Risk model for predicting mortality in patients with necrotizing soft tissue infections in the intensive care unit

BACKGROUND

The goal of this study is to look into the factors that lead to death in patients with necrotizing soft tissue infections（NSTIs） in the intensive care unit and create a mortality risk model.

METHODS

The clinical data of 106 patients with necrotizing soft tissue infections admitted to intensive care unit(ICU) of the First Affiliated Hospital of Wenzhou Medical University between January 2008 and December 2021 were retrospectively analyzed. Univariate analysis and multivariate analysis were performed to evaluate the risk factors impacting patient mortality. The regression coefficient in binary logistic regression analysis was converted into the item score in the model, and then the model score of each patient was calculated. Finally, an ROC curve was constructed to evaluate the efficiency of the model for predicting mortality. Thirteen patients with NSTIs admitted to ICU between January 2022 and November 2022 were used to validate the model.

RESULTS

The death group had 44 patients, while the survival group had 62 patients. The overall mortality was 41.5%. Binary logistic regression analysis showed that risk factors for mortality were age≥ 60 years(OR:4.419; 95%CI:1.093-17.862; P = 0.037), creatinine ≥ 132μmol/L(OR:11.166; 95%CI:2.234-55.816; P = 0.003), creatine kinase ≥ 1104 U/L(OR:4.019; 95%CI:1.134-14.250; P = 0.031), prothrombin time ≥ 24.4 s(OR:11.589; 95%CI:2.510-53.506; P = 0.002), and invasive mechanical ventilation (OR:17.404; 95%CI:4.586-66.052; P＜0.000). The AUC of the model for predicting mortality was 0.940 (95% CI:0.894-0.986). When the cut-off value for the model was 4 points, the sensitivity was 95.5% and the specificity was 83.9%.

CONCLUSION

The death risk model in this study for NSTIs patients in the intensive care unit shows high sensitivity and specificity. Patients with a score of ≥ 4 points have a higher risk of mortality.

No role for standard imaging workup of patients with clinically evident necrotizing soft tissue infections: a national retrospective multicenter cohort study

PURPOSE

To assess the diagnostic contribution of different imaging studies to diagnose necrotizing soft tissue infections (NSTIs) and the time to surgery in relation to imaging with the hypothesis that imaging studies may lead to significant delays without being able to sufficiently dismiss or confirm the diagnosis since a NSTI is a surgical diagnosis.

METHODS

A retrospective multicenter cohort study of all NSTI patients between 2010 and 2020 was conducted. The primary outcome was the number of cases in which imaging contributed to or led to change in treatment. The secondary outcomes were time to treatment determined by the time from presentation to surgery and patient outcomes (amputation, intensive care unit (ICU) admission, length of ICU stay, hospital stay, and mortality).

RESULTS

A total of 181 eligible NSTI patients were included. The overall mortality was 21% (n = 38). Ninety-eight patients (53%) received imaging in the diagnostic workup. In patients with a clinical suspicion of a NSTI, 81% (n = 85) went directly to the operating room and 19% (n = 20) underwent imaging before surgery; imaging was contributing in only 15% (n = 3) by ruling out or determining underlying causes. In patients without a clinical suspicion of a NSTI, the diagnosis of NSTI was considered in 35% and only after imaging was obtained.

CONCLUSION

In patients with clinically evident NSTIs, there is no role for standard imaging workup unless it is used to examine underlying diseases (e.g., diverticulitis, pancreatitis). In atypical presenting NSTIs, CT or MRI scans provided the most useful information. To prevent unnecessary imaging and radiation and not delay treatment, the decision to perform imaging studies in patients with a clinical suspicion of a NSTI must be made extremely careful.

Outcomes in necrotizing soft tissue infections are worse in rural versus urban Montana: a 10-year single center retrospective review

Time to definitive surgical debridement has been recognized as a predictor for morbidity and mortality in necrotizing soft-tissue infections (NSTI). Rural patients are at particular risk due to limited local resources, decreased access to care, and prolonged transport times. The aim of the current study was to examine the outcomes of NSTI requiring surgical treatment in a previously non-described setting. This retrospective study (2010-2020) from a single tertiary care center in Montana reviewed patients ≥18 years old with a NSTI via ICD9/10 codes. Rural-Urban Continuum Codes (RUCC; characterizing counties by population size) were used to distinguish urban versus rural counties. Race (White and American Indian/Alaskan Native (AI/AN)) was self-described. Qualitative and quantitative comparisons between groups were determined using the appropriate two-tailed statistical tests. An aggregate of 177 patients was identified. Mean age in AI/AN was significantly lower (P<0.0001) compared to White patients with no preexisting condition delineation. NSTI demonstrated an elevated incidence in both rural areas and AI/AN patients. Diabetes was also significantly higher (P=0.0073) in rural versus urban patients. Both rural and AI/AN patients faced extended travel distance for treatment. AI/AN patients had a significantly different infection location than White. Furthermore, polymicrobial species were significantly more prevalent in AI/AN patients. Morbidities (defined as septic shock and/or amputation) were significantly higher in AI/AN patients and rural environments (P<0.01). There was no significant difference in all-cause mortality between respective groups. The state of Montana presents unique challenges to optimizing NSTI treatment due to excessive distances to regional tertiary care facilities. This delay in treatment can lead to increased morbidity.

Neutrophil-derived reactive agents induce a transient SpeB negative phenotype in Streptococcus pyogenes

BACKGROUND

Streptococcus pyogenes (group A streptococci; GAS) is the main causative pathogen of monomicrobial necrotizing soft tissue infections (NSTIs). To resist immuno-clearance, GAS adapt their genetic information and/or phenotype to the surrounding environment. Hyper-virulent streptococcal pyrogenic exotoxin B (SpeB) negative variants caused by covRS mutations are enriched during infection. A key driving force for this process is the bacterial Sda1 DNase.

METHODS

Bacterial infiltration, immune cell influx, tissue necrosis and inflammation in patient´s biopsies were determined using immunohistochemistry. SpeB secretion and activity by GAS post infections or challenges with reactive agents were determined via Western blot or casein agar and proteolytic activity assays, respectively. Proteome of GAS single colonies and neutrophil secretome were profiled, using mass spectrometry.

RESULTS

Here, we identify another strategy resulting in SpeB-negative variants, namely reversible abrogation of SpeB secretion triggered by neutrophil effector molecules. Analysis of NSTI patient tissue biopsies revealed that tissue inflammation, neutrophil influx, and degranulation positively correlate with increasing frequency of SpeB-negative GAS clones. Using single colony proteomics, we show that GAS isolated directly from tissue express but do not secrete SpeB. Once the tissue pressure is lifted, GAS regain SpeB secreting function. Neutrophils were identified as the main immune cells responsible for the observed phenotype. Subsequent analyses identified hydrogen peroxide and hypochlorous acid as reactive agents driving this phenotypic GAS adaptation to the tissue environment. SpeB-negative GAS show improved survival within neutrophils and induce increased degranulation.

CONCLUSIONS

Our findings provide new information about GAS fitness and heterogeneity in the soft tissue milieu and provide new potential targets for therapeutic intervention in NSTIs.

Point-of-care ultrasonography in diagnosing necrotizing fasciitis-a literature review

INTRODUCTION

Necrotizing fasciitis (NF) is a rapidly progressive necrosis of the fascial layer with a high mortality rate. It is a life-threatening medical emergency that requires urgent treatment. Lack of skin finding in NF made diagnosis difficult and required a high clinical index of suspicion. The use of ultrasound may guide clinicians in improving diagnostic speed and accuracy, thus leading to improved management decisions and patient outcomes. This literature search aims to review the use of point-of-care ultrasonography in diagnosing necrotizing fasciitis.

METHOD

We searched relevant electronic databases, including PUBMED, MEDLINE, and SCOPUS, and performed a systematic review. Keywords used were "necrotizing fasciitis" or "necrotising fasciitis" or "necrotizing soft tissue infections" and "point-of-care ultrasonography" "ultrasonography" or "ultrasound". No temporal limitation was set. An additional search was performed via google scholar, and the top 100 entry was screened.

RESULTS

Among 540 papers screened, only 21 were related to diagnosing necrotizing fasciitis using ultrasonography. The outcome includes three observational studies, 16 case reports, and two case series, covering the period from 1976 to 2022.

CONCLUSION

Although the use of ultrasonography in diagnosing NF was published in several papers with promising results, more studies are required to investigate its diagnostic accuracy and potential to reduce time delay before surgical intervention, morbidity, and mortality.

Outcome of necrotizing fasciitis and Fournier's gangrene with and without hyperbaric oxygen therapy: a retrospective analysis over 10 years

BACKGROUND

Necrotizing soft tissue infections (NSTI) require immediate radical debridement, broad-spectrum antibiotics and intensive care. Hyperbaric oxygen therapy (HBOT) may be performed adjunctively, but unequivocal evidence for its benefits is still lacking.

METHODS

We performed a retrospective single-center study including 192 patients with necrotizing fasciitis or Fournier's gangrene to assess in-hospital mortality and outcome dependent on patient, disease and treatment characteristics with or without HBOT.

RESULTS

The in-hospital mortality rate was 27.6%. Factors associated with increased mortality according to multivariate analysis were higher age, affection of multiple or problem localizations (odds ratio (OR) = 2.88, P = 0.003), ineligibility for HBOT despite clinical indication (OR = 8.59, P = 0.005), pathogens in blood cultures (OR = 3.36, P = 0.002), complications (OR = 10.35, P < 0.001) and sepsis/organ dysfunction (OR = 19.58, P < 0.001). Factors associated with better survival included vacuum-assisted wound closure (OR = 0.17, P < 0.001), larger number of debridements (OR = 0.83, P < 0.001) and defect closure with mesh graft (OR = 0.06, P < 0.001) or flap (OR = 0.09, P = 0.024). When participants were stratified into subgroups without requirement of HBOT (n = 98), treated with HBOT (n = 83) and ineligible for HBOT due to contraindications (n = 11), the first two groups had similar survival rates (75.5% vs. 73.5%) and comparable outcome, although patients with HBOT suffered from more severe NSTI, reflected by more frequent affection of multiple localizations (P < 0.001), sepsis at admission (P < 0.001) and intensive care treatment (P < 0.001), more debridements (P < 0.001) and a larger number of antibiotics (P = 0.001). In the subgroup ineligible for HBOT, survival was significantly worse (36.4%, P = 0.022).

CONCLUSION

These results point to a benefit from HBOT for treatment of NSTI in critically ill patients.

The importance of intravenous immunoglobulin treatment in critically ill patients with necrotizing soft tissue infection: a retrospective cohort study

Background

Necrotizing soft-tissue infections are infections with high mortality. The use of immunoglobulins within a combination therapy including broad-spectrum antibiotics has been debated. We assessed potential benefits of immunoglobulins and hypothesized that they were associated with a treatment benefit in a high-resource setting.

Methods

Patients with necrotizing soft-tissue infection hospitalized in the tertiary intensive care unit of the University Hospital of Zurich, Switzerland, between 2008 and 2020 were included retrospectively. The association between immunoglobulin administration and in-hospital survival, intensive care unit length of stay, the incidences of acute renal failure, acute respiratory distress syndrome and septic shock were analyzed.

Results

After adjustment for confounders, no difference for in-hospital survival (hazard ratio 2.20, 95% confidence interval [CI] 0.24–20.20, p = 0.5), intensive care unit length of stay (subhazard ratio [SHR] 0.90, CI 0.41–1.98, p = 0.8) and the development of acute respiratory distress syndrome (SHR 1.2, CI 0.36–4.03, p = 0.77) was observed in patients with or without immunoglobulin treatment. The Simplified Acute Physiology Score II, the risk of developing acute renal failure (SHR 2.86, CI 1.33–6.15, p = 0.01) and septic shock (SHR 1.86, CI 1.02–3.40, p = 0.04) was higher in patients treated with immunoglobulins, possibly reflecting a higher disease severity beyond measured confounders.

Conclusions

No clear evidence for a benefit of immunoglobulins in our cohort with consistent antibiotic use was found. Patients receiving immunoglobulins appeared more severely ill. Complementary to high treatment standards and appropriate antibiotics including beta lactams and protein synthesis inhibitors, immunoglobulins should be administered on a case-to-case basis, at least while more evidence from larger randomized controlled trials is missing.

The impact of operative time on the outcomes of necrotizing soft tissue infections: a multicenter cohort study

Background

The primary aim of this study was to identify if there is an association between the operative time of the initial debridement for necrotizing soft tissue infections (NSTIs) and the mortality corrected for disease severity.

Methods

A retrospective multicenter study was conducted of all patients with NSTIs undergoing surgical debridement. The primary outcome was the 30-day mortality. The secondary outcomes were days until death, length of intensive care unit (ICU) stay, length of hospital stay, number of surgeries within first 30 days, amputations and days until definitive wound closure.

Results

A total of 160 patients underwent surgery for NSTIs and were eligible for inclusion. Twenty-two patients (14%) died within 30 days and 21 patients (13%) underwent an amputation. The median operative time of the initial debridement was 59 min (IQR 35–90). In a multivariable analyses, corrected for sepsis just prior to the initial surgery, estimated total body surface (TBSA) area affected and the American Society for Anesthesiologists (ASA) classification, a prolonged operative time (per 20 min) was associated with a prolonged ICU (β 1.43, 95% CI 0.46–2.40; p = 0.004) and hospital stay (β 3.25, 95% CI 0.23–6.27; p = 0.035), but not with 30-day mortality. Operative times were significantly prolonged in case of NSTIs of the trunk (p = 0.044), in case of greater estimated TBSA affected (p = 0.006) or if frozen sections and/or Gram stains were assessed intra-operatively (p < 0.001).

Conclusions

Prolonged initial surgery did not result in a higher mortality rate, possible because of a short duration of surgery in most studied patients. However, a prolonged operative time was associated with a prolonged ICU and hospital stay, regardless of the estimated TBSA affected, presence of sepsis prior to surgery and the ASA classification. As such, keeping operative times as limited as possible might be beneficial for NSTI patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01456-0.

Necrotizing Soft Tissue Infections of the Hand and Wrist

Necrotizing soft tissue infections of the upper extremity threaten life and limb. Their presentation is often difficult to recognize and multiple factors contribute to the varied presentation, speed of spread, and morbidity of the disease process. The only treatment to be definitively shown to improve outcomes is prompt surgical treatment. It should be expected to perform multiple debridements as well as reconstructive procedures once the infection and necrosis has been arrested. The use of a multidisciplinary team is mandatory to optimize care for these patients. Despite advances in knowledge and treatment, these infections still have high mortality and morbidity.

Necrotizing Soft Tissue Infections: Case Reports from the Patients Prospective

All who have contributed in writing this chapter have been patients and parents that have experienced an horrific life event. The horrific disease named necrotising fasciitis has affected our lives for ever. All four stories have explained how easily an everyday infection can develop incredibly quickly into a life-threatening experience. Three stories are expressed from the worn hearts of being a mother, fighting for their child every step of the way. Knowing our children and how they react through pain and illness is felt in each word, sentence, paragraph and even between the lines. Dedicating our unmarkable love and devotion for the child we carried for 9 months. To see them suffer in illness is heart wrenching, but to experience this disease necrotising fasciitis is something else. We must live through every day watching them grow with their scars of debridement, and to support them through further operations, let alone mental scars. Parents show a strength of support like no other and we hope that their lives can be enhanced through the battle they have individually won let alone their family. Robert's story from a patient's perspective is quite different and you will read his courage throughout. We continue to raise awareness through education.

The INFECT-Project: An International and Multidisciplinary Project on Necrotizing Soft Tissue Infections

This book describes clinical and microbiologic aspects, pathogenesis, and diagnostics, related to the severe and rapidly spreading necrotizing soft tissue infections. The work has its foundation in a recently completed European Union funded FP7-project called INFECT, which during the period 2013-2018 focused on utilizing a systems medicine approach to increase our understanding of these heterogenous and complex life-threatening infections. In this chapter, the aim and scope as well as key achievements of the INFECT-project are described.

Pathogenic Mechanisms of Streptococcal Necrotizing Soft Tissue Infections

Necrotizing skin and soft tissue infections (NSTIs) are severe life-threatening and rapidly progressing infections. Beta-hemolytic streptococci, particularly S. pyogenes (group A streptococci (GAS)) but also S. dysgalactiae subsp. equisimilis (SDSE, most group G and C streptococcus), are the main causative agents of monomicrobial NSTIs and certain types, such as emm1 and emm3, are over-represented in NSTI cases. An arsenal of bacterial virulence factors contribute to disease pathogenesis, which is a complex and multifactorial process. In this chapter, we summarize data that have provided mechanistic and immuno-pathologic insight into host-pathogens interactions that contribute to tissue pathology in streptococcal NSTIs. The role of streptococcal surface associated and secreted factors contributing to the hyper-inflammatory state and immune evasion, bacterial load in the tissue and persistence strategies, including intracellular survival and biofilm formation, as well as strategies to mimic NSTIs in vitro are discussed.

Pediatric necrotizing soft tissue infection after elective surgery: A case report and literature review

INTRODUCTION

Necrotizing soft tissue infections (NSTIs) are rare but often lethal. Early diagnosis and aggressive surgical debridement are essential to achieve the best possible outcome.

CASE PRESENTATION

A 12-year old boy was diagnosed with a necrotizing soft tissue infection following elective revision surgery for functional impairment resulting from scar tissue of the neck. Fever and inflammation of the surgical wound manifested 24-36 hours postoperatively. Antibiotic therapy with amoxicillin-clavulanic acid was initiated, but the patient was unresponsive. Ultrasonography, a wound culture and surgical exploration confirmed the diagnosis. The culture was positive for a Streptococcus pyogenes infection and antibiotic treatment was switched to penicillin and clindamycin. Following the diagnosis, surgical debridement was performed subcutaneously, and only necrotic tissue was removed to preserve as much skin tissue as possible. After eradication of the infection, vacuum-assisted closure of the wound was used to close the subcutaneous space. The patient was discharged after 40 days.

CONCLUSION

In this patient, we treated a necrotizing soft tissue infection with antibiotics, skin sparing surgeries and negative pressure wound therapy (NPWT). We used ultrasonography as imaging technique to help with the diagnosis. The extensiveness of surgical debridement was rather limited. We focused on opening all affected fascial layers. The surgical debridement was subcutaneous, and only necrotic tissue was removed. Because of the location in the neck, we tried to avoid an aggressive skin debridement to preserve as much skin tissue as possible. Negative pressure wound therapy is not frequently used in this context but it contributed to an enhanced wound healing. Ultrasonography for diagnosing NSTIs is useful, but the clinical findings and an explorative surgery will remain most important.

Antifungal Therapy in Fungal Necrotizing Soft Tissue Infections

BACKGROUND

Necrotizing soft tissue infections (NSTIs) are life-threatening surgical emergencies associated with high morbidity and mortality. Fungal NSTIs are considered rare and have been largely understudied. The purpose of this study was to study the impact of fungal NSTIs and antifungal therapy on mortality after NSTIs.

METHODS

A retrospective chart review was performed on patients with NSTIs from 2012 to 2018. Patient baseline characteristics, microbiologic data, antimicrobial therapy, and clinical outcomes were collected. Patients were excluded if they had comfort care before excision. The primary outcome measured was in-hospital mortality.

RESULTS

A total of 215 patients met study criteria with a fungal species identified in 29 patients (13.5%). The most prevalent fungal organism was Candida tropicalis (n = 11). Fungal NSTIs were more prevalent in patients taking immunosuppressive medications (17.2% versus 3.2%, P = 0.01). A fungal NSTI was significantly associated with in-hospital mortality (odds ratio, 3.13; 95% confidence interval, 1.16-8.40; P = 0.02). Furthermore, fungal NSTI patients had longer lengths of stay (32 d [interquartile range, 16-53] versus 19 d [interquartile range, 11-31], P < 0.01), more likely to require initiation of renal replacement therapy (24.1% versus 8.6%, P = 0.02), and more likely to require mechanical ventilation (64.5% versus 42.0%, P = 0.02). Initiation of antifungals was associated with a significantly lower rate of in-hospital mortality (6.7% versus 57.1%, P = 0.01).

CONCLUSIONS

Fungal NSTIs are more common in patients taking immunosuppressive medications and are significantly associated with in-hospital mortality. Antifungal therapy is associated with decreased in-hospital mortality in those with fungal NSTIs. Consideration should be given to adding antifungals in empiric treatment regimens, especially in those taking immunosuppressive medications.

Treatment of Necrotizing Soft Tissue Infections: Antibiotics

Necrotizing soft tissue infections (NSTIs) are severe, life-threatening infections, and early therapeutic intervention is essential. Prompt administration of potent antimicrobial agents is pivotal, but inadequate empirical therapy is unfortunately common. Optimization of the antibiotic treatment strategy in NSTIs requires consideration of local epidemiology of causative pathogens and antimicrobial resistance patterns, knowledge on common pathogenetic mechanisms in NSTIs, and adaptations to pharmacokinetic and pharmacodynamic physiological changes in critically ill patients. In the present article we address all these issues, as well as review and compare contemporary guidelines for antimicrobial treatment of NSTIs from around the world.

Clinical parameters and outcomes of necrotizing soft tissue infections secondary to gastrointestinal fistulas

Background

Necrotizing soft tissue infections (NSTIs) is severe surgical infections which can occur following trauma or abdominal surgery. NSTIs secondary to gastrointestinal (GI) fistula is a rare but severe complication.

Methods

A retrospective cohort study was performed on all subjects presenting with GI fistulas associated NSTIs were included. Clinical characteristics, microbiological profile, operations performed, and outcomes of patients were analyzed.

Results

Between 2014 and 2017, 39 patients were finally enrolled. The mean age were 46.9 years and male were the dominant. For the etiology of fistula, 25 (64.1%) of the patients was due to trauma. Overall, in-hospital death occurred in 15 (38.5%) patients. Microbiologic findings were obtained from 31 patients and Klebsiella pneumoniae was the most common species (41.0%). Eight patients were treated with an open abdomen; negative pressure wound therapy was used in 33 patients and only 2 patients received hyperbaric oxygen therapy. Younger age and delayed abdominal wall reconstruction repair were more common in trauma than in non-trauma. Non-survivors had higher APACHE II score, less source control< 48 h and lower platelet count on admission than survivors. Multiple organ dysfunction syndrome, multidrug-resistant organisms and source control failure were the main cause of in-hospital mortality.

Conclusions

Trauma is the main cause of GI fistulas associated NSTIs. Sepsis continues to be the most important factor related to mortality. Our data may assist providing enlightenment for quality improvement in these special populations.

Effect of non-steroidal anti-inflammatory drugs on post-surgical complications against the backdrop of the opioid crisis

The USA is currently going through an opioid crisis, associated with tremendous economic and societal impacts. In response to this crisis, healthcare professionals are looking for alternative pain management methods, and non-steroidal anti-inflammatory drugs (NSAIDs) are a sensible choice because of their effectiveness after surgical procedures. However, before surgeons start prescribing NSAIDs in place of opioids, it is crucial to first understand their potential post-surgical complications. The goal of this review is to summarize the data obtained through both animal and human studies, which suggest how a dramatic increase in NSAID use may affect these post-surgical complications. We first provide a short review outlining the mechanisms of action of NSAIDs, followed by a summary of animal studies, which show a trend towards the negative effects of NSAIDs on wound healing and an association between NSAID use and wound infections. Lastly, we present evidence from human studies on the association of NSAIDs with the following complications: anastomotic leaks, necrotizing soft tissue infections, bleeding complications, orthopedic injuries, wound healing, and cancer care. The human studies are much more variable in their conclusions as to whether NSAIDs are beneficial or not, with the only strong evidence showing that NSAIDs inhibit bone healing. This may partially be explained by male and female differences in response to NSAIDs as many animal studies showing the inhibitory effects of NSAIDs were performed on females, while all the human studies were performed with both sexes. We conclude that strong caution should be used in the prescription of NSAIDs, especially in female patients, but larger scale studies are warranted before solid recommendations can be made.

Septic shock due to NSTI caused by Actinomyces Turicensis: the role of clinical pharmacology. Case report and review of the literature

Critical septic patients affected by necrotizing soft tissue infections (NSTI) require an early, aggressive and multidisciplinary treatment. Pharmacokinetic alterations in antibiotic therapy are peculiar in these infections. Clinical pharmacology represents a first step in this setting. We report a case of septic shock due to NSTI in which clinical pharmacology is taken into account.

Comparing culture and molecular methods for the identification of microorganisms involved in necrotizing soft tissue infections

Background

Necrotizing soft tissue infections (NSTIs) are a group of infections affecting all soft tissues. NSTI involves necrosis of the afflicted tissue and is potentially life threatening due to major and rapid destruction of tissue, which often leads to septic shock and organ failure. The gold standard for identification of pathogens is culture; however molecular methods for identification of microorganisms may provide a more rapid result and may be able to identify additional microorganisms that are not detected by culture.

Methods

In this study, tissue samples (n = 20) obtained after debridement of 10 patients with NSTI were analyzed by standard culture, fluorescence in situ hybridization (FISH) and multiple molecular methods. The molecular methods included analysis of microbial diversity by 1) direct 16S and D2LSU rRNA gene Microseq 2) construction of near full-length 16S rRNA gene clone libraries with subsequent Sanger sequencing for most samples, 3) the Ibis T5000 biosensor and 4) 454-based pyrosequencing. Furthermore, quantitative PCR (qPCR) was used to verify and determine the relative abundance of Streptococcus pyogenes in samples.

Results

For 70 % of the surgical samples it was possible to identify microorganisms by culture. Some samples did not result in growth (presumably due to administration of antimicrobial therapy prior to sampling). The molecular methods identified microorganisms in 90 % of the samples, and frequently detected additional microorganisms when compared to culture. Although the molecular methods generally gave concordant results, our results indicate that Microseq may misidentify or overlook microorganisms that can be detected by other molecular methods.

Half of the patients were found to be infected with S. pyogenes, but several atypical findings were also made including infection by a) Acinetobacter baumannii, b) Streptococcus pneumoniae, and c) fungi, mycoplasma and Fusobacterium necrophorum.

Conclusion

The study emphasizes that many pathogens can be involved in NSTIs, and that no specific “NSTI causing” combination of species exists. This means that clinicians should be prepared to diagnose and treat any combination of microbial pathogens. Some of the tested molecular methods offer a faster turnaround time combined with a high specificity, which makes supplemental use of such methods attractive for identification of microorganisms, especially for fulminant life-threatening infections such as NSTI.

Rectal cancer and Fournier’s gangrene - current knowledge and therapeutic options

Fournier’s gangrene (FG) is a rapid progressive bacterial infection that involves the subcutaneous fascia and part of the deep fascia but spares the muscle in the scrotal, perianal and perineal region. The incidence has increased dramatically, while the reported incidence of rectal cancer-induced FG is unknown but is extremely low. Pathophysiology and clinical presentation of rectal cancer-induced FG per se does not differ from the other causes. Only rectal cancer-specific symptoms before presentation can lead to the diagnosis. The diagnosis of rectal cancer-induced FG should be excluded in every patient with blood on digital rectal examination, when urogenital and dermatological causes are excluded and when fever or sepsis of unknown origin is present with perianal symptomatology. Therapeutic options are more complex than for other forms of FG. First, the causative rectal tumor should be removed. The survival of patients with rectal cancer resection is reported as 100%, while with colostomy it is 80%. The preferred method of rectal resection has not been defined. Second, oncological treatment should be administered but the timing should be adjusted to the resolution of the FG and sometimes for the healing of plastic reconstructive procedures that are commonly needed for the reconstruction of large perineal, scrotal and lower abdominal wall defects.

Necrotizing soft tissue infections

Necrotizing soft tissue infections (NSTIs) are infrequent yet highly lethal infections, and a high index of suspicion is required for early diagnosis. Diagnosing NSTIs early can be challenging, and knowledge of the available tools is essential to provide appropriate treatment. The mainstay of treatment is early and complete surgical debridement combined with antimicrobial therapy, close monitoring with further debridement as needed, and physiologic support. Mortality continues to be high, and delayed surgical treatment is the most important risk factor. For the long-term recovery of patients with NSTI, providing early physiologic and nutritional support and physical rehabilitation is essential.

Aggressiveness - The key to a Successful Outcome in Necrotizing Soft Tissue Infection

16 patients with necrotizing soft tissue infections were managed during last three years in various service hospitals. The experience indicates that there is considerable overlap in clinical findings and bacteriology. The infections seem to be variations of the same disease process, a spreading necrotizing infection. The number of these patients suggests that there is an increasing incidence of this entity. Staphylococcus and coliforms were the commonest organisms cultured in most of these patients. Because of the high mortality rate upto 50% as reported, we advocate aggressive and early treatment of this condition. Urgent radical exploration, excision of all necrotic tissue and adequate drainage of the deep fascial planes was done in all patients until healthy tissue planes were reached. A strong index of suspicion aids early diagnosis which ensures a favourable outcome. Our study indicates that the lower gastrointestinal tract should be considered as a possible cause of infection in all patients with synergistic gangrene. The involvement of the perineum and scrotum was most common. All these patients were treated with a common approach of resuscitation, broad spectrum antibiotics, immediate surgical excision of all necrotic tissue, aggressive nutritional therapy and early skin coverage with 20% mortality. The infection was primary in 8, postsurgical in 4 and following trauma in 4 cases. In majority of patients, Staphylococcus with beta haemolytic streptococci and E coli were the organisms isolated initially. Mortality was highest in intensive infections extending the abdomen and chest. Aggressive, effective and early treatment of necrotizing soft tissue infections is imperative to prevent a fatal outcome. Urgent radical exploration by the most experienced surgeon available is essential and includes wide excision of all necrotic tissue and adequate drainage of the deep fascial planes until indubitably healthy tissue is experienced. The surgeon must be prepared to proceed to a laparotomy, diverting colostomy or a suprapubic cystotomy where there exists any element of doubt. Aggression is also of significance in resuscitation, early institution of empirical broad spectrum antibiotic therapy, elaborate repeated daily dressings with hydrogen peroxide and to allow further debridement till the process is controlled.