Burn Wound Infection Research Articles

Antibacterial Efficacy of a Chitosan-Based Hydrogel Modified With Epsilon-Poly-l-Lysine Against Pseudomonas aeruginosa in a Murine-Infected Burn Wound Model.

Because antibiotic resistance is increasing worldwide and the leading cause of death in burn patients is an infection, an urgent need exists for nonantibiotic approaches to eliminate multidrug-resistant bacteria from burns to prevent their systemic dissemination and sepsis. We previously demonstrated the significant antibiofilm activity of a chitosan (CS) hydrogel containing the antimicrobial peptide epsilon-poly-l-lysine (EPL) against multidrug-resistant Pseudomonas aeruginosa using ex vivo porcine skin. In this study, we evaluated the in vivo antibacterial efficacy of a CS/EPL hydrogel against P. aeruginosa in a murine burn wound infection model. Full-thickness burns were created on the dorsum using a heated brass rod and were inoculated with bioluminescent, biofilm-forming P. aeruginosa (Xen41). Mice were treated with CS/EPL, CS, or no hydrogel applied topically 2 or 24 hours after inoculation to assess the ability to prevent or eradicate existing biofilms, respectively. Dressing changes occurred daily for 3 days, and in vivo bioluminescence imaging was performed to detect and quantitate bacterial growth. Blood samples were cultured to determine systemic infection. In vitro antibacterial activity and cytotoxicity against human primary dermal fibroblasts, keratinocytes, and mesenchymal stem cells were also assessed. CS/EPL treatment initiated at early or delayed time points showed a significant reduction in bioluminescence imaging signal compared to CS on days 2 and 3 of treatment. Mice administered CS/EPL had fewer bloodstream infections, lower weight loss, and greater activity than the untreated and CS groups. CS/EPL reduced bacterial burden by two orders of magnitude in vitro and exhibited low cytotoxicity against human cells. A topical hydrogel delivering the antimicrobial peptide EPL demonstrates in vivo efficacy to reduce but not eradicate established P. aeruginosa biofilms in infected burn wounds. This biocompatible hydrogel shows promise as an antimicrobial barrier dressing for the sustained protection of burn wounds from external bacterial contamination.

Epidemiological and bacteriological profile of sepsis in burns patients: A report from tertiary care hospital, India

Background: Burns are one of the most prevalent and mortifying forms of trauma. Patients burn with significant thermal injury require immediate intensive care unit (ICU) care to minimize morbidity and mortality. Burns patients are generally more predisposed to sepsis because of two main reasons, i.e., burn wound infection and catheter-related bloodstream infection (CRBSI). Due to extensive skin barrier disruption and an alteration in the cellular and humoral immune responses burn wounds has a much higher incidence of sepsis as compared to other forms of trauma. Aims and Objectives: The present study was undertaken to study the bacteriological profile and sources of sepsis in burns patients and their antimicrobial susceptibility pattern. Materials and Methods: It is a prospective observational study conducted in the Department of Burns, Plastic and Maxillofacial Surgery, ICU and Department of Microbiology of a tertiary care hospital, Uttar Pradesh, India, between January 2020 and June 2022. Adult patients with 30–70% of total body surface area burns with central venous catheter (CVC) inserted during ICU admission were enrolled in the study. The presence of clinical sepsis in the burn patients was evaluated using the American Burn Association Sepsis criteria. For all patients with suspected clinical sepsis, paired blood cultures were collected simultaneously; one from the CVC and another from a peripheral site and were sent for bacteriological culture. Blood culture samples were processed as per standard procedures. CRBSI was defined if the same organism was isolated in paired blood cultures. Burn wound biopsy was sent for quantitative culture and 105 organisms/g of tissue were considered significant. Results: In the present study, the overall incidence of clinical sepsis was 28.4% (39/137), out of which 48.7% of cases were found to be due to CRBSI and the most common organism involved was Klebsiella spp. (42.1%), 33.3% of cases were due to burn wound sepsis and the most common organism involved was Pseudomonas spp. (61.5%); and 18.0% of cases were those in which no known source could be found. Possible explanations for these cases could be sepsis without bacteremia due to endotoxins and Gram-negative endotoxemia. Conclusion: To find out microorganisms causing burn wound infection by culture and provide suitable antibiotics according to their antibiotic sensitivity patterns helping us in managing these infection and decreasing overall morbidity and mortality in burn patients.

Angiogenesis, hemocompatibility and bactericidal effect of bioactive natural polymer-based bilayer adhesive skin substitute for infected burned wound healing.

Thermal wounds are complex and lethal with irregular shapes, risk of infection, slow healing, and large surface area. The mortality rate in patients with infected burns is twice that of non-infected burns. Developing multifunctional skin substitutes to augment the healing rate of infected burns is vital. Herein, we 3D printed a hydrogel scaffold comprising carboxymethyl chitosan (CMCs) and oxidized alginate grafted catechol (O-AlgCat) on a hydrophobic electrospun layer, forming a bilayer skin substitute (BSS). The functional layer (FL) was fabricated by physiochemical crosslinking to ensure favorable biodegradability. The gallium-containing hydrophobic electrospun layer or backing layer (BL) could mimic the epidermis of skin, avoiding fluid penetration and offering antibacterial activity. 3D printed FL contains catechol, gallium, and biologically active platelet rich fibrin (PRF) to adhere to both tissue and BL, show antibacterial activity, encourage angiogenesis, cell growth, and migration. The fabricated bioactive BSS exhibited noticeable adhesive properties (P≤0.05), significant antibacterial activity (P≤0.05), faster clot formation, and the potential to promote proliferation (P≤0.05) and migration (P≤0.05) of L929cells. Furthermore, the angiogenesis was significantly higher (P≤0.05) when evaluated in vivo and in ovo. The BSS-covered wounds healed faster due to low inflammation and high collagen density. Based on the obtained results, the fabricated bioactive BSS could be an effective treatment for infected burn wounds.

Epidemiology and early bacterial colonization of minor and moderate pediatric burns: A retrospective study from a developing country

ObjectivesInfection is still the leading cause of morbidity and mortality among burn patients worldwide. Isolation and identification of pediatric burn wound bacterial colonizers can prevent infection and improve burn trauma treatment. In this study, we explored early microbial colonizers within the burn wounds and the susceptibility of those isolates to antibiotics among hospitalized pediatric patients with minor and moderate burns, clinically significant infections and outcomes. MethodsA retrospective analysis of pediatric patients admitted to the inpatient pediatric surgical ward and treated for minor and moderate burns from 2009 to 2018 was performed. ResultsOne hundred six patients met the inclusion criteria. The mean age was 3.6 ± three years (0.2–14.1 years). The most common type of burn was scald burns (82.1%). The mean TBSA of the hospitalized pediatric burn cases was 8.5% (IQR, 6–12%). Seventy-nine (74.5%) patients had positive wound cultures at admission, regardless of the hospital admission day. Fifty-eight (73.4%) had one bacterial growth (mono isolate), while 21 (26.6%) had mixed growth or poly isolates. Among patients with mixed growth or poly isolate, 16 had two bacteria, three had three bacteria, and one had four bacteria isolated, totaling 105 isolated microorganisms (14 different species, 70.5% Gram-positive bacteria and 29.5% Gram-negative bacteria). Twelve patients (11%) developed clinically significant infections (eleven got burn wound infection, and one had septicemia). All patients received prophylactic systemic antibiotics. Only 35.2% of the isolated bacteria from the wounds were sensitive to the prophylactic antibiotics, and only ∼17% in case of clinically significant infections. We found a statistically significant difference in the length of hospital stay between patients with initially colonized samples of burn wounds compared with patients with initial negative samples (p = 0.008). All patients in the cohort survived hospital discharge. ConclusionDespite common bacterial colonization of acute burn wounds, only ∼10% of the patients developed clinically significant infections, a minority of which were sensitive to prophylactic antibiotics. Our findings indicate the need to refine the antibiotic approach in pediatric patients with minor/moderate burns in our local setting.

Advanced Management of the Burn Patient

Burn injuries are a significant public health concern, with a substantial global burden. These injuries can result in complex, life-threatening situations that require advanced management strategies. This review explores the epidemiology, significance, and advanced management of burn patients. We delve into the theoretical framework, covering definitions, risk factors, complications, and various management approaches. The discussion highlights the latest advances in burn care, including early burn wound excision, fluid resuscitation, infection control, and rehabilitation. The evolving landscape of burn care research and its implications for improved patient outcomes are emphasized. In conclusion, this article underscores the importance of a multidisciplinary approach to burn patient care and the need for continued research to enhance the quality of life for survivors.

The Distribution and the Antimicrobial Susceptibility Features of Microorganisms Isolated From the Burn Wounds: A 10-Year Retrospective Analysis.

In this study, we aimed to evaluate the distribution features and antimicrobial susceptibility test results of the microorganisms isolated from the wounds of pediatric and adult patients with burn. The culture and susceptibility test results of the microorganisms, isolated from the wound swabs of the patients hospitalized in a tertiary-burn care center in 10-year period, were retrospectively screened on the microbiology department databases. Their distribution of isolated microorganisms regarding species and susceptibility test results were compared with previous studies. A total of 367 microorganisms, isolated from the burn wounds of 293 patients (13 ± 18.9 years, F/M: 0.93) (73 adults and 220 pediatric patients), were included in this study. A solitary agent was isolated in 239 (81.6%) patients, while 2 were isolated in 43 (14.7%) and 3 or more agents in 11 (3.8%). From these, 33% of the isolated microorganisms were gram-positive cocci, 61% were gram-negative bacteria, and 6% were Candida spp. The most common isolated microorganisms were Staphylococcus aureus (18.5%), Pseudomonas spp. (16.9%), and Escherichia coli (11.2%), while the least common was Streptococcus spp. (2.5%). Methicillin resistance was 15% among the S. aureus strains. No resistance was observed against levofloxacin, vancomycin, teicoplanin, linezolid, daptomycin, fusidic acid, and tigecycline in S. aureus strains. The highest resistance rates were observed against levofloxacin (64%), tobramycin (64%), pip/tazobactam (63%), imipenem (63%), and the lowest against colistin (5%) and ceftazidime (29%), among Pseudomonas spp. The most common causative agents in burn wound infections and their current antimicrobial susceptibility features should be well identified, in order for prevention of serious complications and optimal management the condition to occur.

Evaluation of combined carbon dots and ciprofloxacin on the expression level of pslA, pelA, and ppyR genes and biofilm production in ciprofloxacin-resistant Pseudomonas aeruginosa isolates from burn wound infection in Iran

Antimicrobial resistance and biofilm formation are increasingly significant public health concerns. This study aimed to examine the antibacterial and antibiofilm properties of carbon dots (C-dots) alone and in combination with antibiotics against biofilm-forming isolates of Pseudomonas aeruginosa. The antibacterial property of C-dots was investigated by broth microdilution method against ATCC PAO1 and P. aeruginosa clinical isolates. The antibacterial effect of the C-dots and ciprofloxacin combination was investigated using the checkerboard method. The antibiofilm effect of the C-dots alone and its combination with ciprofloxacin was evaluated using the microtiter plate method. Subsequently, the toxicity of each agent was tested on L929 fibroblast cells. In the end, the effects of C-dots on the expression levels of pslA, pelA, and ppyR genes were determined using real-time quantitative PCR. The combination of C-dots and ciprofloxacin exhibited a synergistic effect. Additionally, this compound substantially decreased bacterial growth (P < 0.0001) and inhibited biofilm formation at MIC (96 µg/mL) and sub-MIC (48 µg/mL) concentrations (P < 0.0053, P < 0.01). After being exposed to C-dots at a concentration of 1mg/mL for 24 hours, the survival rate of L929 cells was 87.3%. The expression of genes pslA, pelA, and ppyR, associated with biofilm formation in P. aeruginosa, was significantly reduced upon exposure to C-dots (P < 0.0023). The findings demonstrate a promising new treatment method for infections. Furthermore, reducing the dosage of antibiotics can lead to an improvement in the toxic effects caused by dose-dependent antibiotics and antimicrobial activity.

Bacteriophage entrapped chitosan microgel for the treatment of biofilm-mediated polybacterial infection in burn wounds

Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) bacteria are most commonly present in burn wound infections. Multidrug resistance (MDR) and biofilm formation make it difficult to treat these infections. Bacteriophages (BPs) are proven as an effective therapy against MDR as well as biofilm-associated wound infections. In the present work, a naturally inspired bacteriophage cocktail loaded chitosan microparticles-laden topical gel has been developed for the effective treatment of these infections. Bacteriophages against MDR S. aureus (BPSAФ1) and P. aeruginosa (BPPAФ1) were isolated and loaded separately and in combination into the chitosan microparticles (BPSAФ1-CHMPs, BPPAФ1-CHMPs, and MBP-CHMPs), which were later incorporated into the SEPINEO™ P 600 gel (BPSAФ1-CHMPs-gel, BPPAФ1-CHMPs-gel, and MBP-CHMPs-gel). BPs were characterized for their morphology, lytic activity, burst size, and hemocompatibility, and BPs belongs to Caudoviricetes class. Furthermore, BPSAФ1-CHMPs, BPPAФ1-CHMPs, and MBP-CHMPs had an average particle size of 1.19 ± 0.11, 1.42 ± 0.21, and 2.84 ± 0.28 μm, respectively, and expressed promising in vitro antibiofilm eradication potency. The ultrasound and photoacoustic imaging in infected burn wounds demonstrated improved wound healing reduced inflammation and increased oxygen saturation following treatment with BPs formulations. The obtained results suggested that the incorporation of the BPs in the MP-gel protected the BPs, sustained the BPs release, and improved the antibacterial activity.

Efficacy and optimal dose of acetic acid to treat colonised burns wounds: protocol for a pilot randomised controlled trial

IntroductionDespite of recent advancement in the burns wound management, burn wound infection (BWI) is still one of the major cause of burns mortality. Patients who survive their burns injury still...

Retraction note to: Treatment of methicillin resistant Staphylococcus aureus wound infection using vancomycin-loaded nanoparticles: An in vitro and in vivo study.

Due to the rise of bacteria that are resistant to multiple drugs, treating infections in burn wounds has become a worldwide problem. It is important to find new ways to treat these infections. Lipid-based drug delivery systems have emerged as a promising type of carrier for antibiotics as well as antibacterial agents, such as antimicrobial peptides and nucleic acids, for wound infections. To this end, the current study assessed the antibacterial effects and wound healing properties of vancomycin-loaded solid lipid nanoparticles (SLN) against methicillin-resistant Staphylococcus aureus (MRSA) surgical wound infections. vancomycin-SLN was synthesized by double emulsion solvent evaporation techniques, and then in vitro antibacterial activity was evaluated by well diffusion and broth microdilution methods. A surgical wound was inflicted on 36 male rats; the infection was caused by MRSA, and free vancomycin and vancomycin-SLN were topically applied. Particle size, PDI, zeta potential, drug loading, and encapsulation efficiency of the optimum vancomycin-SLN were 350 ± 24 nm, 0.402 ± 0.014, -16.3 ± 2.5 mV, 13.9 ± 1.4%, and 92.14 ± 3.1%, respectively. In vitro antibacterial assays showed lower MICs for free vancomycin and killed bacteria more efficiently than vancomycin-SLN. However, the synthesized nanoparticles indicated long-term antibacterial activity against MRSA. Animals that were treated with vancomycin-SLN showed the best wound healing procedure. Treatment of rats with vancomycin-SLN increased re-epithelialization and decreased granulation tissue development, as seen by histological analysis. Antibiotic-loaded SLN could not only manage wound infection but also enhance wound healing. Therefore, this kind of treatment should be considered by scientists as an applicable treatment for wounds.

A new strategy to treat Pseudomonas aeruginosa infected burn wounds: Antimicrobial cocktails as potent topical therapy

Burn insults are traumatic as they inflict intense damage on different layers of skin and other organic body tissues, causing alterations in host's immune system, thereby, impairing the wound healing process. Weakened immune system and damaged natural cutaneous barrier opens a doorway for microorganisms to inhabit and infect burn wounds, lengthening hospital stays, and escalating the mortality rates. The most prominent burn wound infection-causing bacteria is Pseudomonas aeruginosa, which is accountable for higher mortality rates and is most ubiquitous among all the other burn wound pathogens because of its inclination to flourish in the moist environment causing invasive infections and selective advantage to grow within burn wound exudates. Due to the alarming rise in multi-drug resistance, the conventional therapy to treat burn insults and subsequent infections involving surgical removal of devitalized tissue, flushing wound site with normal saline, and employment of antibiotics topically is rendered ineffective suppressing physicians in their treatment choices and resulting in adverse outcomes observed in burn units. Despite advancements in the burn care field, rising drug resistance and its related consequences is necessitating vigorous research to devise an antimicrobial therapy targeting three broad areas collectively, for instance, P. aeruginosa infection management, immunomodulation, and wound healing. Hence, we propose formulating an antimicrobial cocktail exhibiting anti-infective, immunomodulatory, and wound healing properties having potential to improve survival rates among the P. aeruginosa infected burn populations, owning to its simple and easy application in resource-limited settings.

Molecular typing and characterization of Staphylococcus aureus isolates from burn wound infections in Fujian, China.

Staphylococcus aureus (S. aureus) is the most common causative agent of burn wound infection, that often leads to high morbidity and mortality. However, there is not enough knowledge about the molecular epidemiology and antimicrobial susceptibility of S. aureus isolates from burn wound infections in Fujian, China. Between 2016 and 2021, 90 S. aureus isolates were collected from burn wound infections in Fujian, China, including 59 methicillin-resistant (MRSA) strains and 31 methicillin-susceptible (MSSA) strains. These were investigated for molecular characteristics, virulence genes, biofilms, and antimicrobial susceptibility. All the isolates were genotyped by multilocus sequence typing (MLST), spa typing, agr typing, and SCCmec typing. Conventional PCR was performed for the detection of virulence genes. Biofilm formation capacity was assessed by tissue culture plate assay (TCP). The antimicrobial susceptibility of the isolates was evaluated using the dilution method. In total, 37 sequence types (ST) and 34 Staphylococcal protein A (spa) types (including a new type named spa-t20720) were identified based on multilocus sequence typing (MLST) and spa typing, respectively. CC8-ST239-t030-agrI-SCCmecIII (57.6%,34/59) and CC7-ST7-t091-agrI (16.1%, 5/31) represented the main clone of MRSA and MSSA isolates, respectively. Antibiotic susceptibility testing identified a significant difference in resistance rates between ST239 and non-ST239 isolates (p < 0.05). Twelve virulence genes were detected, of which the most common were icaA and icaD (both 100%), followed by icaB and icaC (both 96.7%), icaR (95.6%), lukED (81.1%), lukAB (62.2%), pvl (50%), hlgBC (26.7%), and eta (4.4%). Moreover, lukAB, hlgBC, agrI, and agrIII were significantly correlated with burn severity (p < 0.05). MRSA isolates were less likely, compared with MSSA isolates, to carry pvl, lukAB, and hlgBC (p < 0.05). A new spa type, t20720, was identified that contains pvl, lukED, lukAB, hlgBC, icaA, icaB, icaC, icaD, and icaR genes and has strong biofilm formation ability. CC8-ST239-t030-agrI-SCCmecIII and CC7-ST-7-t091-agrI were the prevalent molecular signatures of MRSA and MSSA isolates from burn wound infections in Fujian, China, respectively. The newly identified spa-t20720 isolate, which carries a wide range of virulence genes and has strong biofilm formation ability, requires special clinical attention.

Versatile Hydrogel Dressings That Dynamically Regulate the Healing of Infected Deep Burn Wounds.

Severe burns threaten patient lives due to pain, inflammation, bacterial infection, and scarring. Most burn dressings that are commonly used perform a single function and are not well suited for the management of deep burns. Therefore, a multifunctional antimicrobial peptide- and stem cell-loaded macroporous hydrogel that can fight bacterial infection and regulate wound healing progression by temporally regulating cytokine production by internal stem cells is developed. The macroporous skeletal hydrogel is manufactured via the cryogenic gelation of hyaluronic acid (cryogel). Based on the oxidative polymerization reaction of dopamine, the antimicrobial peptide DP7 is immobilized on the surface of the cryogel (DA7CG). Placental mesenchymal stem cells (PMSCs) are then packaged inside the macroporous hydrogel (DA7CG@C). According to the results of in vitro and in vivo experiments, during the inflammatory phase, DP7 inhibits infection and modulates inflammation; during the proliferative phase, DA7CG@C accelerates the regeneration of skin, blood vessels, and hair follicles via internal stem cells; and during the remodeling phase, DA7CG@C contributes to extracellular matrix remodeling due to the ability of DP7 to regulate the paracrine secretion of PMSCs, synergistically promoting scar-free healing. DA7CG@C can participate in all phases of wound healing; therefore, it is a promising dressing for burn treatment.

Risk Factors and Pathogens of Wound Infection in Burn Inpatients from East China.

Infection is the predominant contributor to morbidity and mortality in burn patients, and burn wound infection (BWI) is the most common reason. The objective of this research was to analyze the incidence, factors and progression of BWI, in terms of events and bacteria. Clinical variables of all qualified patients admitted to burn wards were analyzed retrospectively in 2021 at a tertiary hospital in eastern China through univariate analysis and multivariate logistic regression. The Kaplan-Meier method was also used for plotting survival curves. Isolates and resistance data were evaluated to demonstrate the evolution of targeted antibiotics of strains from BWI. A total of 580 (median age, 39.5 years (23-56 years); 372/580 (64.14%) male) patients were evaluated, 348 (60.0%) of whom experienced BWI. A variety of factors are associated with BWI. Multivariate logistic regression analysis showed that depth and area of burn and duration from burn to first hospitalization are independent risk factors for BWI. For BWI onset in these patients, 47.24% (274/580) occurred in the first week. The most frequently isolated causative organism was Staphylococcus aureus (15.7%) in patients with BWI. The duration of transition from Gram-positive strains (median 3 days, (2-7 days)) to Gram-negative (median 10 days, (4-17 days)) ones isolated from burn wound shrunk. Hospital length of stay was considered as a protective factor for BWI. The precise assessment of factors affecting BWI in burn patients enhances prompt and suitable management. Swab cultures for surveillance could be utilized to monitor the microbiological status of burn patients.

Emergence of Multidrug Resistant Microbial Species in the Bacterial Profile of Burn Wounds: A Cohort Study from Pak Italian Modern Burn Center, Multan

Objective: To document the prevalence of microflora causing burn wound infections in our setup, track any trends of change in the flora after a 7-day treatment period, and document any rise in the incidence of multidrug-resistant microbes. Methods: This cohort study was conducted at the Pak Italian Modern Burn Centre (PIBC), Multan, over a one-year period from January 2022 to December 2022. Surface wound swabs were collected from 150 patients admitted to the Burn unit on day 3, day 10, and day 17 after sustaining burns. Standard procedures for isolation and identification of microorganisms were followed, and the growth of microflora obtained was subjected to antibiotic sensitivity testing following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: Gram-negative isolates included Pseudomonas aeruginosa, Escherichia coli, Klebsiella spp., Citrobacter spp., Proteus vulgaris, and Providencia mirabilis. Gram-positive isolates included Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). Pseudomonas aeruginosa caused 39.3% of wound infections within 72 hours of admission and 56.9% of wound infections by the first week post-burn. Proteus vulgaris (36%) was the most frequently isolated microorganism in the second week post-burn. All these isolates exhibited an alarming level of resistance to routinely used antibiotics, necessitating the use of older, less safe antibiotics like colistin for gram-negative infections. Conclusions: The rising incidence of antimicrobial resistance can be attributed to the emergence of multidrug-resistant bacterial species found in burn patients. Overcrowding in burn treatment facilities further exacerbates the risk of cross-contamination.

DETECTION OF BIOFILM PRODUCTION AMONG MBLS-PRODUCING PSEUDOMONAS AERUGINOSA CARRYING ALGD, PELF, PSLD GENES ISOLATED FROM BURN CENTER IN AL-NAJAF GOVERNORATE, IRAQ

Background: Pseudomonas aeruginosa is a worldwide cause of chronic and acute infections of burn wounds. Aim of study: Detection of algD, pelF, and pslD genes encoding biofilm formation among isolates of Pseudomonas aeruginosa that producing metallo β-lactamases. Materials and Methods: 93 isolates of Pseudomonas aeruginosa were isolated from 362 inpatients with infected burn wounds at the burn center in Al-Najaf Governorate, Iraq, from September 2022 to February 2023. Results: Pseudomonas aeruginosa isolates were identified microscopically, phenotypically, culturally, and biochemically then by using the double-disc synergy method to test their capacity to produce metallo β-lactamases. Out of the 25 MBLs-producers, 22 (88%) were biofilm-producing isolates when tested by tissue culture plate method, 4 (16%), 10 (40%), and 8 (32%) were, respectively, weak, medium, and strongly biofilm producers. 25 metallo β-lactamases-producers under study, which had previously been evaluated using biofilm phenotypic method, were subjected to the investigation of biofilm encoding genes by using polymerase chain reaction technique. This molecular technique detected 21 (84%) isolates carried single and multiple biofilm encoding genes, 10(40%) isolates had algD gene, 6 (24%) isolates harbored algD and pslD genes and 5(20%) isolates carried algD, pelF and pslD genes. The single pslD and pelF genes were not detected among test isolates. Conclusions: There was a high prevalence of biofilmproducers among metallo β-lactamases-producing P. aeruginosa isolates. In addition, a clear positive correlation was observed between the multiple genes encoding biofilm and the degree of biofilm production among metallo β-lactamases-producers and close association between metallo β-lactamases and biofilms production, which explains the prevalence of carbapenems resistance and biofilm-production in this study because biofilm provides the appropriate environment for antibiotic resistance in general and carbapenems in particular

Electrospun Nanofibrous Biocomposite of Royal Jelly/Chitosan/Polyvinyl Alcohol (RJ/CS/PVA) Gel as a Biological Dressing for P. aeruginosa-Infected Burn Wound.

Burn wounds are vulnerable to various infections due to damage to the tissue and changes in immune responses. Pseudomonas aeruginosa is a critical bacterium that can cause burn wound infections, which can be life-threatening and delay wound healing. Therefore, it is essential to develop an efficient strategy to prevent the spread of infection in burn wounds. The present study aims to investigate the effectiveness of electrospun nanofibers of royal jelly on a chitosan/polyvinyl alcohol polymer scaffold in repairing burn wounds infected with Pseudomonas aeruginosa. To achieve this, the researchers analyzed the morphology and physicochemical properties of the synthesized nanofibers using SEM, FTIR, BET, and TGA analyses. They also examined the antibacterial properties of the nanofibers using agar diffusion and spread plate techniques. In addition, hemolysis tests were carried out to assess biocompatibility. Finally, the ability of the nanofibers to repair burn wounds infected with Pseudomonas aeruginosa was evaluated using a laboratory mouse model. The study results showed that the synthesized nanofibers had desirable morphology and physicochemical properties and significant antibacterial effects in both in vitro and in vivo conditions. Also, loading RJ into the polymer scaffold significantly reduced erythrocyte lysis. The wound healing and contraction rates were significantly higher than the control groups, and tissue repair, re-epithelialization, and collagen synthesis occurred faster, preventing the spread of infection to deeper tissue areas. Based on these findings, the synthesized system has the potential to serve as a suitable substitute for some invasive treatments and chemical drugs to improve chronic wounds and manage infection control in burn injuries.

Synergy between Winter Flounder antimicrobial peptides

Some antimicrobial peptides (AMPs) have potent bactericidal activity and are being considered as potential alternatives to classical antibiotics. In response to an infection, such AMPs are often produced in animals alongside other peptides with low or no perceivable antimicrobial activity, whose role is unclear. Here we show that six AMPs from the Winter Flounder (WF) act in synergy against a range of bacterial pathogens and provide mechanistic insights into how this increases the cooperativity of the dose-dependent bactericidal activity and potency that enable therapy. Only two WF AMPs have potent antimicrobial activity when used alone but we find a series of two-way combinations, involving peptides which otherwise have low or no activity, yield potent antimicrobial activity. Weakly active WF AMPs modulate the membrane interactions of the more potent WF AMPs and enable therapy in a model of Acinetobacter baumannii burn wound infection. The observed synergy and emergent behaviour may explain the evolutionary benefits of producing a family of related peptides and are attractive properties to consider when developing AMPs towards clinical applications.

A Bacteriophage-Loaded Microparticle Laden Topical Gel for the Treatment of Multidrug-Resistant Biofilm-Mediated Burn Wound Infection.

Klebsiella pneumoniae is regarded as one of the most profound bacteria isolated from the debilitating injuries caused by burn wounds. In addition, the multidrug resistance (MDR) and biofilm formation make treating burn patients with clinically available antibiotics difficult. Bacteriophage therapy has been proven an effective alternative against biofilm-mediated wound infections caused by MDR bacterial strains. In the current study, the bacteriophage (BPKPФ1) against MDR Klebsiella pneumoniae was isolated and loaded into the chitosan microparticles (CHMPs), which was later incorporated into the Sepineo P 600 to convert into a gel (BPKPФ1-CHMP-gel). BPKPФ1 was characterized for lytic profile, morphological class, and burst size, which revealed that the BPKPФ1 belongs to the family Siphoviridae. Moreover, BPKPФ1 exhibited a narrow host range with 128PFU/host cellof burst size. The BPKPФ1-loaded CHMPs showed an average particle size of 1.96 ± 0.51 μm, zeta potential 32.16 ± 0.41 mV, and entrapment efficiency in the range of 82.44 ± 1.31%. Further, the in vitro antibacterial and antibiofilm effectiveness of BPKPФ1-CHMPs-gel were examined. The in vivo potential of the BPKPФ1-CHMPs-gel was assessed using a rat model with MDR Klebsiella pneumoniae infected burn wound, which exhibited improved wound contraction (89.22 ± 0.48%) in 28 days with reduced inflammation, in comparison with different controls. Data in hand suggest the potential of bacteriophage therapy to be developed as personalized therapy in case of difficult-to-treat bacterial infections.

Immobilization of Bacteriophages in Ex Tempore Hydrogel for the Treatment of Burn Wound Infection.

The resistance of bacteria to antibiotics is a major problem for anti-bacterial therapy. This problem may be solved by using bacteriophages-viruses that can attack and destroy bacteria, including antibiotic-resistant ones. In this article, the authors compared the efficacy of topical bacteriophage therapy and systemic antibiotic therapy in the treatment of wound infections caused by ESKAPE pathogens in patients with limited (less than 5% of the body surface) full-thickness burns. Patients in the study group (n = 30) were treated with PVA-based hydrogel dressings saturated ex tempore with a bacteriophage suspension characterized by its lytic activity against the bacteria colonizing the wound. Patients in the control group (n = 30) were treated using etiotropic systemic antibiotic therapy, and the wounds were covered with gauze bandages soaked in an aqueous solution of povidone-iodine. An assessment of the decrease in the level of bacterial contamination of the recipient wounds in both groups was conducted after 7 days, and after that, free skin grafting was performed. On day 14 after free skin grafting, patients in both groups underwent incisional biopsy. The study group demonstrated an increase in the indices of proliferative activity (Ki-67), and angiogenesis (CD-31, VEGF) in the area of engraftment of the split-thickness skin grafts. The results indicate that PVA-based hydrogel wound dressings can be used as bacteriophage carriers for local antimicrobial therapy ahead of free skin grafting.