Search

National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) for funding this work NC/V001582/1 to RRMC and EM. RRMC is supported by a Biotechnology and Biological Sciences Research Council New Investigator Award BB/V007823/1 and the Academy of Medical Sciences/the Wellcome Trust/ the Government Department of Business, Energy and Industrial Strategy/the British Heart Foundation/Diabetes UK Springboard Award 364 [SBF006\1040].

Aim. To identify the frequency of occurrence of staphylococcal enterotoxins of the SEC and SEI type produced by Staphylococcus aureus strains isolated from patients with different nosology. As you know, the infection process in them proceeds with severe intoxication without vomiting and intestinal disorders.Materials and methods. 79 strains were studied (43 were isolated in case of pneumonia, 13 - in burns, 11 - in sepsis) S. aureus in the presence of SES and SEI using enzymelinked immunosorbent assay (ELISA).Results. It was found that 48.3% of S. aureus strains isolated from patients with pneumonia produced SEC and 72.1% - SEI. The frequency of occurrence of S. aureus strains producing SEC and SEI isolated in patients with burn infections was 23.0 and 15.4%, respectively. 36.4% of staphylococcal strains isolated in patients with sepsis produced SEC, 45.5% - SEI.Discussion. It was found that the proportion of S. aureus cultures producing SEC enterotoxins during sepsis is significantly higher than the strains producing SEB (5.4%) and much smaller than SEA (75.6%). A high percentage of SEI-positive strains was found compared to strains that produce the classic enterotoxins SEA, SEB and SEC isolated from pneumonia. In burn infections, the proportions of strains producing SEC and SEI were 15.4 and 23.0%, respectively, which is significantly lower than SEA (92.9%).Conclusion. The data obtained indicate the need to identify staphylococcus strains that produce both classic and newly discovered enterotoxins, which are crucial virulence factors leading to lethal sepsis, infectious endocarditis and toxic shock syndrome to eliminate them.

Hossein Rahimi,1 Shahla Roudbarmohammadi,1 Hamid Delavari H,2 Maryam Roudbary31Department of Medical Mycology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; 2Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran, Iran; 3Department of Medical Mycology and Parasitology, School of Medicine, Iran University of Medical Sciences, Tehran, IranBackground: Candida albicans as an opportunistic fungus is one of the most important causes of late-onset morbidity and mortality in patients with major burns and severely impaired immune system. In recent years, the emergence of resistance to opportunistic fungi and toxicity of antimicrobial drugs make it necessary to develop new drugs.Methods: In the present study, we investigated anticandidal effects of indolicidin, as a representative of host defense peptide, conjugated with gold nanoparticles in fluconazole-resistant clinical isolates of C. albicans. After characterizing the conjugation of indolicidin using biophysical methodologies, the cytotoxicity and hemolytic activity of the nanocomplex were examined. In addition, the expression level of ERG11, responsible for antifungal resistance, and the immunomodulatory effect of peptide-nanomaterial conjugates were assessed.Results: Our data indicated that the nanocomplex was nontoxic for the fibroblast cells and erythrocytes. Treatment with the nanocomplex significantly reduced the expression levels of the ERG11 gene in fluconazole-resistant C. albicans isolates and the iNOS gene in macrophages.Conclusion: The study data provides a chance to develop innovative therapies for the treatment of C. albicans burn infections. However, further investigation is required to examine the efficiency of the nanocomplex.Keywords: burn infection, Candida albicans, indolicidin, gold nanoparticles, antimicrobial peptides

Failure in the treatment of P. aeruginosa, due to its broad spectrum of resistance, has been associated with increased patient mortality. One alternative approach for infection control is quorum quenching which was found to decrease virulence of such pathogen. In this study, the efficiency of a recombinant Ahl-1 lactonase formulated as a hydrogel was investigated to control the infection of multidrug resistant (MDR) P. aeruginosa infected burn using a murine model. The recombinant N-acylhomoserine lactonase (Ahl-1) was formulated as a hydrogel. To test its ability to control the infection of MDR P. aeruginosa, a thermal injury model was used. Survival rate, and systemic spread of the infection were evaluated. Histopathological examination of the animal dorsal skin was also done for monitoring the healing and cellular changes at the site of infection. Survival rate in the treated group was 100% relative to 40% in the control group. A decrease of up to 3 logs of bacterial count in the blood samples of the treated animals relative to the control group and a decrease of up to 4 logs and 2.3 logs of bacteria in lung and liver samples, respectively were observed. Histopathological examination revealed more enhanced healing process in the treated group. Accordingly, by promoting healing of infected MDR P. aeruginosa burn and by reducing systemic spread of the infection as well as decreasing mortality rate, Ahl-1 hydrogel application is a promising strategy that can be used to combat and control P. aeruginosa burn infections.

Infection is the leading cause of complications and deaths after burns. However, the difference in infection patterns between the burn intensive care unit (BICU) and burn common wards (BCW) have not been clearly investigated. The present study aimed to compare the infection profile, antimicrobial resistance, and their changing patterns in burn patients in BICU and BCW. Clinical samples were analyzed between January 1, 2011, and December 31, 2019, in the Institute of Burn Research in Southwest China. The patient information, pathogen distribution, sources, and antimicrobial resistance were retrospectively collected. A total of 3457 and 4219 strains were detected in BICU and BCW, respectively. Wound secretions accounted for 86.6% and 44.9% in BCW and BICU, respectively. Compared with samples in BCW, samples in BICU had more fungi (11.8% vs. 8.1%), more Gram-negative bacteria (60.0% vs. 50.8%), and less Gram-positive bacteria (28.2% vs. 41.1%). Acinetobacter baumannii were the most common pathogen in BICU, compared with Staphylococcus aureus in BCW. S. aureus was the most frequent pathogen in wound secretions and tissues from both BICU and BCW. However, A. baumannii were the first in blood, sputum, and catheter samples from BICU. Overall, the multidrug-resistance (MDR) rate was higher in BICU than in BCW. However, the gap between BICU and BCW gradually shortened from 2011 to 2019. The prevalence of MDR A. baumannii and Klebsiella pneumonia significantly increased, especially in BCW. Furthermore, Carbapenem resistance among K. pneumoniae significantly increased in BICU (4.5% in 2011 vs. 40% in 2019) and BCW (0 in 2011 vs. 40% in 2019). However, the percentage of MDR P. aeruginosa sharply dropped from 85.7% to 24.5% in BICU. The incidence of MRSA was significantly higher in BICU than in BCW (94.2% vs. 71.0%) and stayed at a high level in BICU (89.5% to 96.3%). C. tropicalis and C. albicans were the two most frequent fungi. No resistance to Amphotericin B was detected. Our study shows that the infection profile is different between BICU and BCW, and multidrug resistance is more serious in BICU than BCW. Therefore, different infection-control strategies should be emphasized in different burn populations.

Bingjie Mai,1,2 Yiru Gao,1,2 Min Li,1,2 Xiaobing Wang,1,2 Kun Zhang,1,2 Quanhong Liu,1,2 Chuanshan Xu,3 Pan Wang1,2 1Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, 2National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi’an, 3School of Chinese Medicine, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China Background and objectives: Antibiotic resistance has emerged as one of the most important determinants of outcome in patients with serious infections, along with the virulence of the underlying pathogen. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for the inactivation of bacteria. This study aims to evaluate the antibacterial effect of sinoporphyrin sodium (DVDMS)-mediated PACT on Staphylococcus aureus and multidrug resistant S. aureus in vitro and in vivo.Materials and methods: Bacteria were incubated with DVDMS and exposed to treatment with light. After PACT treatment, colony-forming units were counted to estimate the bactericidal effect. Intracellular reactive oxygen-species production was detected by flow cytometry. Flow cytometry and fluorescence-microscopy detection of bacterial cell-membrane permeability. Enzyme-linked immunosorbent assays were used to determine expression of VEGF, TGFβ1, TNFα, IL6, and bFGF factors in burn infection.Results: DVDMS-PACT effectively killed bacterial proliferation. Intracellular ROS levels were enhanced obviously in the PACT-treatment group. SYTO 9 and propidium iodide staining showed a decrease in the ratio of green:red fluorescence intensity in the PACT-treatment group in comparison to the control group. Enzyme-linked immunosorbent-assay results revealed that in the healing process, the expression of bFGF, TGFβ1, and VEGF in the treatment group were higher than in the control group, which inhibited inflammation-factor secretion. In addition, skin-tissue bacteria were reduced after treatment.Conclusion: These results indicate that DVDMS-PACT presents significant bactericidal activity and promotes wound healing after burn infections. Keywords: PACT, antibacterial efficacy, burn infection, MDR&nbsp

Bingjie Mai,1,2 Yiru Gao,1,2 Min Li,1,2 Xiaobing Wang,1,2 Kun Zhang,1,2 Quanhong Liu,1,2 Chuanshan Xu,3 Pan Wang1,2 1Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, 2National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China, College of Life Sciences, Shaanxi Normal University, Xi’an, 3School of Chinese Medicine, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China Background and objectives: Antibiotic resistance has emerged as one of the most important determinants of outcome in patients with serious infections, along with the virulence of the underlying pathogen. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for the inactivation of bacteria. This study aims to evaluate the antibacterial effect of sinoporphyrin sodium (DVDMS)-mediated PACT on Staphylococcus aureus and multidrug resistant S. aureus in vitro and in vivo.Materials and methods: Bacteria were incubated with DVDMS and exposed to treatment with light. After PACT treatment, colony-forming units were counted to estimate the bactericidal effect. Intracellular reactive oxygen-species production was detected by flow cytometry. Flow cytometry and fluorescence-microscopy detection of bacterial cell-membrane permeability. Enzyme-linked immunosorbent assays were used to determine expression of VEGF, TGFβ1, TNFα, IL6, and bFGF factors in burn infection.Results: DVDMS-PACT effectively killed bacterial proliferation. Intracellular ROS levels were enhanced obviously in the PACT-treatment group. SYTO 9 and propidium iodide staining showed a decrease in the ratio of green:red fluorescence intensity in the PACT-treatment group in comparison to the control group. Enzyme-linked immunosorbent-assay results revealed that in the healing process, the expression of bFGF, TGFβ1, and VEGF in the treatment group were higher than in the control group, which inhibited inflammation-factor secretion. In addition, skin-tissue bacteria were reduced after treatment.Conclusion: These results indicate that DVDMS-PACT presents significant bactericidal activity and promotes wound healing after burn infections. Keywords: PACT, antibacterial efficacy, burn infection, MDR&nbsp

Hospital-acquired infections are common in burn patients and are the major contributors of morbidity and mortality. Bacterial infections such as Staphylococcus aureus (S. aureus) and Acinetobacter baumannii (A. baumannii) are difficult to treat due to their biofilm formation and rapidly acquiring resistance to antibiotics. This work presents a newly developed hydrogel that has the potential for treating bacterial wound infections. The hydrogel formulation is based on an antimicrobial peptide (AMP), epsilon-poly-l-lysine (EPL) and catechol, which was cross-linked via mussel-inspired chemistry between the amine and phenol groups. In vitro studies showed that EPL-catechol hydrogels possess impressive antimicrobial and antibiofilm properties toward multidrug-resistant A. baumannii (MRAB). In addition, cytotoxicity study with the clonal mouse myoblast cell line (C2C12) revealed the good biocompatibility of this hydrogel. Furthermore, we created a second-degree burn wound on the mice dorsal skin surface followed by contamination with MRAB. Our results showed that the hydrogel significantly reduced the bacterial burden by more than four orders of magnitude in infected burn wounds. Additionally, there was no significant histological alteration with hydrogel application on mice skin. Based on these results, we concluded that EPL-catechol hydrogel is a promising future biomaterial to fight against multidrug-resistant bacterial infections.

Introduction Burns are one of the most common and devastating forms of trauma. Patients with serious thermal injury require immediate specialized care in order to minimize morbidity and mortality. (1) The main purpose of this study was to determine the prevalence of bacterial wound infection in critically ill burn patients in surgical intensive care unit in Egypt. Objectives The aim of this study was to determine the bacterial isolates in sever burn wound infection, suitability to antibiotics and there are mortalities. Methods We conducted a one year retrospective study in the surgical ICU. Wound swab Culture and sensitivity reports of admitted patients. All the patients of all age groups suffering with flame burnt and both sexes having complete Culture and sensitivity reports were included. Results The main finding of the current study described herein was the percent of isolates from burn wound (60%). The most common organism was pseudomonas (49%). Multidrug resistant gram negative organisms represent about 60% of the isolates. Pattern of antibiotic sensitivity was 84% for colistin, 39% for amikacin and 35% for imipenem. The mortalities in our study were 80%.

Background: Candida albicans as an opportunistic fungus is one of the most important causes of late-onset morbidity and mortality in patients with major burns and severely impaired immune system. In recent years, the emergence of resistance to opportunistic fungi and toxicity of antimicrobial drugs make it necessary to develop new drugs. Methods: In the present study, we investigated anticandidal effects of indolicidin, as a representative of host defense peptide, conjugated with gold nanoparticles in fluconazole-resistant clinical isolates of C. albicans. After characterizing the conjugation of indolicidin using biophysical methodologies, the cytotoxicity and hemolytic activity of the nanocomplex were examined. In addition, the expression level of ERG11, responsible for antifungal resistance, and the immunomodulatory effect of peptide-nanomaterial conjugates were assessed. Results: Our data indicated that the nanocomplex was nontoxic for the fibroblast cells and erythrocytes. Treatment with the nanocomplex significantly reduced the expression levels of the ERG11 gene in fluconazole-resistant C. albicans isolates and the iNOS gene in macrophages. Conclusion: The study data provides a chance to develop innovative therapies for the treatment of C. albicans burn infections. However, further investigation is required to examine the efficiency of the nanocomplex.

Background and Objectives: Pseudomonas aeruginosa is the most common organism, which is separated from the burn infections. Due to increased antibiotic resistance, there are many problems to deal with the infections caused by Pseudomonas aeruginosa. This study aimed to determine the resistance to antibiotics against clinical isolates of Pseudomonas using phenotype methods. Material and Methods: 100 strains of Pseudomonas aeruginosa were collected from the burn patients in Taleghani hospital in Ahwaz, Iran, during a six-month period. After phenotypically initial identification, antibiotic sensitivity of isolated strains to conventional antibiotics against Pseudomonas aeruginosa was determined using a disk diffusion technique, and Phenotypic screening for MBLs production was performed. Results: the maximum percentage was related to wound infection and the frequencies of the resistance to imipenem, meropenem, piperacillin, piperacillin-tazobactam, ceftazidime, gentamicin, amikacin, and ciprofloxacin, doripenem, ertapenem and colistin sulphate, were 70%, 53%, 83%, 67%, 91%, 88%, 84%, 84%, 33%, 90%, and 0%, respectively. The use of CD Test methods was approved for determining resistance to Carbapenems. Conclusion: antibiotic resistance to Pseudomonas aeruginosa is increasing and colistin sulphate is the most effective antibiotic. Keywords: Pseudomonas Aeruginosa; Burn Infection; Antibiotic Resistance.

As queimaduras encontram-se entre as causas principais de morbidade e mortalidade nos países em desenvolvimento e é o ambiente ideal para infecção sendo responsável por pelo menos 75% dos casos de óbito. A mortalidade é bimodal com um pico precoce associado ao choque do queimado e/ou injúrias inalatórias e um pico ligado à complicações sépticas. Durante o período de 15 anos 2000-2015 duzentos e vinte e três (68%) foram classificados como tendo queimaduras graves, satisfazendo os critérios e foram incluídos no nosso estudo. O Tabagismo esteve presente aumentando a chance de infecção em 5,37 vezes, Etilismo não foi significativo quando relacionado a infecção em queimados. O risco de infecção em pacientes foi 4,4 vezes maior naqueles internados mais de 15 dias. Os pacientes que sofrem queimadura na rua apresentam o risco 3,7 vezes maior de infecção do que os pacientes que sofrem queimadura em outros ambientes. A infecção esteve presente em 90 casos (39,1%)com cultura positiva Infecção no local da queimadura (17,4%), urina (6,5%), pulmonar (6,1%)infecções da corrente sanguínea (5,2%), infecções do cateter (3,25%). Os agentes isolados foram Staphylococcus aureu (4,3%), Pseudomonas sp.(3,9%) Escherichia coli (3,5%) Acinetobacter baumanni(3,0%). Burns are among the leading causes of morbidity and mortality in developing countries and is the ideal environment for infection accounting for at least 75% of death cases. Mortality is bimodal with an early peak associated with the shock of burnt and / or inhalation injuries and a peak linked to septic complications. During the 15 year period 2000-2015 two hundred twenty-three (68%) were classified as having severe burns, satisfying the criteria and were included in our study. The smoking was present increasing the chance of infection in 5.37 times, Alcoholism was not significant when related to infection in burn. The risk of infection in patients was 4.4 times higher among those hospitalized longer than 15 days. Patients suffering from sunburn on the street have the 3.7 times greater risk of infection than patients suffering burns in other environments. The infection was present in 90 cases (39.1%) with positive culture infection in burn site (17.4%), urine (6.5%), lung (6.1%) bloodstream infections (5, 2%), catheter infection (3.25%). The agents were Staphylococcus aureu (4.3%), Pseudomonas sp. (3.9%) Escherichia coli (3.5%) Acinetobacter baumannii (3.0%). Tese (Doutorado)

Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein synthesis. The aim of this study was to evaluate the effect of exotoxin A on mice WBC and comparison of the results with human WBC that contaminated with Pseudomonas aeruginosa. Materials & Methods: This is an experimental study which was conducted in 1384 on burn disease patients referred to Shiraz Ghotbodin hospital. Sample that contaminated with PA was taken from these patients for WBC count and WBC differentiation. Sample was also taken from 100 burn patients without infection (50 male and 50 female). Toxigenic strain of PA103 was cultured on liquid media and used for purification of exotoxin A. This sample was injected to 50 mice (I.V) and after different incubation time, WBC was counted. Ten normal mice was used as control. Collected data analyzed by SPSS. Results: WBC count decreased in mice that received Pseudomonas aeruginosa exotoxin A in comparison with normal mice (P

Background: Infection of burn wounds is a serious problem because it can delay healing, increase scarring and invasive infection may result in the death of the patient. Antibiotic prophylaxis is one of several interventions that may prevent burn wound infection and protect the burned patient from invasive infections. Objectives: To assess the effects of antibiotic prophylaxis on rates of burn wound infection. Search methods: In January 2013 we searched the Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid MEDLINE - In-Process & Other Non-Indexed Citations (2013); Ovid EMBASE; EBSCO CINAHL and reference lists of relevant articles. There were no restrictions with respect to language, date of publication or study setting. Selection criteria: All randomised controlled trials (RCTs) that evaluated the efficacy and safety of antibiotic prophylaxis for the prevention of BWI. Quasi-randomised studies were excluded. Data collection and analysis: Two review authors independently selected studies, assessed the risk of bias, and extracted relevant data. Risk ratio (RR) and mean difference (MD) were estimated for dichotomous data and continuous data, respectively. When sufficient numbers of comparable RCTs were available, trials were pooled in a meta-analysis to estimate the combined effect. Main results: This review includes 36 RCTs (2117 participants); twenty six (72%) evaluated topical antibiotics, seven evaluated systemic antibiotics (four of these administered the antibiotic perioperatively and three administered upon hospital admission or during routine treatment), two evaluated prophylaxis with non absorbable antibiotics, and one evaluated local antibiotics administered via the airway. The 11 trials (645 participants) that evaluated topical prophylaxis with silver sulfadiazine were pooled in a meta analysis. There was a statistically significant increase in burn wound infection associated with silver sulfadiazine compared with dressings/skin substitute (OR = 1.87; 95% CI: 1.09 to 3.19, I2 = 0%). These trials were at high, or unclear, risk of bias. Silver sulfadiazine was also associated with significantly longer length of hospital stay compared with dressings/skin substitute (MD = 2.11 days; 95% CI: 1.93 to 2.28). Systemic antibiotic prophylaxis in non-surgical patients was evaluated in three trials (119 participants) and there was no evidence of an effect on rates of burn wound infection. Systemic antibiotics (trimethoprim-sulfamethoxazole) were associated with a significant reduction in pneumonia (only one trial, 40 participants) (RR = 0.18; 95% CI: 0.05 to 0.72) but not sepsis (two trials 59 participants) (RR = 0.43; 95% CI: 0.12 to 1.61). Perioperative systemic antibiotic prophylaxis had no effect on any of the outcomes of this review. Selective decontamination of the digestive tract with non-absorbable antibiotics had no significant effect on rates of all types of infection (2 trials, 140 participants). Moreover, there was a statistically significant increase in rates of MRSA associated with use of non-absorbable antibiotics plus cefotaxime compared with placebo (RR = 2.22; 95% CI: 1.21 to 4.07). There was no evidence of a difference in mortality or rates of sepsis with local airway antibiotic prophylaxis compared with placebo (only one trial, 30 participants). Authors' conclusions: The conclusions we are able to draw regarding the effects of prophylactic antibiotics in people with burns are limited by the volume and quality of the existing research (largely small numbers of small studies at unclear or high risk of bias for each comparison). The largest volume of evidence suggests that topical silver sulfadiazine is associated with a significant increase in rates of burn wound infection and increased length of hospital stay compared with dressings or skin substitutes; this evidence is at unclear or high risk of bias. Currently the effects of other forms of antibiotic prophylaxis on burn wound infection are unclear. One small study reported a reduction in incidence of pneumonia associated with a specific systematic antibiotic regimen. © 2013 The Cochrane Collaboration.

Children with burn injuries are prone to increased risk for infection. Pantoea agglomerans is a particularly uncommon microorganism related to burn wound infections. A previously healthy, 28-month-old-boy was admitted with scald due to hot water. His general condition was moderate with normal vital signs. He had full thickness (right anterior forearm, 1.5%) and partial thickness (upper part of left arm, 0.5%; left anterior forearm, 2%; right thigh, 1%; right leg, 0.5%; left thigh, 0.5%; and left leg, 1%) burn wounds with totally estimated surface area percentage of 7%. Laboratory findings (hemogram, C-reactive protein, erythrocyte sedimentation rate, and blood biochemistry) were unremarkable. As well as hemodynamic stabilization and nutritional support, daily dressing with silver sulfadiazine was performed. Ten days later, grafting was carried out as the wound on right anterior forearm did not heal. Prophylactic intravenous cefazolin treatment (50mg/kg/day) was started. Four days after operation, he had 38.8°C fever and wound infection was realized. Gram stain of the swab revealed gram negative rods. Antibiotic treatment changed to ceftriaxone (75 mg/kg/day). While blood culture was negative, swab culture grew Pantoea agglomerans, resistant to cefazolin, sensitive to ceftriaxone. His fever subsided after 24 hours of ceftriaxone treatment and he was discharged on the 10th day. His immunological investigation was normal. One week later on control examination, his lesion was epithelized. Burn wound infections in pediatric age group can be caused by rare organisms. Other than presence of immunodeficiency, a graft tissue may ease this situation. [Med-Science 2016; 5(3.000): 878-83]