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This review aims at presenting the main strategies that are currently available for the delivery of bacteriophages to combat bacterial infections in humans, animals, and plants. It can be seen that the main routes for phage delivery are topical, oral, systemic, and airways for humans. In animals, the topical and oral routes are the most used. To combat infections in plant species, spraying the plant’s phyllosphere or drenching the soil are the most commonly used methods. In both phage therapy and biocontrol using phages, very promising results have been obtained so far. However, more experiments are needed to establish forms of treatment and phage doses, among other parameters. Furthermore, in general, there is a lack of specific standards for the use of phages to combat bacterial infections.

Bacteriophages (phages) are nano-sized viruses characterized by their inherent ability to live off bacteria. They utilize diverse mechanisms to absorb and gain entry into the bacterial cell wall via the release of viral genetic material, which uses the replication mechanisms of the host bacteria to produce and release daughter progeny virions that attack the surrounding host cells. They possess specific characteristics, including specificity for particular or closely related bacterial species. They have many applications, including as potential alternatives to antibiotics against multi-resistant bacterial pathogens and as control agents in bacteria-contaminated environments. They are ubiquitously abundant in nature and have diverse biota, including in the gut. Gut microbiota describes the community and interactions of microorganisms within the intestine. As with bacteria, parasitic bacteriophages constantly interact with the host bacterial cells within the gut system and have obvious implications for human health. However, it is imperative to understand these interactions as they open up possible applicable techniques to control gut-implicated bacterial diseases. Thus, this review aims to explore the interactions of bacteriophages with bacterial communities in the gut and their current and potential impacts on human health.

E. coli is one of the etiological agents responsible for pyometra in female dogs, with conventional treatment involving ovariohysterectomy. Here, we report the isolation and full characterization of two novel lytic phages, viz. vB_EcoM_Uniso11 (ph0011) and vB_EcoM_Uniso21 (ph0021). Both phages belong to the order Caudovirales and present myovirus-like morphotypes, with phage ph0011 being classified as Myoviridae genus Asteriusvirus and phage ph0021 being classified as Myoviridae genus Tequatrovirus, based on their complete genome sequences. The 348,288 bp phage ph0011 and 165,222 bp phage ph0021 genomes do not encode toxins, integrases or antimicrobial resistance genes neither depolymerases related sequences. Both phages were shown to be effective against at least twelve E. coli clinical isolates in in vitro antibacterial activity assays. Based on their features, both phages have potential for controlling pyometra infections caused by E. coli. Phage ph0011 (reduction of 4.24 log CFU/mL) was more effective than phage ph0021 (reduction of 1.90 log CFU/mL) after 12 h of incubation at MOI 1000. As a cocktail, the two phages were highly effective in reducing the bacterial load (reduction of 5.57 log CFU/mL) at MOI 100, after 12 h of treatment. Both phages were structurally and functionally stabilized in vaginal egg formulations.

The worldwide increase in serious infections caused by multidrug-resistant (MDR) K. pneumoniae emphasizes the urgent need of new therapeutic strategies for the control of this pathogen. There is growing interest in the use of bacteriophages (or phages) to treat K. pneumoniae infections, and newly isolated phages are needed. Here, we report the isolation and physical/biological/molecular characterization of a novel lytic phage and its efficacy in the control of MDR K. pneumoniae. The phage vB_KpnS_Uniso31, referred to hereafter as phage Kpn31, was isolated from hospital wastewater using K. pneumoniae CCCD-K001 as the host. Phage Kpn31 presents a siphovirus-like morphotype and was classified as Demerecviridae; Sugarlandvirus based on its complete genome sequence. The 113,444 bp Kpn31 genome does not encode known toxins or antimicrobial resistance genes, nor does it encode depolymerases related sequences. Phage Kpn31 showed an eclipse time of 15 min and a burst size of 9.12 PFU/host cell, allowing us to conclude it replicates well in K. pneumoniae CCCD-K001 with a latency period of 30 min. Phage Kpn31 was shown to be effective against at least six MDR K. pneumoniae clinical isolates in in vitro antibacterial activity assays. Based on its features, phage Kpn31 has potential for controlling infections caused by MDR K. pneumoniae.

Psoriasis is a clinically heterogeneous skin disease with an important genetic component, whose pathophysiology is not yet fully understood and for which there is still no cure. Hence, alternative therapies have been evaluated, using plant species such as turmeric (Curcuma longa Linn.) in topical preparations. However, the stratum corneum is a barrier to be overcome, and ionic liquids have emerged as potential substances that promote skin permeation. Thus, the main objective of this research was to evaluate a biopolysaccharide hydrogel formulation integrating curcumin with choline and geranic acid ionic liquid (CAGE-IL) as a facilitator of skin transdermal permeation, in the treatment of chemically induced psoriasis in mice. The developed gel containing curcumin and CAGE-IL showed a high potential for applications in the treatment of psoriasis, reversing the histological manifestations of psoriasis to a state very close to that of normal skin.

In the present research work, we addressed the changes in skin by which deep eutectic solvents (DES) enhanced transdermal permeation of bioactive compounds and propose a rationale for this mechanism. Several studies showed that these unusual liquids were ideal solvents for transdermal delivery of biomolecules, but to date, no histological studies relating the action of DES to changes in the structure of the outer skin barrier have been reported. In the research effort described herein, we presented an in-depth analysis of the changes induced in the skin by choline geranate DES, a compound with proven capabilities of enhancing transdermal permeation without deleterious impacts on the cells. The results obtained showed that a low percentage of DES acted as a transient disruptor of the skin structure, facilitating the passage of bioactive compounds dissolved in it.