The impact of simultaneous inoculation of Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans on rodent burn wounds

Enhancement of burn wound healing using optimized bioactive probiotic-loaded alginate films

Wound infection can prolong the healing process, leading to various complications. Although the use of antibiotics is common, it presents challenges such as poor pharmacokinetics. The prevalence of antibiotic resistance has further complicated wound management. Studies have demonstrated the potential of topical probiotics; however, stabilizing these cells and creating appropriate conditions for their colonization are essential. In this study, polymeric films were utilized to immobilize probiotics and provide an effective dressing. Aloe vera gel was incorporated into the films to enhance anti-inflammatory activity and probiotic viability. The optimal film was developed using sodium alginate and zinc chloride, with manufacturing parameters optimized to achieve the highest cell viability and suitable properties through the D-optimal method. The models were verified by comparing the actual and predictive responses of the optimized formulation. The optimal film was characterized using microscopic, mechanical, and microbial examinations. The cross-linked alginate matrix improved the stability of probiotics during storage. In vivo tests demonstrated that the formulation could reduce microbial counts and shorten healing duration. This dressing improved wound healing with immobilized probiotics and aloe vera gel, offering promising directions for future research on advanced biomaterials to enhance wound care and combat antibiotic resistance.

Rapid and simple detection of Candida albicans using closed dumbbell-mediated isothermal amplification

Introduction

Candida albicans, a human fungal pathogen, multiplies to invade body cells and causes fungal diseases in the condition of insufficient body's immune function. Early detection of C. albicans is required to guide appropriate prevention and treatment.

Methods

The purpose of this study was to establish a C. albicans assay based on newly developed closed dumbbell-mediated isothermal amplification (CDA) to achieve rapid and simple point of care diagnostic. The CDA technique was carried out by specific primers targeting at the conserved C. albicans ITS2 gene. All primers were selected and evaluated by real-time fluorescence monitoring and endpoint visual judgement indicated by hydroxy naphthol blue (HNB). Optimal primers and accelerate primers (out primers and loop primers) were designed and selected after confirmation of the fundamental CDA primers to achieve more efficient CDA reaction for C. albicans detection (CA-OL-CDA).

Results

After establishment of the assay, 9 non-Candida albicans strains, including 3 Candida species were tested to negative by adopting the established CA-OL-CDA assay, indicated high specificity. The limit of detection of Candida albicans DNA by CA-OL-CDA assay was 6.2×10-6 ng/μL of DNA (10 copies/μL), 10-fold more sensitive than real-time quantitative PCR (qPCR).

Discussion

The CA-OL-CDA assay exhibited advantages of high specificity, sensitivity, simpler and more efficient operation. In addition, the CA-OL-CDA method holds potential in on-site detection for C. albicans using color shift by adopting the reaction mixture based on HNB.

An Injectable Living Hydrogel with Embedded Probiotics as a Novel Strategy for Combating Multifaceted Pathogen Wound Infections

Wound infections pose a significant challenge in healthcare, and traditional antibiotic treatments often result in the development of resistant pathogens. Addressing this gap, ProGel is introduced, a living hydrogel created by entrapping probiotic Lactobacillus plantarum as a therapeutic component within a gelatin matrix. With a double-syringe system, ProGel can be easily mixed and applied, conforming swiftly to any wound shape and forming hydrogel in situ. It also demonstrates robust mechanical and self-healing properties owing to the Schiff-base bonds. ProGel sustains more than 80% viability of the entrapped L. plantarum while restricting their escape from the hydrogel. After a week of storage, more than 70% viability of the entrapped L. plantarum is preserved. Importantly, ProGel exhibits broad-spectrum antimicrobial efficacy against pathogens commonly associated with wound infections, i.e., Pseudomonas aeruginosa (7Log reduction), Staphylococcus aureus (3-7Log reduction), and Candida albicans (40-70% reduction). Moreover, its cytocompatibility is affirmed through coculture with human dermal fibroblasts. The effectiveness of ProGel is further highlighted in more clinically relevant tests on human skin wound models infected with P. aeruginosa and S. aureus, where it successfully prevents the biofilm formation of these pathogens. This study showcases an injectable living hydrogel system for the management of complex wound infections.

The Profile of Bacterial Infections in a Burn Unit during and after the COVID-19 Pandemic Period

Infections represent a major complication for burn-injured patients. The aim of this study was to highlight the changes in the incidence and antimicrobial resistance of bacterial strains isolated from burn patients, at the end of the COVID-19 pandemic, in relation to the antibiotics used during the pandemic. A comparative analysis of the demographic data and the microorganisms identified in the clinical samples of two groups of burn patients admitted to a university hospital in Romania was carried out. The first group consisted of 48 patients and the second of 69 patients, hospitalized in January-August 2020 and 2023, respectively. The bacterial species with the highest incidence were S. aureus, A. baumannii, Pseudomonas spp. The significant changes between 2023 and 2020 are reflected in the increase in the frequency of non-fermentative Gram-negative bacteria, especially S. maltophilia, and the increase in antimicrobial resistance of Pseudomonas and Klebsiella spp. Klebsiella spp. did not change in frequency (7%), but there was a significant increase in the incidence of K. pneumoniae strains with pan-drug resistant behaviour to antibiotics (40%), including colistin. The phenomenon can be explained by the selection of specimens carrying multiple resistance genes, as a result of antibiotic treatment during the COVID-19 period. The post-pandemic antimicrobial resistance detected in burn patients indicates the need for permanent surveillance of the resistance trends, primarily due to the limited therapeutic options available for these patients.

Interkingdom interactions between Pseudomonas aeruginosa and Candida albicans affect clinical outcomes and antimicrobial responses

Infections that involve interkingdom microbial communities, such as those between bacteria and yeast pathogens, are difficult to treat, associated with worse patient outcomes, and may be a source of antimicrobial resistance. In this review, we address co-occurrence and co-infections of Candida albicans and Pseudomonas aeruginosa, two pathogens that occupy multiple infection niches in the human body, especially in immunocompromised patients. The interaction between the pathogen species influences microbe-host interactions, the effectiveness of antimicrobials and even infection outcomes, and may thus require adapted treatment strategies. However, the molecular details of bacteria-fungal interactions both inside and outside the infection sites, are insufficiently characterised. We argue that comprehensively understanding the P. aeruginosa-C. albicans interaction network through integrated systems biology approaches will capture the highly dynamic and complex nature of these polymicrobial infections and lead to a more comprehensive understanding of clinical observations such as reshaped immune defences and low antimicrobial treatment efficacy.

Correlation between Bacterial Wound Colonization and Skin-Graft Loss in Burn Patients

Loss of skin grafts can be a dangerous complication during the early postoperative course of patients with extensive burns. A major risk factor for impaired healing of grafts is local wound infection due to bacterial colonization. Burn wounds are particularly prone to bacterial colonization. In this retrospective cohort study, we analyzed correlations between bacteria isolates from burn wounds and loss of skin grafts after surgical treatment. A cohort of patients with burn wounds who received split-skin grafts for wound coverage was divided into groups with and without loss of skin grafts. Demographics, comorbidities, trauma characteristics and bacterial isolates from wound cultures were reviewed and compared. Bacterial colonization isolated from burn wounds upon hospital admission was found to be a significant predictor of skin-graft loss. Additionally, an Abbreviated Burn Severity Index greater 6 predicted graft loss. When comparing bacterial swab results from admission with isolates from revision surgery after graft loss, causative pathogens were found to have changed.

Royal Jelly as a Nutraceutical Natural Product with a Focus on Its Antibacterial Activity

Royal jelly (RJ) is one of the most valued natural products and is known for its health-promoting properties. Due to its therapeutic effects, it has been used in medicine since antiquity. Nowadays, several studies indicate that RJ acts as a powerful antimicrobial agent. Indeed, researchers shed light on its antioxidant and anticancer activity. RJ's biological properties are related to its bioactive compounds, such as proteins, peptides, phenolic, and fatty acids. The aim of this review is to highlight recent findings on RJ's main bioactive compounds correlated with its health-promoting properties. The available literature suggests that these bioactive compounds can be used as an alternative approach in order to enhance human health. Moreover, throughout this paper, we underline the prominent antibacterial effect of RJ against several target bacterial strains. In addition, we briefly discuss other therapeutic activities, such as antioxidative and anticancer effects, of this outstanding natural product.

Burns and biofilms: priority pathogens and in vivo models

Burn wounds can create significant damage to human skin, compromising one of the key barriers to infection. The leading cause of death among burn wound patients is infection. Even in the patients that survive, infections can be notoriously difficult to treat and can cause lasting damage, with delayed healing and prolonged hospital stays. Biofilm formation in the burn wound site is a major contributing factor to the failure of burn treatment regimens and mortality as a result of burn wound infection. Bacteria forming a biofilm or a bacterial community encased in a polysaccharide matrix are more resistant to disinfection, the rigors of the host immune system, and critically, more tolerant to antibiotics. Burn wound-associated biofilms are also thought to act as a launchpad for bacteria to establish deeper, systemic infection and ultimately bacteremia and sepsis. In this review, we discuss some of the leading burn wound pathogens and outline how they regulate biofilm formation in the burn wound microenvironment. We also discuss the new and emerging models that are available to study burn wound biofilm formation in vivo.