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

Presentation and outcomes of necrotizing soft tissue infections

BACKGROUND

Necrotizing soft tissue infections (NSTIs) are aggressive infections associated with significant morbidity, including amputation and organ failure, and high mortality. The rapid progression and significant risk of morbidity and mortality associated with NSTIs makes quick diagnosis and treatment critical. The objective of this study was to determine the presentation of patients diagnosed with NSTIs and their in-hospital outcomes.

METHODS

This was a retrospective review of adult (>17 years) patients with a discharge diagnosis of necrotizing fasciitis at London Health Sciences Centre (annual census 125,000) over a 5-year period (April 2008-March 2013).

RESULTS

Sixty patients with confirmed NSTI were included in this study. Common comorbidities at presentation included immunocompromise (58.3%), diabetes mellitus (41.7%), vascular disease (45.0%), and obesity (24.6%). Initial presentations included swelling (91.7%), erythema (86.7%), bullae (28.3%), petechiae (8.3%), and bruising (45.0%). Fifty (83.3%) underwent surgery, with a median (interquartile range) time from initial emergency department presentation to surgery of 15.5 hours (7.8, 74.9). In-hospital mortality among those who had surgical intervention was 14.0%, compared to 60.0% for patients who did not have surgery (Δ46.0%; 95% CI: 14.8% to 70.2%).

CONCLUSION

Diabetes mellitus, immune-compromise, vascular disease, and obesity are common comorbidities of NSTIs. Survival is higher among patients who receive surgical treatment. Patients presenting with this clinical picture warrant a high degree of suspicion.

Management and Novel Adjuncts of Necrotizing Soft Tissue Infections

Necrotizing soft tissue infections (NSTI) have been recognized for millennia and continue to impose considerable burden on both patient and society in terms of morbidity, death, and the allocation of resources. With improvements in the delivery of critical care, outcomes have improved, although disease-specific therapies are lacking. The basic principles of early diagnosis, of prompt and broad antimicrobial therapy, and of aggressive debridement have remained unchanged. Clearly novel and new therapeutics are needed to combat this persistently lethal disease. This review emphasizes the pillars of NSTI management and then summarizes the contemporary evidence supporting the incorporation of novel adjuncts to the pharmacologic and operative foundations of managing this disease.

The laboratory risk indicator for necrotizing fasciitis (LRINEC) scoring: the diagnostic and potential prognostic role

BACKGROUND

Necrotizing fasciitis (NF) is a devastating soft tissue infection associated with potentially poor outcomes. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score has been introduced as a diagnostic tool for NF. We aimed to evaluate the prognostic value of LRINEC scoring in NF patients.

METHODS

A retrospective analysis was conducted for patients who were admitted with NF between 2000 and 2013. Based on LRINEC points, patients were classified into (Group 1: LRINEC < 6 and Group 2: LRINEC ≥ 6). The 2 groups were analyzed and compared. Primary outcomes were hospital length of stay, septic shock and hospital death.

RESULTS

A total of 294 NF cases were identified with a mean age 50.9 ± 15 years. When compared to Group1, patients in Group 2 were 5 years older (p = 0.009), more likely to have diabetes mellitus (61 vs 41%, p < 0.001), Pseudomonas aeruginosa infection (p = 0.004), greater Sequential Organ Failure Assessment (SOFA) score (11.5 ± 3 vs 8 ± 2, p = 0.001), and prolonged intensive care (median 7 vs 5 days) and hospital length of stay (22 vs 11 days, p = 0.001). Septic shock (37 vs. 15%, p = 0.001) and mortality (28.8 vs. 15.0%, p = 0.005) were also significantly higher in Group 2 patients. Using Receiver operating curve, cutoff LRINEC point for mortality was 8.5 with area under the curve of 0.64. Pearson correlation analysis showed a significant correlation between LRINEC and SOFA scorings (r = 0.51, p < 0.002).

DISCUSSION

Early diagnosis, simplified risk stratification and on-time management are vital to achieve better outcomes in patients with NF.

CONCLUSIONS

Beside its diagnostic role, LRINEC scoring could predict worse hospital outcomes in patients with NF and simply identify the high-risk patients. However, further prospective studies are needed to support this finding.

Outcomes in necrotizing soft tissue infections treated with therapeutic plasma exchange

BACKGROUND

Treatment of necrotizing soft tissue infections (NSTIs) includes prompt surgical debridement and antibiotics, but despite standard care, the morbidity and mortality remain high. Since therapeutic plasma exchange (TPE) has been considered for treatment of severe sepsis, this study evaluates the efficacy of TPE for patients with NSTI.

STUDY DESIGN AND METHODS

This is a retrospective study of patients with diagnosis of NSTI who received treatment with and without TPE over an 11-year period. The primary outcome was in-hospital mortality.

RESULTS

Fifty-two patients with NSTI treated with TPE (TPE group) and 125 patients with NSTI not treated with TPE (non-TPE group) were assessed. Nineteen (36.5%) patients died in the TPE group, and 35 (28%) patients died in the non-TPE group. Within the TPE group, there was significant improvement in white blood cell (WBC) count and sodium levels 7 days after TPE treatment, but no improvement in creatinine. Inverse probability weighting based on propensity scores was used to compare survival in the TPE and non-TPE groups and demonstrated that TPE was associated with an increased odds of death (odds ratio, 2.8). A second analysis matched for six variables yielded 31 pairs and demonstrated no significant difference in mortality or length of stay.

CONCLUSIONS

This study describes the largest series of patients with NSTIs treated with TPE and showed no evidence of clinical benefit. Further carefully designed studies with meaningful clinical endpoints would prove useful in assessing reproducibility and determining if there is a role for TPE in other forms of severe sepsis.

Bilateral thigh methicillin-resistant Staphylococcus aureus necrotising fasciitis in a man with newly diagnosed Human Immunodeficiency Virus (HIV)

Methicillin-resistant Staphylococcus aureus (MRSA) necrotising fasciitis (NF) is rare and constitutes a medical and surgical emergency. We report a case of a 53-year-old man with type-2 diabetes mellitus and newly diagnosed HIV infection who presented with 1 week of progressively worsening bilateral sharp thigh pain. On presentation, he was febrile, tachycardic and had bilateral thigh erythema and mild tenderness without open wounds. He had leucocytosis, lactic acidosis and acute kidney injury. Urgent incision and drainage (I&D) was performed for suspected NF. Blood cultures and I&D were positive for MRSA. Biopsy of bilateral thighs showed NF. He was treated with wound washout and 6 weeks of intravenous antibiotics. After undergoing skin graft for wounds, he was discharged to physical rehabilitation. Here we report severe sepsis from bilateral thigh MRSA NF in a patient with newly diagnosed HIV.

Clinical Guidelines for the Antibiotic Treatment for Community-Acquired Skin and Soft Tissue Infection

Skin and soft tissue infection (SSTI) is common and important infectious disease. This work represents an update to 2012 Korean guideline for SSTI. The present guideline was developed by the adaptation method. This clinical guideline provides recommendations for the diagnosis and management of SSTI, including impetigo/ecthyma, purulent skin and soft tissue infection, erysipelas and cellulitis, necrotizing fasciitis, pyomyositis, clostridial myonecrosis, and human/animal bite. This guideline targets community-acquired skin and soft tissue infection occurring among adult patients aged 16 years and older. Diabetic foot infection, surgery-related infection, and infections in immunocompromised patients were not included in this guideline.

A Multi-Center Review of Care Patterns and Outcomes in Necrotizing Soft Tissue Infections

BACKGROUND

Surgical debridement and broad-spectrum empiric antibiotics are first-line therapy for necrotizing soft tissue infections (NSTI). The objective of this multi-center retrospective review was to evaluate antimicrobial agent initiation and duration and compare outcomes in the treatment of patients with NSTI.

PATIENTS AND METHODS

This review included adults with NSTI, as indicated by International Classification of Diseases, 9th Edition, Clinical Modification codes 728.86, 608.33, or 040.0, who were admitted to three academic institutions between 1/1/09 and 5/15/14. Demographics, antibiotic practices, operative management, and clinical outcomes were compared.

RESULTS

A total of 341 patients were identified at the three centers. Subjects were comparable in age (median 53 years, p = 0.14), gender (67% male, p = 0.57) and body mass index (median 31.9 (p = 0.31) between sites. No significant difference was found in time from admission to start of empiric antibiotic therapy between the three centers (median 1 d for each, p = 0.70), but duration of antibiotic therapy was significantly different (Site A = 16 d, Site B = 12 d, Site C = 9 d, medians, p < 0.001). Although total number of operations differed between sites (median of two at Sites A and B, three at Site C, p = 0.001), sites consistently operated on the day of patient arrival to their facility, and the number of debridements did not differ (median of two for all sites, p = 0.10). Mortality rate (Site A = 22%, Site B = 18%, and Site C = 9%, p = 0.02) and length of stay for survivors (Site A = 29 d, Site B = 16 d, Site C = 19 d, medians, p = 0.001) was significantly different among centers.

CONCLUSIONS

Variation in antibiotic duration between centers with expertise in the care of NSTI illustrates how little is known about best care practices for patients with NSTI. Future studies should emphasize development of evidence-based practices for NSTI management to further improve the outcomes of this complex group of patients.

Pattern and predictors of mortality in necrotizing fasciitis patients in a single tertiary hospital

Background

Necrotizing fasciitis (NF) is a fatal aggressive infectious disease. We aimed to assess the major contributing factors of mortality in NF patients.

Methods

A retrospective study was conducted at a single surgical intensive care unit between 2000 and 2013. Patients were categorized into 2 groups based on their in-hospital outcome (survivors versus non-survivors).

Results

During a14-year period, 331 NF patients were admitted with a mean age of 50.8 ± 15.4 years and 74 % of them were males Non-survivors (26 %) were 14.5 years older (p = 0.001) and had lower frequency of pain (p = 0.01) and fever (p = 0.001) than survivors (74 %) at hospital presentation. Diabetes mellitus, hypertension, and coronary artery disease were more prevalent among non-survivors (p = 0.001). The 2 groups were comparable for the site of infection; except for sacral region that was more involved in non-survivors (p = 0.005). On admission, non-survivors had lower hemoglobin levels (p = 0.001), platelet count (p = 0.02), blood glucose levels (p = 0.07) and had higher serum creatinine (p = 0.001). Non-survivors had greater median LRINEC (Laboratory Risk Indicator for NECrotizing fasciitis score) and Sequential Organ Failure Assessment (SOFA) scores (p = 0.001). Polybacterial and monobacterial gram negative infections were more evident in non-survivors group. Monobacterial pseudomonas (p = 0.01) and proteus infections (p = 0.005) were reported more among non-survivors. The overall mortality was 26 % and the major causes of death were bacteremia, septic shock and multiorgan failure. Multivariate analysis showed that age and SOFA score were independent predictors of mortality in the entire study population.

Conclusion

The mortality rate is quite high as one quarter of NF patients died during hospitalization. The present study highlights the clinical and laboratory characteristics and predictors of mortality in NF patients.

Laboratory evaluation for pediatric patients with suspected necrotizing soft tissue infections: A case-control study

BACKGROUND/PURPOSE

Optimal outcomes for necrotizing soft tissue infections (NSTI) depend on rapid diagnosis and management. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score is a validated diagnostic tool for adult NSTI, but its value for children remains unknown. We hypothesized that modification of the LRINEC score may increase its diagnostic accuracy for pediatric NSTI.

METHODS

We performed a case-control study of pediatric patients (age <18) with NSTI (cases) and patients with severe soft tissue infections prompting surgical consultation (controls). The LRINEC score was calculated for cases and controls and compared to a modified, pediatric LRINEC (P-LRINEC) score. Diagnostic accuracy was analyzed through receiver operating characteristic (ROC) curves.

RESULTS

From 2010 to 2014, 20 cases and 20 controls were identified at two children's hospitals. Median LRINEC score was 3.5 (1-8) for cases and 2 (1-7) for controls (p=0.03). The P-LRINEC was comprised of serum CRP >20 (sensitivity=95% (95%CI 79-100%)) and serum sodium <135 (specificity=95% (95%CI 82-100%)). Area under ROC curves was 0.70 (95%CI 0.54-0.87) for the LRINEC score and 0.84 (95%CI 0.72-0.96) for the P-LRINEC score (p=0.06).

CONCLUSION

The P-LRINEC is a simplified version of the LRINEC score utilizing only CRP and sodium and may provide superior accuracy in predicting pediatric NSTI.

Necrotising Soft Tissue Infections: The Effect of Hyperbaric Oxygen on Mortality

In a single-centre, retrospective, case-controlled study of patients attending the Alfred Hospital in Prahran, Victoria, we assessed the effect of hyperbaric oxygen therapy (HBOT) in reducing mortality or morbidity in patients with necrotising fasciitis (NF) over a 13-year period from 2002 to 2014. A total of three hundred and forty-one patients with NF were included in the study, of whom 275 received HBOT and 66 did not. The most commonly involved sites were the perineum (33.7%), lower limb (29.9%) and trunk (18.2%). The commonest predisposing factor was diabetes mellitus (34.8%). Polymicrobial NF (type 1 NF) occurred in 50.7% and Group A streptococcal fasciitis (type 2 NF) occurred in 25.8% of patients. Mortality was 14.4% overall, 12% in those treated with, and 24.3% in those not treated with, HBOT. ICU support was required in 248 (72.7%) patients. Independent factors impacting on mortality included HBOT (odds ratio [OR] 0.42 [0.22 to 0.83], P=0.01), increased age (OR 1.06 [1.03 to 1.08], P=0.001) and immunosuppression (OR 2.6 [1.23 to 5.51], P=0.01). Mortality was linked to illness severity at presentation, however when adjusted for severity score and need for intensive care management, HBOT was associated with significant reduction in mortality.

Prognostic factors in necrotizing soft-tissue infections (NSTI): A cohort study

BACKGROUND

Necrotizing soft-tissue infection (NSTI) is uncommon but life-threatening. A recent meta-analysis estimated the overall mortality at 23.5%.

OBJECTIVE

We sought to identify risk factors associated with mortality in a cohort of patients with NSTI in a tertiary care center.

METHODS

We identified 512 patients with NSTI between 1996 and 2012 in the national hospital database Program for Medicalization of Information Systems and examined risk factors of mortality with NSTI by univariate and multivariate analysis.

RESULTS

We included 109 patients with a confirmed diagnosis of NSTI; 31 (28%) died at a median follow-up of 274 days (range 2-6135 days). On multivariate analysis, independent risk factors of mortality were age older than 75 years (hazard ratio [HR] 4.4, 95% confidence interval [CI] 1.8-10.3), multifocal NSTI (HR 5.9, 95% CI 1.9-18.5), severe peripheral vascular disease (HR 5.1, 95% CI 1.5-17.0), hospital-acquired infection (HR 3.9, 95% CI 1.4-10.7), severe sepsis (HR 7.4, 95% CI 1.7-33.1), and septic shock on hospital admission (HR 13.9, 95% CI 3.8-50.4).

LIMITATIONS

This was a retrospective cohort, which disallows a precise record of the delay between diagnosis and surgery.

CONCLUSION

Our findings for this robust cohort of patients with a definite diagnosis of NSTI could help clinicians stratify NSTI severity at clinical course onset.

Impact and Progression of Organ Dysfunction in Patients with Necrotizing Soft Tissue Infections: A Multicenter Study

BACKGROUND

Necrotizing soft tissue infections (NSTI) represent a rare but devastating disease for which the systemic manifestations have been poorly characterized. In an effort to define an optimal endpoint for clinical trials in this condition, the objective of this study was to establish the pattern of organ dysfunction over time and determine the correlation between organ dysfunction and clinical outcome in patients with NSTI.

METHODS

We conducted a multicenter, retrospective clinical study of patients with NSTI presenting to 12 academic medical centers in the U.S. during 2013. Patients with a diagnosis of NSTI confirmed by surgical findings were included. Organ dysfunction was assessed using a modified Sequential Organ Failure Assessment (SOFA) score (mSOFA: excluding liver) on admission and on hospital days 1, 2, 3, 7, 10, and 14. The presence of organ dysfunction on admission and resolution of organ dysfunction were correlated with clinical parameters, including intensive care unit (ICU)-free days (of 28 d), ventilator-free days, number of debridements, and mortality rate. The incidence of acute kidney injury (AKI) and recovery also were assessed.

RESULTS

There were 198 patients enrolled, of whom 62% were male, the mean age was 51 years, and 40% had monomicrobial infections. The mean mSOFA score on admission was 2.4 ± 3.0, with 49% of the patients having a score ≥2 and 35% a score of ≥3. Patients typically demonstrated worsening of the mSOFA score over the first 24 h followed by gradual resolution. An mSOFA ≥3 at admission was associated with a significant decrease in ventilator-free days (mean 20.1 vs. 25.6 days; p < 0.001); ICU-free days (15.2 vs. 23.1, p < 0.001); more debridements (mean 2.3 vs. 2.0; p = 0.11); a higher mortality rate (15.9% vs. 3.1%; p = 0.003); and a higher rate of AKI (59.4 vs. 35.9%; p < 0.001). The persistence of organ dysfunction (mSOFA >1) among survivors at day 14 was associated with fewer ICU-free days (17.8 vs. 23.6; p < 0.001) and ventilator-free days (23.6 vs. 27; p = 0.001) and a lower recovery rate from AKI (38.7% vs. 81.3%; p < 0.001).

CONCLUSION

Early development of systemic organ dysfunction in patients with NSTI is associated with higher morbidity and mortality rates. Failure of the resolution of organ dysfunction by day 14 forecasts a poor outcome. The mSOFA score may be a useful marker for patient selection for inclusion in interventional trials, and the resolution of organ dysfunction by day 14 may be an important clinical endpoint.

Risk Stratification of Necrotizing Fasciitis Based on the Initial Procalcitonin Concentration: A Single Center Observational Study

BACKGROUND

Necrotizing fasciitis (NF) is a potentially fatal subcutaneous tissue and fascia infection. We studied the role of serum procalcitonin in the identification and assessment of severity of sepsis in patients with NF.

METHODS

A retrospective analysis was conducted from January 2000 to December 2013 for all patients who admitted to surgical intensive care with provisional diagnosis of NF. Patients were categorized into four groups based on the initial procalcitonin concentrations (Group I: <0.5 low risk, Group II: ≥0.5-<2 moderate risk, Group III: ≥2-<10 high risk, and Group IV: ≥10 ng/mL high likelihood of severe sepsis).

RESULTS

During the study period, 331 cases were identified to have NF with a mean age of 51 ± 14 years. Serum procalcitonin was tested in 62 cases (only between 2011 and December 2013) and all were positive (Group I: 22%, Group II: 18%, Group III: 21%, and Group IV: 39%). The most common affected regions were thigh and chest in Group II (46% and 9%, respectively), lower limbs in Group III (46%), and perineum and abdomen in Group IV (25% and 21%, respectively). In the four groups, 21 patients developed septic shock (Group I: 0%, Group II: 14%, Group III: 24%, and Group IV: 62%). The cut off procalcitonin value for septic shock was 5.6 ng/mL. Using receiver-operating characteristic curve, this cut off with the Area under the Curve (AUC) of 0.77 was found to have sensitivity 81% and specificity 67%. Sequential Organ Failure Assessment (SOFA) score was substantially greater in Group III and Group IV in comparison to Group I and Group II, p = 0.006. Procalcitonin levels were correlated well with SOFA score (r = 0.34, p = 0.007). There were 17 deaths in the four groups (Group I: 6%, Group II: 23%, Group III: 12%, and Group IV: 59%).

CONCLUSION

Initial procalcitonin concentration in NF carries an important prognostic value and it correlates well with SOFA score and can predict the development of septic shock early in patients with NF.

The Prediction Predicament: Rethinking Necrotizing Soft Tissue Infections Mortality

BACKGROUND

Our study sought to identify independent risk factors predisposing patients with necrotizing soft tissue infections (NSTIs) to mortality from among laboratory values, demographic data, and microbiologic findings in a small population. To this end, a retrospective review was conducted of the medical records of all patients with NSTI who had been treated at our institution from 2003 to 2012 (n=134).

METHODS

Baseline demographics and comorbidities, clinical and laboratory values, hospital course, and the microbiologic characteristics of surgical incision cultures were recorded. Each variable was tested for association with survival status and all associated variables with p<0.15 were included in a logistic regression model to seek factors associated independently with mortality.

RESULTS

Surprisingly, no demographic or pre-existing condition proved to be a predictor of mortality. Two laboratory values had an inverse correlation to mortality: High C-reactive protein (CRP) and highest recorded CRP. Of surgical incisions that grew bacteria in culture, 33.6% were polymicrobial. Mortality rates were highest with Enterococcus-containing polymicrobial infections (50%), followed by those containing Pseudomonas (40%), and Streptococcus spp. (27%). Understanding why so many studies across the literature, now including our own, find such disparate results for correlation of NSTI mortality with patient data may lie in the fundamentally dynamic nature of the organisms involved.

CONCLUSIONS

This study suggests that no single factor present on admission is a robust predictor of outcome; it is likely that survival in NSTI is predicated upon a complex interaction of multiple host and microbial factors that do not lend themselves to reduction into a simple formula. It is also abundantly clear that the well-established principles of NSTI surgery should continue to be followed in all cases, with an emphasis on early debridement, irrespective of apparent severity of initial presentation.

Necrotizing soft tissue infections after injection therapy: Higher mortality and worse outcome compared to other entry mechanisms

OBJECTIVES

Necrotizing Soft Tissue Infections represent a rare entity of infection associated with a high mortality. The aim of this retrospective study was to analyze patients with an iatrogenic etiology of injection or infiltration to compare the outcome with other etiologies.

METHODS

The study group consisted of 21 patients treated with a Necrotizing Fasciitis caused by injection or infiltration. Risk factors and outcome were compared to 134 patients with a Necrotizing Fasciitis caused by other entry mechanisms.

RESULTS

Overall mortality in our study group was 14 of 21 (67%) with an amputation rate of 11 of 15 (73%) if an extremity was involved. The survival rate was significantly worse after injection or infiltration (p < 0.001) as was the amputation rate (p = 0.013), the percentage of patients requiring intensive care (100% vs. 83%, p = 0.038) and vasopressors (81% vs. 54%, p = 0.02). Injection or infiltration therapy proved to be the strongest prognostic factor (p = 0.003) besides the known risk factors obesity (0.007) and renal insufficiency (0.025).

CONCLUSIONS

Our results demonstrate that patients with a Necrotizing Soft Tissue Infection after injection or infiltration therapy have a significantly worse prognosis.

Necrotising soft tissue infection in a UK metropolitan population

INTRODUCTION

Necrotising soft tissue infection (NSTI) is a rare but life threatening diagnosis. Geographic, economic and social variances influence presentation and prognosis. As the current literature does not reflect a UK metropolitan population, we conducted a retrospective chart review to establish pertinent features relevant to our practice.

METHODS

Patients with histologically confirmed diagnoses of NSTI presenting to two London teaching hospitals between January 2007 and July 2013 were included in the study. Features of presentation, surgical and medical management, microbiological findings and outcome were evaluated.

RESULTS

Twenty-four patients with histologically confirmed NSTI were included. Two age clusters were identified, with means of 46 years (standard deviation [SD]: 10 years) and 80 years (SD: 6 years). Pain, erythema and sepsis were common findings. Hypertension, hypercholesterolaemia and type II diabetes mellitus were common co-morbidities. A third of younger patients had human immunodeficiency virus or hepatitis C, with a quarter dependent on drugs and/or alcohol. The mean Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score was 5.8 (SD: 3.3). The lower extremities, groin and perineum were common sites of infection. Fourteen patients required inotropic support and seventeen required transfusions. The median number of surgical procedures was 5 (range: 1-17). Group A Streptococcus was the most frequently identified pathogen. Five patients died. Being elderly, female sex and failure to use clindamycin as a first-line antibiotic were associated with significantly higher mortality.

CONCLUSIONS

In contrast to other recent series, group A streptococcal monomicrobial NSTI remains the most common presentation in our population. Survival is anticipated in young patients, regardless of premorbid status. Elderly patients have a poor prognosis. The negative predictive value of the LRINEC score is questioned. Use of clindamycin as a first-line antibiotic is supported.

Monomicrobial necrotizing fasciitis in a single center: the emergence of Gram-negative bacteria as a common pathogen

BACKGROUND

Necrotizing fasciitis (NF) is a life-threatening soft tissue infection. It is usually caused by Streptococcus pyogenes and other Gram-positive bacteria. Several reports, however, emphasize the importance of Gram-negative rods in this infection.

METHODS

We retrospectively studied all cases of monomicrobial necrotizing fasciitis hospitalized in our center during the years 2002-2012. We compared clinical characteristics and outcomes of patients with Gram-negative versus Gram-positive infection.

RESULTS

Forty-five cases were reviewed, 19 caused by Gram-negative organisms, 10 of them Escherichia coli, and 26 caused by Gram-positive organisms, 10 of them S. pyogenes. Compared to Gram-positive infections, patients with Gram-negative infections were more likely to have a baseline malignancy (9/19, 47.4%) or to have undergone recent surgery (4/19, 42.3%). The 30-day mortality was higher among Gram-negative infected patients (8/19, 42.1% vs. 8/26, 30.8%). Creatine phosphokinase (CPK) was elevated in a minority of patients with Gram-negative necrotizing fasciitis, and its absolute value was lower than in Gram-positive necrotizing fasciitis.

CONCLUSIONS

In our center, 42% of monomicrobial necrotizing fasciitis cases were found to be caused by Gram-negative organisms, mostly E. coli. These infections usually appeared in immunocompromised or postoperative patients, often presented with normal CPK levels, and were associated with high mortality rates.

Management of necrotizing skin and soft tissue infections

Although rare, necrotizing skin and soft tissue infections can be devastating infections that are difficult to diagnose and challenging to manage. Clinical presentation is often insidious, and a low index of suspicion is critical. Various diagnostic tools, such as scoring systems or imaging techniques, have been introduced, but none is convincingly superior to sound clinical judgment. Early diagnosis allows early adequate therapy that includes antibiotic therapy, critical care support, specific interventions such as intravenous immunoglobulin in selected patients and, most importantly, early source control. Empirical antibiotic therapy should cover a broad range of both Gram-negative and Gram-positive aerobic and anaerobic microorganisms, and clindamycin is recommended when group A Streptococcus is a suspected pathogen.

Predictors of Mortality and Limb Loss in Necrotizing Soft Tissue Infections

Necrotizing soft tissue infections (NSTIs) require prompt diagnosis and treatment. Early identification of patients at greatest risk of limb amputation and death may help in targeting aggressive medical and surgical management. The aim of this study was to assess predictors of limb loss and mortality in patients with NSTI based on admission variables. We performed a retrospective review of two hospitals that care for a large volume of patients with NSTI. Univariate and multi-variable analyses were used to determine the association of admission biochemical markers to limb loss and mortality. Of 174 patients with NSTI, there were 19 deaths (10.9%) and 42 required amputations (24.1%). Multivariable logistic regression analysis revealed that only arterial lactate was predictive for both mortality (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1 to 2.0; P = 0.009) and limb loss (OR, 1.3; 95% CI, 1.0 to 1.7; P = 0.02). In patients with a suspected NSTI, an arterial lactate should be ordered early on to guide aggressive therapeutic interventions and to provide information with regard to long-term outcomes of amputation and death that is needed for early discussion with the patient and family.

Procalcitonin ratio as a predictor of successful surgical treatment of severe necrotizing soft tissue infections

BACKGROUND

Necrotizing soft tissue infections often are characterized by fulminant presentation and lethal outcomes. Besides critical care support and antibiotic therapy, aggressive surgical treatment is important for the therapy of necrotizing fasciitis. The aim of this study was to develop a procalcitonin (PCT) ratio indicating successful surgical intervention.

METHODS

The study group consisted of 38 patients treated with clinical signs of sepsis caused by a necrotizing soft tissue infection. All patients received radical surgical treatment, and serum levels of PCT and C-reactive protein were monitored postoperatively. The ratio of day 1 to day 2 was calculated and correlated with the successful elimination of the infectious source and clinical recovery.

RESULTS

An eradication of the infectious focus was successfully performed in 84% of patients, averaging 1.9 operations (range 1 to 6) to achieve an elimination of the infectious source. The PCT ratio was significantly higher in the group of patients with successful surgical intervention (1.665 vs .9, P < .001). A ratio higher than the calculated cutoff of 1.14 indicated successful surgical treatment with a sensitivity of 83.3% and a specificity of 71.4%. The positive predictive value was 75.8%, and the negative predictive value was 80.0%.

CONCLUSIONS

The PCT ratio of postoperative day 1 to day 2 following major surgical procedures for necrotizing soft tissue infections represents a valuable clinical tool indicating successful surgical eradication of the infectious focus.

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 infection of the upper limb]

Necrotizing soft tissue infections and necrotizing fasciitis are life-threatening infections affecting the hypodermis, muscular fascia, and dermis secondarily. Mortality is high, with an average of 30%. The early diagnosis of necrotizing soft tissue infection is challenging, but is key to successful management of these patients. The mainstay of therapy includes early and wide surgical debridement, antibiotics and supportive care. Adjunctive therapies may have a role, but their effectiveness remains unproven. A review of the literature allows us to highlight this multidisciplinary management.

A 3-Year Experience with Necrotizing Fasciitis: Favorable Outcomes despite Operative Delays in a Busy Acute Care Hospital

Necrotizing fasciitis is a rare severe soft tissue infection that has historically been associated with high mortality. We sought to evaluate our experience with necrotizing fasciitis focusing on outcomes based on timing of operative intervention. Our study hypothesis was that delays in surgical management would negatively impact outcomes. Fifty-four patients were identified for a retrospective chart review from January 2008 to January 2011. Data analysis included demographics, admission laboratory values, imaging results, examination findings, timing and nature of operations, length of stay (LOS), and outcomes. Surgical intervention in 12 hours or more was considered a delay in care. Our study cohort was high risk based on a high prevalence of intravenous drug abuse, diabetes mellitus, hypertension, and end-stage liver disease. The average time to surgical intervention was 18 ± 25 hours and the overall mortality rate was 16 per cent. A delay to surgery did not impact mortality or the number of débridements and LOS. Mortality was high, 45 per cent, in patients requiring amputation. We observed a high-risk population managed with aggressive surgical care for necrotizing fasciitis. Our mortality was low compared with historical data and surgical delays did not impact outcomes. Those patients requiring amputation had worse outcomes.

Hyperbaric oxygen therapy in necrotizing soft tissue infections

BACKGROUND

Surgical debridement and antibiotics are the mainstays of therapy for patients with necrotizing soft tissue infections (NSTIs), but hyperbaric oxygen therapy (HBO) is often used as an adjunctive measure. Despite this, the efficacy of HBO remains unclear. We hypothesized that HBO would have no effect on mortality or amputation rates.

METHODS

We performed a retrospective analysis of our institutional experience from 2005 to 2009. Inclusion criteria were age > 18 y and discharge diagnosis of NSTI. We abstracted baseline demographics, physiology, laboratory values, and operative course from the medical record. The primary endpoint was in-hospital mortality; the secondary endpoint was extremity amputation rate. We compared baseline variables using Mann-Whitney, chi-square, and Fisher's exact test, as appropriate. Significance was set at P < 0.05.

RESULTS

We identified 80 cases over the study period. The cohort was 54% male (n = 43) and 53% white (n = 43), and had a mean age of 55 ± 16 y. There were no significant differences in demographics, physiology, or comorbidities between groups. In-hospital mortality was not different between groups (16% in the HBO group versus 19% in the non-HBO group; P = 0.77). In patients with extremity NSTI, the amputation rate did not differ significantly between patients who did not receive HBO and those who did (17% versus 25%; P = 0.46).

CONCLUSIONS

Hyperbaric oxygen therapy does not appear to decrease in-hospital mortality or amputation rate after in patients with NSTI. There may be a role for HBO in treatment of NSTI; nevertheless, consideration of HBO should never delay operative therapy. Further evidence of efficacy is necessary before HBO can be considered the standard of care in NSTI.