Immunomodulatory Effects of Cinnamaldehyde in Staphylococcus aureus-Infected Wounds.

Cinnamaldehyde (CNM) is an essential-oil component with reported anti-infective, anti-inflammatory, and healing effects, making it an interesting compound for the treatment of wound infection. Herein, we evaluated the effects of topical administration of CNM in experimental wounds infected by Staphylococcus aureus. Swiss mice (n = 12/group) were randomly allocated into three groups (CON: animals with uninfected lesions; Sa: animals with untreated infected lesions; Sa + CNM: animals with infected wounds and treated with CNM). Excisional lesions (64 mm2) were induced at the dorsal area followed by the addition of S. aureus (80 µL of a 1.5 × 108 CFU/mL bacterial suspension). The wounds were treated with CNM (200 µg/wound/day) or vehicle (2% DMSO) for 10 days. Skin samples were taken on the 3rd or 10th treatment day for quantification of inflammatory mediators, bacterial load, immunophenotyping, and histological analysis. The treatment with CNM improved the healing process and attenuated the severity of skin lesions infected by S. aureus. These effects were associated with significant decreases in bacterial loads in CNM-treated wounds. The levels of neutrophils, TNF-α, IL-6, NO, and VEGF were decreased in the lesions treated with CNM. Taken together, these data provide further evidence of the effectiveness of CNM for the treatment of skin infections.

Antimicrobial and anti-inflammatory effects of Eugenia brejoensis essential oil in mice wounds infected by Staphylococcus aureus.

Eugenia brejoensis Mazine (Myrtaceae) is source of an essential oil (EbEO) with anti-infective activities against Staphylococcus aureus. This study evaluated the antimicrobial and anti-inflammatory potentials of EbEO in S. aureus-infected skin wounds. The excisional lesions (64 mm2) were induced on Swiss mice back (6 to 8-week-old) that were allocated into 3 groups (n = 12): 1) non-infected wounds (CON); 2) wounds infected with S. aureus ATCC 6538 (Sa); 3) S. aureus-infected wounds and treated with EbEO (Sa + EbEO). The infected groups received approximately 104 CFU/wound. The animals were treated with EbEO (10 µg/wound/day) or vehicle from the 1-day post-infection (dpi) until the 10th dpi. The clinical parameters (wound area, presence of exudate, edema intensity, etc.) were daily analyzed. The levels of inflammatory mediators (cytokines, nitric oxide, VEGF) and bacterial load were measured at the cutaneous tissue at 4th dpi and 10th dpi. Topical application of EbEO accelerated wound contraction with an average contraction of 83.48 ± 11.27 % of the lesion area until 6th dpi. In this period, the rates of lesion contraction were 54.28 ± 5.57% and 34.5 ± 2.67% for CON and Sa groups, respectively. The positive effects of EbEO on wound contraction were associated with significantly (p < 0.05) reduction on bacterial load and the release of inflammatory mediators (IL-6, IL-17A, TNF-α, NO and VEGF). Taken together, these data confirm the antimicrobial potential of EbEO and provide insights into its anti-inflammatory effects, making this essential oil an interesting candidate for the development of new therapeutic alternatives for infected cutaneous wounds.

Interplay between ESKAPE Pathogens and Immunity in Skin Infections: An Overview of the Major Determinants of Virulence and Antibiotic Resistance.

The skin is the largest organ in the human body, acting as a physical and immunological barrier against pathogenic microorganisms. The cutaneous lesions constitute a gateway for microbial contamination that can lead to chronic wounds and other invasive infections. Chronic wounds are considered as serious public health problems due the related social, psychological and economic consequences. The group of bacteria known as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp.) are among the most prevalent bacteria in cutaneous infections. These pathogens have a high level of incidence in hospital environments and several strains present phenotypes of multidrug resistance. In this review, we discuss some important aspects of skin immunology and the involvement of ESKAPE in wound infections. First, we introduce some fundamental aspects of skin physiology and immunology related to cutaneous infections. Following this, the major virulence factors involved in colonization and tissue damage are highlighted, as well as the most frequently detected antimicrobial resistance genes. ESKAPE pathogens express several virulence determinants that overcome the skin's physical and immunological barriers, enabling them to cause severe wound infections. The high ability these bacteria to acquire resistance is alarming, particularly in the hospital settings where immunocompromised individuals are exposed to these pathogens. Knowledge about the virulence and resistance markers of these species is important in order to develop new strategies to detect and treat their associated infections.

Exploring lectin-glycan interactions to combat COVID-19: Lessons acquired from other enveloped viruses.

The emergence of a new human coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has imposed great pressure on the health system worldwide. The presence of glycoproteins on the viral envelope opens a wide range of possibilities for the application of lectins to address some urgent problems involved in this pandemic. In this work, we discuss the potential contributions of lectins from nonmammalian sources in the development of several fields associated with viral infections, most notably COVID-19. We review the literature on the use of nonmammalian lectins as a therapeutic approach against members of the Coronaviridae family, including recent advances in strategies of protein engineering to improve their efficacy. The applications of lectins as adjuvants for antiviral vaccines are also discussed. Finally, we present some emerging strategies employing lectins for the development of biosensors, microarrays, immunoassays and tools for purification of viruses from whole blood. Altogether, the data compiled in this review highlight the importance of structural studies aiming to improve our knowledge about the basis of glycan recognition by lectins and its repercussions in several fields, providing potential solutions for complex aspects that are emerging from different health challenges.