Antifungal nanosuspensions with surfactants and silver for the treatment of onychomycosis.

Fungal nail infection (Onychomycosis) often requires prolonged treatment and is associated with a high risk of resistance to treatment. Here in this contribution, we introduce a novel approach to enhance penetration and antifungal activity of the antifungal drug griseofulvin (GF). Solid dispersions were prepared with hydroxypropyl methylcellulose acetate succinate (HPMCAS) and combined with surfactant (either sodium dodecyl sulphate (SDS), dodecyl trimethylammonium bromide (DTAB), or Pluronic F127) using mechanochemical activation. The prepared powders were then suspended with spray-dried silica-coated silver nanoparticles and applied onto infected bovine hooves to assess permeability and antifungal activity. The results showed that the prepared nanosuspensions significantly suppressed fungal activity causing disruption of fungal biofilms. Raman mapping showed enhanced permeation while dynamic vapor sorption (DVS), and particle size measurements showed varied effects depending on the type of surfactant and milling conditions. The prepared nanosuspensions displayed enhanced solubility of the poorly soluble drug reaching approximately 1.2 mg/mL. The results showed that the dispersions that contained DTAB displayed maximum efficacy while the inclusion of colloidal silver did not seem to significantly improve the antifungal activity compared to other formulations.

Effect of quorum quenchers on virulence factors production and quorum sensing signalling pathway of non-mucoid, mucoid, and heavily mucoid Pseudomonas aeruginosa.

Quorum quenching (QQ), a mechanism which inhibits, interferes or inactivates quorum sensing, has been investigated for control of biofilms instigated by quorum sensing process. Application of quorum quenchers (QQs) provides the possibility to investigate how different phenotypes of Pseudomonas aeruginosa (non-mucoid, mucoid, and heavily mucoid strains) modulate their gene expression to form biofilms, their quorum sensing (QS) mediated biofilm to be formed, and their virulence expressed. The mRNA expression of the AHL-mediated QS circuit and AHL-mediated virulence factors in P. aeruginosa was investigated in presence of QQs. qPCR analysis showed that farnesol and tyrosol actively reduce the expression of the synthase protein, LasI and RhlI, and prevent production of 3OC12-HSL and C4-HSL, respectively. Also, the use of farnesol and tyrosol significantly moderated gene expression for exo-proteins toxA, aprA, LasB, as well as rhlAB, which are responsible for rhamnolipid production. Our findings were promising, identifying several suppressive regulatory effects of furanone and Candida albicans QS signal molecules, tyrosol, and farnesol on the AHL-mediated P. aeruginosa QS network and related virulence factors.

Quorum quenchers affect the virulence regulation of non-mucoid, mucoid and heavily mucoid biofilms co-cultured on cell lines.

Biofilm formation conferring pathogenicity is a survival strategy for Pseudomonas aeruginosa. P. aeruginosa's virulence may differ due to differences in host-microbe interactions and the growth environment. The epithelial cell line within the respiratory system and the keratinocytes on the skin form the first physical barrier of defence. P. aeruginosa spp. biofilm formation and virulence factor secretion with and without quorum quenching (QQ) treatment was studied in co-culture using A549 and HaCaT cell lines; pyocyanin and rhamnolipid productions and elastolytic activity as virulence factors were quantified by independent assays. Biofilm formation was evaluated under dynamic conditions by quantifying total carbohydrates, alginate, proteins and eDNA. A sandwich ELISA was performed to study IL-8 secretion by the epithelial cells. The difference in gene expression of the quorum sensing (QS) and virulence factors between strains during individual and combination treatments was analysed by qPCR. Combination treatment by farnesol and tyrosol was more effective against P. aeruginosa biofilms when grown in co-cultures. The strain RBHi was found to be 3 to 4 times more virulent compared to PAO1 and NCTC 10,662, respectively, and combination treatment was more effective against RBHi strain when grown in co-culture with A549 cell line. The addition of quorum quenchers (QQs) individually and in combination reduced IL-8 secretion by A549 cells. Relative mRNA expression showed upregulation of the QS genes and virulence factors. Co-culture of P. aeruginosa and HaCaT cell line showed a general decrease in gene expression, especially in the case of P. aeruginosa RBHi when treated with farnesol and tyrosol combination.Key points• Differentiating the interactions of biofilm formed by different phenotypes of P. aeruginosa, NCTC 10,662 (non-mucoid), PAO1 (semi mucoid) and RBHi (heavily mucoid).• Biofilm formed by these P. aeruginosa strains on two commonly afflicted tissues represented by A549 (lung) and HaCaT (skin) cell lines.• Anti-biofilm/anti-virulence roles of quorum quenchers, tyrosol and farnesol in co-cultures.

Generation of High Dose Inhalable Effervescent Dispersions against Pseudomonas aeruginosa Biofilms.

PURPOSE: Novel particle engineering approach was used in this study to generate high dose inhalable effervescent particles with synergistic effects against Pseudomonas aeruginosa biofilms. METHODS: Spray dried co-amorphous salt of ciprofloxacin (CFX) and tartaric acid (TA) was prepared and coated with external layer of sodium bicarbonate and silica coated silver nanobeads. Design of experiments (DOE) was used to optimize physicochemical properties of particles for enhanced lung deposition. RESULTS: Generated particles were co-amorphous CFX/TA showing that CFX lost its zwitterionic form and exhibiting distinct properties to CFX/HCl as assessed by FTIR and thermal analysis. Particles exhibited mass mean aerodynamic diameter (MMAD) of 3.3 µm, emitted dose of 78% and fine particle dose of 85%. Particles were further evaluated via antimicrobial assessment of minimum inhibitory concentrations (MIC) and minimum biofilm eradication concentration (MBEC). MIC and MBEC results showed that the hybrid particles were around 3-5 times more effective when compared to CFX signifying that synergistic effect was achieved. Diffusing wave spectroscopy results showed that the silver containing particles had a disruptive effect on rheological properties as opposed to silver free particles. CONCLUSIONS: Overall, these results showed the potential to use particle engineering to generate particles that are highly disruptive of bacterial biofilms.

Griseofulvin solvate solid dispersions with synergistic effect against fungal biofilms.

Fungal biofilms are invariably recalcitrant to antifungal drugs and thus can cause recurrent serious infections. The aim of this work was to prepare highly effective form of the antifungal drug griseofulvin using the chloroform solvate embedded into different polymeric matrices. Based on their solid solubility, solvated (chloroform) and non-solvated (methanol and acetone) solid dispersions were prepared using different materials: silica, microcrystalline cellulose, polyvinylpyrrolidone and hydroxypropyl methylcellulose acetate succinate (HPMCAS) by which HPMCAS dispersions showed the highest solubility of about 200 µg/mL compared with ∼30 µg/mL for pure griseofulvin. The anti fungal potential of griseofulvin was assessed against the dermatophytes T. rubrum. Metabolic and protease activity of T. rubrum NCPF 935 with and without the presence of GF:HPMCAS chloroform solvates showed significant reduction compared to the untreated control after 24 h period. Confocal laser scanning microscopy showed thin hyphae compared to Control and GF:HPMCAS (non solvated). Dynamic vapour sorption data showed that HPMCAS formed most stable solvate structure preventing recrystallization and solvate expulsion, which could explain the disruptive effect of the biofilms. This could be explained by the formed hydrogen bonds as revealed by the solid and liquid state NMR data, which was further confirmed via thermal and FTIR analyses.

Fabrication of inhaled hybrid silver/ciprofloxacin nanoparticles with synergetic effect against Pseudomonas aeruginosa.

Ciprofloxacin (CFX) is a fluoroquinolone antibiotic used as a first line treatment against infections caused by Pseudomonas aeruginosa and Streptococcus pneumonia that are commonly acquired by cystic fibrosis (CF) patients. However, no inhalation formulation is currently available for ciprofloxacin. Hybrid silica coated silver nanoparticles were prepared using Stöber reaction and the optimum ratio of chitosan and sodium tripolyphosphate was used to encapsulate CFX. Particle deposition was assessed in vitro using twin stage impinger while antimicrobial activity was evaluated based on the planktonic growth of P. aeruginosa as well as against P. aeruginosa sp biofilm formation. In vitro deposition results showed significant deposition in stage 2 using twin stage impinger (TSI) (∼70%). Compared to CFX, the formed hybrid nanoparticles were 3-4 folds more effective against inhibiting growth and biofilm formation by P. aeruginosa PAO1 and P. aeruginosa NCTC 10662.