Necrotizing fasciitis: manifestations, microbiology and connection with black tar heroin

Under the Skin: A Case Series of Clostridium sordellii Necrotizing Soft Tissue Infections in Patients Who Inject Drugs

Clostridium sordellii has been well-associated as a cause of obstetric infections but is a less commonly recognized organism of necrotizing skin and soft tissue infections (NSTI). C. sordelli infections are rare with only 14 cases reported in the literature to date. These infections are often associated with profound septic shock and the mortality rate remains high. We report four patients who presented with C. sordellii NSTI over a period of two years at an academic medical center. Notably, injection drug use was the main risk factor for infection in these patients. Appropriate management of C. sordellii NSTI necessitates a combination of antibiotics and emergent surgical intervention. However, despite these efforts, the mortality rate remains high, with three of the four patients dying. Clinicians should consider NSTI in the differential diagnosis when evaluating skin and soft tissue infections in people who inject drugs. Furthermore, it is imperative to educate patients who engage in injection drug use on the potential risks associated with NSTI and inform them of warning signs that warrant immediate medical attention. The devastating consequences of C. sordellii-associated NSTI in this vulnerable population can be mitigated by enhancing awareness and facilitating early intervention.

Skin Popping for the Hand Surgeon: A Case Report and Review

INTRODUCTION

Subcutaneous injection of illicit drugs, colloquially known as skin popping, is associated with skin and soft tissue infections of the upper extremity. Sequelae of these infections often present to hand surgeons in the late stages of disease, are associated with challenging clinical scenarios, and are a significant burden to both patients and providers. The authors present an illustrative case and review the literature regarding this growing phenomenon in upper extremity surgery.

METHODS

A case report detailing the surgical reconstruction of a large forearm wound in the setting of intravenous heroin use and skin popping is presented. Search terms related to upper extremity subcutaneous drug injection were used to find relevant articles in PubMed and EMBASE. A total of 488 articles were found, with 22 studies meeting the inclusion criteria.

RESULTS

In this case report, the patient had a long history of skin popping to the forearm and presented with a chronic wound with exposed bone. The patient was treated with serial debridement, bony fixation, intravenous antibiotics, and soft tissue coverage using an arteriovenous loop and a muscle-only latissimus flap. Literature review yielded 22 studies comprising 38 patients with 55% (11/20) women and age range of 23 to 58 years. Heroin was the most commonly used drug (50.0%). The most common presentation was soft tissue infection (6/20 patients), manifestations of noninfected wounds (5/20), and wound botulism (4/20 of patients). Seventy percent of patients presented with multiple injection sites. Surgical management was described in 18% of cases, with all but one case describing drainage and debridement techniques. Only one case of formal reconstruction using a dermal template was described.

CONCLUSIONS

Skin popping infections have unique pathogenesis, presentation, and management patterns that hand surgeons must be aware of when treating these patients. A literature review revealed a relative paucity of reports regarding risk factors and surgical management of "skin popping" sequelae. If patients are reconstructive candidates, complex reconstruction requiring free tissue transfer may be warranted.

Predicting necrotising soft tissue infections in people who inject drugs: poor performance of the Laboratory Risk Indicator for Necrotising Fasciitis score and development of a novel clinical predictive nomogram in a retrospective cohort with internal validation

INTRODUCTION

Necrotising soft tissue infections (NSTI) can threaten life and limb. Early identification and urgent surgical debridement are key for improved outcomes. NSTI can be insidious. Scoring systems, like the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC), exist to aid diagnosis. People who inject drugs (PWID) are high risk for NSTI. This study aimed to assess the utility of the LRINEC in PWID with lower limb infections and develop a predictive nomogram.

METHODS

A retrospective database of all hospital admissions due to limb-related complications secondary to injecting drug use between December 2011 and December 2020 was compiled through discharge codes and a prospectively maintained Vascular Surgery database. All lower limb infections were extracted from this database, dichotomised by NSTI and non-NSTI with the LRINEC applied. Specialty management times were evaluated. Statistical analyses involved: chi-square; Analysis of "variance"; Kaplan-Meier, and receiver operating characteristic curves. Nomograms were developed to facilitate diagnosis and predict survival.

RESULTS

There were 557 admissions for 378 patients, with 124 (22.3%; 111 patients) NSTI. Time from admission to: theatre and computed tomography imaging respectively varied significantly between specialties ( P =0.001). Surgical specialties were faster than medical ( P =0.001). Vascular surgery received the most admissions and had the quickest time to theatre. During follow-up there were 79 (20.9%) deaths: 27 (24.3%) NSTI and 52 (19.5%) non-NSTI. LRINEC ≥6 had a positive predictive value of 33.3% and sensitivity of 74% for NSTI. LRINEC <6 had a negative predictive value of 90.7% and specificity of 63.2% for non-NSTI. Area under the curve was 0.697 (95% CI: 0.615-0.778). Nomogram models found age, C-reactive protein, and non-linear albumin to be significant predictors of NSTI, with age, white cell count, sodium, creatinine, C-reactive protein, and albumin being significant in predicting survival on discharge.

CONCLUSION

There was reduced performance of the LRINEC in this PWID cohort. Diagnosis may be enhanced through use of this predictive nomogram.

Regional Variations in Microbiology and Outcomes of Necrotizing Soft Tissue Infections: A Systematic Review and Meta-Analysis

Background: Frequency, microbiology, and outcomes of necrotizing soft tissue infections (NSTIs) could vary across the United States because of differences in locoregional and environmental factors. We synthesized the literature from across the regions of the United States on NSTIs in a systematic review/meta-analysis. Methods: PubMed, ProQuest, Scopus, and Web of Science databases were systematically searched and screened. DerSimonian-Laird random-effects meta-analyses were performed using 'meta' package in R to determine pooled prevalences. Meta-regression analyses examined moderator effects of risk factors. Results: Twenty-seven studies (2,242 total patients) were included. Pooled prevalences of polymicrobial and monomicrobial infections were 52.2% and 39.9%, respectively. The prevalence of monomicrobial NSTIs increased over the last two decades (p = 0.018), whereas polymicrobial infections declined (p = 0.003). Meta-regression analysis showed that most polymicrobial NSTIs were Fournier gangrene (p < 0.001), whereas monomicrobial NSTIs mostly affected extremities (p < 0.001). Staphylococcus aureus was the most common organism isolated (predominantly in the South), followed by Bacteroides spp. (predominately in the East) and Streptococcus pyogenes. Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 11.9% of NSTIs, mainly in the South. The overall mortality rate was 17.8% and declined over last two decades (p < 0.001), with the lowest rate reported in the last decade at 13% without any regional differences. Conclusions: Advancement in the management of NSTIs may have contributed to the observed decline in NSTI-related mortality in the United States. However, the proportion of monomicrobial NSTIs seems to be increasing, possibly because of increased comorbidities affecting extremities. Causative organisms varied by region. Multi-center observational studies are warranted to confirm our observations.

Global patterns of necrotizing soft tissue infections: A systematic review and meta-analysis

BACKGROUND

Frequency, microbiology, and outcomes of necrotizing soft tissue infections vary based on locoregional and environmental factors; however, there has been no global survey of these patterns. We performed a systematic review/meta-analysis on published reports of necrotizing soft tissue infections from across the globe.

METHODS

Peer-reviewed empirical studies examining rates of polymicrobial and monomicrobial necrotizing soft tissue infections with microbial isolation and overall mortality rate were extracted along with geographic location using PubMed, Scopus, ProQuest, and Web of Science. Random-effects meta-analyses and sensitivity analyses were performed, adjusting for publication bias. Meta-regression analyses examined moderator effects of risk factors.

RESULTS

One hundred and five studies (8,718 total patients) were included. Pooled prevalence of polymicrobial and monomicrobial infections were 53% and 37.9%, respectively. Truncal necrotizing soft tissue infections were commonly polymicrobial (P < .001), whereas monomicrobial infections prevailed in extremities (P = .008). Global prevalence of monomicrobial necrotizing soft tissue infections was observed to increase by 1.1% annually (P = .003). Staphylococcus aureus was the most common organism globally and in North America, Asia, the Middle East, and Africa, followed by Streptococcus pyogenes and Escherichia coli. Methicillin-resistant S. aureus accounted for 16% of necrotizing soft tissue infections globally. Overall mortality was 23.1%, observed to decline globally over the last decade (P = .020). No regional differences were noted for mortality.

CONCLUSION

Although polymicrobial infections remain predominant worldwide, the incidence of monomicrobial infections is increasing. The observed decline in necrotizing soft tissue infection-related mortality is encouraging and may reflect advances in management, despite major variations in available healthcare resources globally.

Skin and Soft Tissue Infections in Persons Who Inject Drugs

Persons who inject drugs are at high risk for skin and soft tissue infections. Infections range from simple abscesses and uncomplicated cellulitis to life-threatening and limb-threatening infections. These infections are predominantly caused by gram-positive organisms with Staphylococcus aureus, Streptococcus pyogenes, and other streptococcal species being most common. Although antimicrobial therapy has an important role in treatment of these infections, surgical incision, drainage, and debridement of devitalized tissue are primary. Strategies that decrease the frequency of injection drug use, needle sharing, use of contaminated equipment, and other risk behaviors may be effective in preventing these infections in persons who inject drugs.

The Heroin Epidemic in America: A Surgeon's Perspective

Background: The United States is currently experiencing a heroin epidemic. Recent reports have demonstrated a three-fold increase in heroin use among Americans since 2007 with a shift in demographics to more women and white Americans. Furthermore, there has been a correlation between the recent opioid epidemic and an increase in heroin abuse. Much has been written about epidemiology and prevention of heroin abuse, but little has been dedicated to the surgical implications, complications, and resource utilization. Discussion: This article focuses on the surgical problems encountered from heroin abuse and how to manage them in a constant effort to improve morbidity and mortality for these heroin abusers.

Heroin Use Is Associated with AA-Type Kidney Amyloidosis in the Pacific Northwest

BACKGROUND AND OBJECTIVES

AA-type kidney amyloidosis is classically associated with chronic autoimmune or inflammatory disorders. However, some urban centers have reported a high prevalence of injection drug use among patients with kidney AA amyloidosis. Previous reports lack control groups to quantify associations and most predate the opioid epidemic in the United States.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a case-control study of 38 patients with biopsy-confirmed kidney AA amyloidosis and 72 matched control individuals without this condition from two large hospital systems in Seattle, Washington. We ascertained the pattern and duration of heroin use by medical chart review and determined associations using logistic regression.

RESULTS

Among case patients, 95% had a prior history of heroin use, 87% had skin abscesses, and 76% and 27% had evidence of muscling and skin popping, respectively. After adjustment for age, race, sex, site, and year of biopsy, any heroin use (past or current) was associated with an estimated 170-times higher risk of kidney AA amyloidosis compared with no heroin use (95% confidence interval, 28 to 1018 times higher; P<0.001). Chronic autoimmune disorders were uncommon among case patients in this study. The median time to ESKD among patients with AA amyloidosis was 2.4 years (interquartile range, 0.5-7.5 years).

CONCLUSIONS

Injection heroin use is strongly associated with kidney AA amyloidosis in the Pacific Northwest. Unique aspects of heroin use, in particular geographic regions or frequent associated soft-tissue infections, may be an important cause of this progressive kidney disease.

Risk Factors Associated With Skin and Soft Tissue Infections Among Hospitalized People Who Inject Drugs

OBJECTIVES

Skin and soft tissue infections (SSTIs) are common among people who inject drugs (PWID), and can lead to serious morbidity and costly emergency room and hospital utilization. A range of high-risk injection practices may contribute to these infections. The goal of the current study was to examine risk practices that were associated with SSTIs in a sample of hospitalized PWID.

METHODS

PWID (N = 143; 40.6% female) were recruited from inpatient medical units at a large urban hospital and completed a baseline interview that focused on infection risk. Measures included demographics, substances used/injected, and self-report of SSTIs (ie, abscesses, ulcers, or cellulitis) within the past year. The Bacterial Infections Risk Scale for Injectors-a 7-item index-assessed specific behaviors expected to increase the risk of acquiring SSTIs (eg, injection without skin cleaning, intramuscular injection).

RESULTS

The sample was 58% Caucasian and averaged 38.7 (SD = 10.7) years of age. Ninety-three participants (65%) reported at least 1 SSTI within the past year. Using a logistic regression model, the Bacterial Infections Risk Scale for Injectors (odds ratio 1.87, P = 0.004) and total number of injections over the past 3 months (odds ratio 2.21, P = 0.002) were associated with past year SSTIs.

CONCLUSIONS

In conclusion, rates of past-year SSTIs were high in this sample of hospitalized PWID. Results suggest that interventions should target specific injection practices to reduce infection risk.

Necrotizing fasciitis: case series and review of the literature on clinical and medico-legal diagnostic challenges

Necrotizing fasciitis (NF) is a life-threatening infection of soft tissues spreading along the fasciae to the surrounding musculature, subcutaneous fat and overlying skin areas that can rapidly lead to septic shock and death. Due to the pandemic increase of medical malpractice lawsuits, above all in Western countries, the forensic pathologist is frequently asked to investigate post-mortem cases of NF in order to determine the cause of death and to identify any related negligence and/or medical error. Herein, we review the medical literature dealing with cases of NF in a post-mortem setting, present a case series of seven NF fatalities and discuss the main ante-mortem and post-mortem diagnostic challenges of both clinical and forensic interests. In particular, we address the following issues: (1) origin of soft tissue infections, (2) micro-organisms involved, (3) time of progression of the infection to NF, (4) clinical and histological staging of NF and (5) pros and cons of clinical and laboratory scores, specific forensic issues related to the reconstruction of the ideal medical conduct and the evaluation of the causal value/link of any eventual medical error.

Nationwide increase in hospitalizations for heroin-related soft tissue infections: Associations with structural market conditions

INTRODUCTION

Little is known about trends in national rates of injection-related skin and soft tissue infections (SSTI) and their relationship to the structural risk environment for heroin users. Use of Mexican-sourced "Black Tar" heroin, predominant in western US states, may have greater risk for SSTI compared with eastern US powder heroin (Colombian-sourced) due to its association with non-intravenous injection or from possible contamination.

METHODS

Using nationally representative hospital admissions data from the Nationwide Inpatient Sample and heroin price and purity data from the Drug Enforcement Administration, we looked at rates of hospital admissions for opiate-related SSTI (O-SSTI) between 1993 and 2010. Regression analyses examined associations between O-SSTI and heroin source, form and price.

RESULTS

Hospitalization rates of O-SSTI doubled from 4 to 9 per 100,000 nationally between 1993 and 2010; the increase concentrated among individuals aged 20-40. Heroin market features were strongly associated with changes in the rate of SSTI. Each $100 increase in yearly heroin price-per-gram-pure was associated with a 3% decrease in the rate of heroin-related SSTI admissions. Mexican-sourced-heroin-dominant cities had twice the rate of O-SSTI compared to Colombian-sourced-heroin-dominant cities.

DISCUSSION

Heroin-related SSTI are increasing and structural factors, including heroin price and source-form, are associated with higher rates of SSTI hospital admissions. Clinical and harm reduction efforts should educate heroin users on local risk factors, e.g., heroin type, promote vein health strategies and provide culturally sensitive treatment services for persons suffering with SSTI.

View from the front lines: an emergency medicine perspective on clostridial infections in injection drug users

Injection drug use (IDU), specifically non-intravenous "skin-popping" of heroin, seems to provide optimal conditions for Clostridial infection and toxin production. IDU is therefore a major risk factor for wound botulism and Clostridial necrotizing soft tissue infections (NSTI) and continues to be linked to cases of tetanus. Case clusters of all 3 diseases have occurred among IDUs in Western U.S. and Europe. Medical personnel who care for the IDU population must be thoroughly familiar with the clinical presentation and management of these diseases. Wound botulism presents with bulbar symptoms and signs that are easily overlooked; rapid acquisition and administration of antitoxin can prevent neuromuscular respiratory failure. In addition to Clostridium perfringens, IDU-related NSTIs can be caused by Clostridium sordellii and Clostridium novyi, which may share a distinct clinical presentation. Early definitive NSTI management, which decreases mortality, requires a low index of suspicion on the part of emergency physicians and low threshold for surgical exploration and debridement on the part of the surgeon. Tetanus should be preventable in the IDU population through careful attention to vaccination status.

Risk factors, microbiological findings and outcomes of necrotizing fasciitis in New Zealand: a retrospective chart review

Background

The incidence and mortality from necrotizing fasciitis (NF) are increasing in New Zealand (NZ). Triggered by a media report that traditional Samoan tattooing was causing NF, we conducted a chart review to investigate the role of this and other predisposing and precipitating factors and to document NF microbiology, complications and interventions in NZ.

Methods

We conducted a retrospective review of 299 hospital charts of patients discharged with NF diagnosis codes in eight hospitals in NZ between 2000 and 2006. We documented and compared by ethnicity the prevalence of predisposing and precipitating conditions, bacteria isolated, complications and interventions used.

Results

Out of 299 charts, 247 fulfilled the case definition. NF was most common in elderly males. Diabetes was the most frequent co-morbid condition, followed by obesity. Nearly a quarter of patients were taking non-steroidal anti-inflammatory drugs (NSAID). Traditional Samoan tattooing was an uncommon cause. Streptococcus pyogenes and Staphylococcus aureus were the two commonly isolated bacteria. Methicillin-resistant Staphylococcus aureus was implicated in a relatively small number of cases. Shock, renal failure, coagulation abnormality and multi-organ dysfunction were common complications. More than 90% of patients underwent surgical debridement, 56% were admitted to an intensive care unit (ICU) and slightly less than half of all patients had blood product transfusion. One in six NF cases had amputations and 23.5% died.

Conclusion

This chart review found that the highest proportion of NF cases was elderly males with co-morbidities, particularly diabetes and obesity. Tattooing was an uncommon precipitating event. The role of NSAID needs further exploration. NF is a serious disease with severe complications, high case fatality and considerable use of health care resources.

Necrotizing soft tissue infections

Necrotising soft tissue infection (NSTI) presents unique challenges in diagnosis and management. The key to a successful outcome is a high index of suspicion in appropriate clinical settings. Type II NSTI tends to occur on an extremity in younger, healthier patients with a history of known trauma, and to be monomicrobial. Type I NSTI tends to occur on the trunk of older, less healthy patients without an obvious history of trauma, and tends to be polymicrobial. Other, rarer types exist as well. The pathophysiology of both types involves superantigen acticivty, as well as a number of microbial byproducts which collectively decrease the viscosity of pus, facilitating its spread along deep tissue planes and ultimately causing diffuse deep thrombosis and aggressive systemic sepsis. The most important physical finding is tenderness to palpation beyond the area of redness, and the lack of crepitus should not be seen as a reassuring sign. Suspected cases should undergo early surgical exploration for diagnosis, which may be performed at bedside through a small incision. Most imaging techniques are not sufficiently specific to warrant a delay in surgical exploration. The Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) shows promise as a tool for excluding suspected cases. Successful outcomes in cases of NSTI require early and aggressive serial debridement and a multidisciplinary critical care approach.

The role of toxin A and toxin B in the virulence of Clostridium difficile

During the past decade, there has been a striking increase in Clostridium difficile nosocomial infections worldwide predominantly due to the emergence of epidemic or hypervirulent isolates, leading to an increased research focus on this bacterium. Particular interest has surrounded the two large clostridial toxins encoded by most virulent isolates, known as toxin A and toxin B. Toxin A was thought to be the major virulence factor for many years; however, it is becoming increasingly evident that toxin B plays a much more important role than anticipated. It is clear that further experiments are required to accurately determine the relative roles of each toxin in disease, especially in more clinically relevant current epidemic isolates.

Non-toxigenic Clostridium sordellii: clinical and microbiological features of a case of cholangitis-associated bacteremia

Toxigenic Clostridium sordellii strains are increasingly recognized to cause highly lethal infections in humans that are typified by a toxic shock syndrome (TSS). Two glucosylating toxins, lethal toxin (TcsL) and hemorrhagic toxin (TcsH) are believed to be important in the pathogenesis of TSS. While non-toxigenic strains of C. sordellii demonstrate reduced cytotoxicity in vitro and lower virulence in animal models of infection, there are few data regarding their behavior in humans. Here we report a non-TSS C. sordellii infection in the context of a polymicrobial bacterial cholangitis. The C. sordellii strain associated with this infection did not carry either the TcsL-encoding tcsL gene or the tcsH gene for TcsH. In addition, the strain was neither cytotoxic in vitro nor lethal in a murine sepsis model. These results provide additional correlative evidence that TcsL and TcsH increase the risk of mortality during C. sordellii infections.

Local variations in the epidemiology, microbiology, and outcome of necrotizing soft-tissue infections: a multicenter study

BACKGROUND

Necrotizing soft-tissue infections (NSTIs) are rare and highly lethal.

METHODS

A retrospective chart review of patients with NSTIs treated at 6 academic hospitals in Texas between January 1, 2004 and December 31, 2007. Patient demographics, presentation, microbiology, treatment, and outcome were recorded. Analysis of variance, chi-square test, and logistic regression analysis were performed.

RESULTS

Mortality rates varied between hospitals from 9% to 25% (n = 296). There was significant interhospital variation in patient characteristics, microbiology, and etiology of NSTIs. Despite hospital differences in treatment, primarily in critical care interventions, patient age and severity of disease (reflected by shock requiring vasopressors and renal failure postoperatively) were the main predictors of mortality.

CONCLUSIONS

Significant center differences occur in patient populations, etiology, and microbiology of NSTIs, even within a concentrated region. Management should be based on these characteristics given that adjunctive treatments are unproven and variations in outcome are likely because of patient disease at presentation.

Shooting up: the interface of microbial infections and drug abuse

Illicit drug control has been on the global agenda for more than a century. Infections have long been recognized as one of the most serious complications of drug abuse. Drug users are susceptible to pulmonary, endovascular, skin and soft tissue, bone and joint, and sexually transmitted infections caused by a wide range of bacterial, viral, fungal and protozoal pathogens. In addition, injection drug users are at increased risk for parenterally acquired infections such as human immunodeficiency virus, hepatitis B virus, hepatitis C virus, tetanus and malaria. Factors related to drug use, such as unsterile injection practices, contaminated drug paraphernalia and drug adulterants, increase the exposure to microbial pathogens. Illicit drugs also affect several components of the complex immune system and thus modulate host immunity. In addition, lifestyle practices such as multiple sexual partners, overcrowded housing arrangements and malnutrition serve as co-factors in increasing the risk of infection. In this review we present an overview of the unique aspects of microbial pathogenesis, immune modulation and common infections associated with drug use. We have restricted the definition of drug abuse to the use of illegal drugs (such as opiates, marijuana, cocaine, heroin and amphetamines), not including alcohol and nicotine.

TcsL is an essential virulence factor in Clostridium sordellii ATCC 9714

Clostridium sordellii is an important pathogen of humans and animals, causing a range of diseases, including myonecrosis, sepsis, and shock. Although relatively rare in humans, the incidence of disease is increasing, and it is associated with high mortality rates, approaching 70%. Currently, very little is known about the pathogenesis of C. sordellii infections or disease. Previous work suggested that the lethal large clostridial glucosylating toxin TcsL is the major virulence factor, but a lack of genetic tools has hindered our ability to conclusively assign a role for TcsL or, indeed, any of the other putative virulence factors produced by this organism. In this study, we have developed methods for the introduction of plasmids into C. sordellii using RP4-mediated conjugation from Escherichia coli and have successfully used these techniques to insertionally inactivate the tcsL gene in the reference strain ATCC 9714, using targetron technology. Virulence testing revealed that the production of TcsL is essential for the development of lethal infections by C. sordellii ATCC 9714 and also contributes significantly to edema seen during uterine infection. This study represents the first definitive identification of a virulence factor in C. sordellii and opens the way for in-depth studies of this important human pathogen at the molecular level.

Adulterants in illicit drugs: a review of empirical evidence

Widespread public perception is that illicit drugs contain substances that are a serious risk to health, even though adulterants are often not considered in clinical or forensic toxicology. This review attempts to present an evidence-based overview of adulterants in illicit drugs, and their associated toxicity. Adulterants are deliberately added to increase bulk, enhance or mimic a pharmacological effect, or to facilitate drug delivery. Those present unintentionally are as a result of poor manufacturing techniques. From the reports gathered, adulterants are predominantly substances which are readily available, commonly being caffeine, procaine, paracetamol, and sugars. These are likely to have minimal impact on users' health at low dosages. Other adulterants, particularly in injectable drugs, have the potential to cause serious health issues, but the quantities reported, such as strychnine in heroin, are not life-threatening. The most commonly identified bacterial contaminants identified are Bacillus and Clostridium species. When death or serious illness due to adulteration occurs, circulation of information is particularly vital, such as in the USA regarding heroin and cocaine adulterated with fentanyl, and in Scotland recently regarding anthrax contaminated heroin. The complex interactions of supply, demand, and control of illicit drugs have a tangible impact on their adulteration. Continuing vigilance and the circulation of information is, therefore, desirable as a public health issue. As part of that strategy, analyses performed for adulterants needs to be encouraged, which are considerably limited in number and scope at the moment.

Necrotizing fasciitis of the extremities: 34 cases at a single centre over the past 5 years

BACKGROUND

Worldwide the incidence of necrotizing fasciitis (NF) is on the rise. This rapidly progressive infection is a true infectious disease emergency due to its high morbidity and mortality. The mainstay of therapy is prompt surgical debridement, intravenous antibiotics, and supportive care with fluid and electrolyte management. Because of its high mortality rate, patients are increasingly referred to burn centres for specialized wound and critical care issues.

METHODS

A retrospective chart review was performed of 34 consecutive patients over a 5-year period with NF of the upper and/or lower extremities that required surgical debridement and reconstruction.

RESULTS

The overall survival rate was 96%, with an average length of hospital stay of 64.0 ± 5.5 days. The time until the first operation was 1.3 days. The average age of the patients was 56.7 ± 10.6 years. The patients averaged 1.6 relevant comorbidities. One patient who had five comorbidities died. The affected total body surface (TBS) averaged 8.2 ± 2.1%.

CONCLUSION

Early recognition and treatment remain the most important factors influencing survival in NF. Yet, early diagnosis of the condition is difficult due to its similarities with other soft-tissue disorders. Repeated surgical debridement and incisional drainage continues to be essential for the survival. However, these infections continue to be a source of high morbidity, mortality and significant healthcare resource consumption. These challenging patients are best served with prompt diagnosis, immediate radical surgical debridement and aggressive critical care management. Referral to a major burn centre may help to provide optimal surgical intervention, wound care and critical care management.

Spore-forming Bacilli and Clostridia in human disease

Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.

Lethal toxin is a critical determinant of rapid mortality in rodent models of Clostridium sordellii endometritis

The toxigenic anaerobe Clostridium sordellii is an uncommon but highly lethal cause of human infection and toxic shock syndrome, yet few studies have addressed its pathogenetic mechanisms. To better characterize the microbial determinants of rapid death from infection both in vitro and in vivo studies were performed to compare a clinical strain of C. sordellii (DA-108), isolated from a patient who survived a disseminated infection unaccompanied by toxic shock syndrome, to a virulent reference strain (ATCC9714). Rodent models of endometrial and peritoneal infection with C. sordellii ATCC9714 were rapidly lethal, while infections with DA-108 were not. Extensive genetic and functional comparisons of virulence factor and toxin expression between these two bacterial strains yielded many similarities, with the noted exception that strain DA-108 lacked the tcsL gene, which encodes the large clostridial glucosyltransferase enzyme lethal toxin (TcsL). The targeted removal by immunoprecipitation of TcsL protected animals from death following injection of crude culture supernatants from strain ATCC9714. Injections of a monoclonal anti-TcsL IgG protected animals from death during C. sordellii ATCC9714 infection, suggesting that such an approach might improve the treatment of patients with C. sordellii-induced toxic shock syndrome.

Comparative analysis of the extracellular proteomes of two Clostridium sordellii strains exhibiting contrasting virulence

Clostridium sordellii is a toxin-producing anaerobic bacillus that causes severe infections in humans and livestock. C. sordellii infections can be accompanied by a highly lethal toxic shock syndrome (TSS). Lethal toxin (TcsL) is an important mediator of TSS. We recently obtained a clinical strain of C. sordellii (DA-108) lacking the TcsL-encoding tcsL gene, which was not fatal in rodent models of infection, in contrast to a tcsL(+) reference strain (ATCC9714). Protein preparations derived from cell-free, stationary phase cultures obtained from ATCC9714 were lethal when injected into mice, while those obtained from DA-108 were not, a difference that was attributed to the unique presence of TcsL in the ATCC9714-derived proteins. We questioned whether there were other major differences between the extracellular proteomes of these two strains, apart from TcsL. Two-dimensional gel electrophoresis was conducted using crude cell-free supernatants from these strains and 14 differentially expressed proteins were subjected to mass spectrometric analysis. Nine of these 14 proteins were more highly expressed by DA-108 and 5 by ATCC9714. Twelve of the 14 proteins isolated from the 2-D gels were putatively identified by mass spectrometry. Several of these proteins were identical, possibly reflecting enzymatic cleavage, degradation, and/or post-translational modifications. Excluding identical sequences, only 5 unique proteins were identified. Four proteins (ferredoxin-nitrite reductase; formate acetyltransferase; Translation Elongation Factor G; and purine nucleoside phosphorylase) were over-expressed by DA-108 and 1 (N-acetylmuramoyl-l-alanine amidase) by ATCC9714. These results support the concept that TcsL is the major determinant of C. sordellii TSS during infection.

Severe necrotizing fasciitis in a human immunodeficiency virus-positive patient caused by methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a rarely reported cause of necrotizing fasciitis. We report an unusually severe case of MRSA necrotizing fasciitis in a previously undiagnosed AIDS patient. Molecular analysis revealed that the strain had the USA300/spa1 genotype, now an abundant cause of community-acquired MRSA infection.