Recurrent bacteremia: A 10-year retrospective study in combat-related burn casualties

CytoSorb® in burn patients with septic shock and Acute Kidney Injury on Continuous Kidney Replacement Therapy is associated with improved clinical outcome and survival

BACKGROUND

In burn patients, septic shock and acute kidney injury (AKI) with use of continuous renal replacement therapy (CRRT) severely increase morbidity and mortality. Sorbent therapies could be an adjunctive therapy to address the underlying metabolic changes in inflammatory and anti-inflammatory cytokines dysregulated production.

METHODS

A retrospectively observational study of 35 severe burn patients admitted to the Burn Center (Turin, Italy, from January 2017 to December 2022), who underwent CRRT for AKI-associated septic shock. Out of 35 patients, 11 were treated with CytoSorb® as adjunctive therapy to CRRT (Sorbent group) and 24 patients only with CRRT (Control group).

RESULTS

The application of CytoSorb® took place in a very dispersed way. Out of 11 patients, 7 started the CRRT together with the sorbent application. The patients of the sorbent group exhibited a significant reduction in norepinephrine use compared to that of the control group. A clinical improvement over the first 4 days of Cytosorb® was observed in both survivors and no survivors of the sorbent group, with significant norepinephrine decreased use on day 4 compared to day 1. In-hospital mortality was 45.4% and 70.8% in the sorbent and control group, respectively, and significantly better at Kaplan-Meier survival analysis at 270 days (p = 0.0445). In both groups, all survivor patients recovered renal function at discharge, whereas no survivors did not.

CONCLUSIONS

Adjunctive treatment with CytoSorb® for burn patients with AKI-CRRT and septic shock poorly responsive to standard therapy led to a significant clinical improvement, and was associated with a lower mortality rate compared to CRRT alone.

Mycosynthesis of silver nanoparticles from endophytic Aspergillus flavipes AUMC 15772: ovat-statistical optimization, characterization and biological activities

BACKGROUND

Mycosynthesis of silver nanoparticles (SNPs) offers a safe, eco-friendly, and promising alternative technique for large-scale manufacturing. Our study might be the first report that uses mycelial filtrate of an endophytic fungus, Aspergillus flavipes, for SNPs production under optimal conditions as an antimicrobial agent against clinical multidrug-resistant (MDR) wound pathogens.

RESULTS

In the present study, among four different endophytic fungi isolated from leaves of Lycium shawii, the only one isolate that has the ability to mycosynthesize SNPs has been identified for the first time as Aspergillus flavipes AUMC 15772 and deposited in Genebank under the accession number OP521771. One variable at a time (OVAT) and Plackett Burman design (PBD) were conducted for enhancing the production of mycosynthesized SNPs (Myco-SNPs) through optimization using five independent variables. The overall optimal variables for increasing the mycosynthesis of SNPs from mycelial filtrate of A. flavipes as a novel endophytic fungus were a silver nitrate concentration of 2 mM, a pH of 7.0, an incubation time of 5 days, and a mycelial filtrate concentration of 30% in dark conditions. UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray spectroscopy (XRD), Transmission electron microscopy (TEM), and Selected-Area Electron Diffraction (SAED) patterns were used to characterize Myco-SNPs, which showed the peak of absorbance at 420 nm, and FTIR showed the bands at 3426.44, 2923.30, 1681.85, 1552.64, and 1023.02 cm-1, respectively, which illustrated the presence of polyphenols, hydroxyl, alkene, nitro compounds, and aliphatic amines, respectively. The XRD pattern revealed the formation of Myco-SNPs with good crystal quality at 2θ = 34.23° and 38.18°. The TEM image and SAED pattern show the spherical crystalline shape of Myco-SNPs with an average size of 6.9232 nm. High antibacterial activity of Myco-SNPs was recorded against MDR wound pathogens as studied by minimum inhibitory concentrations ranging from 8 to 32 µg/mL, time kill kinetics, and post-agent effects. Also, in vitro cell tests indicated that Myco-SNPs support the cell viability of human skin fibroblast cells as a nontoxic compound.

CONCLUSION

The obtained results revealed the successful production of Myco-SNPs using the mycelial filtrate of A. flavipes, which may be a promising nontoxic alternative candidate for combating MDR wound pathogens.

Infections in Burn Patients

Infections are the leading cause of mortality in burn patients who survive their initial resuscitation. Burn injury leads to immunosuppression and a dysregulated inflammatory response which can have a prolonged impact. Early surgical excision along with support of the multidisciplinary burn team has improved mortality in burn patients. The authors review diagnostic and therapeutic challenges as well as strategies for management of burn related infections.

Burn injuries in US service members: 2001-2018

INTRODUCTION

Burns are an important cause of battlefield injury, accounting for 5-20% of the combat injury burden. To date, no report has examined the full range of burns, from mild to severe, resulting from post-9/11 conflicts. The present study leverages the Expeditionary Medical Encounter Database (EMED), a Navy-maintained health database describing all service member medical encounters occurring during deployment, to capture, quantify and characterize burn-injured service members and the injuries they sustained while deployed in support of post-9/11 operations.

METHODS

The EMED was queried for all surviving service members with at least one burn injury, identified using injury-specific Abbreviated Injury Scale codes. Demographic and additional injury information were also obtained from the EMED.

RESULTS

From 2001 through 2018, 2507 deployed service members sustained 5551 burns. Blasts accounted for 82% of injuries, largely attributed to the use of improvised explosive devices. Concurrent injury was common, with 30% sustaining a traumatic brain injury and 10% sustaining inhalation injury. Most burns were small, with 92% involving< 20% TBSA; 85% of burns involved< 10% TBSA. The head and the hands were the most commonly affected areas, accounting for 48% of all burns, with 80% of service members sustaining at least one burn to these areas.

CONCLUSION

The majority of burns tend to be small in size, with the head and hands most commonly affected. As these areas are often left uncovered by the uniform, prevention measures, particularly improvement in and increased usage of personal protective gear, may help reduce these injuries and their consequences.

Exploring the potential of Rhizopus oryzae AUMC14899 as a novel endophytic fungus for the production of L-tyrosine and its biomedical applications

BACKGROUND

A significant threat to the public's health is the rise in antimicrobial resistance among numerous nosocomial bacterial infections. This may be a detriment to present initiatives to enhance the health of immune-compromised patients. Consequently, attention has been devoted to exploring new bioactive compounds in the field of drug discovery from endophytes. Therefore, this study is the first on the production of L-tyrosine (LT) as a promising bio-therapeutic agent from endophytic fungi.

RESULTS

A new endophytic fungal isolate has been identified for the first time as Rhizopus oryzae AUMC14899 from Opuntia ficus-indica (L.) and submitted to GenBank under the accession number MZ025968. Separation of amino acids in the crude extract of this fungal isolate was carried out, giving a higher content of LT, which is then characterized and purified. LT exhibited strong antibacterial and anti-biofilm activities against multidrug-resistant Gram-negative and Gram-positive bacteria. The recorded minimum inhibitory concentration (MIC) values ranged from 6 to 20 µg/ml. In addition, LT caused a strong reduction in biofilm formation and disrupted the preformed biofilm. Moreover, results indicated that LT supported cell viability, evidencing hemocompatibility and no cytotoxicity.

CONCLUSION

Our findings suggest that LT has potential as a therapeutic agent due to its potential antibacterial, anti-biofilm, hemocompatibility, and lack of cytotoxic activities, which may also increase the range of therapy options for skin burn infections, leading to the development of a novel fungal-based drug.

Chronic Wound Infection Model of Acinetobacter baumannii in Outbred Mice

INTRODUCTION

We established a murine wound infection model with doxycycline treatment against multidrug-resistant Acinetobacter baumannii (AB5075) in Institute of Cancer Research (ICR) outbred mice.

METHODS

Using three groups of neutropenic ICR mice, two full-thickness dorsal dermal wounds (6 mm diameter) were made on each mouse. In two groups, wounds were inoculated with 7.0 × 104 colony-forming units of AB5075. Of these two groups, one received a 6-day regimen of doxycycline while the other was sham treated with phosphate-buffered saline as placebo control. Another uninfected/untreated group served as a control. Wound closure, clinical symptoms, bacterial burden in wound beds and organs, and wound histology were investigated.

RESULTS

Doxycycline-treated wounds completely healed by day 21, but untreated, infected wounds failed to heal. Compared to controls, wound infections without treatment resulted in significant reductions in body weight and higher bacterial loads in wound beds, lung, liver, and spleen by day 7. Histological evaluation of wounds on day 21 revealed ulcerated epidermis, muscle necrosis, and bacterial presence in untreated wounds, while wounds treated with doxycycline presented intact epidermis.

CONCLUSIONS

Compared to the previously developed BALB/c dermal wound model, this study demonstrates that the mouse strain selected impacts wound severity and resolution. Furthermore, this mouse model accommodates two dorsal wounds rather than only one. These variations offer investigators increased versatility when designing future studies of wound infection. In conclusion, ICR mice are a viable option as a model of dermal wound infection. They accommodate two simultaneous dorsal wounds, and upon infection, these wounds follow a different pattern of resolution compared to BALB/c mice.

The Ability of a Concentrated Surfactant Gel to Reduce an Aerobic, Anaerobic and Multispecies Bacterial Biofilm In Vitro

Biofilm formation in wounds can lead to increased inflammation, infection and delayed wound healing. Additionally, biofilms show increased recalcitrance to antimicrobials compared to their planktonic counterparts making them difficult to manage and treat. Biofilms are frequently polymicrobial, consisting of aerobic and anaerobic bacteria, as well as fungi and yeasts. The aim of this study was to evaluate the effects of a concentrated surfactant gel with antibacterial preservative agents (CSG) against wound relevant opportunistic pathogens, including an aerobic biofilm, anaerobic biofilm and multispecies biofilm. The CSG was added to a 48 h anaerobic biofilm of Bacteroides fragilis, a 24 h multispecies biofilm of Acinetobacter baumannii, Staphylococcus aureus and Staphylococcus epidermidis and a 24 h biofilm of Pseudomonas aeruginosa grown in an in vitro wound relevant environment. Following a contact time of 24 h with the CSG, the bacterial cell density of the biofilms was reduced by 2-4 log in comparison to an untreated control. The results demonstrate the ability of the CSG to disrupt wound relevant biofilms and support the use of the CSG in the clinic to treat wounds caused by biofilm related infections.

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.

Effect of early enteral nutrition on outcomes of trauma patients requiring intensive care

PURPOSE

To investigate the effect of early enteral nutrition on outcomes of trauma patients in the intensive care unit (ICU).

METHODS

Clinical data of trauma patients in the ICU of Daping Hospital, China from January 2012 to December 2017 was retrospectively analyzed, including patient age, gender, injury mechanism, injury severity score (ISS), nutritional treatment, postoperative complications (wound infection, abdominal abscess, anastomotic rupture, pneumonia), mortality, and adverse events (nausea, vomiting, abdominal distention). Only adult trauma patients who developed bloodstream infection after surgery for damage control were included. Patients were divided into early enteral nutrition group (<48 h) and delayed enteral nutrition group (control group, >48 h). Data of all trauma patients were collected by the same investigator. Data were expressed as frequency (percentage), mean ± standard deviation (normal distribution), or median (Q₁, Q₃) (non-normal distribution) and analyzed by Chi-square test, Student's t-test, or rank-sum test accordingly. Multiple logistic regression analysis was further adopted to investigate the significant variables with enteral nutrition.

RESULTS

Altogether 876 patients were assessed and 110 were eligible for this study, including 93 males and 17 females, with the mean age of (50.0 ± 15.4) years. Traffic accidents (46 cases, 41.8%) and fall from height (31 cases, 28.2%) were the dominant injury mechanism. There were 68 cases in the early enteral nutrition group and 42 cases in the control group. Comparison of general variables between early enteral nutrition group and control group revealed significant difference regarding surgeries of enterectomy (1.5% vs. 19.0%, p = 0.01), ileum/transverse colon/sigmoid colostomy (4.4% vs. 16.3%, p = 0.01) and operation time (h) (3.2 (1.9, 6.1) vs. 4.2 (1.8, 8.8), p = 0.02). Other variables like ISS (p = 0.31), acute physiology and chronic health evaluation≥20 (p = 0.79), etc. had no obvious difference. Chi-square test showed a much better result in early enteral nutrition group than in control group regarding morality (0 vs. 11.9%, p = 0.03), length of hospital stay (days) (76.8 ± 41.4 vs. 81.4 ± 44.7, p = 0.01) and wound infection (10.3% vs. 26.2%, p = 0.03). Logistic regression analysis showed that the incidence of wound infection was related to the duration required to achieve the enteral nutrition standard (OR = 1.095, p = 0.002). Seventy-six patients (69.1%) achieved the nutritional goal within a week and 105 patients (95.5%) in the end. Trauma patients unable to reach the enteral nutrition target within one week were often combined with abdominal infection, peritonitis, bowel resection, intestinal necrosis, intestinal fistula, or septic shock.

CONCLUSION

Early enteral nutrition for trauma patients in the ICU is correlated with less wound infection, lower mortality, and shorter hospital stay.

Difficult to Treat Infections in the Burn Patient

Background: Unusual infections can lead to complications in more severely burned patients and pose major challenges in treatment. Methods: The published literature of retrospective reviews and case series of the uncommon infections of osteomyelitis, polymicrobial bacteremia, recurrent bacteremia, endocarditis, central nervous system (CNS), and rare fungal infections in burned patients have been summarized and presented. Results: When compared with infections occurring in the non-burn population, these infections in burn patients are more likely to be because of gram-negative bacteria or fungi. Because of hyperdynamic physiology and changes in immunomodulatory response secondary to burns, the clinical presentation of these infections in a patient with major burns differs from that of the non-burn patient and may not be identified until the post-mortem examination. Some of these infections (osteomyelitis, endocarditis, CNS, rare fungal infections) may necessitate surgical intervention in addition to antimicrobial therapy to achieve cure. The presence of the burn and allograft can also present unique challenges for surgical management. Conclusions: These difficult and unusual infections in the severely burned patient necessitate an index of suspicion, appropriate diagnosis, identification and sensitivities of the putative pathogen, effective systemic antimicrobial therapy, and appropriate surgical intervention if recovery is to be achieved.