Bacteria In Wounds Research Articles

Semi-Interpenetrating Hydrogel with Long-Term Intrinsic Antibacterial Properties Promotes Healing of Infected Wounds In Vivo.

Bacterial infections significantly deteriorate the process of wound healing. The wound dressings loaded with antimicrobials are widely used to reduce bacterial infections. However, release-based sterilization may increase the risk of drug resistance of bacteria and complicate translation. Thus, the development of long-term intrinsic antibacterial wound dressings is highly desirable. In this study, an intrinsic antibacterial hydrogel (PVA/PPG-HBPL) consisting of poly(vinyl alcohol) (PVA), poly(polyethylene glycol methyl ether methacrylate-co-glycidyl methacrylate) (PPG), and hyperbranched poly-l-lysine (HBPL) was designed and fabricated. The mechanical properties of the PVA/PPG-HBPL hydrogel were enhanced by hydrogen bonding and semi-interpenetrating networks. It also possessed a favorable ability to absorb the wound exudates. The release of antibacterial HBPL was significantly decreased by the methods of cyclic freeze-thawing and covalent cross-linking during hydrogel fabrication, enabling the PVA/PPG-HBPL hydrogel with intrinsic and long-term antibacterial performance. The PVA/PPG-HBPL hydrogel dressing killed 99.9% of methicillin-resistant Staphylococcus aureus (MRSA) cultured on its surface without observable cytotoxicity in vitro. It observably shortened the healing process by 2 orders of magnitude of MRSA colonies compared with the control in the MRSA-infected full-thickness skin wound of rats in vivo even after being soaked in phosphate-buffered saline (PBS) for 21 days (PBS was changed every 3 days). The antibacterial hydrogels could kill wound bacteria in a timely manner, significantly reduce inflammatory cell infiltration, and promote neovascularization and collagen deposition.

An antimicrobial microneedle patch promotes functional healing of infected wounds through controlled release of adipose tissue-derived apoptotic vesicles

The high incidence and mortality rates associated with acute and chronic wound infections impose a significant burden on global healthcare systems. In terms of the management of wound infection, the reconstruction and regeneration of skin appendages are essential for the recovery of mechanical strength and physiological function in the regenerated skin tissue. Novel therapeutic approaches are a requisite for enhancing the healing of infected wounds and promoting the regeneration of skin appendages. Herein, a novel antimicrobial microneedle patch has been fabricated for the transdermal controlled delivery of adipose tissue-derived apoptotic vesicles (ApoEVs-AT@MNP) for the treatment of infected wounds, which is expected to achieve high-quality scarless healing of the wound skin while inhibiting the bacteria in the infected wound. The microneedle patch (MNP) system possesses adequate mechanical strength to penetrate the skin, allowing the tips to remain inside tissue for continuous active release of biomolecules, and subsequently degrades safely within the host body. In vivo transplantation demonstrates that ApoEVs-AT@MNP not only inhibits bacterial proliferation in infected wounds but also significantly promotes effective and rapid scarless wound healing. Particularly noteworthy is the ability of ApoEVs-AT@MNP to promote the rapid formation of mature, evenly arranged hair follicles in infected wounds, observed as early as 8 days following implantation, which is essential for the restoration of skin function. This rapid development of skin appendages has not been reported this early in previous studies. Therefore, ApoEVs-AT@MNP has emerged as an excellent, painless, non-invasive, and highly promising treatment for infected wounds.

Anaerobic bacteria in chronic wounds: Roles in disease, infection and treatment failure.

Infection is among the most common factors that impede wound healing, yet standard treatments routinely fail to resolve chronic wound infections. The chronic wound environment is largely hypoxic/anoxic, and wounds are predominantly colonised by facultative and obligate anaerobic bacteria. Oxygen (O2) limitation is an underappreciated driver of microbiota composition and behaviour in chronic wounds. In this perspective article, we examine how anaerobic bacteria and their distinct physiologies support persistent, antibiotic-recalcitrant infections. We describe the anaerobic energy metabolisms bacteria rely on for long-term survival in the wound environment, and why many antibiotics become less effective under hypoxic conditions. We also discuss obligate anaerobes, which are among the most prevalent taxa to colonise chronic wounds, yet their potential roles in influencing the microbial community and wound healing have been overlooked. All of the most common obligate anaerobes found in chronic wounds are opportunistic pathogens. We consider how these organisms persist in the wound environment and interface with host physiology to hinder wound healing processes or promote chronic inflammation. Finally, we apply our understanding of anaerobic physiologies to evaluate current treatment practices and to propose new strategies for treating chronic wound infections.

Injectable antibacterial hydrogels based on oligolysines for wound healing

Generally, oligolysine has poor antibacterial effect and almost no antibacterial activity. Herein, low cost and easily available oligolysines were chosen to prepare injectable antibacterial hydrogel (PVAL-gel) for wound healing. The hydrogel network was formed by cross-linking vanillin acrylate-N, N-dimethylacrylamide copolymer P(VA-co-DMA), oligolysine and adipate dihydrazide through Schiff base bond. The obtained hydrogel PVAL-gel exhibited not only excellent self-healing capability and injectability, but also the efficient contact antibacterial ability and good inhibitory effects on E.coli and S.aureus. In vitro, 99.9 % of pathogenic bacteria was killed within 160 min. Furthermore, the injectable PVAL-gel could rapidly eradicate bacteria in infected wounds and notably enhance the healing of full-thickness skin wounds. Therefore, PVAL-gel is expected to be used as a high-end dressing for the treatment of infected skin wounds, which can promote wound healing.

Analysis of therapeutic effect of silver-based dressings on chronic wound healing.

Chronic wounds are susceptible to bacterial infections and at high risk of developing antibiotic-resistant bacterial infections. Silver is an antimicrobial by targeting almost all types of bacteria in chronic wounds to reduce the bacterial load in the infected area and further facilitate the healing process. This study focused on exploring whether silver-based dressings were superior to non-silver dressings in the treatment of chronic wounds. PubMed, Web of Science and Embase were comprehensively searched from inception to March 2024 for randomized clinical trials and observational studies. The endpoints in terms of wound healing rate, complete healing time, reduction on wound surface area and wound infection rate were analysed using Review Manager 5.4 software. A total of 15 studies involving 5046 patients were eventually included. The results showed that compared with patients provided with non-silver dressings, patients provided with silver-based dressings had higher wound healing rate (OR: 1.43, 95% CI: 1.10-1.85, p = 0.008), shorter complete healing time (MD: -0.96, 95% CI: -1.08 ~ -0.85, p < 0.00001) and lower wound infection rate (OR: 0.56, 95% CI: 0.40-0.79, p = 0.001); no significant difference in the reduction on wound surface area (MD: 12.41, 95% CI: -19.59-44.40, p = 0.45) was found. These findings suggested that the silver-based dressings were able to enhance chronic wound healing rate, shorten the complete healing time and reduce wound infection rate, but had no significant improvement in the reduction on wound surface area. Large-scale and rigorous studies are required to confirm the beneficial effects of silver-based dressings on chronic wound healing.

Zeolitic imidazolate framework-8@polydopamine decorated carboxylated chitosan hydrogel with photocatalytic and photothermal antibacterial activity for infected wound healing

Open wounds are susceptible to bacterial infections, and antibiotics are commonly used to treat these infections. However, widespread use of antibiotics will easily induce bacterial resistance. Green antibacterial agents serve as excellent alternative for antibiotics in infection therapy. In this work, polydopamine (PDA) was used to modify the surface of ZIF-8, which not only enhances the water stability of Zeolitic imidazolate framework-8(ZIF-8) but also improves its photocatalytic and photothermal capabilities. ZIF-8@PDA was incorporated into carboxylated chitosan (CCS) films as an antibacterial agent, the resulting ZIF-8@PDA-CCS films exhibit excellent ionic/photocatalytic/photothermal antibacterial performance. The film exhibited an impressive 99% in vitro bacterial inhibition rate. After treatment with ZIF-8@PDA-CCS, the bacteria in infected wounds can be completely suppressed. These findings suggest that ZIF-8@PDA-CCS could serve as a potentional antibacterial dressing.

Antibacterial Activity of Mirabilis jalapa Leaves (Karifuma) Extract Against Bacterial Wound Infection from Patients Attending Rango Health Center

Background: Mirabilis jalapa is a perennial herbaceous bushy plant with several pharmacological activities, such as anti-diabetic, anti-inflammatory, anti-oxidative, anti-bacterial, anti-microbial, anti-fungal, anti-viral, diuretic and anthelmintic. Wound infections are a major public health concern in Rwanda, with 8% of the general population having difficulties controlling them and 25% of those above 60 years old. Traditional medicine is used to treat many conditions such as chest infections, coughs, snake-bites and burns. Mirabilis jalapa seeds have been reported to be effective against bacteria causing wound infections. Aim: This study evaluated the antibacterial activity of Mirabilis jalapa leaves extract against infected wound bacteria from patients attending Rango Health Center. Methods: Cross sectional study design and maceration method was used in Mirabilis jalapa leaves extraction with Methanol, Ethanol, Diethyl ether and Distilled water as solvents. Results: Different extracts were obtained according to the solvents with different volumes and concentrations. The highest extract volume obtained was Distilled water with 6 ml and the least was Diethyl ether with 2.7 ml. In 71 participants who had wound infection, 42% had a bacterial infection. Among them, 25% had Staphylococcus aureus, 7% had Klebsiella pneumoniae, 6% had Escherichia coli, and 4% had Pseudomonas aeruginosa. Through the agar well diffusion method, Methanol extracts showed the highest inhibition zones while distilled water extracts exhibited the lowest inhibition zones to the isolated bacteria. Conclusion: The study confirms the antibacterial activity of the Mirabilis jalapa leaves extract against infected wound bacteria, with methanol and ethanol being the best solvents. Keywords: Mirabilis jalapa leaves, wound infections, antibacterial activity

Microneedles for Enhanced Bacterial Pathogen Inactivation and Accelerated Wound Healing

AbstractBacterial wound infections are a significant socioeconomic concern in the modern healthcare industry owing to increased morbidity, prolonged hospital stay, and mortality. Bacterial infectious agents that colonize the wound bed develop biofilms, acting as a physical barrier that prevents the effective penetration of topical antimicrobials. Further, bacteria in such infectious wounds express a wide range of virulence factors promoting intercellular transmigration and host cell invasion complicating the treatment regimen. To address this need, a water‐dissolvable poly‐vinyl pyrrolidine (PVP), calcium peroxide (CPO) infused microneedle structure (denoted as PVP/CPO MN) for effective transdermal delivery of antimicrobial payload deep into the tissues is developed. Fluid exudate from the wound bed dissolves the PVP/CPO MN enabling the release of CPO deep into the infected wound bed. A slow catalytic decomposition of CPO results in the sustained release of reactive oxygen species (ROS) deep within the infected wound inhibiting the inter‐ and intracellular pathogens. Here, a systematic study of microneedle fabrication and sterilization after complete packaging is conducted to ensure scalability and safe applicability while maintaining mechanical and antibacterial properties. In vitro, antibacterial efficacy of the microneedles is validated against two common wound pathogens, Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Moreover, the PVP/CPO MN exhibited significant efficacy in eradicating both extracellular and intracellular bacterial populations within an in vivo porcine wound model. Additionally, the microneedle technology facilitated a faster wound healing, with ≈30% increase compared to control and a 15% improvement over conventional silver dressing.

Analysis of Distribution and Drug Susceptibility Test Results of Pathogenic Bacteria in Diabetic Foot Ulcers.

This study aimed to determine the pathogen distribution and drug susceptibility of diabetic foot wound secretions in a tertiary hospital in a coastal area of southeastern China to guide clinical antibiotic selection. A retrospective analysis was conducted on 212 patients with diabetic foot hospitalized at Xiamen Third Hospital from 2018 to 2023, and foot wound secretions were collected for microbial culture and drug susceptibility testing. Among 212 cases of patients with diabetic foot wound secretions, 163 cases (76.9%) were cultured with pathogenic bacteria, and a total of 207 strains of pathogenic bacteria were cultured, including 75 strains (36.23%) of Gram-positive (G+) bacteria, 118 strains of Gram-negative (G-) bacteria (57.00%), 14 strains of fungi (6.76%), 120 cases of single microorganism infection (73.62%), 43 cases of mixed infection (26.38%), and 15 strains of multidrug-resistant bacteria (7.25%). The top three pathogenic bacteria were Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. G+ bacteria were dominated by S.aureus. Drug susceptibility results showed that G+ bacteria were highly susceptible to vancomycin, linezolid, tigecycline, quinupristin/dalfopristin, rifampicin, and furotoxin, and somewhat resistant to penicillin, erythromycin, clindamycin, and cefoxitin. Among G- bacterial infections, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Proteus were the major species. Drug susceptibility testing indicated that carbapenems such as imipenem and ertapenem were the most effective antibacterial drugs against G- strains, followed by amikacin, piperacillin, and tazabactams to which these bacteria were also relatively sensitive, while resistance to penicillins and first-generation cephalosporins increased significantly. We isolated one strain of pathogenic bacteria from a Wagner grade1 ulcer, which was G+ bacteria. In Wagner grade2 ulcers, the distribution of pathogenic bacteria was mainly G+ bacteria. In Wagner grade3 and 4 ulcers, the distribution of pathogenic bacteria was mainly G- bacteria, and the increased rate of mixed infection was mainly due to mixed infection of G+ and G-. Two strains of pathogenic bacteria were isolated at Wagner grade5, which were mixed infections of G+ and G-. Pathogenic bacteria in diabetic foot wounds are predominantly G- bacteria, followed by G+ bacteria. As the Wagner ulcer grade increases, the distribution of pathogenic bacteria changes from G+ bacteria to G- bacteria, and the mixed infection rate increases. G+ bacteria are highly susceptible to vancomycin, linezolid, tigecycline, quinupristin/dalfopristin, rifampicin, and furotoxin, and somewhat resistant to penicillin, erythromycin, clindamycin, and cefoxitin. G- bacteria are more sensitive to the antimicrobial drugs ertapenem, imipenem, amikacin, piperacillin tazobactam, and have high resistance to penicillin and first-generation cephalosporins.

On-demand release of silver from composite hydrogel by cold atmospheric plasma jet for wound infection control

Silver is an antimicrobial commonly used within wound care chiefly in advanced dressings or in a topical cream form, such as silver sulfadiazine (SSD). Although silver is effective at controlling the growth of many common wound bacteria, it can be cytotoxic and can build up in tissue, stalling the healing process. Here, we demonstrate the development of an on-demand release system for delivery of silver from a composite hydrogel comprising sodium polyacrylate particles dispersed in a cryo-crosslinked polyvinyl alcohol carrier gel. Application of cold atmospheric plasma (CAP) jet to the silver loaded hydrogel resulted in controlled release of silver. This release is thought to occur due to the formation of nitrous acids in the hydrogel by the CAP, resulting in protonation of carboxylate groups in the hydrogel and subsequent gel de-swelling due to the reduction in interchain charge repulsion. The location of silver within the sodium polyacrylate particles was probed using scanning electron microscopy and EDX imaging. The released silver inhibited the growth of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus and significantly reduced the viable cell count of the P. aeruginosa biofilm.

P29 Long-read sequencing provides unprecedented insight into the skin and wound microbial landscape

Abstract Introduction and aims It is becoming increasingly evident that the microbial inhabitants of our skin play a key role in cutaneous health and disease. However, our understanding of the contribution of the complex skin microbiome to wound healing outcome remains incomplete. This is, in part, due to the historic challenges around traditional sampling and profiling Methods, which often fail to capture the abundance and diversity of the skin microbiome. Recent advances in microbiome sequencing technologies now enable more comprehensive characterization of skin bacterial composition and host-microbe interactions. Thus, the aim of this study was to utilize a novel long-read sequencing platform to provide species-level microbiome characterization and deliver important insight into the drivers of pathological skin repair. Methods Microbial DNA samples were collected from the skin and wounds of healthy volunteers and patients with chronic wounds (n = 40 per group). Long-read nanopore sequencing was used to profile microbiome samples, while RNA-Seq enabled generation of donor transcriptomic profiles. A multifaceted approach was used to integrate these datasets to investigate the complex interplay between host skin pathology and the microbiome. Results We first identified perturbations in the skin microbiome of patients with chronic wounds, which was significantly less diverse than healthy skin and colonized with key bacteria associated with pathogenicity. These alterations in the skin microbiome also correlated with transcriptomic changes, such as upregulation of genes associated with inflammation, stress and poor healing. Interestingly, long-read sequencing data displayed poor correlation with routine clinical microbiology swabs, while specific clinical characteristics (e.g. glycaemic control and wound duration) were strongly linked to wound microbiome composition. Conclusions Collectively, these data provide crucial new insight into the skin and wound microbial landscape, demonstrating a potential role for specific wound bacteria in modulating pathological skin repair.

Antibacterial activity and perineal wound healing of swallow’s gel extracts

Background: Swallow's nest has a glycol content of proteins, carbohydrates (25.62–27.26%), and proteins (62–63%); protein is an indispensable content for the healing process of perineal wounds, protein plays the main ingredient in cell formation, and repairs damaged tissues. In previous studies, swallow's nest extract against perineal wounds in mice obtained the results of accelerated healing on days 3 and 4. However, no studies have been conducted on human perineal injuries.Purpose: Knowing the effectiveness of the swallow's nest extract gel (Aerodramus Fuciphagus) 30% against wound healing and a decrease in the number of colonies of staphylococcus aureus bacteria in the perineal wounds of the postpartum mother.Methods: This experiment study has a post-test with a control group design. The sample comprised 34 postpartum maternal respondents divided into two groups randomly (intervention and control groups). The intervention group was given gel from swallow's nest extract while the control group carried out a dry clean treatment; both were treated to the wound. Perineal wound healing based on REEDA scores was analyzed using the Friedman test, while bacteria in perineal wounds were analyzed using the Man-Whitney test.Results: Based on the REEDA scale, the perineal wound healing rate in the intervention group was better, where healing had already occurred on day 5, compared to the control group that occurred on day 7 (p&lt;0.0001). The number of bacteria in the perineal wounds of the intervention group was less, with an average of 0.06 CFU, compared to the control group's average control group's average of 1.11 CFU (p&lt;0.05).Conclusion: Swallow's nest extract is influential and beneficial in healing perineal wounds in postpartum mothers and has antibacterial activity.

A novel NO-releasing composite hydrogel for infected wound healing

Infection and inflammation are key factors affecting wound healing. Hydrogels are excellent wound dressings that provide a moist healing environment and serve as carriers for drugs or functional components. This work proposes a composite hydrogel, APLCE, composed of methyl methacrylate L-arginine (M-L-Arg) as an NO donor, synthesized through free radical polymerization with acrylamide (AM) and polyethylene glycol (PEG). The hydrogel matrix exhibits good water retention and mechanical properties. CaO2 and ε-poly-L-arginine (EPL) are embedded in the hydrogel to form APLCE, where the hydrolysis of CaO2 releases H2O2, triggering the release of arginine to release NO, inhibiting wound inflammation and bacterial growth. EPL added to the hydrogel synergistically with NO exhibits an antibacterial effect, with a bacterial inhibition rate exceeding 99 %. Animal experiments show that APLCE can completely eradicate bacteria in infected wounds, promote new skin formation, and achieve a wound closure rate of 94 % within 14 days. These findings emphasize the potential clinical application of APLCE as an innovative wound dressing material.

Effect of Topical Silver Nanoparticle Formulation on Wound Bacteria Clearance and Healing in Patients With Infected Wounds Compared to Standard Topical Antibiotic Application: A Randomized Open-Label Parallel Clinical Trial.

Infected wounds pose a special challenge for management, with an increased risk of wound chronicity, systemic infection, and the emergence of antibiotic resistance. Silver nanoparticles have multimodal effects on bacteria clearance and wound healing. This study aimed to document the efficacy of a topical silver nanoparticle-based cream on bacteria clearance and wound healing in infected wounds compared to Mupirocin. This open-label parallel randomized clinical trial allocated 86 participants with infected wounds (culture-positive) into Kadermin, silver nanoparticle-based cream arm (n=43) and Mupirocin arm (n=43) and documented the swab culture on day 5 and wound healing at day 28, along with periodic wound status using the Bates-Jensen Wound Assessment Tool. Patients received oral/systemic antibiotics and other medications for underlying diseases. The intention-to-treat principle was adopted for data analysis using the chi-square and Student t tests to document the differences between groups according to variable characteristics. All participants completed the follow-up. On day 5, wound bacteria clearance was observed in 86% and 65.1% of the participants in the Kadermin and Mupirocin arms, respectively (p=0.023). At day 28, complete wound healing was observed in 81.4% and 37.2% of the participants in the Kadermin and Mupirocin arms, respectively (p≤0.001). No local or systemic adverse event or local reaction was observed in any of the participants. Kadermin, the silver nanoparticle-based cream, has better efficacy in achieving faster wound bacteria clearance and healing in infected wounds compared to Mupirocin. This may have relevance for its use as an antibiotic-sparing agent in wound management.

In vitro Inhibitory effects of Polyherbal Formulation on Biofilm-forming bacteria in Chronic wounds

Biofilm is a complex microbial community highly resistant to antimicrobials. The formation of biofilms in biotic and abiotic surfaces is associated with high rates of morbidity and mortality in hospitalized patients. The aim of the present study was to develop a polyherbal formulation for antibacterial activity and inhibition of biofilm formation. Andrographis paniculata (leaves), Cassia fistula (flower), Gymnema sylvestre (leaves), Ocimum tenuiflorforum (leaves), Cinnamomum verum (bark)were the herbs chosen for the study. The extraction of the herbal samples was carried out using the cold extraction method and their phytochemical characterization was carried out by GC-MS analysis. The anti-microbial activity and antibiofilm activity of polyherbal formulation was carried out using the agar well diffusion method and microtitre plate assay. The phytochemical results showed the presence of resins, carbohydrates, proteins, saponin and phenol. The agar well diffusion assay results and microtitre plate assay showed the highest activity exhibited with 500µg/ml of polyherbal extract against Pseudomonas aeruginosa and lowest against Escherichia coli. The results confirm the differences in antibacterial and antibiofilm activity of polyherbal formulation of various concentration. Larger concentration of formulation showed to be more effective against biofilm cells. The purpose of this study was to investigate the anti-biofilm properties and inhibitory impact of ACGOC extracts against the most prevalent clinical isolates such as S. aureus,B.pumilusand P. aeruginosa and so the hypothesis of synergistic interaction of biologically active compounds from five different herbal extracts was proved for its antibiofilm assays.

Intelligent bacteria‐targeting ZIF‐8 composite for fluorescence imaging‐guided photodynamic therapy of drug‐resistant superbug infections and burn wound healing

AbstractInfected burn wounds are characterized by persistent drug‐resistant bacterial infection coupled with an inflammatory response, impeding the wound‐healing process. In this study, an intelligent nanoparticle system (CCM+TTD@ZIF‐8 NPs) was prepared using curcumin (CCM), an aggregation‐induced emission luminogens (TTD), and ZIF‐8 for infection‐induced wound healing. The CCM+TTD@ZIF‐8 NPs showed multiple functions, including bacteria targeting, fluorescence imaging and pH response‐guided photodynamic therapy (PDT), and anti‐inflammatory. The positive charges of ZIF‐8 NPs allowed the targeting of drug‐resistant bacteria in infected wounds, thereby realizing fluorescence imaging of bacteria by emitting red fluorescence at the infected site upon blue light irradiation. The pH‐responsive characteristics of the CCM+TTD@ZIF‐8 NPs also enabled controllable CCM release onto the infected wound site, thereby promoting the specific accumulation of ROS at the infected site, with outstanding bactericidal efficacy against drug‐resistant Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) strains in vitro/in vivo. Additionally, due to the excellent bactericidal effect and anti‐inflammatory properties of CCM+TTD@ZIF‐8 NPs combined with blue light irradiation, the regeneration of epidermal tissue, angiogenesis, and collagen deposition was achieved, accelerating the healing process of infected burn wounds. Therefore, this CCM+TTD@ZIF‐8 NPs with multifunctional properties provides great potential for infected burn wound healing.

Addressing Challenges in Wildlife Rehabilitation: Antimicrobial-Resistant Bacteria from Wounds and Fractures in Wild Birds.

Injuries and bone fractures are the most frequent causes of admission at wildlife rescue centers. Wild birds are more susceptible to open fractures due to their anatomical structure, which can lead to osteomyelitis and necrosis. Antibiotic therapy in these cases is indispensable, but the increase of antimicrobial-resistant isolates in wildlife has become a significant concern in recent years. In this context, the likelihood of antibiotic failure and death of animals with infectious issues is high. This study aimed to isolate, identify, and assess the antimicrobial resistance pattern of bacteria in wounds and open fractures in wild birds. To this end, injured birds admitted to a wildlife rescue center were sampled, and bacterial isolation and identification were performed. Then, antimicrobial susceptibility testing was assessed according to the disk diffusion method. In total, 36 isolates were obtained from 26 different birds. The genera detected were Staphylococcus spp. (63.8%), Escherichia (13.9%), Bacillus (11.1%), Streptococcus (8.3%), and Micrococcus (2.8%). Among Staphylococcus isolates, S. lentus and S. aureus were the most frequent species. Antimicrobial resistance was detected in 82.6% of the isolates, among which clindamycin resistance stood out, and 31.6% of resistant isolates were considered multidrug-resistant. Results from this study highlight the escalating scope of antimicrobial resistance in wildlife. This level of resistance poses a dual concern for wildlife: firstly, the risk of therapeutic failure in species of significant environmental value, and, secondly, the circulation of resistant bacteria in ecosystems.

Variable effects of exposure to ionic silver in wound-associated bacterial pathogens.

Silver compounds are used in wound dressings to reduce bioburden. Where infection is not rapidly resolved, bacteria may be exposed to sub-therapeutic concentrations of antimicrobials over prolonged periods of time. In this study, a panel of chronic wound bacteria, Pseudomonas aeruginosa (two strains), Staphylococcus aureus, and Escherichia coli, were exposed to silver nitrate on agar. Phenotypic characterization was achieved using broth microdilution sensitivity testing, a crystal violet biofilm assay, and a wax moth pathogenesis model. Repeated exposure to ionic silver did not result in planktonic phenotypic silver resistance in any of the test panels, although S. aureus demonstrated reversible increases in minimum bactericidal concentration. An ulcer-derived P. aeruginosa exhibited marked reductions in biofilm eradication concentration as well as significantly increased biofilm formation and wax moth killing when compared to the same progenitor. These changes were reversible, trending towards baseline measurements following 10 passages on silver-free media. Changes in virulence and biofilm formation in the other test bacteria were generally limited. In summary, phenotypic adaptation following exposure to ionic silver was manifested other than through changes in planktonic susceptibility. Significant changes in pseudomonas biofilm formation and sensitivity could have implications for wound care regimes and therefore warrant further investigation.

How effective is simple mechanical wound debridement in reducing bacterial colonisation? Results of a prospective clinical study.

Bacteria in wounds can lead to stagnation of wound healing as well as to local or even systemic wound infections up to potentially lethal sepsis. Consequently, the bacterial load should be reduced as part of wound treatment. Therefore, the efficacy of simple mechanical wound debridement should be investigated in terms of reducing bacterial colonisation. Patients with acute or chronic wounds were assessed for bacterial colonisation with a fluorescence camera before and after mechanical wound debridement with sterile cotton pads. If bacterial colonisation persisted, a second, targeted wound debridement was performed. A total of 151 patients, 68 (45.0%) men and 83 (55.0%) women were included in this study. The male mean age was 71.0 years and the female 65.1 years. By establishing a new analysis method for the image files, we could document that the bacterial colonised areas were distributed 21.9% on the wound surfaces, 60.5% on the wound edges (up to 0.5 cm) and 17.6% on the wound surroundings (up to 1.5 cm). One mechanical debridement achieved a significant reduction of bacterial colonised areas by an average of 29.6% in the wounds, 18.9% in the wound edges and 11.8% in the wound surroundings and was increased by performing it a second time. It has been shown that even a simple mechanical debridement with cotton pads can significantly reduce bacterial colonisation without relevant side effects. In particular, the wound edges were the areas that were often most contaminated with bacteria and should be included in the debridement with special attention. Since bacteria remain in wounds after mechanical debridement, it cannot replace antimicrobial therapy strategies, but offer a complementary strategy to improve wound care. Thus, it could be shown that simple mechanical debridement is effective in reducing bacterial load and should be integrated into a therapeutic approach to wounds whenever appropriate.

Enhancing antibacterial activity against multi-drug resistant wound bacteria: Incorporating multiple nanoparticles into chitosan-based nanofibrous dressings for effective wound regeneration

Wound infection continues to pose a significant challenge in the field of wound healing. Multi-drug resistant bacteria (MDR) make it even more complicated. Therefore, there is a pressing need to fabricate wound dressings with enhanced antimicrobial activity, particularly against MDR strains. In this study, we aimed to incorporate three antimicrobial nanoparticles into a chitosan-based nanofibrous mat (CS) and assess their antimicrobial activity against MDR bacteria. We fabricated CS mats incorporated with silver nanoparticles (CS-nAg), CuO nanoparticles (CS-nCuO), ZnO nanoparticles (CS-nZnO), a combination of Ag and CuO nanoparticles (CS-nAC), and a combination of Ag, CuO, and ZnO nanoparticles (CS-nACZ). The antimicrobial activity of these mats against MDR clinical isolates of four common wound bacteria including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Acinetobacter baumannii were investigated. Each strain was tested using 10 isolates. According to in-vitro study, mats incorporated with a single type of nanoparticle demonstrated antimicrobial activity against certain isolates of P. aeruginosa, S. aureus, and E. coli. However, the antimicrobial activity was enhanced when multiple types of nanoparticles were combined (CS-nAC and CS-nACZ). Notably, CS-nACZ was the only mat that demonstrated antimicrobial activity against A. baumannii. In addition to its superior antimicrobial activity, CS-nACZ did not exhibit cytotoxicity towards fibroblasts. In an animal study using an infected wound rat model, the CS-nACZ mat demonstrated superior antimicrobial activity and excellent wound regeneration ability. These results suggest that the use of multiple nanoparticles in CS based wound dressing can lead to enhanced antimicrobial effects and effective wound regeneration.