Isolation of a lytic bacteriophage against extensively drug-resistant Acinetobacter baumannii infections and its dramatic effect in rat model of burn infection.

OBJECTIVES: Acinetobacter Baumannii is an opportunistic nosocomial pathogen belonging to the Moraxellaceae family. The emergence of multidrug resistant strains of this pathogen caused many problems for hospitals and patients. The aim of the current study was to isolate, identify, and morphologically, physiologically, and in vivo analyze a new lytic bacteriophage targeting extensively drug-resistant (XDR) A. baumannii. MATERIALS AND METHODS: Different wastewater samples were tested for isolation of lytic bacteriophage against 19 A. baumannii isolates obtained from patients hospitalized in a hospital in Arak, Iran, from January 2019 to March 2019. The phenotypic and genotypic characteristics of A. baumannii strains (resistance genes including: adeA, adeB, adeC, adeR, adeS, ISAba1, blaOXA-23, blaOXA-24) were analyzed. The isolated phage characteristics including adsorption time, pH and thermal stability, host range, one-step growth rate, electron microscopy examination, and therapeutic efficacy of the phage were also investigated. Therapeutic efficacy of the phage was evaluated in a rat model with burn infection of XDR A. baumannii. The lesion image was taken on different days after burning and infection induction and was compared with phage untreated lesions. RESULTS: The results showed unique characteristics of the isolated phage (vB-AbauM-Arak1) including high specificity for Acinetobacter baumannii, stability at a relatively wide range of temperatures and pH values, short adsorption time, short latent period, and large burst size. In relation to the therapeutic efficacy of the phage, the lesion area decreased in phage-treated groups over 14 days than in those untreated, significantly (p < 0.05). CONCLUSION: Our findings demonstrated that isolated lytic phage was able to eliminate burn infections caused by XDR A. baumannii in a rat model. So, it may be recommended as alternative options toward to developing a treatment for extensively drug resistant Acinetobacter infections.

Viral Infections in Burns.

Background: Viral infections after burns are less common than bacterial infections but usually occur in the more severely burned patients and have been associated with poor outcomes. Methods: Retrospective reviews and case series were examined to provide an overview of the management of viral infections in the burn patient. Results: The most common viral pathogens in these patients are the herpesviruses, which include herpes simplex, varicella zoster, cytomegalovirus, and human herpesvirus 6. Established viral infections that may complicate patient management include human immunodeficiency virus, hepatitis B and C, and, more recently, the novel coronavirus SARS-CoV-2. Herpesvirus infections can occur as primary or nosocomial pathogens but clinical manifestations most commonly are re-activation of latent viral infection. Because of the paucity of data in the burn population, much of the evidence for specific treatments is extrapolated from patients with severe immunosuppression or critical illness. Antiviral therapy is employed for the burn patient with herpesvirus infections. This is an area of active study, and further research is needed to better understand the risks, clinical manifestations, and attributable morbidity and mortality of viral infections. Conclusions: Major burn injury results in immunosuppression and viral infection in a small number of patients. Recognition and antiviral therapy are employed, but additional studies are necessary to improve outcomes in these patients.

Viral Infections in Burn Patients: A State-Of-The-Art Review.

Infections that are triggered by the accompanying immunosuppression in patients with burn wounds are very common regardless of age. Among burn patients, the most frequently diagnosed infections include the bacterial ones primarily caused by Pseudomonas aeruginosa or Klebsiella pneumonia, as well as fungal infections with the etiology of Candida spp. or Aspergillus spp. Besides, burn wounds are highly susceptible to viral infections mainly due to the impaired immune responses and defective functions of the immune cells within the wound microenvironment. The most prevalent viruses that invade burn wounds include herpes simplex virus (HSV), cytomegalovirus (CMV), human papilloma virus (HPV), and varicella zoster virus (VZV). Likewise, less prevalent infections such as those caused by the orf virus or Epstein-Barr Virus (EBV) might also occur in immunosuppressed burn patients. Viral infections result in increased morbidity and mortality rates in severely burned patients. Additionally, a positive correlation between the hospitalization duration and the severity of the viral infection has been demonstrated. Viral infections trigger the occurrence of various complications, ranging from mild symptoms to even fatal incidents. Accurate detection of viral infection is of great clinical importance because of the possibility for a quicker introduction of proper treatment therapy and shortening of hospitalization time. The aim of this paper is to provide a comprehensive review of the literature and summarize the findings regarding the most common viral infections in immunosuppressed burn patients.

Disseminated zoster in an adult patient with extensive burns: a case report.

BACKGROUND: Shingles (localized zoster) and disseminated zoster are caused by the reactivation of latent varicella zoster virus (VZV). Reactivation of VZV is related to impaired cell-mediated immunity. Extensive burns affecting a patient result in burn-related immunosuppression and cytokine storm. Despite immunosuppression in burn patients, the reactivation of VZV is extremely rare, whereas eczema herpeticum, caused by reactivation of latent herpes simplex virus (HSV), is common. We have found only 1 published case of VZV reactivation during burn treatment in the literature. CASE PRESENTATION: A 51-year-old man was burned in a fire, which affected 60% of his total body surface area (TBSA), and also received inhalation injury (day 0). Despite fluid resuscitation, he showed persistent renal failure. Continuous hemodialysis and filtration (CHDF) combined with polymyxin B-immobilized fiber column direct hemoperfusion (PMX-DHP) therapy was used for cytokine modulation. Autologous and allogeneic skin grafting was performed. On day 15, multiple-drug-resistant Pseudomonas aeruginosa (MDRP) was detected from a blood specimen, and the patient developed multiple organ failure (MOF). On day 31, compact aggregations of small vesicles appeared on the intact skin of his left knee and left buttock. The vesicles were located within the 4th lumbar (L4) spinal dermatome. From day 32 to day 34, similar new vesicles arose on his intact skin and epithelializing skin-graft donor sites. We diagnosed disseminated zoster, based on the patient's age, the characteristic occurrence of the initial vesicles within a limited area of intact skin in the left L4 dermatome, and a positive Tzank smear. Serologic testing on day 36 showed a high level of anti-VZV immunoglobulin (Ig)G with low levels of anti-VZV IgM, anti-HSV IgG, and anti-HSV IgM. The patient was isolated in a negative-pressure room to avoid air-borne spread of VZV. On day 52, the patient died. CONCLUSIONS: To the best of our knowledge, our patient is the second case of reactivation of VZV during burn treatment. It is unclear why reactivation of VZV is rare in patients with burn-related immunosuppression, whereas HSV reactivation is common. Cytokine modulation throughout the treatment period using CHDF combined with PMX-DHP might have been related to the rare reactivation of VZV in our patient. Our case provides an additional information on the relationship between the immune status of a patient with extensive burns and reactivation of latent VZV or HSV.

Stability of bacteriophages in burn wound care products.

Bacteriophages could be used along with burn wound care products to enhance antimicrobial pressure during treatment. However, some of the components of the topical antimicrobials that are traditionally used for the prevention and treatment of burn wound infection might affect the activity of phages. Therefore, it is imperative to determine the counteraction of therapeutic phage preparations by burn wound care products before application in patients. Five phages, representatives of two morphological families (Myoviridae and Podoviridae) and active against 3 common bacterial burn wound pathogens (Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus) were tested against 13 different products commonly used in the treatment of burn wounds. The inactivation of the phages was quite variable for different phages and different products. Majority of the anti-infective products affected phage activity negatively either immediately or in the course of time, although impact was not always significant. Products with high acidity had the most adverse effect on phages. Our findings demonstrate that during combined treatment the choice of phages and wound care products must be carefully defined in advance.

Herpesviradae infections in severely burned children.

OBJECTIVE: Burn-related immunosuppression can promote human herpesviridae infections. However, the effect of these infections on morbidity and mortality after pediatric burn injuries is unclear. METHODS: We retrospectively analyzed pediatric patients with burns ≥10% of the total body surface area (TBSA) who were admitted between 2010 and 2015. On clinical suspicion of a viral infection, antiviral therapy was initiated. Viral infection was confirmed via Tzanck smear, viral culture, and/or PCR. Study endpoints were mortality, days of antiviral agent administration, type of viral test used, type of viral infection, and length of hospitalization. RESULTS: Of the 613 patients were analyzed, 28 presented with clinically diagnosed viral infections. The use of Tzanck smears decreased over the past 5 years, whereas PCR and viral cultures have become standard. Patients with viral infections had significantly larger burns (53±15% vs. 38±18%, p<0.001); however, length of stay per TBSA burn was comparable (0.5±0.4 vs. 0.6±0.2, p=0.211). The most commonly detected herpesviridae was herpes simplex virus 1. Two patients died due to sepsis, which was accompanied by HSV infection. The mortality rate among all patients (2.7%) was comparable to that in the infected group (7.1%, p=0.898). Acyclovir was given systemically for 9±8days (N=76) and/or topically for 9±9days for HSV (N=39, combination of both N=33). Ganciclovir was prescribed in three cases for CMV. CONCLUSIONS: Viral infections occur more commonly in patients suffering from larger burns, and HSV infections can contribute to mortality.

Human herpes viruses in burn patients: A systematic review.

OBJECTIVE: The contribution of human herpes viruses, including herpes simplex virus (HSV), cytomegalovirus (CMV), and varicella zoster virus (VZV) to morbidity and mortality after burns remains controversial. This systematic review was undertaken to assess evidence of herpes virus-related morbidity and mortality in burns. MATERIALS AND METHODS: PubMed, Ovid, and Web of Science were searched to identify studies of HSV, CMV, or VZV infections in burn patients. Exclusion criteria included: A level of evidence (LoE) of IV or V; nonhuman in vivo studies; and non-English articles. There was no limitation by publication date. RESULTS: Fifty articles were subjected to full-text analysis. Of these, 18 had LoE between I-III and were included in the final review (2 LoE I, 16 LoE II-III). Eight had a prospective study design, 9 had a retrospective study design, and 1 included both. CONCLUSIONS: No direct evidence linked CMV and HSV infection with increased morbidity and mortality in burns. Following burn, CMV reactivation was more common than a primary CMV infection. Active HSV infection impaired wound healing but was not directly correlated to mortality. Infections with VZV are rare after burns but when they occur, VZV infections were associated with severe complications including mortality. The therapeutic effect of antiviral agents administered after burns warrants investigation via prospective randomized controlled trials.

Unique Presentation of Orf Virus Infection in a Thermal-Burn Patient After Receiving an Autologous Skin Graft.

We describe a burn patient who developed skin lesions on her skin-graft harvest and skin-graft recipient (burn) sites. Orf virus infection was confirmed by a combination of diagnostic assays, including molecular tests, immunohistochemical analysis, pathologic analysis, and electron microscopy. DNA sequence analysis grouped this orf virus isolate among isolates from India. Although no definitive source of infection was determined from this case, this is the first reported case of orf virus infection in a skin graft harvest. Skin graft recipients with exposures to animals may be at risk for this viral infection.

Cytomegalovirus Colitis in a Burn Patient.

The prevalence of cytomegalovirus in the burn population is high. However, its role in the clinical management of burn patients is still being defined. This report documents a 41-year-old man who developed cytomegalovirus (CMV) colitis after being admitted with a 72% burn. Before the administration of ganciclovir, the authors had difficulty controlling his quantitative wound cultures with serial debridements, topical agents, and systemic antibiotics for known pathogens, which led to graft loss. After the ganciclovir was given, his quantitative wound cultures improved without changing the authors' topical agents or systemic antibiotics and had improved graft take. Whether CMV infection alone contributed to an increased morbidity in this patient or the combination of bacteria/fungal infection with CMV led to a synergistic effect is still not clearly understood. CMV may have contributed to a dysfunction in his cell mediated immunity, which, in turn, lowered the bacterial and fungal load necessary to cause graft loss. Patients who continue to do poorly despite adequate treatment for known pathogens may need to be screened for CMV and treated.

Divergent and dynamic activity of endogenous retroviruses in burn patients and their inflammatory potential.

Genes constitute ~3% of the human genome, whereas human endogenous retroviruses (HERVs) represent ~8%. We examined post-burn HERV expression in patients' blood cells, and the inflammatory potentials of the burn-associated HERVs were evaluated. Buffy coat cells, collected at various time points from 11 patients, were screened for the expression of eight HERV families, and we identified their divergent expression profiles depending on patient, HERV, and time point. The population of expressed HERV sequences was patient-specific, suggesting HERVs' inherent genomic polymorphisms and/or differential expression potentials depending on characteristics of patients and courses of injury response. Some HERVs were shared among the patients, while the others were divergent. Interestingly, one burn-associated HERV gag gene from a patient's genome induced IL-6, IL-1ß, Ptgs-2, and iNOS. These findings demonstrate that injury stressors initiate divergent HERV responses depending on patient, HERV, and disease course and implicate HERVs as genetic elements contributing to polymorphic injury pathophysiology.

The prevalence of human endogenous retroviruses in the plasma of major burn patients.

BACKGROUND: Approximately 8% of the human genome is composed of retroviral sequences, which are known as human endogenous retroviruses (HERVs) and, have been implicated in both health status and disease. Recently, indirect evidence for a possible role of retroviral elements in the systemic response to stress signals has been provided by several studies. In the present study, we sought to evaluate the relationship between HERVs and major burn in humans. METHOD: We investigated the prevalence of HERV families by reverse transcriptase PCR (RT-PCR) in cell-free plasma samples from patients with burns and from normal individuals. RESULTS: Different prevalences of HERV families were observed in the plasma samples from the burn patient group and normal group. Compared with the prevalences of HERV-W and HERV-K in the normal group, in the burn patient group, the prevalence of HERV-W was significantly lower (P<0.001), but the prevalence of HERV-K was higher (P=0.059). CONCLUSIONS: Our study of the prevalences of HERVs revealed that the activation of certain HERV families may be influenced not only by burns but also by the initial treatments that were used to address these injuries.

Injury-elicited stressors alter endogenous retrovirus expression in lymphocytes depending on cell type and source lymphoid organ.

BACKGROUND: Murine leukemia virus-type endogenous retroviruses (MuLV-ERVs) constitute ~10% of the mouse genome and are associated with various pathophysiologic processes. In this study, we examined whether MuLV-ERVs' response to burn-elicited stressors is specific for certain lymphocyte populations and/or locations of lymphoid organ. RESULTS: B- and T-cells, which were sorted from nine lymphoid organs of C57BL/6J mice after burn, were subjected to MuLV-ERV expression analyses. Overall, the post-burn MuLV-ERV expression pattern was dependent on lymphocyte type, time after injury, location of lymphoid organ, and MuLV-ERV type. For instance, the MuLV-ERV expression in T-cells from the thymus and three cervical lymph nodes decreased at 3 hours post-burn while the expression of some MuLV-ERVs was augmented in B-cells derived from the mesenteric lymph node. The MuLV-ERV U3 sequences population of the burn-24 hours group was less diverse in comparison to the no burn and burn-3 hours groups. In addition, it was apparent that at the 24 hours time point, the U3 populations of B-cells from both no burn and burn groups were less heterogeneous than the T-cells' U3 populations. Using the U3 sequences, some of which were isolated only from specific experimental groups (B- vs. T-cells; no burn vs. burn), as probes, 51 putative MuLV-ERVs, including 16 full-length proviruses, were mapped followed by characterization of their biologic properties. CONCLUSION: MuLV-ERVs' response to burn-elicited stressors may be differentially controlled depending on lymphocyte type, location of lymphoid organ, MuLV-ERV type, and stress duration.

Is prophylactic acyclovir treatment warranted for prevention of herpes simplex virus infections in facial burns? A review of the literature.

Both cosmetic facial resurfacing and facial burns cause an injury to the dermal layer of the skin. This injury renders the patient susceptible to primary herpes simplex virus (HSV) infection or, more commonly, to HSV reactivation. This in turn can lead to bacterial superinfection, possibly resulting in scarring and systemic dissemination in the immunosuppressed burn patient. HSV reactivation rates have been reported to be up to 50% in cosmetic procedures without acyclovir prophylaxis and up to 25% in patients with burn injury. Currently, acyclovir prophylaxis is a common practice in facial resurfacing, but no such recommendations have been issued for patients with burn injury. HSV usually presents in a febrile burn patient between the first and third postburn weeks as a cluster of small, umbilicated vesicles or vesicopustules on an erythematous base found within or around the margins of healing partial-thickness wounds. Diagnosis is confirmed through viral culture from the base of an unroofed vesicle, and treatment is begun with intravenous acyclovir. Antiviral prophylaxis should be strongly considered for HSV infection prevention in patients with major burn injury, particularly with burns involving the face. Acyclovir is the primary drug of choice, and contact precautions should be practiced. High suspicion levels and alertness to this entity can help prompt diagnosis and timely treatment while alleviating late complications.

Cytomegalovirus infection in severe burn patients monitoring by real-time polymerase chain reaction: A prospective study.

BACKGROUND: Cytomegalovirus (CMV) infection has been shown to occur not rarely in critically ill patients in the past decade. However, little data are available on CMV infection in burn patients whereas their susceptibility to CMV infection has been proved. METHODS: We prospectively assessed CMV viremia by real-time polymerase chain reaction and clinical outcome in immunocompetent burn patients with total burn surface area greater than 15%. RESULTS: Twenty-nine patients were enrolled. The rate of CMV infection was of 71% in CMV seropositive burn patients, and of 12.5% in CMV seronegative burn patients. CMV reactivation was associated with a higher IGS 2 score on admission. High grade CMV viremia was associated with longer mechanical ventilation duration, higher infection number, higher transfused red blood cell number, and longer ICU stays. There were no differences on mortality rate between patients with and without CMV reactivation. CONCLUSION: CMV infection rate is considerable in burn patients with TBSA greater than 15%. This infection seems to be mostly due to reactivation of latently existing virus.

Overwhelming disseminated herpes simplex virus type 2 infection in a patient with severe burn injury: case report and literature review.

Viral-mediated organ disease is an infrequent but recognized complication of severe burn injury. This occurs primarily because of herpes family viruses such as cytomegalovirus, herpes simplex virus (HSV), and Epstein-Barr virus given their ability to establish lifelong latency after primary infection and reactivate in the setting of altered immune function. In this report, we describe a severely burned patient who succumbed to fulminant HSV-2 pneumonitis and hepatitis, and summarize the existing literature on HSV infections in this unique patient population. To our knowledge, this is the first report of disseminated visceral HSV-2 infection in a burn patient in the medical literature.