Burn Wound Infection Research Articles

Dual drug delivery system based on pH-sensitive silk fibroin/alginate nanoparticles entrapped in PNIPAM hydrogel for treating severe infected burn wound

Herein, the pH-sensitive vancomycin (VANCO) loaded silk fibroin-sodium alginate nanoparticles (NPs) embedded in poly(N-isopropylacrylamide) (PNIPAM) hydrogel containing epidermal growth factor (EGF) are introduced for treating chronic burn wound infections. The hybrid system was developed to control the release rates of an antibiotic and growth factor for optimal treatment of burn infections. VANCO had a pH responsive release behavior from the nanoparticle (NP) and showed higher release rate in an alkaline pH compared to the neutral pH during 10 d. About 30% of EGF was also released from the hydrogel within 20 d. The released VANCO and EGF preserved their bioactivity more than ∼ 80%. The suitable physico-chemical properties and cellular behaviors of PNIPAM hydrogel supported the proliferation and growth of the fibroblast cells. Furthermore, the higher re-epithelialization with good wound contraction rate, neovascular formation, and expression of transforming growth factor-beta were observed in S. aureus infected rat burn wound by using the hydrogel containing VANCO and EGF compared with untreated wounds and hydrogel alone. The wound infection was also significantly reduced in the groups treated with the hydrogels containing VANCO. Overall, in vitro and in vivo results suggested that developed hybrid system would be a promising construct to treat severe wound infection.

Infection in Elderly Burn Patients: What Do We Know?

Background: Infection is the greatest cause of mortality in burn patients. As our population ages, the need to care for elderly burn patients will increase, and with it our understanding of how infection affects older patients with burn injuries. This article presents a review of the available literature on the effect of aging on the physiologic response to burns, of the known effects of infection in the elder population, and of the contribution of underlying medical comorbidities to the outcomes for the elderly burn patient. The potential for more serious outcomes from multi-drug resistance in the elder population is also discussed. Methods: This article is a review of the available literature on infection in elderly burn patients. A literature search was performed for key words: elderly; geriatric; burn; infection; comorbidity; multi-drug resistance; central line; urinary tract infection; and burn sepsis. Relevant findings were included in each section. Results: Pre-existing conditions are common in the elderly and contribute to a higher rate of development of pneumonia, cellulitis, urinary tract infection, central line infections, and burn wound infections. Specific data pertaining to infections in the elderly burn population are scarce or confined to single-center reports. Conclusions: Because of the inherent susceptibility of the elder population to infection because of pre-existing medical conditions, immunosenescence, and potential exposure via frequent interaction with the medical system, vigilance must be maintained for preventing and treating infection in elderly burn patients. More research is needed to define the risks and extent of this increasingly important issue.

Fungal Infections in Burn Patients.

Background: Fungal burn wound infections are among the most devastating complications in patients who are severely burned. Increasing incidence of burn wound infections caused by fungi led to new challenges in diagnostic and therapeutic approaches. The wide use of broad-spectrum antibiotic agents, an increased prevalence of molds and non-Candida albicans spp., and the variety of available antifungal agents underline the importance of identifying the causative species, to initiate adequate therapy within an adequate timeframe. Methods: Review of the pertinent English and German literature. Results: Fungal burn wound infections go along with a delay of identifying the causative fungus species and can be mistaken for early bacterial burn wound infection. Recently, an increase of uncommon fungal pathogens and fungi resistance against antifungal agents has been reported. Amphotericin B and voriconazole remain the antifungal drugs used most commonly. Conclusions: Adequate therapy remains challenging. Early radical debridement and wound closure play an imperative part, particularly in preventing infections caused by yeasts and molds or any other agent. Prophylactic empiric pharmacologic treatment is reserved for those highly at risk for invasive burn wound infection only. Because of the emergence of drug-resistant fungi, the development of new antifungal drugs is essential for the battle against fungal burn wound infections.

Synergistic Effect of Chitosan and Selenium Nanoparticles on Biodegradation and Antibacterial Properties of Collagenous Scaffolds Designed for Infected Burn Wounds.

A highly porous scaffold is a desirable outcome in the field of tissue engineering. The porous structure mediates water-retaining properties that ensure good nutrient transportation as well as creates a suitable environment for cells. In this study, porous antibacterial collagenous scaffolds containing chitosan and selenium nanoparticles (SeNPs) as antibacterial agents were studied. The addition of antibacterial agents increased the application potential of the material for infected and chronic wounds. The morphology, swelling, biodegradation, and antibacterial activity of collagen-based scaffolds were characterized systematically to investigate the overall impact of the antibacterial additives. The additives visibly influenced the morphology, water-retaining properties as well as the stability of the materials in the presence of collagenase enzymes. Even at concentrations as low as 5 ppm of SeNPs, modified polymeric scaffolds showed considerable inhibition activity towards Gram-positive bacterial strains such as Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis in a dose-dependent manner.

The SPaCE diagnostic: a pilot study to test the accuracy of a novel point of care sensor for point of care detection of burn wound infection

Wound infection in burn patients is common and has an impact on outcomes. There is no objective method to diagnose infection at point of care (PoC). Early diagnosis prevents progression to sepsis. Diagnostic subjectivity supports over-diagnosis, unnecessary hospitalization, and antibiotic overuse. This pilot study aimed to investigate the accuracy of a novel PoC wound infection diagnostic in burn patients. We produced, and invitro tested, a PoC diagnostic for early wound infection diagnosis. The prototype SPaCE diagnostic uses a patented lipid vesicle suspension into which a clinical swab is placed. The diagnostic delivers a colour-response to Staphylococcus aureus, Pseudomonas aeruginosa, Candida species and Enterococcus faecalis at toxin release. A pilot clinical diagnostic accuracy study was undertaken. The reference standard was a retrospective decision made by an expert clinical panel using routinely available data. Data was available from 33 of 34 patients. Of these, 52% were considered to have a wound infection, 42% not, and two (6%) were equivocal. The diagnostic results showed 24% were infected, 42% were not and 33% produced intermediate results. Agreement between clinical judgement and diagnostic result, assessed using a weighted Kappa, was 0.591 suggesting moderate agreement. If the intermediate results were excluded, 22 sets of data with definitive results achieved a Kappa statistic of 0.81 suggesting 'almost perfect' agreement. Sensitivity and specificity were 57% (8/14) and 71% (12/17), respectively. This pilot study provided evidence that the SPaCE diagnostic could provide valuable and timely data to support clinical decision-making at PoC for wound infection.

Targeting the gut to prevent sepsis from a cutaneous burn.

Severe burn injury induces gut barrier dysfunction and subsequently a profound systemic inflammatory response. In the present study, we examined the role of the small intestinal brush border enzyme, intestinal alkaline phosphatase (IAP), in preserving gut barrier function and preventing systemic inflammation after burn wound infection in mice. Mice were subjected to a 30% total body surface area dorsal burn with or without intradermal injection of Pseudomonas aeruginosa. Mice were gavaged with 2000 units of IAP or vehicle at 3 and 12 hours after the insult. We found that both endogenously produced and exogenously supplemented IAP significantly reduced gut barrier damage, decreased bacterial translocation to the systemic organs, attenuated systemic inflammation, and improved survival in this burn wound infection model. IAP attenuated liver inflammation and reduced the proinflammatory characteristics of portal serum. Furthermore, we found that intestinal luminal contents of burn wound–infected mice negatively impacted the intestinal epithelial integrity compared with luminal contents of control mice and that IAP supplementation preserved monolayer integrity. These results indicate that oral IAP therapy may represent an approach to preserving gut barrier function, blocking proinflammatory triggers from entering the portal system, preventing gut-induced systemic inflammation, and improving survival after severe burn injuries.

Epidemiology of burn wound bacterial infections at a Meknes hospital, Morocco.

This study aimed to determine the prevalence of burn wound infection in the ward of Burns and Plastic Surgery at Mohammed V Hospital, Meknes, Morocco, and to determine the pathogenic bacterial species responsible for this infection as well as the susceptibility of these isolates to various antibiotics. Over the 1-year study period, 126 patients were admitted. The main sources of burns were flames (52.38%) and hot water (28.57%); 71% had burns with 11% to 40% burn surface and 48.41% had burns between 11% and 20% total burn surface. The mean ± SD duration of hospitalization was 22.15 ± 13.84 days after injury. Eighty-six patients were found to have at least one positive culture requiring treatment and were thus included in this study. The predominant bacteria isolated were Staphylococcus aureus (33.85%), followed by Pseudomonas spp. (18.46%), Acinetobacter baumannii (15.38%), Klebsiella pneumoniae (13.85%), Escherichia coli (8.46%) and Proteus mirabilis (4.42%). Disc-diffusion susceptibility testing indicated a high prevalence of resistance to various antimicrobial agents. Among the Staphylococcus aureus and Enterobacteriaceae strains isolated, 86.36% were methicillin resistant and 48.64% were extended-spectrum β-lactamase producers respectively.

Stenotrophomonas maltophilia Infections in Geriatric Patients

We present Stenotrophomonas maltophilia infections in 317 hospitalized patients in a large health network over a 3-year period. The majority of patients were elderly. Most infections were polymicrobial: respiratory 95.2%, wound 91%, urinary 80.8% and blood 64.3%. Younger patients were small in number and were more common in those with otitis externa, infections from injection drug use and those with line infections. Most deaths were in patients with terminal conditions and polymicrobial infections and mortality could not be directly attributed to Stenotrophomonas maltophilia. None of the sputum, bronchial, urinary or wound culture positive patients had positive blood cultures. Only blood (14/317) or ear (7/317) culture positive patients had significant numbers of younger individuals with only 3 out of 14 over age 50 in blood culture positive patients and 1/7 in those with otitis externa. Those with bacteremia included patients with injection drug use, chronic pain syndromes and vascular catheter infections. 94% of urinary infections, 91.7% wound infections and 85.8% respiratory isolates were in those above age 50. Overwhelming majority of urinary infections were in males with drainage devices present in 75%. Recurrent infections were uncommon. Respiratory specimens were frequently associated with tracheostomies and endotracheal tubes. Most wound infections were in chronic lower extremity ulcers. Prior carbapenem use was not significant in this study. Isolates from all sites were over 98% susceptible to Trimethoprim/sulphamethoxazole. Limitations: The study group only had 1 organ transplant and 2 cystic fibrosis patients and no burn wound infections.

Biosynthesis of Zinc oxide nanoparticles and their application for antimicrobial treatment of burn wound infections

The current study demonstrated the green fabrication of Zinc oxide nanoparticles (ZnO NPs) using the leaf extract of Coleus amboinicus (C. amboinicus) by an environment-friendly method. The leaf extract of C. amboinicus acts as capping and reducing agent during the fabrication of ZnO NPs. The prepared ZnO NPs were characterized by utilizing analytical techniques such as photoluminescence spectroscopy (PL), Transmission Electron microscopy (TEM), Energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis) and x-ray diffraction spectroscopy (XRD). The XRD pattern confirmed the formation of polydisperse ZnO NPs having crystalline nature. The FTIR spectrum demonstrated the biomolecular capping on the surface of zinc oxide nanoparticles. The prepared ZnO NPs displayed excellent antimicrobial activities over several gram positive and gram-negative microbial pathogens. Further, wound healing studies in rats revealed that wound closure rate was greater in the ZnO NPs treated rats at all doses when related with the untreated group (negative control group), therefore, this indicates the effective wound healing ability of prepared ZnO NPs.

The Antibacterial Activity of Amber Honey and White Honey on Pseudomonas aeruginosa Multi Resistant (PaMR) and Methicillin Resistant Staphylococcus aureus (MRSA)

Introduction: Infection of burn wound is a chronical disturbance to the skin, which is caused by Staphylococcus aureus and Pseudomonas aeruginosa, but lately many cases found that both bacteria have been resistant to the antibiotic. To overcome the infection caused by those bacteria, it is important to search for natural substance that has antibacterial activity to both bacteria. The power of natural substance is underestimated. Studies reveal that honey can be more effective for healing burns than modern medicine. The previous research revealed that amber honey and white honey were used as an alternative treatment against Pseudomonas aeruginosa Multi Resistant (PaMR) and Methicillin Resistant Staphylococcus aureus (MRSA). The aim of this study was to evaluate the antibacterial activity of amber honey and white honey on PaMR and MRSA.Methods: This research was conducted by performing antibacterial test phase, determining Minimum Inhibitory Concentration (MIC), and determining comparison value of antibacterial activity from amber honey and white honey to tetracycline.Results: The result of this research showed that both amber honey and white honey have antibacterial activity to both bacteria, by way of stronger antibacterial activity from white honey than amber honey. Amber honey and white honey have the same PaMR activity. MIC of white honey was 7.1% (to MRSA) and 12.3% (to PaMR), while MIC of amber honey was 10% (to MRSA) and 12.5% (to PaMR). The comparison value of antibacterial activity between amber honey and white honey to tetracycline for MRSA was equal to 1:1.08 x 10-4 and 1:1.62 x 10-4. The comparison value of antibacterial activity between amber honey and white honey to tetracycline for PaMR was equal to 1:5.62 x 10-6 and 1:1.03 x 10-5 .Conclusion: Amber honey and white honey have antibacterial activity against MRSA and PaMR.

Nano gold incorporated into Aerva javanica chitosan hydrogels disrupting agents against infections of burn wound

ABSTRACT S. aureus (SA) and P. aeruginosa (PA) contaminations in thermally hurt patients have controlled invasive illness producing humanity. Gold nanoparticles (AuNPs) engaged in behaviour have limits owed to their oxidative damage. Current examinations demonstrated the biosynthesis of highly biocompatible AuNPs from rich antioxidant of aqueous cutting of Aerva javanica (A. javanica). The cell viability of the biosynthesised AuNPs was examined by cancerous cell lines (MCF-7 and MDA-MB-231) and non-cancerous cell lines (HUVECs), which displayed the high biocompatibility in all the cell lines. We developed the encapsulation with chitosan hydrogels to the AuNPs for the burn wound infections created by the Sprague Dawley rats. Remarkable burn wound reduction in the chitosan hydrogels was found. The histological analysis also suggested the burn wound contracting without causing any damages. The outcomes indicated that AuNPs incorporate to the chitosan hydrogels are promising burn wound dressing resources for the treatment for wound healing.

Autologous mesenchymal stem cells application in post-burn scars treatment: a preliminary study

Mesenchymal stem cells (MSCs) are multi-potent cells characterized by long term self-renewal and by potential for differentiation into cells of different mesenchymal tissue types such as fibroblasts, osteocytes, chondrocytes, and adipocytes. Their unique properties offer broad therapeutic potentials. Bone marrow has been used as the most common MSCs source, but it is gradually going to be replaced by adipose tissue which showed to contain more MSCs per unit than the bone marrow and clinical application of MSCs procured from the adipose tissue have been demonstrating at least similar results. Post-burn scars result frequently in severe both functional and aesthetic impairments in restitution and rehabilitation periods of the burn disease. Despite extensive research in the last decades, the exact mechanisms of scar formation remains unclear. The development of post-burn scars is influenced by multiple factors such as initial depth of the burn, methods of burn wound therapy, duration of the open wound until final wound closure, burn wound infection, genetic predisposition, and many others in both acute and rehabilitation periods. The aim of this study was to point out versatility of the implementation of this method with respect to different types of scars (atrophic scars, hypertrophic scars, keloids). Autologous adipose tissue derived MSCs were applied to post-burn scars in all 8 patients undergoing surgical scar reconstructions at the Department of Burns and Reconstructive Surgery of the University Hospital in Bratislava. The study was approved by Ethical Committee of Ruzinov Hospital. The procedures used for scar reconstructions included dermabrasion, scar excisions, contractures corrections and local plasties combined by lipografting of lipoaspirate containing parenchymal adipocytes and stromal vascular fraction including MSCs, or application of separated autologous MSCs isolated from lipoaspirates. Based on desired result one of these MSCs application methods was selected depending on characteristics of reconstructed scar and required volume of transferred fat. Isolation of MSCs following procurement was provided by the Central Tissue Bank cell culture laboratory which is one of the parts of the burn department. The average time of scars duration was 79months, ranging from 6 to 216months. The postburns scars were assessed clinically according to Vancouver Scar Scale (VSS) prior to surgery, including photo documentation, and re-evaluated after 6months following MSCs application. As the results have shown, the average VSS score before treatment was 7.88 points ranging from 4 to 11 points. The average VSS 6months after surgical procedure and MSCs application was 2.34 points ranging from 1 to 4 points. According to the results obtained, the favourable effect of adipose tissue derived autologous MSCs application on scar remodelling following surgical reconstruction of post-burn scars could be promising.

Spectrum of Fungal Pathogens in Burn Wound Specimens: Data From a Tertiary Care Hospital Laboratory in Pakistan.

Burn patients are at great risk of developing fungal wound infections. Fungi are frequently cultured from burn tissue specimens alone or in combination with bacteria. However, the spectrum of fungi in burn patients from Pakistan has not been reported previously. A retrospective laboratory-based study was conducted and data on all positive cultures from burn wounds were included. During the study period, specimens were cultured on appropriate media and incubated for anaerobic and aerobic growth. Clinical and demographic information recorded during clinical reporting was also collected. Seventy tissue cultures were positive for microorganisms. Of these, 27 (39%) had growth of either filamentous mold (17 cases) or Candida species (14 cases). Two cases had growth of both mold and yeast. Aspergillus flavus was the most common mold (9) followed by Fusarium species (3). Candida tropicalis was the most common yeast (7) followed by Candida parapsilosis (4). There was concomitant bacterial growth in 19 cases, predominantly of Staphylococcus aureus (13), Pseudomonas aeruginosa (8), and other Gram-negative rods (6). Of the 35 patients in which treatment history was available, 33 were receiving broad-spectrum antibiotics. A high incidence of fungal isolation was seen in this study. Their findings are consistent with the global increase in fungal infections in burn wounds. High index of suspicion by clinicians and revision of culture protocols in burn patients may be warranted for optimal patient management.

Pediatric Burn Infection.

Background: Severe burns lead to a profound hypermetabolic, hypercatabolic, hyper-inflammatory state. Pediatric burn patients are at significantly increased risk for infection and sepsis secondary to loss of the skin barrier and subsequent immunosuppression. Infection is the most common cause of morbidity and death in pediatric burn patients, and the mortality rate from sepsis remains high. Methods: Review of pertinent English-language literature pertaining to infection among pediatric burn patients. Results: Established risk factors for infection in pediatric burn patients are the depth of injury, presence of inhalation injury, indwelling devices, and total body surface area burned. Total body surface area remains one of the most important risk factors for the development of infectious complications, and mortality risks increase significantly if the burn size is >40%. The predominant colonization of burn wound starts with gram-positive organisms, which are replaced later by gram-negative organisms. Most cases of sepsis in burn patients originate from infected burn wounds. Treatment options include topical and systemic antimicrobial drugs, but surgical intervention often is the most definitive treatment. Excision of burn eschar to remove the source of potential infection is a key component of the treatment as well as prevention of infection. Conclusion: Key principles in improving outcomes for septic pediatric burn patients is early recognition, resuscitation, and adherence to management strategies such as prompt antimicrobial drug administration and source control.

Comparison of the effects of Lactobacillus plantarum versus imipenem on infected burn wound healing.

Background: Infection of burn wounds is one of the most important problems in the world. Lactobacillus plantarum is known for burn wound healing because of the immunomodulatory and anti-microbial roles. This study was performed to compare the effects of L. plantarum and imipenem – alone and in combination – on infected burn wound healing. Methods: Burn wounds were experimentally induced on 50 rats in three test groups (germ and supernatant of L. plantarum ) and two control groups (n=10 each) and were inoculated with Pseudomonas aeruginosa. During a 14-day period, wounds in all groups were daily treated topically. The data were analyzed using one-way analysis of variance followed by Tukey–Kramer and LSD. A p-value of < 0.05 was considered as statistically significant. Results: The mean size of the wound on day 14 after the treatment in the probiotic group was significantly lower than the control and the supernatant treated groups (p<0.05). The percentage of wound healing was significantly higher in the probiotic pellet treated group compared to the imipenem and the supernatant groups (by Anova test: 69.58%, p=0.022). The mean leukocyte count in the probiotic pellet group (12110) and supernatant group (13650) was significantly higher than the imipenem group (7670) (p=0.002 and 0.001, respectively). Wound cultures revealed that the percentage of cases where the pathogens had no growth was significantly different among the comparison groups. In all three test groups, P. aeruginosa was completely eliminated in comparison to the positive control group (p<0.05). Conclusion: The results of our study showed that L. plantarum and its by-products promote wound healing and can be used as an alternative to antibiotics to treat ulcer infections caused by resistant bacteria.

Microbiological and Biochemical Analysis of Methicillin-resistant Staphylococcus aureus Isolated from Patients Admitted in RIMS, Ranchi

Background: Since methicillin-resistant Staphylococcus aureus strains are resistant to multiple antibiotics, there is a possibility of extensive outbreaks which may be difficult to control. Early detection of methicillin-resistant Staphylococcus is important from patients and hospitals point of view. Materials and Methods: The present study was carried out in the Department of Microbiology, Rajendra Institute of Medical Sciences, Ranchi, clinical isolates of methicillin-resistant S. aureus strains were obtained from admitted patients of Rajendra Institute of Medical Sciences, Ranchi. The sources of isolate included pus from infected surgical wounds, infected burn wounds, conjunctival swab, aural swab, throat swab, vaginal swab, and urine for microbiological and biochemical analysis of methicillin-resistant S. aureus. Results: All the 264 cases of staphylococcal species isolated from different clinical specimens were subjected to coagulase test. It was observed that out of 264 strains of staphylococci isolated from different sites, 165 strains (62.5%) were coagulase positive and 99 strains (37.5%) were coagulase negative by tube method. Out of the 165 strains of coagulase-positive staphylococci, maximum isolation was obtained from pus 74 followed by throat swab 55, aural swab 21, vaginal 4, conjunctival swab 9, and urine 2. All the 165 cases of coagulase-positive Staphylococcus isolated from different clinical specimens were studied for hemolysis, mannitol fermentation, pigment production, and phosphatase production. Out of these 165 strains, 162 (98%) strains produced β-hemolysis on blood agar medium. Pigment production was noted in 160 (97%) of cases. Majority of strains produced characteristic golden yellow pigment on nutrient agar plate. A total of 155 (94%) strains of staphylococci fermented mannitol with the production of acid only. Phosphatase production was observed in 157 (95%) strains of pathogenic staphylococci. Conclusion: Considering the above-mentioned pathogenicity test, it was observed that coagulase test was the single most reliable test, though coagulase-negative staphylococci are sometimes pathogenic too.

Consensus demonstrates four indicators needed to standardize burn wound infection reporting across trials in a single-country study (ICon-B study)

Evidence-based interventions are needed to treat burn wound infection (BWI). Evidence syntheses have been limited by heterogeneity of indicators used to report BWI across trials. Consistent reporting of BWI would be facilitated by an agreed minimum set of indicators. The Infection Consensus in Burns study aimed to achieve expert consensus about a core indicator set (CIS) for BWI. The CIS was established through development of a long list of BWI indicators identified from a systematic review and expert input. In a Delphi survey, UK expert participants rated the indicators according to use in everyday practice, importance for diagnosis and frequency of observation in patients with BWI. Indicators were included in the CIS if ≥75% of participants agreed it was important for diagnosis and used in everyday practice, and ≥50% of participants rated it as frequently observed in patients with BWI. One hundred and ninety-five indicators were identified from the systematic review and reduced to 29 survey items through merging of items with the same meaning. Seventy-five UK experts participated in the Delphi survey. Following a single survey round and a consensus meeting with an expert panel, four items were included in the CIS: pyrexia, spreading erythema, change in white cell count, and presence of pathogenic microbes. To facilitate evidence synthesis, a single-country systematic, expert-informed approach was taken to develop a CIS to be reported consistently across trials reporting BWI as an outcome. Future work requires verification of the CIS with international experts.

Global Sequence Analysis and Expression of Azurin Gene in Different Clinical Specimens of Burn Patients with Pseudomonas aeruginosa Infection.

AimThe purpose of this study was to analyze the sequence of azurin gene in relation to its expression in Pseudomanas aeruginosa strains isolated from different clinical specimens of burn patients. Moreover, in silico sequence analysis of azurin gene using globally reported sequences was intended.Materials and MethodsFifty-nine multidrug-resistant P. aeruginosa isolates were selected from different clinical specimens of patients suffering from burn wound infections in two university hospitals and subjected to antibacterial susceptibility testing. The frequency and genetic diversity of the azurin gene was determined by polymerase chain reaction (PCR) and Sanger sequencing. The azurin gene sequences were compared with the sequence data from other countries. The expression level of azurin gene in P. aeruginosa isolates with different azurin sequences from different clinical specimens was evaluated by real-time PCR.Results and ConclusionAbout 98%–100% of the isolates were resistant to gentamicin, tobramycin, cefoxitin, ciprofloxacin, amikacin, and imipenem, while 100% and 23.9% of the isolates were susceptible to colistin and ceftazidime, respectively. Only eight point mutations were detected with amino acid substitutions in only two positions (81 and 102). In global analysis, 93% of strains showed missense mutation at positions 81 (alanine to threonine). The majority (81%) of Iranian strains were allocated to two major clusters distinct from the rest of world, which may suggest that strains from Iran have made a distinct genetic stockpile through point mutations which has established them separate from the other counties. However, 19% were distributed in different clusters together with the strains from different countries of North and South America, Europe, South and East Asia. The expression level of the azurin gene was statistically higher in the isolates collected from the blood of burns patients with systemic infection compared to the isolates collected from other specimens (wound, catheter and tissue), which shows a positive correlation between azurin gene expression and increased pathogenicity and capability for dissemination. This study may open new insight about azurin genetic variation and significance in P. aeruginosa pathogenesis.

Prevalence of vanA Gene among Methicillin Resistant S. aureus Strains Isolated from Burn Wound Infections in Menoufia University Hospitals

Background: Staphylococcus aureus is a leading cause of burn wound infection. Vancomycin resistance among methicillin-resistant Staphylococcus aureus (MRSA) is becoming a worldwide growing threat. Objectives: to detect the prevalence of MRSA in burn patients and its antibiotic susceptibility patterns. In addition, the resistance patterns of MRSA to vancomycin and the prevalence of vanA gene among MRSA isolates were investigated. Methodology: A total 250 clinical samples were obtained from patients admitted to Burn Unit in Menoufia University Hospitals. Identification and antimicrobial susceptibility testing of S. aureus isolates were performed. Cefoxitin disk diffusion method was used to identify MRSA strains. Vancomycin resistance was determined by agar dilution method. Detection of mecA and vanA genes by multiplex PCR was done. Results: Staphylococcus aureus represented 43.3% of all isolates. By cefoxitin disc diffusion method, 94% (79/84) of isolated S. aureus were MRSA that showed a high resistance to most antimicrobials used with rates ranged from 40.5 % to 100%. Phenotypically among MRSA isolates, vancomycin sensitive S. aureus (VSSA), vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) were 59.5%, 15.2%, 25.3% respectively. Among MRSA isolates, 17 (21.5%) isolates had vanA gene by PCR (16 isolates were VRSA and one isolate was VSSA).Conclusion: This study is considered as an alarm demonstrating that implementation of proper infection control measures is mandatory to control spread of such resistant strains in our hospital.

Biocompatible and Smart Composites from Cellulose, Wool, and Phase-Change Materials Encapsulated in Natural Sporopollenin Microcapsules

Natural pollen grains were cleaned to remove all external and internal cytoplastic materials to produce sporopollenin exine capsules (SECs). SECs are empty microcapsules with extensive networks of holes that are ∼200 nm in diameter, which remain intact. Various substances including phase-change materials (PCMs) such as n-octadecane (C18), n-eicosane (C20, EIS), n-docosane (C22), or a mixture of them (C18 + C22) can be encapsulated into the cavity of SECs. [EIS (or PCMs)@SEC] was obtained with an encapsulation efficiency of at least 76 wt %. SECs are robust and very stable. They protect encapsulated EIS during phase transitions, so they retain their phase change property and guard them against corrosive environments and elevated temperatures. [EIS@SEC] can therefore be incorporated into cellulose (CEL) and keratin (KER, from wool) composites using butylmethylimmidazolium chloride [BMIM+Cl–], a simple ionic liquid, as a sole solvent to synthesize [CEL + KER + EIS@SEC] composites. EIS in the [CEL + KER + EIS@SEC] composites behaves similarly to EIS alone. It will melt when heated and crystallize when cooled. Energy resulting from these phase transitions allows [CEL + KER + EIS@SEC] composites, like other PCMs, to warm their surroundings by releasing energy and, conversely, to cool their surroundings as they heat up by absorbing energy. The latent heat storage and release efficiency of the [CEL + KER + EIS@SEC] composites is estimated to be about 80%. After going through the heating–melting cycle 200 times, the DSC curves of the [CEL + KER + EIS@SEC] composites remained the same. This indicates that SECs are in fact fully and effectively retaining the encapsulated EIS and protecting it from leaking out. The [CEL + KER + EIS@SEC] composites are robust, have strong mechanical properties, and possess antibacterial activity. This makes them superior to other microencapsulated PCMs that are currently available. Furthermore, the composites are sustainable and biocompatible as they are synthesized from naturally abundant materials (cellulose, wool, natural pollen grains, and wax) using a green and recyclable synthesis. More importantly, the fact is that not only individual PCM such as EIS but also a mixture of two different PCMs such as a mixture of (C22 + C18) can be simultaneously encapsulated into the SEC. These features enable the [CEL + KER + EIS@SEC] composites to be uniquely suited as high-performance materials for such uses as dressings to treat infected burn wounds, smart textiles for clothing, smart building materials, and energy storage at any given temperature.