method. MIC of biofilms (MBIC50 ) and killing time for 48 hr matured biofilms were determined by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Scanning electron microscopy (SEM) was used to determine pre- and postexposure architecture of biofilms. The mechanism of the antibiofilm activity of curcuminoids-LDH was determined using UV-visible spectroscopy. All tested bacteria had given a zone of inhibition in the presence of curcuminoids-LDH. The MIC values were 0.200 g/ml for P. aeruginosa, 0.025 g/ml for S. aureus, and 0.100 g/ml for E. faecalis. The 48 hr matured biofilms were reduced by curcuminoids-LDH with an MBIC50 of 0.100 g/ml. The minimum time to achieve MBIC50 was 3 hr, and the reduction was constant until 48 hr. SEM images showed a significant reduction of biofilm cell density and exopolymer matrics for all biofilms in the presence of curcuminoids-LDH. UV-visible studies revealed the antibiofilm activity of curcuminoids-LDH as due to the auto-oxidation of curcuminoids. The oxidation products are more limited in both product concentration per unit time and the variety of products, compared to pure curcuminoids, resulting in sharper UV-visible peaks than in the case of the latter. Curcuminoids-LDH has a potential antibacterial activity against P. aeruginosa, S. aureus, and E. faecalis. An antibiofilm activity has been achieved within 3 hr of the treatment. Curcuminoids released from the LDH showed the antibacterial activity due to oxidation products interfering with bacterial cell functions, and also encapsulation in the LDH causes curcuminoids to exhibit the activity in a persistent manner compared to pure curcuminoids.

Influence of Laboratory Culture Media on in vitro Growth, Adhesion, and Biofilm Formation of Pseudomonas aeruginosa and Staphylococcus aureus.

OBJECTIVE: Pseudomonas aeruginosa and Staphylococcus aureus dual-species biofilm infections are notoriously difficult to manage. This study aimed at investigating the influence of four different culture media on the planktonic growth, adhesion, and biofilm formation of P. aeruginosa and S. aureus. MATERIALS AND METHODS: We monitored four different culture media including Nutrient Broth, Brain Heart Infusion (BHI) broth, Luria-Bertani broth, and RPMI 1640 medium on the planktonic growth, adhesion, and biofilm formation of P. aeruginosa (ATCC 27853) and S. aureus (ATCC 25923) using MTT assay and scanning electron microscopy (SEM). RESULTS: The most robust growth of the mono- and dual-species cultures was noted in BHI broth. On the contrary, RPMI 1640 medium promoted maximal initial adhesion of both the mono- and dual-species, but BHI broth fostered the maximal biofilm growth. SEM images showed profuse extracellular polysaccharide production in biofilms, particularly in coculture, in BHI medium. CONCLUSION: Our data demonstrate that BHI broth, relative to the other tested media, is the most conducive for in vitro evaluation of biofilm and planktonic growth kinetics of these two pathogens, both in mono- and coculture.