Severe group A streptococcal infections associated with a toxic shock-like syndrome and scarlet fever toxin A

First Case of Necrotizing Fasciitis and Septicemia Caused by Pigmentibacter ruber

We report the first case of necrotizing fasciitis caused by Pigmentibacter ruber. The isolated strain could not be identified by biochemical characterization or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry but was identified as P. ruber by 16S ribosomal RNA and whole-genome sequencing. Although much remains unknown about the pathogenicity of this bacterial species in humans, it has been shown to cause life-threatening infections such as septicemia and necrotizing fasciitis. Because the isolate was highly resistant to β-lactams, it was difficult to treat with antimicrobial therapy. Thus, further documentation of cases and analyses are required.

Emerging infection: streptococcal toxic shock-like syndrome caused by group B Streptococcus (GBS), Streptococcus agalactiae

Streptococcus agalactiae or Group B Streptococcus (GBS) infections are commonly associated with infections in neonates and pregnant women. However, there has been a rising incidence in nonpregnant adults. The risk of GBS infection in nonpregnant adults is increased for patients of advanced age and those with underlying medical conditions such as diabetes mellitus and cancer. We present a 77-year-old female with type-2 diabetes mellitus, hypertension, and bilateral foot ulcers that presented in probable septic shock with necrotic foot ulcers and necrotizing fasciitis and underwent bilateral lower limb amputations. The patient fulfilled the Streptococcal Toxic Shock Syndrome (STSS) criteria as defined by The Working Group on Severe Streptococcal Infections. These criteria were created for group A Streptococcus (Streptococcus pyogenes). Our patient fulfilled the Working Group's criteria, except that the blood culture was positive for group B Streptococcus (Streptococcus agalactiae). Numerous studies demonstrate the importance of early detection and antibiotic treatment for GBS infections in general and early surgical management for necrotizing soft tissue infections (NSTIs) such as necrotizing fasciitis.

Invasive group A streptococcal infection can be fatal to pregnant women in restricted medical resources remote areas-Emergent alert after COVID-19 pandemic

Invasive group A streptococcal (iGAS) infection is a leading cause of maternal death. The increase in the number of patients with iGAS in Japan is markedly greater than before the coronavirus pandemic. We encountered a case of iGAS infection, on a remote island with restricted medical resources, in a third-trimester pregnant woman, resulting in both maternal and fetal death. A 34-year-old woman was admitted via a local general hospital with a high fever. Intrauterine fetal death disseminated intravascular coagulation, and septic shock were confirmed. Broad-spectrum antibiotics were started, and the patient was returned to the local general hospital. Eight hours after arrival, the patient died of circulatory and respiratory dysfunction complications. iGAS infections in remote areas may directly lead to life-threatening conditions and should be treated as an emergency, comparable to the serious conditions of placental abruption or placenta previa.

Toxic Shock Syndrome (TSS) Caused by Group A Streptococcus: Novel Insights Within the Context of a Familiar Clinical Syndrome

The emergence of invasive infections attributed to group A Streptococcus (GAS) infections, has resurged since the 1980s. The recent surge in reports of toxic shock syndrome due to GAS in Japan in 2024, while sensationalized in the media, does not represent a novel infectious disease per se, as its diagnosis, treatment, and prevention are already well-established. However, due to signs of increasing incidence since 2011, further research is needed. Health authorities in neighboring countries like The Republic of Korea should not only issue travel advisories but also establish meticulous surveillance systems and initiate epidemiological studies on the genotypic variations of this disease while awaiting various epidemiological research findings from Japan.

A Cross-Sectional Analysis of Pediatric Necrotizing Soft Tissue Infection Cases and Racial Disparities From the 2016 to 2020 National Inpatient Sample

INTRODUCTION

The incidence, treatment, and outcomes of necrotizing soft tissue infections (NSTIs) and associated racial disparities have been described in adults, but research in the pediatric population is limited. The purpose of this study is to provide a nationally representative characterization of pediatric NSTI and determine the presence of any racial disparities.

METHODS

The National Inpatient Sample was analyzed from 2016 through 2020. Patients aged less than 20 y with a diagnosis of necrotizing fasciitis, Fournier's gangrene, or gas gangrene (based on International Classification of Diseases, Tenth Revision, Clinical Modification codes) were included for analysis.

RESULTS

A total of 355 patients were identified. Black and Hispanic patients accounted for the most admissions in 2016 and 2018, respectively (P = 0.024). Compared to White patients, more Black patients were insured by Medicaid (P = 0.037) and were in the first zip code-based income quartile (P = 0.005). The leading infection overall was necrotizing fasciitis and most patients (81.7%) underwent a surgical procedure by the first calendar day after admission. Although the proportion of Black patients undergoing subcutaneous tissue and fascia excisions was more than that of White patients (P = 0.005), there were no significant differences by race in the time to first procedure, the total number of procedures, or number of postoperative complications. Our amputation and mortality rates were low and unreportable, but there were no differences by race.

CONCLUSIONS

NSTI is rare in the pediatric population and mortality is low. Black patients are disproportionately diagnosed, but these disparities do not extend to disease treatment or outcomes.

Necrotizing fasciitis: an update on epidemiology, diagnostic methods, and treatment

PURPOSE OF REVIEW

The aim of this review is to discuss the latest evidence of epidemiology, diagnostic methods, and treatment of necrotizing soft tissue infections (NSTIs) with a particular focus on necrotizing fasciitis (NF).

RECENT FINDINGS

NSTIs have been historically referred to as NF but encompass a broader range of infections, with variable rates ranging from 0.86 to 32.64 per 100 000 person-years, influenced by factors such as climate and seasonal variations. They have diverse microbiological profiles categorized into different types based on the involved pathogens, including polymicrobial or monomicrobial infections caused by organisms such as group A streptococcus (GAS), Staphylococcus aureus , some Gram-negative pathogens, and filamentous fungi following trauma and natural disasters. Diagnosis relies on clinical symptoms and signs, laboratory markers, and imaging. However, the gold standard for diagnosis remains intraoperative tissue culture. Treatment involves repeated surgical debridement of necrotic tissues in addition to intravenous antibiotics. Adjuvant therapies with intravenous immunoglobulin (IVIG) and hyperbaric oxygen therapy (HBOT) might have a role. Soft tissue reconstruction may be necessary following surgery.

SUMMARY

Prompt diagnosis and proper medical and surgical management of NSTI will improve outcomes.

Catastrophic Streptococcus pyogenes Disease: A Personalized Approach Based on Phenotypes and Treatable Traits

Streptococcal toxic shock syndrome (STTS) is a critical medical emergency marked by high morbidity and mortality, necessitating swift awareness, targeted treatment, and early source control due to its rapid symptom manifestation. This report focuses on a cohort of 13 patients admitted to Vall d'Hebron University Hospital Intensive Care Unit, Barcelona, from November 2022 to March 2023, exhibiting invasive Streptococcus pyogenes infections and meeting institutional sepsis code activation criteria. The primary infections were community-acquired pneumonia (61.5%) and skin/soft tissue infection (30.8%). All patients received prompt antibiotic treatment, with clinical source control through thoracic drainage (30.8%) or surgical means (23.1%). Organ support involved invasive mechanical ventilation, vasopressors, and continuous renal replacement therapy as per guidelines. Of note, 76.9% of patients experienced septic cardiomyopathy, and 53.8% required extracorporeal membrane oxygenation (ECMO). The study identified three distinct phenotypic profiles-hyperinflammatory, low perfusion, and hypogammaglobulinemic-which could guide personalized therapeutic approaches. STTS, with a mean SOFA score of 17 (5.7) and a 53.8% requiring ECMO, underscores the need for precision medicine-based rescue therapies and sepsis phenotype identification. Integrating these strategies with prompt antibiotics and efficient source control offers a potential avenue to mitigate organ failure, enhancing patient survival and recovery in the face of this severe clinical condition.

Toxic Shock Syndrome: A Literature Review

Toxic shock syndrome (TSS) is a rare, life-threatening, toxin-mediated infectious process linked, in the vast majority of cases, to toxin-producing strains of Staphylococcus aureus or Streptococcus pyogenes. The pathophysiology, epidemiology, clinical presentation, microbiological features, management and outcome of TSS are described in this review. Bacterial superantigenic exotoxins induces unconventional polyclonal lymphocyte activation, which leads to rapid shock, multiple organ failure syndrome, and death. The main described superantigenic exotoxins are toxic shock syndrome toxin-1 (TSST-1) and enterotoxins for Staphylococcus aureus and Streptococcal pyrogenic exotoxins (SpE) A, B, and C and streptococcal superantigen A (SsA) for Streptococcus pyogenes. Staphylococcal TSS can be menstrual or nonmenstrual. Streptococcal TSS is linked to a severe group A streptococcal infection and, most frequently, to a necrotizing soft tissue infection. Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration. The interest of polyclonal intravenous immunoglobulin G administration as an adjunctive treatment for TSS requires further evaluation. Scientific literature on TSS mainly consists of observational studies, clinical cases, and in vitro data; although more data on TSS are required, additional studies will be difficult to conduct due to the low incidence of the disease.

Successful treatment of streptococcal toxic shock syndrome complicated by primary peritonitis and bilateral empyema in a healthy young woman: Identification of uncommon clone emm103 and novel sequence type 1363

Streptococcal toxic shock syndrome (STSS) has a dramatic clinical course and high mortality rate. Here, we report a case of STSS complicated by primary peritonitis and bilateral empyema. A previously healthy young woman was diagnosed with STSS complicated by primary peritonitis and bilateral empyema. Blood culture results on admission were negative. Sever shock, respiratory failure, systemic inflammation, thrombocytopenia, renal failure, ascites, and pleural effusion occurred, mimicking thrombocytopenia, anasarca, fever, reticulin fibrosis/renal failure and organomegaly (TAFRO) syndrome. Retesting blood cultures identified Streptococcus pyogenes. Gram staining of ascites and pleural fluid indicated gram-positive cocci in chains. Antibiotics, immunoglobulins, and surgical intervention led to recovery without complications. Ex-post genotypic analyses showed uncommon emm103.0 (cluster E3) of emm long sequence (784 base) and novel sequence type 1363. STSS diagnosis can be difficult as it mimics other systemic inflammatory diseases. Therefore, it is crucial for clinicians to perform microbiological examinations from infection foci, even if the initial culture is negative.

Practical Review of Necrotizing Fasciitis: Principles and Evidence-based Management

Necrotizing fasciitis is a severe, life-threatening soft tissue infection that presents as a surgical emergency. It is characterized by a rapid progression of inflammation leading to extensive tissue necrosis and destruction. Nonetheless, the diagnosis might be missed or delayed due to variable and nonspecific clinical presentation, contributing to high mortality rates. Therefore, early diagnosis and prompt, aggressive medical and surgical treatment are paramount. In this review, we highlight the defining characteristics, pathophysiology, diagnostic modalities, current principles of treatment, and evolving management strategies of necrotizing fasciitis.

Analysis of FctB3 crystal structure and insight into its structural stabilization and pilin linkage mechanisms

Streptococcus pyogenes harboring an FCT type 3 genomic region display pili composed of three types of pilins. In this study, the structure of the base pilin FctB from a serotype M3 strain (FctB3) was determined at 2.8 Å resolution. In accordance with the previously reported structure of FctB from a serotype T9 strain (FctB9), FctB3 was found to consist of an immunoglobulin-like domain and proline-rich tail region. Data obtained from structure comparison revealed main differences in the omega (Ω) loop structure and the proline-rich tail direction. In the Ω loop structure, a differential hydrogen bond network was observed, while the lysine residue responsible for linkage to growing pili was located at the same position in both structures, which indicated that switching of the hydrogen bond network in the Ω loop without changing the lysine position is advantageous for linkage to the backbone pilin FctA. The difference in direction of the proline-rich tail is potentially caused by a single residue located at the root of the proline-rich tail. Also, the FctB3 structure was found to be stabilized by intramolecular large hydrophobic interactions instead of an isopeptide bond. Comparisons of the FctB3 and FctA structures indicated that the FctA structure is more favorable for linkage to FctA. In addition, the heterodimer formation of FctB with Cpa or FctA was shown to be mediated by the putative chaperone SipA. Together, these findings provide an alternative FctB structure as well as insight into the interactions between pilin proteins.

Group A Streptococcus Infection in Neonatal Population: A Systematic Review of The Literature

(1) Background: The importance of group A streptococcus (GAS) infection severity has been recognized in children and adults. However, to our knowledge, there have been no systematic reviews or pooled assessments of the incidence and outcome of invasive GAS (iGAS) disease in neonates, a potentially high-risk population. Therefore, we performed a systematic review of available data regarding the risk factors, clinical presentation, and outcome of GAS infection in neonates. (2) Methods: An electronic search of the existing literature was carried out during the period July 2023-September 2023 in the PubMed and Scopus databases, considering studies referring to GAS infection in the neonatal population. (3) Results: Overall, 39 studies met all the inclusion criteria and were included in this review, evaluating data from 194 neonates. Unfortunately, there were a lot of missing data among the retrieved studies. Our systematic review highlighted the presence of differences with regards to clinical presentation, infection sites, and outcome of GAS invasive disease between neonates with early-onset (EOS) or late-onset sepsis (LOS). Common characteristics of EOS included respiratory distress, rapid deterioration, and high mortality rate irrespective of the infection site, while rash, gastrointestinal tract symptoms, and fever appeared to be the most frequent symptoms/clinical signs and manifestations of LOS disease. The management of severe invasive iGAS disease consists mainly of specific antimicrobial treatment as well as supportive care with fluids and electrolyte supplementation, minimizing or counteracting the effects of toxins. Furthermore, a mortality rate of approximately 14% was recorded for iGAS disease in the total of all studies' neonates. (4) Conclusions: Although iGAS is a rare entity of neonatal infections, the potential severity of the disease and the rapid deterioration requires the development of quick analysis methods for the detection of GAS allowing the prompt diagnosis and administration of the indicated antibiotic treatment. Furthermore, given the exceptional risk for both the pregnant woman and the neonate, it is very important to raise awareness and create easily accessible guidelines that could facilitate the prevention and management of maternal as well as the subsequent neonatal severe iGAS disease.

Streptococcal Bacteremia and Toxic Shock Syndrome: A Rare Etiology Requiring Prompt Diagnosis

Bullous impetigo leading to streptococcal toxic shock syndrome (STSS) immune activation and massive cytokine release is a rare condition. It has a significant mortality rate, which calls for quick diagnosis, early suspicion, and integrated treatment. Herein, we discuss the case of a 66-year-old man who underwent evaluation for leg swelling before quickly going into shock and experiencing respiratory failure, which necessitated invasive mechanical intubation. Streptococcus pyogenes was identified by blood culture, and STSS was identified. Recommended antibiotics, intravenous (IV) immunoglobulin, and fluids made up the treatment regimen. In this case, the streptococcal infection deteriorated very quickly, and there was a rare relationship with bullous impetigo, which led to shock and respiratory failure. This case sheds lights on the need of having an early suspicion of this syndrome when a diabetic patient develops a skin lesion. A prompt diagnosis is necessary.

Factors associated with mortality in patients with extremity necrotizing soft-tissue infections: a single academic center experience

PURPOSE

Necrotizing soft-tissue infection (NSTI) is a surgical emergency associated with high mortality. This study primarily aimed to identify the factors associated with in-hospital mortality due to NSTI in the extremities at a single institution. Secondarily, we aimed to clarify the effectiveness of the optimal combination of hyperbaric oxygen therapy (HBOT) and surgery for NSTI treatment.

STUDY DESIGN

Retrospective observational study.

METHODS

This study included all patients newly diagnosed with NSTI in the extremity from 2003 to 2021 in our hospital. Factors associated with mortality, including patient's characteristics, duration from onset to hospitalization, NSTI type, and clinical data at the initial visit; acute disseminated intravascular coagulation (DIC), laboratory risk indicator for necrotizing fasciitis score, and sequential organ failure assessment score; treatment, initial surgery, surgery times, amputation, HBOT, combined surgery with HBOT, and clinical outcomes; amputation rate, mortality rate, and hospitalization duration were examined.

RESULTS

A total of 37 cases were treated for NSTIs. The median age was 64 years (range: 22-86). Five cases (13.5%) died during hospitalization. Ten patients were diagnosed with DIC at the initial visit, of whom four died. HBOT combined with surgery was performed in 23 cases, and 16 cases underwent multiple surgeries. Factors associated with mortality included DIC (p = 0.015, 95% confidence interval [CI]: 0.015-0.633) and multiple surgeries combined with HBOT (p = 0.028, 95% CI: 1.302-95.418).

CONCLUSION

This study demonstrates that DIC at the initial visit is associated with mortality in extremity NSTI. Additionally, HBOT might improve prognosis when combined with multiple surgeries.

Agr Regulation of Streptococcal Pyrogenic Exotoxin A in Staphylococcus aureus

Group A streptococcal pyrogenic exotoxins (SPEs A, B, and C) are superantigens. SPE A shares high sequence similarity with Staphylococcus aureus enterotoxins (SEs) B and C. Since SPE A is bacteriophage-encoded, we hypothesized that its gene ( speA ) was acquired from S. aureus . speA , when cloned into S. aureus , was stably expressed, its protein resistant to proteases, and the gene under accessory gene regulator control. speA was acquired by streptococci from cross-species transduction. speB was not expressed in S. aureus. SPE C was degraded by staphylococcal proteases. The genes speB and speC were not recently acquired from S. aureus.

Antiphospholipid syndrome after streptococcal toxic shock syndrome later diagnosed as Behcet's disease

Streptococcal toxic shock syndrome is a severe complication of group A streptococci. The production of antiphospholipid antibodies has been associated with streptococcal infections and with autoimmune diseases. Furthermore, streptococcal infections could be a trigger of Behcet's disease. We report a case of a boy who presented antiphospholipid syndrome after streptococcal toxic shock syndrome later he was diagnosed with Behcet's disease.

Probable enterotoxin-associated toxic shock syndrome caused by Staphylococcus epidermidis

BACKGROUND

We describe a case of a toxic shock-like syndrome in a child, which was associated with Staphylococcus epidermidis instead of Staphylococcus aureus or Streptococcus pyogenes, the usual causes of toxic shock syndrome.

CASE PRESENTATION

The patient was an 8-year-old boy who developed a toxic shock syndrome-like illness, including fever, hypotension, and rash. The Staphylococcus epidermidis isolate was cultured from urine, but this organism was unavailable for toxin testing. Multiple blood cultures were negative. Instead, a highly novel assay was used on acute plasma from the patient which demonstrated the presence of the genes for superantigens, staphylococcal enterotoxins A, C, D, and E. Superantigens are the known causes of toxic shock syndrome.

CONCLUSIONS

Our study suggests strongly that Staphylococcus epidermidis was causing the TSS symptoms through the known Staphylococcus aureus superantigens. It is unknown how many other such patients exist; this should be explored. Of great importance is that PCR performed directly on blood plasma in the absence of microbial isolation could be used to demonstrate superantigen genes.

Diagnostic and prognostic value of the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) based on an 18 years' experience

BACKGROUND

Necrotising fasciitis (NF) represents a rare but often life-threatening condition. Early diagnosis and surgical treatment are of vital importance. The LRINEC score was developed to distinguish necrotising fasciitis from other soft tissue infections (STI) at initial evaluation using six laboratory values. In this retrospective study, we attempted to determine the diagnostic and prognostic value of the LRINEC score.

METHODS

A total of 125 patients, hospitalised in our clinic between 2003 and 2021 with a histologically confirmed diagnosis of necrotising fasciitis (NF group) and 319 patients with surgically treated soft tissue infections (STI group) were included in this study. Individual LRINEC scores were calculated and analysed retrospectively.

RESULTS

The sensitivity of the LRINEC score at the cut-off point of ≥ 6 was 59%, whereas the specificity was 82%. The positive and negative predictive values were 57% and 84%, respectively. The mean LRINEC score was significantly higher in the NF group than in the STI group (6.0 compared to 2.4, respectively). All clinical outcome parameters such as amputation and mortality rates (15% vs 1%) were found to be significantly higher in the NF group (p<0.001). Within the NF group, there was no statistically significant association between the LRINEC score and clinical outcomes except for the necessary number of operations.

CONCLUSION

In isolation, we found the LRINEC score not to be a reliable enough diagnostic tool for the differentiation between NF and other soft tissue infections, because of its low sensitivity. Although we cannot recommend it as a prognostic tool either, we do believe it can be a useful adjunct to the clinical suspicion of NF.

Necrotizing fasciitis and septic shock due to streptococcal toxic shock syndrome in an elderly patient: A case report

Streptococcal toxic shock syndrome (STSS) has a high mortality rate, and most patients die within a few days of onset. We report an elderly patient with STSS, necrotizing fasciitis and septic shock caused by group G streptococcus who was successfully treated with multidisciplinary therapy.

Hemodialysis Patient with Streptococcal Toxic Shock Syndrome and Penile Necrosis

A 72-year-old man on hemodialysis due to diabetic nephropathy presented with a fever and penile pain. Although his physical examination was unremarkable, his general condition deteriorated. Penile necrosis was observed by evening on the same day of presentation, and the patient died the next morning. Blood cultures revealed the presence of Group G Streptococcus, leading to a diagnosis of streptococcal toxic shock syndrome (STSS). Autopsy suggested penile necrosis due to septic shock. STSS in hemodialysis patients with vascular calcification, even in the absence of calciphylaxis, can lead to severe organ damage due to ischemia.

Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis

OBJECTIVES

To quantify the prognostic effects of demographic and modifiable factors in streptococcal toxic shock syndrome (STSS).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, EMBASE and CINAHL from inception to 19 September 2022, along with citations of included studies.

ELIGIBILITY CRITERIA

Pairs of reviewers independently screened potentially eligible studies of patients with Group A Streptococcus-induced STSS that quantified the association between at least one prognostic factor and outcome of interest.

DATA EXTRACTION AND SYNTHESIS

We performed random-effects meta-analysis after duplicate data extraction and risk of bias assessments. We rated the certainty of evidence using the Grading of Recommendations, Assessment, Development and Evaluation approach.

RESULTS

One randomised trial and 40 observational studies were eligible (n=1918 patients). We found a statistically significant association between clindamycin treatment and mortality (n=144; OR 0.14, 95% CI 0.06 to 0.37), but the certainty of evidence was low. Within clindamycin-treated STSS patients, we found a statistically significant association between intravenous Ig treatment and mortality (n=188; OR 0.34, 95% CI 0.15 to 0.75), but the certainty of evidence was also low. The odds of mortality may increase in patients ≥65 years when compared with patients 18-64 years (n=396; OR 2.37, 95% CI 1.47 to 3.84), but the certainty of evidence was low. We are uncertain whether non-steroidal anti-inflammatory drugs increase the odds of mortality (n=50; OR 4.14, 95% CI 1.13 to 15.14; very low certainty). Results failed to show a significant association between any other prognostic factor and outcome combination (very low to low certainty evidence) and no studies quantified the association between a prognostic factor and morbidity post-infection in STSS survivors.

CONCLUSIONS

Treatment with clindamycin and within clindamycin-treated patients, IVIG, was each significantly associated with mortality, but the certainty of evidence was low. Future research should focus on morbidity post-infection in STSS survivors.

PROSPERO REGISTRATION NUMBER

CRD42020166961.

Suggested organism entry portal of necrotizing fasciitis with complete DNA from fascia, blood, and pharyngeal ulcers: A case report

Introduction and importance

In approximately 50% of patients with necrotizing fasciitis, infection begins deep in the soft tissues. A history of trauma is often absent. The mechanism of spread has not been elucidated. We report a case of type II necrotizing fasciitis in which the streptococcal strain was identical to isolates from other locations in the same patient.

Case presentation

A 42-year-old man presented with left leg pain. Two days prior, he had a non-penetrating injury to the left thigh while playing futsal. Workup revealed swelling of the left gastrocnemius. He was admitted to orthopaedics. On the third hospital day, he was referred to our department for hypotension, impending respiratory failure, and decreased sensorium, and subsequently admitted to the ICU. A biopsy was done on the left gastrocnemius fascia. He was diagnosed with necrotizing fasciitis. On the seventh hospital day, left hip amputation and extensive debridement of the trunk were done. Patient improved and eventually recovered.

Clinical discussion

Group A streptococcus was isolated in from the fascia, blood, and pharyngeal ulcer. Pulsed field gel electrophoresis showed all isolates to be genetically identical. An oral route of infection was considered.

Conclusions

This is the first report in which etiologic agent of necrotizing fasciitis is genetically identical with isolates from other parts in the absence of trauma.

•

Point of entry for bacteria occurs after a non-penetrating injury is unknown.

•

The same strain from the fascia was isolated from blood, and a pharyngeal ulcer.

•

This is the first report of entry portal for necrotizing fasciitis via the mouth.

Household Transmission of Group A Streptococcus Necrotizing Fasciitis

A healthy 40-year-old woman was diagnosed with necrotizing fasciitis 2 days after her husband's death from the same infectious process. Prompt identification and immediate surgical intervention prevented a similar result in this patient. Additional investigation into both patients' medical records found the inciting organism to be group A streptococcus. Although the exact mechanism of inoculation is unknown, the spread of this infection within a household prompts the question of whether antibiotic prophylaxis should be given among close contacts in future cases of necrotizing fasciitis.

Streptococcus pyogenes NAD+-Glycohydrolase Reduces Skeletal Muscle βNAD+ Levels Independently of Streptolysin O

Necrotizing soft tissue infections caused by Streptococcus pyogenes (group A streptococcus [GAS]) are characterized by rapid and extensive necrosis of fascia and muscle. Molecular epidemiological studies have demonstrated a positive correlation between GAS isolates that cause invasive infections and the production of S. pyogenes NAD+-glycohydrolase (SPN), an NADase secreted by GAS, but the effect of SPN on muscle cells has not been described. Thus, using standard βNAD+ and ATP quantification assays, we investigated the effects of SPN on cultured human skeletal muscle cell (SkMC) βNAD+ and ATP with and without streptolysin O (SLO)–a secreted cholesterol-dependent cytolysin known to act synergistically with SPN. We found that culture supernatants from GAS strains producing SLO and SPN depleted intracellular βNAD+ and ATP, while exotoxins from a GAS strain producing SLO and an enzymatically-inactive form of SPN had no effect on βNAD+ or ATP. Addition of purified, enzymatically-active SPN to NADase-negative culture supernatants or sterile media reconstituted βNAD+ depletion but had no effect ATP levels. Further, SPN-mediated βNAD+ depletion could be augmented by SLO or the homologous cholesterol-dependent cytolysin, perfringolysin O (PFO). Remarkably, SPN-mediated βNAD+ depletion was SkMC-specific, as purified SPN had minimal effect on epithelial cell βNAD+. Taken together, this study identifies a previously unrecognized role for SPN as a major disruptor of skeletal muscle βNAD+. Such activity could contribute to the rapid and widespread myonecrosis characteristic of severe GAS soft tissue infections.

Comparing Genomic Characteristics of Streptococcus pyogenes Associated with Invasiveness over a 20-year Period in Korea

Background

Few studies have investigated the invasiveness of Streptococcus pyogenes based on whole-genome sequencing (WGS). Using WGS, we determined the genomic features associated with invasiveness of S. pyogenes strains in Korea.

Methods

Forty-five S. pyogenes strains from 1997, 2006, and 2017, including common emm types, were selected from the repository at Gyeongsang National University Hospital in Korea. In addition, 48 S. pyogenes strains were randomly selected depending on their invasiveness between 1997 and 2017 to evaluate the genetic evolution and the associations between invasiveness and genetic profiles. Using WGS datasets, we conducted virulence-associated DNA sequence determination, emm genotyping, multi-locus sequence typing (MLST), and superantigen gene profiling.

Results

In total, 87 strains were included in this study. There were no significant differences in the genomic features throughout the study periods. Four genes, csn1, ispE, nisK, and citC, were detected only in invasive strains. There was a significant association between invasiveness and emm cluster type A-C3, including, emm1.0, emm1.18, emm1.3, and emm1.76 (P<0.05). The predominant emm1 lineage belonged to ST28. There were no associations between invasiveness and superantigen gene profiles.

Conclusions

This is the first study using WGS datasets of S. pyogenes strains collected between 1997 and 2017 in Korea. Streptococcal invasiveness is associated with the presence of csn1, ispE, nisK, and citC. The emm1 lineage and ST28 clone are explicitly associated with invasiveness, whereas genomic features remained stable over the 20-year period.

Fatal consequence after MiraDry® treatment: Necrotizing fasciitis complicated with streptococcal toxic shock syndrome

MiraDry® is a microwave-based cosmetic device commonly used to treat hyperhidrosis and osmidrosis by affecting apocrine and eccrine sweat glands. In most countries, its application is limited to the axillary region. A healthy woman received MiraDry® treatment in the perineal, genital, and perianal regions for body odor in a cosmetic clinic. She experienced severe adverse effects after treatment, including persistent fever, sustained pain, and bleeding in the treated area. The condition deteriorated rapidly with systemic symptoms, and she died on the sixth day. Group A Streptococcus was detected in her skin in the treated areas, and in blood obtained in the hospital and during autopsy. Combined with the clinical diagnosis and autopsy findings, the woman's death was attributed to fatal necrotizing fasciitis (Fournier's gangrene) complicated by streptococcal toxic shock syndrome. Pathogen inoculation was most likely attributable to skin disruption caused by MiraDry® treatment. The MiraDry® application on the genital and perineum is occasionally performed by cosmetic surgeons; however, this case demonstrates the possibility of a rare but fatal complication. Therefore, this case report may be noteworthy and beneficial in forensic practice, and relevant in cosmetic clinical practice.

Case Report: Therapeutic Strategy With Delayed Debridement for Culture-Negative Invasive Group A Streptococcal Infections Diagnosed by Metagenomic Next-Generation Sequencing

Streptococcal toxic shock syndrome (STSS) caused by group A streptococcus is a rare condition that rapidly developed to multiple organ failure even death. Therefore, prompt diagnosis, initiate appropriate antibiotics and other supportive treatments are critical. Here we reported a case of STSS caused by group A streptococcus infection. A healthy 39-year-old man presented a sudden pain in the left lower extremity, followed by a high fever (40.0 °C) with dizziness, nausea, and shortness of breath. Twenty-four hours before the visit, the patient showed anuria. The patient was then admitted to the intensive care unit. Blood examination revealed elevated levels of inflammatory markers and creatinine. He suffered from septic shock, dysfunction of coagulation, acute kidney dysfunction, acute respiratory distress syndrome, and acute liver function injury. The diagnosis was obtained through clinical manifestation and metagenomic next-generation sequencing (mNGS) drawn from the pustule and deep soft tissue (lower limb) samples while all bacterial cultures came back negative. The pustule mNGS report detected a total of 132 unique group A streptococcus sequence reads, representing 96.3% of microbial reads while the soft tissue mNGS report identified a total of 142474 unique group A streptococcus sequence reads, representing 100% of microbial reads. The patient was treated with aggressive fluid resuscitation, antibiotics comprising piperacillin/tazobactam and clindamycin, respiratory support, following the delayed surgical debridement. Intravenous immunoglobulin was also used for 5 days. On the 14th day after admission, he was transferred to the general ward for follow-up treatment. Our case highlighted, for the first time, the key role of mNGS in the early diagnosis of culture-negative invasive group A streptococcal infection. The case also suggested that clindamycin combined with beta-lactam antibiotics and adjunction of intravenous immunoglobulin therapy with delayed debridement performed well in the management of unstable STSS patients.

Early Diagnosis and Surgical Management of Necrotizing Fasciitis of the Lower Extremities: Risk Factors for Mortality and Amputation

Objective: In this study, we seek to identify patient characteristics associated with limb loss and mortality while exploring the potential impact a multidisciplinary care team may have. Approach: This was a 10-year retrospective review of patients presenting to our tertiary care center for limb salvage with a diagnosis of lower extremity (LE) necrotizing fasciitis (NF). Patient demographics, clinical history, and outcomes were compared between survivors and nonsurvivors and between those who underwent LE amputation and those who did not. The article adheres to the strengthening the reporting of observational studies in epidemiology statement. Results: Sixty-two patients presented to our tertiary care center for limb salvage with LE NF. Forty-two patients underwent LE amputation: 27 (43.5%) underwent below-knee amputation, 1 (1.6%) underwent above-knee amputation, 8 (12.9%) underwent transmetatarsal amputation and 2 (3.2%) underwent calcanectomy. The overall mortality rate was 16.1% (n = 10). Risk factors for mortality included increased age (p = 0.034), higher Charlson Comorbidity Index (p = 0.011), thrombocytopenia (p = 0.002), hypotension (p = 0.015), erythema (p = 0.010), pain (p = 0.027), diabetes mellitus (p = 0.012), and malignancy (p < 0.001). Risk factors for LE amputation included DM (p = 0.017), peripheral vascular disease (p = 0.033), and an elevated laboratory risk indicator for necrotizing fasciitis (LRINC) (p = 0.033). Innovation: To identify outcomes after admission to a tertiary hospital with a dedicated limb salvage team with LE NF and to analyze risk factors for mortality and amputation. Conclusions: This is a comprehensive analysis of risk factors for mortality and amputation after LE NF. Our institution's experience highlights the importance of a multidisciplinary approach in the care of these patients.

Pathogen Stimulation of Interleukin-8 from Human Vaginal Epithelial Cells through CD40

Many bacterial and fungal pathogens cause disease across mucosal surfaces, and to a lesser extent through skin surfaces. Pathogens that potentially cause disease vaginally across epithelial cells include Staphylococcus aureus, group A and B streptococci, Escherichia coli, Neisseria gonorrhoeae, and Candida albicans. We have previously shown that staphylococcal and streptococcal superantigens induce inflammatory chemokines from vaginal epithelial cells through the immune costimulatory molecule CD40 through use of a CRISPR cas9 knockout mutant and complemented epithelial cell line. In this study, we show that the potential vaginal pathogens S. aureus, group A and B streptococci, E. coli, an Enterococcus faecalis strain, and C. albicans in part use CD40 to stimulate interleukin-8 (IL-8) production from human vaginal epithelial cells. In contrast, N. gonorrhoeae does not appear to use CD40 to signal IL-8 production. Normal flora Lactobacillus crispatus and an Enterococcus faecalis strain that produces reutericyclin do not induce IL-8. These data indicate that many potential pathogens, but no normal commensals, induce IL-8 to help disrupt the human vaginal epithelial barrier through CD40, thus providing a potential therapeutic target for drug development.

IMPORTANCE Most bacterial and fungal pathogens cause disease across mucosal, and to a lesser extent, skin barriers with the help of induced chemokines from epithelial cells. In this study, we showed that potential vaginal pathogens Staphylococcus aureus, group A and B streptococci, some Enterococcus faecalis strains, Escherichia coli, and Candida albicans use the immune costimulatory molecule CD40 to induce the chemokine interleukin-8 production. In contrast, Neisseria gonorrhoeae does not use CD40 to stimulate interleukin-8. Normal flora lactobacilli and at least one E. faecalis strain do not induce interleukin-8.

Bacterial Lymphatic Metastasis in Infection and Immunity

Lymphatic vessels permeate tissues around the body, returning fluid from interstitial spaces back to the blood after passage through the lymph nodes, which are important sites for adaptive responses to all types of pathogens. Involvement of the lymphatics in the pathogenesis of bacterial infections is not well studied. Despite offering an obvious conduit for pathogen spread, the lymphatic system has long been regarded to bar the onward progression of most bacteria. There is little direct data on live virulent bacteria, instead understanding is largely inferred from studies investigating immune responses to viruses or antigens in lymph nodes. Recently, we have demonstrated that extracellular bacterial lymphatic metastasis of virulent strains of Streptococcus pyogenes drives systemic infection. Accordingly, it is timely to reconsider the role of lymph nodes as absolute barriers to bacterial dissemination in the lymphatics. Here, we summarise the routes and mechanisms by which an increasing variety of bacteria are acknowledged to transit through the lymphatic system, including those that do not necessarily require internalisation by host cells. We discuss the anatomy of the lymphatics and other factors that influence bacterial dissemination, as well as the consequences of underappreciated bacterial lymphatic metastasis on disease and immunity.

Streptococcal toxic shock syndrome after hemorrhoidectomy: A case report

BACKGROUND

Streptococcal toxic-shock syndrome after hemorrhoidectomy is rare but may be catastrophic. Group A streptococci have produced various surface proteins and exotoxins due to genetic changes to fight the human body’s immune response. Though life threatening infection after hemorrhoidectomy rarely occurs, all surgeons should be aware of the potential complications of severe sepsis after hemorrhoidectomy and keep in mind their clinical presenting features in order to diagnose early and administer appropriate and effective therapeutic drugs early.

CASE SUMMARY

Here, we present a case of a 56-year-old man with a painful thrombotic external hemorrhoid who presented to our outpatient department for management. There was no history of systemic diseases or recent disease infection. Hemorrhoidectomy was suggested and performed. After surgery, the patient developed hypotension, tachycardia, fever with chills and renal function impairment on day 2 post-operation. The clinical condition progressed to severe septic shock and metabolic acidosis. The patient responded poorly to treatment and expired after 1 d even with use of extracorporeal membrane oxygenation. The results of the blood and wound cultures showed group A streptococcus pyogenes.

CONCLUSION

Although extremely uncommon, all surgeons should be aware of these potential life-threatening septic complications and alert to the presenting features for patients receiving hemorrhoidectomy.

Antibiotic Treatment, Mechanisms for Failure, and Adjunctive Therapies for Infections by Group A Streptococcus

Group A Streptococcus (GAS; Streptococcus pyogenes) is a nearly ubiquitous human pathogen responsible for a significant global disease burden. No vaccine exists, so antibiotics are essential for effective treatment. Despite a lower incidence of antimicrobial resistance than many pathogens, GAS is still a top 10 cause of death due to infections worldwide. The morbidity and mortality are primarily a consequence of the immune sequelae and invasive infections that are difficult to treat with antibiotics. GAS has remained susceptible to penicillin and other β-lactams, despite their widespread use for 80 years. However, the failure of treatment for invasive infections with penicillin has been consistently reported since the introduction of antibiotics, and strains with reduced susceptibility to β-lactams have emerged. Furthermore, isolates responsible for outbreaks of severe infections are increasingly resistant to other antibiotics of choice, such as clindamycin and macrolides. This review focuses on the challenges in the treatment of GAS infection, the mechanisms that contribute to antibiotic failure, and adjunctive therapeutics. Further understanding of these processes will be necessary for improving the treatment of high-risk GAS infections and surveillance for non-susceptible or resistant isolates. These insights will also help guide treatments against other leading pathogens for which conventional antibiotic strategies are increasingly failing.

A case of necrotizing fasciitis following intra-articular injections - Iatrogenic or spontaneous?

Here, we report a case of necrotizing fasciitis following intra-articular injection of hyaluronic acid. A 73-year-old female received intra-articular injections of hyaluronic acid due to arthralgia at the left shoulder and knee, and was found dead in her living room at one day. At the forensic autopsy, injection marks with bullae and erythema were found at the left shoulder and knee and liquefactive necrosis of muscle tissues was observed in the left but not right extremities. Histopathological examinations of the left upper arm and thigh revealed severe rhabdomyolysis with lots of bacterial clusters. Bacteriological examinations detected group A Streptococcus from intracardiac blood and affected muscle tissues. Postmortem biochemical analysis of blood showed escalated blood urea nitrogen (133.8 mg/dL), creatinine (4.57 mg/dL) and C-reactive protein (45.0 mg/dL). The cause of her death was diagnosed as streptococcal toxic shock syndrome (STSS). Moreover, it was suggested that the injection was inappropriately conducted and served as a portal of bacterial entry.

Streptococcal Toxic Shock Syndrome Induced by Group A Streptococcus with the emm28 Genotype That Developed after a Uterine Cancer Test

A 69-year-old woman without pre-existing disease visited our hospital due to general malaise, diarrhea, and arthralgia 3 days after a uterine cancer test. We diagnosed her with sepsis of unknown focus and started treatment immediately, but she died 20 hours after the first visit due to multi-organ failure and septic shock. Later, group A streptococcus was detected from the blood culture, and streptococcal toxic shock syndrome (STSS) was diagnosed. The strain had the emm28 genotype and a mutation in csrR with increased NADase activity. These virulence factors were considered to be related to STSS development in this patient.

Superantigen Recognition and Interactions: Functions, Mechanisms and Applications

Superantigens are unconventional antigens which recognise immune receptors outside their usual recognition sites e.g. complementary determining regions (CDRs), to elicit a response within the target cell. T-cell superantigens crosslink T-cell receptors and MHC Class II molecules on antigen-presenting cells, leading to lymphocyte recruitment, induction of cytokine storms and T-cell anergy or apoptosis among many other effects. B-cell superantigens, on the other hand, bind immunoglobulins on B-cells, affecting opsonisation, IgG-mediated phagocytosis, and driving apoptosis. Here, through a review of the structural basis for recognition of immune receptors by superantigens, we show that their binding interfaces share specific physicochemical characteristics when compared with other protein-protein interaction complexes. Given that antibody-binding superantigens have been exploited extensively in industrial antibody purification, these observations could facilitate further protein engineering to optimize the use of superantigens in this and other areas of biotechnology.

Group A Streptococcal Toxic Shock Syndrome after a Routine Gynecological Procedure

Streptococcal toxic shock syndrome (STSS) is a life-threatening illness mainly caused by invasive group A Streptococcus (GAS) infection. Herein, we report a case of a postmenopausal woman who developed STSS from an ascending vaginal GAS infection after cytocervical sampling. The patient complained of vaginal discharge, for which she underwent gynecological examination with vaginal sampling. The following day, there was onset of diarrhea and vomiting. After 7 days, she was admitted to our hospital with septic shock. Necrotizing enterocolitis was suspected and surgical intervention was performed; however, the patient was diagnosed with primary peritonitis and antibiotics were initiated. On day 2, GAS was suspected by blood cultures, and antibiotics were changed in consideration of STSS. On day 4, GAS was confirmed in blood, ascitic fluid, and vaginal swab specimens, and STSS caused by an ascending vaginal GAS infection was diagnosed. This case report indicates that STSS could occur following cytocervical sampling for vaginal discharge. If a woman has unexplained septic shock, especially with gastroenteritis symptoms, STSS should be considered as a differential diagnosis.

Manifestations of Toxic Shock Syndrome in Children, Columbus, Ohio, USA, 2010-20171

Data are limited on the incidence and management of streptococcal toxic shock syndrome (TSS) and nonstreptococcal TSS in children. We aimed to define the clinical patterns of TSS at Nationwide Children's Hospital in Ohio as they relate to published criteria, diagnostic decisions, and treatment options. Through retrospective chart reviews, we identified 58 patients with TSS (27 streptococcal, 31 nonstreptococcal) during January 2010-September 2017. We observed clinical and laboratory findings that are not part of TSS criteria, such as pyuria in streptococcal TSS (50% of patients) and pulmonary involvement (85%) and coagulopathy (92%) in nonstreptococcal TSS patients. Recommended treatment with clindamycin and intravenous immunoglobulin was delayed in streptococcal TSS patients without rash (3.37 days vs. 0.87 days in patients with rash), leading to prolonged hospitalization and complications. Incorporation of additional TSS signs and symptoms would be helpful in TSS diagnosis and management.

Necrotizing soft tissue infection: clinical characteristics, diagnosis, and management of 32 cases in Beijing

OBJECTIVE

Necrotizing soft tissue infection (NSTI) is a rare but life-threatening bacterial infection. This study was performed to analyze the clinical characteristics of patients with NSTI admitted to the intensive care unit of a trauma and burn center in Beijing and to summarize the treatment experience.

METHODS

This retrospective study involved patients with NSTI admitted to the intensive care unit from January 2010 to January 2020. The clinical manifestations, pathogens, laboratory test results, and prognosis were compared between survivors and nonsurvivors.

RESULTS

Thirty-two patients were enrolled (28 men, 4 women), including 25 (78.1%) survivors and 7 (21.9%) nonsurvivors. The patients' median age was 41.5 years (range, 30.0-52.5 years). Mortality was significantly higher in patients with a blood urea nitrogen concentration of ≥11.5 mg/dL, creatinine concentration of <3.4 mg/dL, prothrombin time of ≥15.9 s, and international normalized ratio of ≥1.3. Streptococcus pyogenes and Clostridium perfringens infections were associated with higher mortality.

CONCLUSIONS

More attention should be given to elderly patients and those with hyponatremia, coagulation disorder, and higher blood urea nitrogen or creatinine concentrations. The finding of large gram-positive rods or large numbers of gram-positive cocci in wound secretion smears is a helpful early warning sign of highly lethal NSTI.

Risk Factors and Predictors of Mortality in Streptococcal Necrotizing Soft-tissue Infections: A Multicenter Prospective Study

BACKGROUND

Necrotizing soft-tissue infections (NSTI) are life-threatening conditions often caused by β-hemolytic streptococci, group A Streptococcus (GAS) in particular. Optimal treatment is contentious. The INFECT cohort includes the largest set of prospectively enrolled streptococcal NSTI cases to date.

METHODS

From the INFECT cohort of 409 adults admitted with NSTI to 5 clinical centers in Scandinavia, patients culture-positive for GAS or Streptococcus dysgalactiae (SD) were selected. Risk factors were identified by comparison with a cohort of nonnecrotizing streptococcal cellulitis. The impact of baseline factors and treatment on 90-day mortality was explored using Lasso regression. Whole-genome sequencing of bacterial isolates was used for emm typing and virulence gene profiling.

RESULTS

The 126 GAS NSTI cases and 27 cases caused by SD constituted 31% and 7% of the whole NSTI cohort, respectively. When comparing to nonnecrotizing streptococcal cellulitis, streptococcal NSTI was associated to blunt trauma, absence of preexisting skin lesions, and a lower body mass index. Septic shock was significantly more frequent in GAS (65%) compared to SD (41%) and polymicrobial, nonstreptococcal NSTI (46%). Age, male sex, septic shock, and no administration of intravenous immunoglobulin (IVIG) were among factors associated with 90-day mortality. Predominant emm types were emm1, emm3, and emm28 in GAS and stG62647 in SD.

CONCLUSIONS

Streptococcal NSTI was associated with several risk factors, including blunt trauma. Septic shock was more frequent in NSTI caused by GAS than in cases due to SD. Factors associated with mortality in GAS NSTI included age, septic shock, and no administration of IVIG.

A brief review on Group A Streptococcus pathogenesis and vaccine development

Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is a Gram-positive human-exclusive pathogen, responsible for more than 500 000 deaths annually worldwide. Upon infection, GAS commonly triggers mild symptoms such as pharyngitis, pyoderma and fever. However, recurrent infections or prolonged exposure to GAS might lead to life-threatening conditions. Necrotizing fasciitis, streptococcal toxic shock syndrome and post-immune mediated diseases, such as poststreptococcal glomerulonephritis, acute rheumatic fever and rheumatic heart disease, contribute to very high mortality rates in non-industrialized countries. Though an initial reduction in GAS infections was observed in high-income countries, global outbreaks of GAS, causing rheumatic fever and acute poststreptococcal glomerulonephritis, have been reported over the last decade. At the same time, our understanding of GAS pathogenesis and transmission has vastly increased, with detailed insight into the various stages of infection, beginning with adhesion, colonization and evasion of the host immune system. Despite deeper knowledge of the impact of GAS on the human body, the development of a successful vaccine for prophylaxis of GAS remains outstanding. In this review, we discuss the challenges involved in identifying a universal GAS vaccine and describe several potential vaccine candidates that we believe warrant pursuit.

Early intravenous immunoglobulin therapy for group A β-haemolytic streptococcal meningitis with toxic shock syndrome

A woman in her forties was transferred to a Sydney (Australia)-based tertiary hospital, following presentation to a regional hospital with group A Streptococcus (GAS) otomastoiditis; complicated by meningitis, venous sinus thrombosis, haemorrhagic cerebral infarction and subdural empyema. She rapidly deteriorated with profound cardiovascular collapse. Despite initiation of high dose vasoactive therapy, she remained shocked and developed multiorgan dysfunction syndrome. Early intravenous immunoglobulin therapy (140 g in two doses) was initiated as an adjunct to antimicrobial, surgical and supportive care for refractory streptococcal toxic shock syndrome. Over the course of a twelve-day intensive care unit stay she made good progress with de-escalation of her vasoactive supportive care and reversal of her organ injuries. She was subsequently discharged to ward-based care. At her three-month follow-up appointment she had significantly reduced neurological deficit. Five months following her presentation to hospital she had returned to full-time work.

Structural analysis of alternate sigma factor ComX with RpoC, RpoB and its cognate CIN promoter reveals a distinctive promoter melting mechanism

Alternate sigma factors play a major role in the survival of pathogenic bacteria such as Streptococcus pyogenes in adverse environment conditions. Stress induced sigma factors mediate gene expression under conditions of pathogenesis, dormancy and unusual environmental cues. In the present work, ComX, an alternate sigma factor from S. pyogenes has been characterized. The structures of ComX, RpoB β subunit and RpoC β' subunit of RNA polymerase have been predicted using comparative and homology modelling respectively and validated. Attempts have been made to study RpoB-RpoC-ComX complex interactions with Double Strand (DS) and Single Strand (SS) promoter regions. Stability of these complexes and the promoter melting mechanism have been analysed using Molecular Dynamic (MD) simulations. This study suggests that ComX, although identifies promoter analogous to the alternate sigma factor SigH of M. tuberculosis, follows a distinctive promoter flip out mechanism.Communicated by Ramaswamy H. Sarma.

Streptococcal toxic shock syndrome with fatal outcome: Report on four forensic autopsy cases

Streptococcal toxic shock syndrome (STSS) is a severe infection most commonly caused by group A streptococcus. It is clinically characterized by rapidly progressive multiple organ failure and septic shock. This report presents four fatal cases associated with STSS. In two cases (cases 2 and 3), the portals of entry may be ulcer and mucosa at the surgical site; the initial symptoms in these cases included fever. In the other cases, the portal of entry was unknown; the initial symptom was pain. In two cases (cases 1 and 3), malpractice was suspected before autopsy. At autopsy, blood culture was positive for group A streptococcus in all of the present cases. Although C-reactive protein levels were increased, procalcitonin levels were not markedly elevated. This is the first report of autopsy cases associated with STSS in which postmortem computed tomography was performed; the swelling of muscles and increased concentrations of peripheral subcutaneous tissue without gas may be characteristic findings. Histology revealed extensive bacterial colonies and necrosis with mild neutrophilic reaction in two cases (cases 3 and 4), and hemophagocytosis in two cases (cases 1 and 4). It is essential to perform appropriate examinations and make a proper diagnosis because STSS still has a high fatality rate and medical malpractice is often suspected. In addition, it is important to evaluate STSS again for the reduction of the fatal cases associated with STSS.

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.