Toxicity and Antimicrobial Properties of ZnO@ZIF-8 Embedded Silicone against Planktonic and Biofilm Catheter-Associated Pathogens

Abstract

were determined by X-ray diffraction, high resolution electron microscopy, energy dispersive spectroscopy and nitrogen adsorption. The antimicrobial potential of ZnO@ZIF-8 for reduction of microorganisms often implicated with catheter-associated urinary tract infections (CAUTIs) was studied in detail using four target pathogens, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Staphylococcus aureus. The ability of the compound to kill all four microorganisms in suspension was established and a minimum bactericidal concentration of 0.25 mg mL -1 was determined for each microorganism. ZnO@ZIF-8 compound was found to be no more toxic to Galleria mellonella than distilled water, which was assessed by injection of Galleria with 10 µL of ZnO@ZIF-8 of concentrations of up to 2 mg mL -1 . ZnO@ZIF-8 suspensions (2 mg mL -1 concentration) were able to reduce well-established biofilms of all four oraganisms containing between 10 7 and 10 9 CFU mL -1 to below limit of detection (BLD) over a 24-h period. Silicone-embedded ZnO@ZIF-8 (2wt.% or 4 wt.% ZnO@ZIF-8 loading) also demonstrated antimicrobial properties with all four microorganisms being eliminated from the surface within 24 h. The ZnO@ZIF-8 high potency and rapid anti-biofilm activity against all four test organisms coupled with its non-toxicity offers a new avenue for control of microbial colonization of catheters, which would ultimately result in reduction of CAUTIs.

Nanoparticles as Potential Novel Therapies for Urinary Tract Infections

“…The ZnO-ZIF-8 showed a reduction of 6-8 log, when compared to the control solution, over a 24 h period. Finally, authors of this research prepared ZnO-ZIF-8 embedded silicone elastomers with 2 or 4 w/w % and observed that they effectively eliminated all four microorganisms from the surface after 24 h of exposition, showing their utility to prevent CAUTI (Redfern et al, 2018).…”

Antibacterial efficacy from NO-releasing MOF–polymer films

“…There are, however, very few studies reporting the formulation of MOFs into polymeric articles for antimicrobial purposes; and those which exist mostly employ metal ion release as the antimicrobial mechanism. [48][49][50][51][52] In this contribution we report the successful formulation of NO-releasing CPO-27 into a model medical polyurethane using solvent casting to generate standalone films. We show that NO gas can be successfully loaded into the composite and released in antibacterial concentrations when in a moist atmosphere.…”

Minimising Blood Stream Infection: Developing New Materials for Intravascular Catheters

“…Putting the issue of dwell time aside, the release of antibiotic moieties (i.e., rifampicin) have a long history but the increasing threat of bacterial resistance has driven considerable effort to examine alternative antimicrobial agents. Various antimicrobial peptides [100,108,[113][114][115], guanidine derivatives (i.e., poly hexamethyl biguanide, polyarginines) [103,104], quaternary ammonium compounds [96,98], nitric oxide precursors [105,106,116,117], silver [118][119][120] and a host of other small molecules/metal ions or nanoparticles [107,110,118,[121][122][123][124] with possible biocidal activity have all been investigated as potential modifiers for use in catheters and, while these invariably impact bacterial colonisation, they have yet to make the leap to commercial exploitation and/or substantive clinical trials.…”