Polymeric Microneedles for Health Care Monitoring: An Emerging Trend.

Bioanalyte collection by blood draw is a painful process, prone to needle phobia and injuries. Microneedles can be engineered to penetrate the epidermal skin barrier and collect analytes from the interstitial fluid, arising as a safe, painless, and effective alternative to hypodermic needles. Although there are plenty of reviews on the various types of microneedles and their use as drug delivery systems, there is a lack of systematization on the application of polymeric microneedles for diagnosis. In this review, we focus on the current state of the art of this field, while providing information on safety, preclinical and clinical trials, and market distribution, to outline what we believe will be the future of health monitoring.

Designing an antimicrobial film for wound applications incorporating bacteriophages and ε-poly-l-lysine.

Alginate-based dressings have been shown to promote wound healing, leveraging the unique properties of alginate. This work aimed to develop and characterize flexible individual and bilayered films to deliver bacteriophages (phages) and ε-Poly-l-lysine (ε-PLL). Films varied in different properties. The moisture content, swelling and solubility increased with higher alginate concentrations. The water vapour permeability, crucial in biomedical films to balance moisture levels for effective wound healing, reached optimal levels in bilayer films, indicating these will be able to sustain an ideal moist environment. The bilayer films showed improved ductility (lower tensile strength and increased elongation at break) compared to individual films. The incorporated phages maintained viability for 12 weeks under vacuum and refrigerated conditions, and their release was sustained and gradual. Antibacterial immersion tests showed that films with phages and ε-PLL significantly inhibited Pseudomonas aeruginosa PAO1 growth (>3.1 Log CFU/cm2). Particle release was influenced by the swelling degree and diffusional processes within the polymer network, providing insights into controlled release mechanisms for particles of varying size (50 nm to 6 µm) and charge. The films developed, demonstrated modulated release capabilities for active agents, and may show potential as controlled delivery systems for phages and wound healing adjuvants.

Paving the way forward: Escherichia coli bacteriophages in a One Health approach.

Escherichia coli is one of the most notorious pathogens for its ability to adapt, colonize, and proliferate in different habitats through a multitude of acquired virulence factors. Its presence affects the food-processing industry and causes food poisoning, being also a major economic burden for the food, agriculture, and health sectors. Bacteriophages are emerging as an appealing strategy to mitigate bacterial pathogens, including specific E. coli pathovars, without exerting a deleterious effect on humans and animals. This review globally analyzes the applied research on E. coli phages for veterinary, food, and human use. It starts by describing the pathogenic E. coli pathotypes and their relevance in human and animal context. The idea that phages can be used as a One Health approach to control and interrupt the transmission routes of pathogenic E. coli is sustained through an exhaustive revision of the recent literature. The emerging phage formulations, genetic engineering and encapsulation technologies are also discussed as a means of improving phage-based control strategies, with a particular focus on E. coli pathogens.

Isolation of Bacteriophages for Clinically Relevant Bacteria.

The isolation of bacteriophages targeting most clinically relevant bacteria is reasonably straightforward as long as its targeted host does not have complex chemical, physical, and environmental requirements. Often, sewage, soil, feces, and different body fluids are used for bacteriophage isolation procedures, and following enrichment, it is common to obtain more than a single phage in a sample. This chapter describes a simple method for the enrichment and isolation of bacteriophages from liquid and solid samples that can be adapted for different clinically important aerobic bacteria.

Bacteriophage Control of Infectious Biofilms.

Biofilm formation, a strategy of bacterial survival, is a significant concern in different areas, including health, where infectious biofilms are very difficult to combat with conventional antimicrobial therapies. Bacteriophages, the viruses that infect bacteria, are promising agents to prevent and control biofilm-related infections. This chapter describes a series of standard procedures that can be used to study the potential of bacteriophages for biofilm control, from biofilm formation to bacteriophage treatment and evaluation of its efficacy.

Complete genome sequence of a novel bacteriophage vB_Pci_PCMW57 infecting phytobacteria pseudomonas cichorii.

BACKGROUND: A novel virulent bacteriophage infecting phytobacteria Pseudomonas cichorii (P. cichorii) was isolated from leafy vegetables in Brazil. P. cichorii is a Gram-negative soil phytobacterium, the causal agent of a number of economically important plant diseases worldwide. METHODS AND RESULTS: In this study, a new phage specific for P. cichorii was isolated from solid samples (lettuce, chicory and cabbage), designated vB_Pci_PCMW57. Electron microscopy revealed a small virion (~ 50-nm-diameter icosahedral capsid) with a short, non-contractile tail. The genome of vB_Pci_PCMW57 is 40,117 bp in size, with a GC content of 57.6% and encodes 49 open reading frames. The phage is genetically similar to P. syringae phages Pst_GM1 and Pst_GIL1, and the P. fluorescens phages WRT and KNP. According to electron microscopy and whole-genome sequence analysis, vB_Pci_PCMW57 should be classified as a Caudoviticetes, family Autographiviridae, subfamily Studiervirinae. CONCLUSIONS: The complete phage genome was annotated, and the sequence identity of the virus with other Pseudomonas viruses was higher than 95%. To our knowledge, this is the first report of a bacteriophage infecting Pseudomonas cichorii.

Bacteriophage Delivery Systems for Food Applications: Opportunities and Perspectives.

Currently, one-third of all food produced worldwide is wasted or lost, and bacterial contamination is one of the main reasons. Moreover, foodborne diseases are a severe problem, causing more than 420,000 deaths and nearly 600 million illnesses yearly, demanding more attention to food safety. Thus, new solutions need to be explored to tackle these problems. A possible solution for bacterial contamination is using bacteriophages (phages), which are harmless to humans; these natural viruses can be used to prevent or reduce food contamination by foodborne pathogens. In this regard, several studies showed the effectiveness of phages against bacteria. However, when used in their free form, phages can lose infectivity, decreasing the application in foods. To overcome this problem, new delivery systems are being studied to incorporate phages and ensure prolonged activity and controlled release in food systems. This review focuses on the existent and new phage delivery systems applied in the food industry to promote food safety. Initially, an overview of phages, their main advantages, and challenges is presented, followed by the different delivery systems, focused in methodologies, and biomaterials that can be used. In the end, examples of phage applications in foods are disclosed and future perspectives are approached.

Suggestion for a new bacteriophage genus for the Klebsiella pneumoniae phage vB_KpnS-Carvaje.

This work describes the newly isolated Klebsiella pneumoniae phage vB_KpnS-Carvaje that presents unique features in relation to other phages reported to date. These findings provide new insights into the diversity and evolutionary pathways of Klebsiella phages. The genome characterization of the Carvaje phage revealed that its genome length is approximately 57 kb with 99 open reading frames (ORFs), 33 of which have assigned functions while 66 are unknown. This phage differs from other sequenced Klebsiella phages, showing the closest resemblance (up to 65.32%) with Salmonella phages belonging to the Nonanavirus and Sashavirus genera. Comparisons at the amino acid level and phylogeny analysis among homologous genomes indicate that the Klebsiella Carvaje phage forms a novel sister taxon within the node of the Nonanaviruses and Sashaviruses cluster. Due to the unique features of the Carvaje phage, we propose the constitution of a new genus within the Caudoviricetes class. Further studies include the exploitation of this phage and its identified proteins for the control of Klebsiella infections and as recognition molecules in diagnostic methods.

Antibiofilm Efficacy of the Pseudomonas aeruginosa Pbunavirus vB_PaeM-SMS29 Loaded onto Dissolving Polyvinyl Alcohol Microneedles

Resistant bacteria prevail in most chronic skin wounds and other biofilm-related topical skin infections. Bacteriophages (phages) have proven their antimicrobial effectiveness for treating different antibiotic-resistant and multidrug-resistant bacterial infections, but not all phages are effective against biofilms. Phages possessing depolymerases can reach different biofilm layers; however, those that do not have depolymerase activity struggle to penetrate and navigate in the intricate 3D biofilm structure and mainly infect bacteria lodged in the outer biofilm layers. To address this, Pseudomonas aeruginosa phage vB_PaeM-SMS29, a phage with poor antibiofilm properties, was incorporated into polyvinyl alcohol (PVA, Mowiol 4:88) supplemented with 0.1% (v/v) of glycerol, and cast onto two different microneedle arrays varying in geometry. The dissolving microneedles were thoroughly characterized by microscopy, force-displacement, swelling, phage release and stability. Furthermore, 48 h-old biofilms were formed using the colony biofilm procedure (absence of broth), and the antibiofilm efficacy of the phage-loaded microneedles was evaluated by viable cell counts and microscopy and compared to free phages. The phages in microneedles were fairly stable for six months when stored at 4 °C, with minor decreases in phage titers observed. The geometry of the microneedles influenced the penetration and force-displacement characteristics but not the antimicrobial efficacy against biofilms. The two PVA microneedles loaded with phages reduced P. aeruginosa PAO1 biofilms by 2.44 to 2.76 log10 CFU·cm-2 at 24 h. These values are significantly higher than the result obtained after the treatment with the free phage (1.09 log10 CFU·cm-2). Overall, this study shows that the distribution of phages caused by the mechanical disruption of biofilms using dissolving microneedles can be an effective delivery method against topical biofilm-related skin infections.

Ex vivo transtympanic permeation of the liposome encapsulated S. pneumoniae endolysin MSlys.

An increase in bacterial resistance to systemic antibiotics has sparked interest into alternative antimicrobial compounds as well as methods for effective local, non-invasive drug delivery. Topical treatments, however, may be hindered by the presence of biological barriers, such as the tympanic membrane in the case of otitis media. Herein, the transtympanic permeation ability of liposomes loaded with the pneumococcal endolysin MSlys and of free MSlys was evaluated ex vivo. MSlys loaded in PEGylated liposomes showed an increased permeation across human tympanic membranes, as compared to its free form, being able to reduce the pneumococcal cell load after 2 h of permeation. However, antipneumococcal activity was no longer detected after 4 h of permeation and hydrolysis of the endolysin was observed after an extended incubation time (≥48 h). This work provides a first assessment of a successful, non-invasive delivery method for endolysins across an intact tympanic membrane. Findings have implications for non-systemic, local treatment of otitis media.