Novel antibiotic-loaded particles conferring eradication of deep tissue bacterial reservoirs for the treatment of chronic urinary tract infection

Abstract

A significant proportion of urinary tract infection (UTI) patients experience recurrent episodes, due to deep tissue infection and treatment-resistant bacterial reservoirs. Direct bladder instillation of antibiotics has proved disappointing in treating UTI, likely due to the failure of infused antibiotics to penetrate the bladder epithelium and accumulate to high enough levels to kill intracellular bacteria. This work investigates the use of nitrofurantoin loaded poly(lactic-co-glycolic acid) (PLGA) particles to improve delivery to intracellular targets for the treatment of chronic UTI. Using electrohydrodynamic atomisation, we produced particles with an average diameter of 2.8 µm. In broth culture experiments, the biodegradable particles were effective against a number of UTI-relevant bacterial strains. Dye-loaded particles demonstrated that intracellular delivery was achieved in all cells in 2D cultures of a human bladder epithelial progenitor cell line in a dose-dependent manner, achieving far higher efficiency and concentration than equivalent quantities of free drug. Time-lapse video microscopy confirmed that delivery occurred within 30 minutes of administration, to 100% of cells. Moreover, the particles were able to deliver the drug to cells through multiple layers of a 3D human bladder organoid model causing minimal cell toxicity, displaying superior killing of bacterial reservoirs harboured within bladder cells compared with unencapsulated drug. The particles were also able to kill bacterial biofilms more effectively than the free drug. These results illustrate the potential for using antibiotic-loaded microparticles to effectively treat chronic UTIs. Such a delivery method could be extrapolated to other clinical indications where robust intracellular delivery is required, such as oncology and gene therapy.

An immunoresponsive three-dimensional urine-tolerant human urothelial (3D-UHU) model to study urinary tract infection

“…Uropathogenic Escherichia coli (UPEC) strains UTI89 49 , CFT073 50 (ATCC 700928), and E. coli 83972 (bei Resources) associated with asymptomatic bacteriuria (ABU) were grown in static Luria-Bertani (LB, Sigma Aldrich) broth at 37°C for 48h to induce expression of type 1 pili. Clinical isolates of Enterococcus faecalis ( E. faecalis 36 [EF36], previously isolated and reported from a patient with chronic UTI 51 , and E. faecalis 77 52 , previously isolated and reported from an asymptomatic healthy male) and Streptococcus agalactiae , previously isolated and reported 52 (Group B Streptococcus), were grown overnight in Tryptone Soya Broth (TSB, Thermo Fisher Scientific) at 37°C.…”

“…[EF36], previously isolated and reported from a patient with chronic UTI 51 , and E. faecalis 77 52 , previously isolated and reported from an asymptomatic healthy male) and Streptococcus agalactiae, previously isolated and reported 52 (Group B Streptococcus), were grown overnight in Tryptone Soya Broth (TSB, Thermo Fisher Scientific) at 37°C.…”

Evaluating the effect of synthesis, isolation, and characterisation variables on reported particle size and dispersity of drug loaded PLGA nanoparticles

“…1,[4][5][6][7][8] There are many examples in the literature using PLGA-based materials for delivery of therapeutics to promote either fast or prolonged drug release with applications in cancer treatment, pain management, immunotherapy, and more recently, in the treatment of pulmonary tuberculosis, urinary tract infections, migraine and glaucoma. 5,6,[9][10][11][12][13][14][15] There are several techniques that are used for the preparation of PLGA particles including single and double emulsion solvent evaporation (ESE), nanoprecipitation, spray-drying, microfluidics, and hydrogel templating. 2,[16][17][18][19] These techniques enable the synthesis of a wide range of PLGA nano-and sub-micron sized particles.…”

Phosphoglyceride‐coated polylactic acid porous microspheres and its regulation of curcumin release behavior

“…Because its operation process is much simpler and easier to control. It is reported that the prepared microspheres by this method are more likely to have large specific surface area, ideal morphology and longer carrier life, which could also expand the application range of microspheres 38–40 . More importantly, electrospraying can easily fabricate the microspheres with different physical shapes by adjusting its conditions, such as porous, hollow, honeycomb, double‐walled structure core‐shell structure and other special‐shaped microspheres, and so forth 9,34,41–44 .…”

“…It is reported that the prepared microspheres by this method are more likely to have large specific surface area, ideal morphology and longer carrier life, which could also expand the application range of microspheres. [38][39][40] More importantly, electrospraying can easily fabricate the microspheres with different physical shapes by adjusting its conditions, such as porous, hollow, honeycomb, double-walled structure core-shell structure and other special-shaped microspheres, and so forth. 9,34,[41][42][43][44] These microspheres can achieve the ability to increase the drug loading efficiency, the protective effect of some drugs, and reaching the purpose of sustained release or even controlled release profiles to avoid adverse reactions caused by the rapid release of some drugs.…”