Characterization and in vitro testing of newly isolated lytic bacteriophages for the biocontrol of Pseudomonas aeruginosa.

Aim: Two lytic phages were isolated using P. aeruginosa DSM19880 as host and fully characterized. Materials & methods: Phages were characterized physicochemically, biologically and genomically. Results & conclusion: Host range analysis revealed that the phages also infect some multidrug-resistant (MDR) P. aeruginosa clinical isolates. Increasing MOI from 1 to 1000 significantly increased phage efficiency and retarded bacteria regrowth, but phage ph0034 (reduction of 7.5 log CFU/ml) was more effective than phage ph0031 (reduction of 5.1 log CFU/ml) after 24 h. Both phages belong to Myoviridae family. Genome sequencing of phages ph0031 and ph0034 showed that they do not carry toxin, virulence, antibiotic resistance and integrase genes. The results obtained are highly relevant in the actual context of bacterial resistance to antibiotics.

Bacteriophage-Based Biosensing of Pseudomonas aeruginosa: An Integrated Approach for the Putative Real-Time Detection of Multi-Drug-Resistant Strains.

During the last decennium, it has become widely accepted that ubiquitous bacterial viruses, or bacteriophages, exert enormous influences on our planet's biosphere, killing between 4-50% of the daily produced bacteria and constituting the largest genetic diversity pool on our planet. Currently, bacterial infections linked to healthcare services are widespread, which, when associated with the increasing surge of antibiotic-resistant microorganisms, play a major role in patient morbidity and mortality. In this scenario, Pseudomonas aeruginosa alone is responsible for ca. 13-15% of all hospital-acquired infections. The pathogen P. aeruginosa is an opportunistic one, being endowed with metabolic versatility and high (both intrinsic and acquired) resistance to antibiotics. Bacteriophages (or phages) have been recognized as a tool with high potential for the detection of bacterial infections since these metabolically inert entities specifically attach to, and lyse, bacterial host cells, thus, allowing confirmation of the presence of viable cells. In the research effort described herein, three different phages with broad lytic spectrum capable of infecting P. aeruginosa were isolated from environmental sources. The isolated phages were elected on the basis of their ability to form clear and distinctive plaques, which is a hallmark characteristic of virulent phages. Next, their structural and functional stabilization was achieved via entrapment within the matrix of porous alginate, biopolymeric, and bio-reactive, chromogenic hydrogels aiming at their use as sensitive matrices producing both color changes and/or light emissions evolving from a reaction with (released) cytoplasmic moieties, as a bio-detection kit for P. aeruginosa cells. Full physicochemical and biological characterization of the isolated bacteriophages was the subject of a previous research paper.

Newly isolated lytic bacteriophages for Staphylococcus intermedius, structurally and functionally stabilized in a hydroxyethylcellulose gel containing choline geranate: Potential for transdermal permeation in veterinary phage therapy.

In the present research work, we propose a new antimicrobial treatment for pyoderma via cutaneous permeation of bacteriophage particles conveyed in a hydroxyethylcellulose (HEC) gel integrating ionic liquid as a permeation enhancer. Ionic liquids are highly viscous fluids constituted exclusively by ions, that are usually hydrolytically stable and promote solubilization of amphipathic molecules such as proteins, hence serving as green solvents and promoting the transdermal permeation of biomolecules. In the research effort entertained herein, the synthesis and use of choline geranate for integrating a HEC gel aiming at the structural and functional stabilization of a cocktail of isolated lytic bacteriophage particles was sought, aiming at transdermal permeation in the antimicrobial treatment of animal pyoderma. The results obtained showed a high ability of the ionic liquid in enhancing transdermal permeation of the bacteriophage particles, with concomitant high potential of the HEC gel formulation in the antimicrobial treatment of animal skin infections.

Non-invasive Transdermal Delivery of Human Insulin Using Ionic Liquids: In vitro Studies.

In this research project, synthesis and characterization of ionic liquids and their subsequent utilization as facilitators of transdermal delivery of human insulin was pursued. Choline geranate and choline oleate ionic liquids (and their deep eutectic solvents) were produced and characterized by nuclear magnetic resonance (1H NMR), water content, oxidative stability, cytotoxicity and genotoxicity assays, and ability to promote transdermal protein permeation. The results gathered clearly suggest that all ionic liquids were able to promote/facilitate transdermal permeation of insulin, although to various extents. In particular, choline geranate 1:2 combined with its virtually nil cyto- and geno-toxicity was chosen to be incorporated in a biopolymeric formulation making it a suitable facilitator aiming at transdermal delivery of insulin.

Biotechnological applications of bacteriophages: State of the art.

Bacteriophage particles are the most abundant biological entities on our planet, infecting specific bacterial hosts in every known environment and being major drivers of bacterial adaptive evolution. The study of bacteriophage particles potentially sheds light on the development of new biotechnology products. Bacteriophage therapy, although not new, makes use of strictly lytic phage particles as an alternative in the antimicrobial treatment of resistant bacterial infections and is being rediscovered as a safe method due to the fact that these biological entities devoid of any metabolic machinery do not have affinity to eukaryotic cells. Furthermore, bacteriophage-based vaccination is emerging as one of the most promising preventive strategies. This review paper discusses the biological nature of bacteriophage particles, their mode(s) of action and potential exploitation in modern biotechnology. Topics covered in detail include the potential of bacteriophage particles in human infections (bacteriophage therapy), nanocages for gene delivery, food biopreservation and safety, biocontrol of plant pathogens, phage display, bacterial biosensing devices, vaccines and vaccine carriers, biofilm and bacterial growth control, surface disinfection, corrosion control, together with structural and functional stabilization issues.