Burn wounds infected by contaminated water: case reports, review of the literature and recommendations for treatment

Use of a dynamic tissue system and biological xenograft in complex traumatic wound closure

OBJECTIVE

Asymmetrical dimensions and nonlinear margins of a multilayered traumatic wound often preclude healing via primary intention. We present the case of an otherwise healthy 21-year-old male who sustained trauma following a boating accident.

METHOD

The patient sustained three lacerations to the posterior thighs from the boat propeller. The most extensive wound measured 25×10×6cm of muscle extrusion with a divot fracture involving the posterior femur.

RESULTS

Primary closure and restoration of muscle biomechanics was achieved using a combination of a dynamic tissue system (DTS) and porcine urinary bladder matrix (PUBM) xenograft. After 24 days of treatment in hospital, the patient was discharged without the need for home health, outpatient wound care, or ongoing negative pressure wound therapy. The patient recovered full function of the legs and was cleared for participation in all activities.

CONCLUSION

This complex traumatic boat propeller injury presented many challenges, including a transverse orientation on the extremity, degree of muscle injury/extrusion, and significant soft tissue loss. The combined application of a DTS with PUBM biological xenograft achieved a primary myocutaneous closure without the need for skin graft or flap reconstruction by plastic surgery.

Diagnosis and Management of Severe Water-Related Skin and Soft Tissue Sepsis: A Summative Review of the Literature

BACKGROUND

Skin and soft tissue infections (SSTIs) are common presentations in the emergency department. However, this is less common after contact with contaminated saltwater or freshwater. This review presents the diagnosis and management of water-related soft tissue sepsis in this vulnerable and difficult-to-treat subgroup of necrotizing soft tissue sepsis.

METHODS

A summative literature overview is presented regarding bacterial and fungal SSTI after contact with contaminated water, with practical diagnostic and management aspects.

RESULTS

The literature indicates that these wounds and infections remain difficult to treat. An approach using appropriate diagnostic tools with both medical and surgical management strategies is provided.

CONCLUSIONS

SSTIs due to water contamination of wounds involve unusual organisms with unusual resistance patterns, and require a nuanced and directed diagnostic approach with an adaptation of the usual antibiotic or antifungal selection to achieve a successful cure, along with aggressive debridement and wound care.

Aeromonas and Human Health Disorders: Clinical Approaches

The genus Aeromonas comprises more than 30 Gram-negative bacterial species and naturally inhabitants from aquatic environments. These microorganisms, commonly regarded as pathogens of fish and several other animals, have been gaining prominence on medical trial due to its ability to colonize and infect human beings. Besides water, Aeromonas are widely spreaded on most varied sources like soil, vegetables, and food; Although its opportunistic nature, they are able to cause infections on immunocompromised or immunocompetent patients. Aeromonas species regarded as potential human pathogens are usually A. hydrophila, A. caviae, and A. veronii biovar sobria. The main clinical manifestations are gastrointestinal tract disorders, wound, and soft tissue infections, as well as septicemia. Regarding to antibiotic responses, the bacteria present a diversified susceptibility profile and show inherence resistance to ampicillin. Aeromonas, as an ascending genus in microbiology, has been carefully studied aiming comprehension and development of methods for detection and medical intervention of infectious processes, not fully elucidated in medicine. This review focuses on current clinical knowledge related to human health disorders caused by Aeromonas to contribute on development of efficient approaches able to recognize and impair the pathological processes.

Evaluation the ability of acellular ovine small intestine submucosa to load and release of mineral pitch and its anti-inflammatory effects

Injury from the severe burn is exacerbated by a persistent inflammatory response. This response is mediated by cytokines and chemokines, which are released from various immune cells, including mast cells. In this study, the ability of the acellular ovine small intestine submucosa (AOSIS) to load and release of Mineral Pitch (MP) was first investigated, and it was found that the preparation of the scaffold by a modified method enables it to load and release water-soluble drugs. Then, 32 male Wistar rats were divided into four groups, a third-degree burn was created, and except for the control group, the others were treated with: AOSIS, WJ-MSCs seeded AOSIS, or AOSIS loaded with WJ-MSCs and MP. Wound sampling on the 5th day after treatment showed that the number of intact and degranulated mast cells in the treatment groups was associated with a decrease compared to the control group. In the last group, this decrease was the largest (and statically significant (p < 0.05)). Also, by measuring the level of inflammatory factors in blood serum, it was found that in the treatment groups compared to the control group, IL-10 was associated with an increase, and TNF-α was associated with a decrease. The changes in inflammatory factors were more significant (p < 0.05) in the last group. So, our results indicate that AOSIS loaded with WJ-MSCs and MP could be used as an innovative tissue-engineered device to control inflammatory condition during burn wound healing.

Mucormycosis in burns: a review

Mucormycosis is a rare fungal infection with a high mortality rate. It presents with scattered black/necrotic ulcers, white fungal elements, and progression of wounds despite seemingly adequate debridement. Diagnosis is confirmed on wound histology, however this is often delayed. There is currently no comprehensive review of burn related mucormycosis within the literature, making this the first paper to provide evidence-based treatment guidance. We performed a review of publications from 1946 - present. There were 151 cases of mucormycosis complicating burns. The mortality rate was 54.5%, and there was a significant increase in mortality with axial body site involvement compared with isolated peripheral involvement. The standard treatment was prompt and radical debridement. Utilisation of frozen section to guide debridement aided in clinical decision making. No systemic treatment reached statistical significance, however amphotericin B trended towards significance. Although there is no strong evidence for topical amphotericin B or hyperbaric oxygen, there may be benefit in some cases. This study recommends early radical debridement in conjunction with the European Confederation of Medical Mycology guidelines of IV liposomal/lipid complex amphotericin B >5mg/kg/day, with posaconazole 800mg daily in divided doses as a salvage or oral step-down 1.

Fungal Infection in Burn Patents: A Review of 36 Case Reports

OBJECTIVES

The aims of this study were to review recent fungal infection case reports published, evaluate the treatment regimens and clinical outcomes, and provide recommendations for future management.

METHODS

A review of case reports published over the last decade was conducted. PubMed was searched to collect the relevant citations using a combination of the key words ("burn," "burned," "burns," "fungal," "fungi," and "fungus") in title or abstract. Case series, reviews, guidelines, and experimental and non-English studies were excluded. Statistical analyses were performed using Microsoft Excel 2019.

RESULTS

A total of 36 case reports encompassing a total of 44 burn patients with fungal infection were included in the final analysis. Ablative surgeries, including surgical excision, debridement, skin graft, vitrectomy, teeth extraction, valve replacement, or amputation, were performed in 38 cases after the suspicion or identification of fungal infection. Twenty-nine of them were eventually discharged, yielding a survival rate of 76.3%. In the remaining 6 cases, ablative surgery was not mentioned and 3 of them eventually died, yielding a survival rate of 50%. The total mortality was 27.27%. Among the 12 death cases, 1 was infected with Candida albicans, 1 with non-albicans Candida, 2 with Aspergillus spp, 2 with Fusarium spp, 4 with Zygomycetes, and 2 with other fungal species.

CONCLUSIONS

The overall mortality of fungal wound infection is still high in burn patients around the world, especially those infected with non-Candida species. Early diagnosis of fungal infection, early initiation of appropriate antifungal therapy, and effective surgical intervention are key measures to improve the treatment effect and reduce the mortality of fungal infection in burn patients.

Factors Associated with Mortality Following Burns Complicated by Necrotizing Skin and Soft Tissue Infections: A Systematic Review and Meta-analysis of Individual Participant Data

We reviewed studies with individual participant data of patients who sustained burn injury and subsequently developed necrotizing skin and soft tissue infections (NSTI). Characteristics and managements were compared between patients who lived and patients who died to determine factors associated with mortality. Six databases (PubMed, EMBASE, Cochrane Library, Web of Science, Scopus and CINAHL) were searched. PRISMA-IPD guidelines were followed throughout the review. Eligible patients sustained a burn injury, treated in any setting, and diagnosed with a NSTI following burn injury. Comparisons were made between burned patients who lived "non-mortality" and burned patients who died "mortality" following NSTI using non-parametric univariate analyses. Fifty-eight studies with 78 patients were published from 1970 through 2019. Non-mortality resulted in 58 patients and mortality resulted in 20 patients. Patients with mortality had significantly greater median %TBSA burned (45%[IQR:44-64%] versus 35%[IQR:11-59%],p=0.033), more intubations (79% versus 43%,p=0.013), less debridements (83% versus 98%,p=0.039), less skin excisions (83% versus 98%,p=0.039), more complications (100% versus 50%,p<0.001), management at a burn center (100% versus 71%,p=0.008), underwent less flap surgeries (5% versus 35%,p=0.014), less graft survival (25% versus 86%,p<0.001), and less healed wounds (5% versus 95%,p<0.001), compared to patients with non-mortality, respectively. Non-mortality patients had more debridements, skin excised, systemic antimicrobials, skin graft survival, flaps, improvement following surgery and healed wounds compared to mortality patients. Mortality patients had greater %TBSA burned, intubations, management at a burn center and complications compared to non-mortality patients.

Identification of potential drug targets in human pathogen Bacillus cereus and insight for finding inhibitor through subtractive proteome and molecular docking studies

Bacillus cereus is a gram-positive, anaerobic, spore-forming bacterium related to food poisoning in humans. Vomit and diarrhea are the symptoms of foodborne B. cereus infection caused by emetic toxins and three enterotoxins, respectively. This bacterium is broadly present in soil and foods such as vegetables, spices, milk, and meat. The antibiotics impenem, vancomycin, chloramphenicol, gentamicin, and ciprofloxacin are used for all susceptible strains of B. cereus. But these antibiotics cause side effects in the host due to the drug-host interaction; because the targeted proteins by the drugs are not pathogen specific proteins, they are similar to human proteins also. To overcome this problem, this study focused on identifying putative drug targets in the pathogen B. cereus and finding new drugs to inhibit the function of the pathogen. The identification of drug targets is a pipeline process, starting with the identification of targets non-homologous to human and gutmicrobiota proteins, finding essential proteins, finding other proteins that highly interact with these essential proteins that are also highly important for protein network stability, finding cytoplasmic proteins with a clear pathway and known molecular function, and finding non-druggable proteins. Through this process, two novel drug targets were identified in B. cereus. Among the various antibiotics, Gentamicin had showed good binding affinity with the identified novel targets through molecular modeling and docking studies using Prime and GLIDE module of Schrödinger. Hence, this study suggest that the identified novel drug targets may very useful in drug therapeutic field for finding inhibitors which are similar to Gentamicin and designing new formulation of drug molecules to control the function of the foodborne illness causing pathogen B. cereus.

Microbiology and clinical characteristics of industrial oil burns

INTRODUCTION

Infections complicating burns generally transition from Gram-positive to Gram-negatives over the first couple weeks, but this depends on multiple factors. The microbiology of infections complicating crude oil (CO) and hydraulic fracturing (FRAC) burns is unknown.

METHODS

We performed a retrospective study of patients with industrial thermal burns hospitalized >2 days with ≥1 day in the ICU between 4/2011-11/2016. Burns were oil-related (ORB; CO or FRAC) or non-oil related (NORB). Epidemiology and microbiology during the first 15 hospital days was compared.

RESULTS

149 patients were included, with 11 FRAC and 24 CO. CO burns were more severely burned than those with FRAC and NORB (p<0.05). Mortality was 17% and 18% for CO and FRAC burns compared to 3% in NORB (p<0.01). More cultures were obtained from ORB than NORB (p<0.05). ORB were associated with Stenotrophomonas maltophilia and FRAC associated with Serratia marcescens and Candida glabrata. Patients with FRAC, CO and NORB had a median of 13, 3.5, and 4 days to first positive culture respectively (p=0.03).

CONCLUSION

ORB were associated with more severe burns and unique microbiology. FRAC burns had longer to initial positive culture, potentially suggesting our current methodology is inadequate to diagnose infections associated with FRAC.

Mucormycosis in Burn Patients

Patients with extensive burns are an important group at risk for cutaneous mucormycosis. This study aimed to perform a systematic review of all reported mucormycosis cases in burn patients from 1990 onward. A Medline search yielded identification of 7 case series, 3 outbreaks, and 25 individual cases reports. The prevalence reached 0.04%–0.6%. The median age was 42–48 in the case series and outbreaks, except for the studies from military centers (23.5–32.5) and in individual reports (29.5). The median total body surface area reached 42.5%–65%. Various skin lesions were described, none being pathognomonic: the diagnosis was mainly reached because of extensive necrotic lesions sometimes associated with sepsis. Most patients were treated with systemic amphotericin B or liposomal amphotericin B, and all underwent debridement and/or amputation. Mortality reached 33%–100% in the case series, 29%–62% during outbreaks, and 40% in individual cases. Most patients were diagnosed using histopathology and/or culture. Mucorales qPCR showed detection of circulating DNA 2–24 days before the standard diagnosis. Species included the main clinically relevant mucorales (i.e., Mucor, Rhizopus, Absidia/Lichtheimia, Rhizomucor) but also more uncommon mucorales such as Saksenaea or Apophysomyces. Contact with soil was reported in most individual cases. Bandages were identified as the source of contamination in two nosocomial outbreaks.

Near-Complete Traumatic Amputation of the Forefoot After Motorboat Propeller Injury

We report a case of a near-complete amputation of the forefoot of a 20-year-old man as a result of a motorboat propeller injury sustained in a saltwater river. He was treated with open reduction, percutaneous pinning, extensor tendon repair, and an extended course of antibiotic prophylaxis. We review the literature regarding motorboat propeller injuries to the foot and ankle.

Raoultella planticola bacteremia-induced fatal septic shock following burn injury

BACKGROUND

Raoultella planticola, a Gram-negative, aerobic bacillus commonly isolated from soil and water, rarely causes invasive infections in humans. Septic shock from R. planticola after burn injury has not been previously reported.

CASE PRESENTATION

A 79-year-old male was admitted to the emergency intensive care unit after extensive flame burn injury. He accidently caught fire while burning trash and plunged into a nearby tank filled with contaminated rainwater to extinguish the fire. The patient developed septic shock on day 10. The blood culture detected R. planticola, which was identified using the VITEK-2 biochemical identification system. Although appropriate antibiotic treatment was continued, the patient died on day 12.

CONCLUSIONS

Clinicians should be aware of fatal infections in patients with burn injury complicated by exposure to contaminated water.

Nanofibrous artificial skin substitute composed of mPEG–PCL grafted gelatin/hyaluronan/chondroitin sulfate/sericin for 2nd degree burn care: in vitro and in vivo study

The aim of this study was to investigate the efficacy of a skin substitute composed of mPEG–PCL–grafted-gelatin (Bio-Syn)/hyaluronan/chondroitin sulfate/sericin and to study its in vitro biocompatibility with human fibroblasts, human keratinocytes and hMSCs in terms of cellular adhesion and proliferation (∼5–6 fold). mPEG–PCL was grafted into a gelatin backbone via a Michael addition reaction to prepare Bio-Syn and it was characterized using ATR-FTIR, ¹H NMR and TNBS assay. Additionally, keratinocyte–hMSC contact co-culture studies showed that Bio-Syn composite scaffolds loaded with sericin promote hMSCs’ epithelial differentiation with regard to qRT-PCR gene expression (ΔNp63α and keratin 14) and expression of various epithelial markers (Pan-cytokeratin, ΔNp63α and keratin 14). In vivo efficacy studies on a 2^nd degree burn wound model in Wistar rats showed an improved rate of wound contraction, histology (H&E and Van Gieson’s staining) and pro-healing marker (hexosamine, hydroxyproline, etc.) expression in granular tissue compared to using the commercial dressing Neuskin™ and a cotton gauze control.

The paper demonstrates the fabrication of sericin loaded hybrid polymeric composite nanofibrous scaffold and evaluation of its cytocompatibilty in three human monocultures and biocompatibility in second degree burn wound model in Wistar rats.

Successful Treatment by Surgery of a Primary Cutaneous Mucormycosis Caused by Mucor irregularis

We report a case of primary cutaneous mucormycosis caused by Mucor irregularis. A 66-year-old man was presented to our hospital with a history of gradually enlarging plaque on the right leg for about a year. The identification of pathogen based on the fungus morphology and DNA sequencing revealed M. irregularis as the responsible fungus for skin lesion. The lesion was removed incidentally by a surgery procedure, and no recrudescence was seen during a follow-up of 24-month observation.

The influence of the mating type on virulence of Mucor irregularis

Mucor irregularis is an emerging fungal pathogen that cause cutaneous infection and could cause death. However, little is known about its mechanism of pathogenesis. There is evidence suggesting virulence vary with mating types in fungi, including the Mucorales. Here, we characterized the mating type locus of M. irregularis and the mating type ratio of 17 clinical isolates in China. Genomic data indicated M. irregularis is heterothallic having two mating types – bearing either SexP or SexM allele. Also, we employed a mice model to study the inflammation and pathological effects of different mating types. The comparison of the inflammatory response, cytokine profiles and Th-1, Th-2 and Th-17 cells numbers in each mating type treated mice showed that the severity and disease progress were enhanced in (+) mating type treated mice. One (+/0) mutant strain, with multiple mutations at the mating locus, had defects in sexual mating ability but appeared to be more virulent than the (−) mating type. Although (+) mating type appeared to be more virulent, most of our clinical isolates presented belonged to (−) mating type. Our findings support the involvement of MAT genes in sexual fertility, and the influence of mating type on the severity of cutaneous infection.

Rural and Metropolitan Pediatric Burns in New South Wales and the Australian Capital Territory: Does Distance Make a Difference?

To determine if differences exist between children who sustain burns in rural areas and in metropolitan areas, an analysis of children presenting to the Burns Unit at The Children's Hospital at Westmead, from the January 1, 2008 to December 31, 2012 was performed. In all, 4326 children met the inclusion criteria, of which 21.2% came from rural regions. Just more than a quarter (26.0%) of rural children and 11.6% from metropolitan areas were Indigenous Australian (P < 0.0001). The average age of rural child was 4.5 years; metropolitan child was 3.9 years (P = 0.0001). Boys were more likely to sustain burns in both populations. Of the rural children, 40.8% sustained contact burns, 37.7% scald, and 12.5% flame. In contrast, 58.8% metropolitan children sustained scalds, 27.4% contact, and 4.5% flame. The home was the most common place for all burns to occur, but rural injuries commonly occurred outdoors. Burns were associated with risk-taking behavior in 15.3% rural and 8.7% metropolitan children (P < 0.0001). Nearly two thirds (65.9%) of children in both groups received adequate first aid (20 minutes of cool running water). Major burn injuries (≥10% Total BSA) occurred in 3.4% of rural and 2.1% metropolitan children (P = 0.02). Skin grafting was required in 28.3% rural and 16.3% metropolitan children (P = 0.0001). Nearly 32% of rural children required admission to the Burns Unit for >24 hours (15.9% metropolitan; P = 0.0001). Significant differences exist between burns sustained by rural and metropolitan children. This should be accounted for in burns prevention campaigns and the education of local health practitioners.

Feces Derived Allergens of Tyrophagus putrescentiae Reared on Dried Dog Food and Evidence of the Strong Nutritional Interaction between the Mite and Bacillus cereus Producing Protease Bacillolysins and Exo-chitinases

Tyrophagus putrescentiae (Schrank, 1781) is an emerging source of allergens in stored products and homes. Feces proteases are the major allergens of astigmatid mites (Acari: Acaridida). In addition, the mites are carriers of microorganisms and microbial adjuvant compounds that stimulate innate signaling pathways. We sought to analyze the mite feces proteome, proteolytic activities, and mite-bacterial interaction in dry dog food (DDF). Proteomic methods comprising enzymatic and zymographic analysis of proteases and 2D-E-MS/MS were performed. The highest protease activity was assigned to trypsin-like proteases; lower activity was assigned to chymotrypsin-like proteases, and the cysteine protease cathepsin B-like had very low activity. The 2D-E-MS/MS proteomic analysis identified mite trypsin allergen Tyr p3, fatty acid-binding protein Tyr p13 and putative mite allergens ferritin (Grp 30) and (poly)ubiquitins. Tyr p3 was detected at different positions of the 2D-E. It indicates presence of zymogen at basic pI, and mature-enzyme form and enzyme fragment at acidic pI. Bacillolysins (neutral and alkaline proteases) of Bacillus cereus symbiont can contribute to the protease activity of the mite extract. The bacterial exo-chitinases likely contribute to degradation of mite exuviae, mite bodies or food boluses consisting of chitin, including the peritrophic membrane. Thus, the chitinases disrupt the feces and facilitate release of the allergens. B. cereus was isolated and identified based on amplification and sequencing of 16S rRNA and motB genes. B. cereus was added into high-fat, high-protein (DDF) and low-fat, low-protein (flour) diets to 1 and 5% (w/w), and the diets palatability was evaluated in 21-day population growth test. The supplementation of diet with B. cereus significantly suppressed population growth and the suppressive effect was higher in the high-fat, high-protein diet than in the low-fat, low-protein food. Thus, B. cereus has to coexist with the mite in balance to be beneficial for the mite. The mite-B. cereus symbiosis can be beneficial-suppressive at some level. The results increase the veterinary and medical importance of the allergens detected in feces. The B. cereus enzymes/toxins are important components of mite allergens. The strong symbiotic association of T. putrescentiae with B. cereus in DDF was indicated.

[Disseminated mucormycosis in immunocompetent patients: A disease that also exists]

Mucormycosis is usually an acute angioinvasive infections, which leads to non-suppurative necrosis and significant tissue damage. It represents 1.6% of all the invasive fungal infections and predominates in immunosuppressed patients with risk factors. Incidence has been significantly increased even in immunocompetent patients. Due to finding a case of disseminated mucormycosis caused by Rhizomucor pusillus in a young immunocompetent patient, a systematic review was carried out of reported cases in PubMed of mucormycosis in immunocompetent adults according to the main anatomic locations, and especially in disseminated cases. A review of the main risk factors and pathogenicity, clinical manifestations, techniques of early diagnosis, current treatment options, and prognosis is presented. Taxonomy and classification of the genus Mucor has also been reviewed.

Mucor irregularis-associated cutaneous mucormycosis: Case report and review

Solid organ transplant recipients are at risk for invasive fungal diseases, and are also exposed to healthcare-associated mucormycosis. Mainly causing localized cutaneous mucormycosis, Mucor irregularis infection is reported for the first time in a kidney-transplant recipient. A healthcare-associated origin was highly suspected in this case. We performed a literature review and highlight the characteristics of this very rare fungus.

Biology, systematics, and clinical manifestations of Zygomycota infections

Fungi cause opportunistic, nosocomial, and community-acquired infections. Among fungal infections (mycoses) zygomycoses are exceptionally severe, with a mortality rate exceeding 50%. Immunocompromised hosts, transplant recipients, and diabetic patients with uncontrolled keto-acidosis and high iron serum levels are at risk. Zygomycota are capable of infecting hosts immune to other filamentous fungi. The infection often follows a progressive pattern, with angioinvasion and metastases. Moreover, current antifungal therapy frequently has an unfavorable outcome. Zygomycota are resistant to some of the routinely used antifungals, among them azoles (except posaconazole) and echinocandins. The typical treatment consists of surgical debridement of the infected tissues accompanied by amphotericin B administration. The latter has strong nephrotoxic side effects, which make it unsuitable for prophylaxis. Delayed administration of amphotericin and excision of mycelium-containing tissues worsens survival prognoses. More than 30 species of Zygomycota are involved in human infections, among them Mucorales is the most abundant. Prognosis and treatment suggestions differ for each species, which makes fast and reliable diagnosis essential. Serum sample PCR-based identification often gives false-negative results; culture-based identification is time-consuming and not always feasible. With the dawn of Zygomycota sequencing projects significant advancement is expected, as in the case of treatment of Ascomycota infections.

Development of rapid phenotypic system for the identification of Gram-negative oxidase-positive bacilli in resource-limited settings

Rapid and accurate identification of bacterial pathogens is a fundamental goal of clinical microbiology. The diagnosis and surveillance of diseases is dependent, to a great extent, on laboratory services, which cannot function without effective reliable reagents and diagnostics. Despite the advancement in microbiology diagnosis globally, resourcelimited countries still struggle to provide an acceptable diagnosis quality which helps in clinical disease management and improve their mortality and morbidity data. During this study an indigenous product, Quick Test Strip (QTS) NE, was developed for the rapid identification of biochemically slower group of Gram-negative oxidase-positive bacilli that covers 19 different bacterial genera. Some of the members belonging to these groups are well-established human pathogens, e.g. various species of Vibrio, Pseudomonas, Burkholderia, Aeromonas, Achromobacter and Stenotrophomonas. This study also evaluates the performance of QTS-NE by comparing with genotypic characterization methods. A total of 232 clinical and reference bacterial isolates were tested by three different methods. QTSNE provides 100 percent concordant results with other rapid identification and molecular characterization methods and confirms the potential to be used in clinical diagnosis.

Taxonomy and epidemiology of Mucor irregularis, agent of chronic cutaneous mucormycosis

Mucormycosis usually presents as a progressive infection with significant angio-invasion. Mucormycosis due to Mucor irregularis (formerly Rhizomucor variabilis var. variabilis), however, is exceptional in causing chronic cutaneous infection in immunocompetent humans, ultimately leading to severe morbidity if left untreated. More than 90 % of the cases known to date were reported from Asia, mainly from China. The nearest neighbour of M. irregularis is the saprobic species M. hiemalis. The aim of this study was to evaluate the taxonomic position, epidemiology, and intra- and inter-species diversity of M. irregularis based on 21 strains (clinical n = 17) by multilocus analysis using ITS, LSU, RPB1 and RPB2 genes, compared to results of cluster analysis with amplified fragment length polymorphism (AFLP) data. By combining MLST and AFLP analyses, M. irregularis was found to be monophyletic with high bootstrap support, and consisted of five subgroups, which were not concordant in all partitions. It was thus confirmed that M. irregularis is a single species at 96.1–100 % ITS similarity and low recombination rates between populations. Some geographic structuring was noted with some localised populations, which may be explained by limited air-dispersal. The natural habitat of the species is likely to be in soil and decomposing plant material.

Mucor irregularis infection and lethal midline granuloma: a case report and review of published literature

Mucor irregularis (Rhizomucor variabilis) infection and lethal midline granuloma (LMG) are characterized by progressive swelling, ulceration, and destruction of the central face that is usually fatal. Pathological features are inflammation, necrosis, and granulation. LMG has been called by various names, and in recent years, it has been known as NK/T cell lymphoma. However, diagnosis still relies on the progressive necrosis course rather than malignancy in histology. The disease has long challenged physicians, particularly when it worsens with radiotherapy or chemotherapy but sometimes achieves total remission without anti-malignancy therapies. We describe a 35-year-old man who had typical clinical-pathological symptoms of LMG, which turned out to be primary M. irregularis infection; that was diagnosed by positive tissue culture and fungal elements in histology. The patient was successfully treated with antifungal therapy (liposomal amphotericin B, total 4,600 mg and amphotericin B total 277 mg, over a duration of 70 days). We hereby review current knowledge about the epidemiology, clinical manifestations, radiographic characteristics, and pathologic features of LMG with those of M. irregularis infection and their associations. We conclude that primary M. irregulars infection can mimic the clinico-pathological symptoms of LMG and the condition responds favorably to aggressive antifungal therapy.

Soft tissue infections caused by marine bacterial pathogens: epidemiology, diagnosis, and management

Skin and soft tissue infections (SSTIs) are one of the most common infection syndromes and may be caused by a large number of microorganisms. Some principles of aquatic injuries are different than those of land-based trauma. Wounds sustained in marine environment are exposed to a milieu of bacteria rarely encountered in different settings. These include Vibrio spp., Aeromonas spp., Shewanella spp., Erysipelothrix rhusiopathiae, Mycobacterium marinum, Streptococcus iniae, and other microbes. Failure to recognize and treat these uncommon pathogens in a timely manner may result in significant morbidity or death. These infections are frequently contracted as a result of recreational swimming, fishing injuries, or seafood handling. The spectrum of manifestations is wide, varying from cases of mild cellulitis, to severe life-threatening necrotizing fasciitis requiring radical surgery, to sepsis and death. This review will focus on the epidemiology, clinical manifestations, and treatment of SSTIs caused by the most important marine pathogens.

Multidisciplinary team response to a mass burn casualty event: outcomes and implications

OBJECTIVES

To describe the characteristics of patients with burn injury admitted to a major trauma hospital in Melbourne following the Black Saturday bushfires of 7 February 2009, and to provide a detailed analysis of the hospital's response to the crisis.

DESIGN, SETTING AND PARTICIPANTS

A retrospective chart review of ambulance and hospital records of patients admitted to the Victorian Adult Burns Service (VABS) at The Alfred Hospital (The Alfred) following the bushfires.

MAIN OUTCOME MEASURES

Patient characteristics and outcomes: age, sex, total and full thickness body surface area burnt, type and site of burn, hospital and intensive care unit length of stay (LOS) and receipt of standard burn care practices. Estimated glomerular filtration rate, theatre time and LOS data for the bushfire cohort compared with corresponding data for historical cohorts from VABS and from a similar institution in New Zealand.

RESULTS

Nineteen patients were admitted to VABS over the first 48 hours after the bushfires. Of these, nine patients were subsequently admitted to The Alfred's intensive care unit. Most patients (74%) were men with a mean age of 52.7 years (SD, 12.4 years). Seventeen patients (89%) underwent at least one surgical procedure, which resulted in 4355 minutes of theatre time for the bushfire cohort in the first week. Hospital LOS was similar for the bushfire and New Zealand cohorts. Compared with the VABS historical cohort, there was a higher incidence of abnormal renal function among the bushfire cohort patients.

CONCLUSIONS

Although relatively few patients with severe burns were admitted to VABS, significant increases in resource allocation were required to manage them in terms of additional theatre time, consumables and staffing. The experience of VABS may aid planning for future mass burns casualty events.

Bacillus cereus, a volatile human pathogen

Bacillus cereus is a Gram-positive aerobic or facultatively anaerobic, motile, spore-forming, rod-shaped bacterium that is widely distributed environmentally. While B. cereus is associated mainly with food poisoning, it is being increasingly reported to be a cause of serious and potentially fatal non-gastrointestinal-tract infections. The pathogenicity of B. cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. The major hurdle in evaluating B. cereus when isolated from a clinical specimen is overcoming its stigma as an insignificant contaminant. Outside its notoriety in association with food poisoning and severe eye infections, this bacterium has been incriminated in a multitude of other clinical conditions such as anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections, particularly in immunosuppressed individuals, intravenous drug abusers, and neonates. Its role in nosocomial acquired bacteremia and wound infections in postsurgical patients has also been well defined, especially when intravascular devices such as catheters are inserted. Primary cutaneous infections mimicking clostridial gas gangrene induced subsequent to trauma have also been well documented. B. cereus produces a potent beta-lactamase conferring marked resistance to beta-lactam antibiotics. Antimicrobials noted to be effective in the empirical management of a B. cereus infection while awaiting antimicrobial susceptibility results for the isolate include ciprofloxacin and vancomycin.