Debridement increases survival in a mouse model of subcutaneous anthrax

Anthrax is caused by infection with Bacillus anthracis, a spore-forming gram-positive bacterium. A major virulence factor for B. anthracis is an immunomodulatory tripartite exotoxin that has been reported to alter immune cell chemotaxis and activation. It has been proposed that B. anthracis infections initiate through entry of spores into the regional draining lymph nodes where they germinate, grow, and disseminate systemically via the efferent lymphatics. If this model holds true, it would be predicted that surgical removal of infected tissues, debridement, would have little effect on the systemic dissemination of bacteria. This model was tested through the development of a mouse debridement model. It was found that removal of the site of subcutaneous infection in the ear increased the likelihood of survival and reduced the quantity of spores in the draining cervical lymph nodes (cLN). At the time of debridement 12 hours post-injection measurable levels of exotoxins were present in the ear, cLN, and serum, yet leukocytes within the cLN were activated; countering the concept that exotoxins inhibit the early inflammatory response to promote bacterial growth. We conclude that the initial entry of spores into the draining lymph node of cutaneous infections alone is not sufficient to cause systemic disease and that debridement should be considered as an adjunct to antibiotic therapy.     

Subcutaneous Phaeohyphomycosis Caused by <Emphasis Type="Italic">Exophiala oligosperma</Emphasis> in an Immunocompetent Host: Case Report and Literature Review

We report a case of subcutaneous infection caused by Exophiala oligosperma. Erythematous ulcerated plaque with exudate was major clinical features. Histopathological examination showed yeast-like cells and fungal hyphae. Mycological and molecular identification revealed E. oligosperma as etiologic agent. Local debridement and oral itraconazole were effective. To the best of our knowledge, this is the first report of phaeohyphomycosis caused by E. oligosperma in mainland China. This report highlights the potential role of E. oligosperma as an emerging cause of infection in immunocompetent patients.     

Bilobed fasciocutaneous flap for reconstruction of the posterior neck after necrotizing fasciitis

Necrotizing fasciitis is an aggressive, deep-seated infection of the fascia and subcutaneous fat with necrosis of overlying skin. Eleven cases of necrotizing fasciitis of the posterior neck are reviewed to demonstrate the advantage of using a bilobed fasciocutaneous flap for repair following surgical debridement. Nine men and two women aged 40 to 65 years (mean age, 54.8 years) presented for reconstruction from April of 1999 to March of 2003. The blood supply of the bilobed fasciocutaneous flap originates from a constant row of musculocutaneous perforators of posterior intercostal arteries. The technique enabled regional reconstruction, conserved tissues, and provided satisfactory aesthetic results.     

Staphylococcus aureus subcutaneous abscess complicating acupuncture: need for implementation of proper infection control guidelines

We report a case of Staphylococcus aureus subcutaneous abscess centered over the Jizhong acupuncture point (DU 6) which lies along the Du (Back midline) meridian after acupuncture at the corresponding acupuncture point for low back pain. The patient recovered after surgical debridement and drainage and 5 weeks of cloxacillin therapy. Among the 16 anecdotal case reports of pyogenic bacterial infections complicating acupuncture described in the English literature (MEDLINE Search 1996-2002), S. aureus was documented to be the causative agent in 9 (56%). Three patients had septic arthritis, 2 had chronic osteomyelitis, 2 had abscess formation, 1 had chondritis, and 1 had infective endocarditis. Five patients had S. aureus bacteremia. All patients who recovered required prolonged antibiotic treatment of 5-6 weeks, and 6 required drainage and/or debridement. Overall, 3 patients (30%) died. S. aureus causes significant morbidity and mortality in patients who receive acupuncture treatment. More resources should be spent on implementation of proper infection control guidelines, as the money lost due to prolonged hospitalization and medication would far exceed that used for implementation.     

Conservative management in full-thickness nipple-areolar necrosis after subcutaneous mastectomy

Nipple-areolar necrosis is a known and expected complication in a small percentage of patients undergoing subcutaneous mastectomy, especially with concomitant mastopexy or in smokers. Impending ischemia or congestion of the areola can often be ameliorated by simple maneuvers such as suture release. When full-thickness necrosis occurs, conservative management with essential debridement, dressings, and careful wound hygiene alone will often yield a surprisingly good result, requiring little or no revisional surgery.     

Continuous Renal Replacement Therapy as a Supportive Treatment for Acute Pediatric Necrotizing Fasciitis

Acute necrotizing fasciitis (NF) in children is a dangerous illness characterized by progressive necrosis of the skin and subcutaneous tissue. The present study summarizes our recent experience with the treatment of pediatric patients with severe NF. Between 2000 and 2009, eight children suffering from NF were admitted to our department. Four of the children received an active treatment strategy including continuous renal replacement therapy (CRRT), radical debridement, and broad-spectrum antibiotics. Another four children presented at a late stage of illness, and did not complete treatment. Clinical data for these two patient groups were retrospectively analyzed. The four patients that completed CRRT, radical debridement, and a course of broad-spectrum antibiotics were cured without any significant residual morbidity. The other four infants died shortly after admission. Early diagnosis, timely debridement, and aggressive use of broad-spectrum antibiotics are key factors for achieving a satisfactory outcome for cases of acute NF. Early intervention with CRRT to prevent septic shock may also improve patient outcome.     

Comparative bacterial clearances of muscle and skin/subcutaneous tissues with and without dead bone: a laboratory study

Seventeen New Zealand White rabbits underwent implantation of three different concentrations of bacteria and a sterile saline control solution with and without dead autologous bone in eight separate muscular and eight separate subcutaneous sites. Following a period of 1 week, each site was surgically explored and samples of tissue were taken for histology and quantitative culture. Results reveal that final bacterial concentrations in the subcutaneous sites were significantly lower than in the muscle sites (p less than or equal to 0.0001) for each concentration of bacteria, with and without dead bone. Dead bone resulted in very significantly greater bacterial concentrations in both subcutaneous and muscle sites. Clinically, these results indicate that a thorough bony wound debridement is more important than the type of tissue used to close the wound. Flap tissue should be selected with regard to the perfusion, contour, and appearance of the recipient site.     

Salvage of jeopardized total-knee prosthesis: the role of the gastrocnemius muscle flap

Total-knee arthroplasty has provided many patients with excellent long-term functional results. However, exposure of a total-knee replacement usually eventuates in failure. The relatively superficial location of the prosthesis, the need for early active motion, previous surgical incisions, and a variety of systemic factors may militate against early wound healing. Restoration of well-vascularized soft-tissue cover can salvage an otherwise disastrous situation. The authors recommend early operative intervention upon observation of wound breakdown, devitalized skin edges, or significant subcutaneous infection leading to necrotic overlying skin. The operative procedure found to salvage the majority of prostheses consists of adequate debridement, antibiotic irrigation (of the joint, if exposed), and coverage with a well-vascularized muscle flap, preferably the medial gastrocnemius muscle. The operative technique and ultimate long-term outcome are reviewed based on experience with 10 consecutive patients presenting with a jeopardized knee prosthesis. Follow-up ranged from 1 to 6 years. Representative case histories are presented.     

Saksenaea vasiformis infections: Case report and literature review

Since the first human infection by Saksenaea vasiformis in 1976 another 26 cases have been reported. Here is a report of a new case which involved an Ecuadorian adolescent who suffered serious burns after a car accident. It developed as a localized cutaneous infection which was successfully treated with surgical debridement and amphotericin B. This is the second report of this infection from South America and the third involving a burn patient. The previously reported 27 cases are reviewed.     

Fascitis necrotizante por Saksenaea vasiformis en una paciente inmunocompetente tras un accidente de tráfico

BackgroundCutaneous mucormycosis (zygomycosis), with subcutaneous spreading and dissemination, in immunocompetent patients is an uncommon disease caused by species belonging to the fungal genera Apophysomyces, Rhizopus and Saksenaea, among others.Case reportA case of necrotising fasciitis by Saksenaea vasiformis in an immunocompetent woman is described. The infection was acquired through a car accident resulting in multiple injuries affecting mainly her right arm. After the surgical reduction of fractures, skin lesions worsened and led to necrosis. The patient quickly developed a severe necrotising fasciitis with negative cultures at first. Despite the extensive surgical debridement and the aggressive antifungal treatment, the patient died. The histopathological study showed a fungal infection due to a fungus belonging to the Mucorales order, which was confirmed by culturing the clinical sample on Sabouraud agar, and identifying the species by cultures on Czapek-Dox agar, and sequencing of the ITS region of the ribosomal DNA.ConclusionsThis case confirm the presence of this fungus in Spain, the value of histopathology for the mucormycosis diagnosis, as well as the need to perform special cultures to facilitate their isolation and identification to the species level by the combined use of Czapek-Dox agar and sequencing of the ITS region.     

Primary cutaneous mucormycosis. Report of a case in a HIV patient

Primary cutaneous mucormycosis is an unusual mycotic infection associated to immunosupression. We present a 34 year-old woman with HIV infection with a necrotic primary mucormycosis of the skin associated to a venous catheter. She was treated with amphotericin B and surgical debridement.     

First-line treatment of deep sternal infection by a plastic surgical approach: superior results compared with conventional cardiac surgical orthodoxy

A majority of cardiac surgeons manage deep sternal infection with sternal wound debridement, rewiring, and closed drainage, with or without antibiotic saline tube irrigation (the traditional approach). The authors' experience with the traditional approach was unsatisfactory; therefore, they undertook a radical change in management: an immediate plastic surgical approach. Hence, deep sternal infection was managed by immediate debridement followed by a bilateral pectoralis major myocutaneous advancement flap with greater omental transposition (PMOFR). This is the first such study reporting the effect of this strategy on the rate of eradication of deep sternal infection, intensive care unit stay, total hospital length of stay, major complications, mortality, intermediate survival, and patient satisfaction, as compared with the traditional approach used by cardiac surgeons at the authors' institution.All patients who developed a deep sternal infection from 1993 through 1998 at a tertiary teaching hospital were included. In the PMOFR group (nine patients), after a diagnosis of clinical sternal wound infection, debridement was performed immediately, either if sternal dehiscence occurred or in the absence of clinical dehiscence, if the patient or the sternotomy wound did not clinically improve with medical therapy within 48 hours from suspected diagnosis. Open irrigation and packing for 2 to 4 days was followed by treatment with a PMOFR. In the group treated using the traditional approach (12 patients), no predetermined plan was present. Thus, at the cardiac surgeon's discretion, wound debridement was undertaken, followed by closed drainage (three patients), closed tube irrigation (six patients), and open granulation with delayed plastic surgery (three patients).The incidence of major complications (PMOFR, 22 percent; traditional approach, 92 percent; p = 0.001), intensive care unit readmission (PMOFR, 0 percent; traditional approach, 58 percent; p = 0.005), total hospital length of stay (PMOFR, 32 days; traditional approach, 79 days; p = 0.001), reoperation rates (PMOFR, 0 percent; traditional approach, 100 percent; p = 0.001) and in-hospital 30-day mortality rate (PMOFR, 0 percent; traditional approach, 33 percent; p = 0.05) were superior in the PMOFR group. At a mean follow-up of 2 years, freedom from recurrence of the infection (PMOFR, 100 percent; traditional approach, 11.5 percent; p = 0.005) and overall survival rate (PMOFR, 100 percent; traditional approach, 50 percent; p = 0.005) were also superior with PMOFR. A majority of patients in the PMOFR group (90 percent) had no functional or cosmetic complaints secondary to the procedure.A predetermined plan of immediate debridement followed by treatment with PMOFR rapidly, reliably, and effectively eradicated deep sternal infection. This translated to reduced length of stay and need for additional surgery, improved survival, and excellent intermediate freedom from deep sternal infection, with minimal patient dissatisfaction. The traditional approach to managing deep sternal infection was thus abandoned.     

Use of a Vacuum-Assisted Device for Fournier's Gangrene: A New Paradigm

Fournier's gangrene is a necrotizing infection of the scrotum or perineum that requires aggressive surgical debridement. Radical debridement of perineal necrotizing fasciitis can leave extensive tissue defects that are difficult to close and often require multiple surgical interventions. Vacuum-assisted closure (VAC) devices have been shown to assist in a more rapid closure of these wounds, but placement of such devices in the perineum can pose significant challenges. We have had success with use of VAC devices and report our techniques for their placement.     

Disseminated infection with Conidiobolus incongruus

The first fatal case of disseminated infection due to Conidiobolus incongruus is reported. The patient presented with a subcutaneous mass, febrility, weight loss, cough and hemoptysis. Histological examination of skin and subcutaneous tissue, lung, lymph nodes, esophagus, liver and jejunum showed a granulomatous reaction with bright eosinophilic amorphous material and broad hyphae. A fungus cultured from skin and subcutaneous tissue was identified as Conidiobolus incongruus.     

Comparison of Mucosal,Subcutaneous and Intraperitoneal Routes of Rat Leptospira Infection

Leptospirosis is a zoonosis found worldwide that is caused by a spirochete. The main reservoirs of Leptospira, which presents an asymptomatic infection, are wild rodents, including the brown rat (Rattus norvegicus). Experimental studies of the mechanisms of its renal colonization in rats have previously used an intraperitoneal inoculation route. However, knowledge of rat-rat transmission requires the use of a natural route of inoculation, such as a mucosal or subcutaneous route. We investigated for the first time the effects of subcutaneous and mucosal inoculation routes compared to the reference intraperitoneal route during Leptospira infection in adult rats. Infection characteristics were studied using Leptospira renal isolation, serology, and molecular and histological analyses. Leptospira infection was asymptomatic using each inoculation route, and caused similar antibody production regardless of renal colonization. The observed renal colonization rates were 8 out of 8 rats, 5 out of 8 rats and 1 out of 8 rats for the intraperitoneal, mucosal and subcutaneous inoculation routes, respectively. Thus, among the natural infection routes studied, mucosal inoculation was more efficient for renal colonization associated with urinary excretion than the subcutaneous route and induced a slower-progressing infection than the intraperitoneal route. These results can facilitate understanding of the infection modalities in rats, unlike the epidemiological studies conducted in wild rats. Future studies of other natural inoculation routes in rat models will increase our knowledge of rat-rat disease transmission and allow the investigation of infection kinetics.     

Primary reconstruction of major human bite wounds of the face.

Primary reconstruction of 36 major human bite wounds of the face without clinical infection has been carried out successfully as late as the fourth day after the initial injury. Primary healing was achieved in all patients. The postoperative period was free from major infection in all patients except one, including the latecomers. Extensive bacteriologic studies reveal that the infection in human bite wounds occurs secondarily as invasion to devitalized tissue. We therefore consider that debridement of wound edges to eliminate the crushed devitalized tissue is the key to success.     

皮瓣移植结合骨牵张技术修复感染性胫骨复合皮肤组织缺损的临床效果观察

目的：观察皮瓣移植结合骨牵张技术修复感染性胫骨复合皮肤组织缺损的临床效果。方法：自2008年6月至2012年6月,共收治了胫骨感染性复合组织缺损16例,采用一期彻底去除病变坏死组织和病变的胫骨断端,切取同侧腓肠肌皮瓣、腓肠神经营养血管皮瓣转位、对侧小腿内侧皮瓣和游离皮瓣移植修复小腿皮肤缺损,二期行骨牵张延长术进行治疗。结果：所有16例胫骨复合组织缺损病例感染均得到了控制,移植的皮瓣顺利成活,胫骨截骨延长区成骨良好,断端骨愈合,其中2例出现针道感染,无血管神经并发症发生。骨延长2～9cm,平均延长5．5cm。外同定延长支架在停止骨延长8-20个月后拆除,双下肢等长,膝关节和踝关节功能良好。术后细菌培养＋药敏结果：金黄色葡萄球菌感染8例,表皮葡萄球菌感染4例,大肠杆菌感染1例,阴沟肠杆菌感染l例,肠球菌感染l例。结论：伤口彻底清创,胫骨断端坏死骨切除后一期行皮瓣移植,二期行骨牵张延长术是一种治疗感染性胫骨复合组织缺损的有效方法。     

Characterization of acute and latent herpes simplex virus infection of dorsal root ganglia in rats.

The characteristics of HSV type-1 infection following subcutaneous inoculation in the dorsum of one hind paw of Sprague-Dawley rats were studied to determine whether infection in rats might more closely parallel the infection in man than is seen in other animals. The serologic and virologic characteristics of acute and latent ganglion infection conformed to those of human infection. Immunohistochemical studies suggested that sensory ganglion infection arose via centripetal axonal migration of virus as is hypothesized in man. In rat, small type B neuronal cell bodies appeared central to the maintenance of latent infection and reactivation observed during cocultivation of lumbar ganglia. Acute and latent lumbar sensory ganglion infection in rats after subcutaneous hind paw injection of HSV-1 appears to be another suitable model of this infection in man.     

Experimental infection routes of Angiostrongylus cantonensis in mice.

Stomach intubation is the most common method used in the experimental infection of animals with Angiostrongylus cantonensis. In order to compare the effectiveness of other possible transmission methods, groups of BALB/c mice were given infective third-stage larvae of A. cantonensis by different routes including intraperitoneal or subcutaneous injections, and penetration of anal mucosa, vaginal mucosa, conjunctival mucosa, lacerated skin, unabraded skin, foot pad and tail skin, while stomach intubation was used as control. Recovery of fifth-stage larvae was higher in mice inoculated with third-stage larvae subcutaneously. Successful infections were established through all experimental transmission routes except tail skin penetration. This study suggests that oral infection may not be the only route for the transmission of human angiostrongyliasis, and subcutaneous infection may be a better method for experimental infection.     

The First Reported Case of Canine Subcutaneous Cryptococcus flavescens Infection

This report describes the first documented case of subcutaneous infection due to Cryptococcus flavescens in a dog. The chief symptoms of the patient dog were abscessed lesions on the dorsal muzzle, right eyelid, and lower jaw. Biopsy specimens from the lesions on the dorsal muzzle and lower jaw showed pyogranulomatous inflammation with numerous yeast cells. The patient dog was diagnosed with a subcutaneous fungal infection and orally received 5 mg/kg itraconazole once a day for 2 months, the abscesses disappeared. After 1 month at the end of treatment, the skin lesions did not redevelop. Isolates from the biopsy specimens were identified as C. flavescens by molecular analysis as well as morphologic and biochemical examination, indicating that C. flavescens is a potential canine pathogen.