Gram-positive toxic shock syndromes

Toxic Shock Syndrome due to Streptococcus Pyogenes: Case Report

BACKGROUND

Toxic shock syndrome (TSS) is one of the most devastating clinical manifestations of Streptococcus pyogenes (also known as Group A Streptococci or GAS), characterized by an overwhelming production of toxins. The incidence of TSS is increasing worldwide, and the mortality rate remains unacceptably high. Due to the rapid progression of infection, rapid diagnosis is crucial, as early initiation of aggressive supportive measures, along with antibiotics, source control, immunoglobulin, and steroids, can improve patient outcomes. IgM- and IgA-enriched immunoglobulins represents a new therapeutic option, as highlighted in the case reported here.

CASE REPORT

A 66-year-old man was admitted for cellulitis of the right arm with shock, disseminated intravascular coagulation (DIC), renal and hepatic compromise, suggestive of toxic shock syndrome (TSS). Blood cultures revealed S. pyogenes, confirming the diagnosis. The patient was treated with combination antibiotic therapy (clindamycin, piperacillin/tazobactam), steroids and enriched immunoglobulins in addition to vasopressor and high flow oxygen. He was discharged home with complete recovery after 1 month. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: In the emergency department, the primary goals of management of TSS include aggressive resuscitation, prompt administration of appropriate antibiotics, source control if feasible, and early intensive care unit admission.

Decoding growth inhibitory associated pathways of xenometal-siderophore antibiotic conjugates in S. aureus

Pathogenic Staphylococcus aureus causes most infectious disease related deaths in the developed world. Continuously evolving resistance to clinically approved antibiotics and combination therapies limits treatment efficacy; new strategies that evade and slow resistance or produce resistant mutants with reduced fitness are needed. We employ antibiotics conjugated to bacterially recognized siderophores to potentiate their efficacy. Acting as a Trojan horse, the siderophore antibiotic conjugates efficiently deliver the antibiotic inside the bacterial cytoplasm by hijacking the iron transport system pathways which are crucial for bacterial survival. Here, we investigated the mechanism of action of gallium xenometallomycins (siderophore antibiotic conjugates incorporating non-endogenous metal ions), Ga-DFO-Cip and Ga-LDFC-Cip, which have demonstrated high potency compared to the parent antibiotic's efficacy in vitro in S. aureus infection. Employing physicochemical, synthetic and transcriptomic analysis studies, this work reveals that kinetically inert, gallium-containing xenometallomycins targeting cytoplasmic bacterial targets impart differential resistance and gene expression profiles when compared to their parent antibiotic in S. aureus bacterial strains. Both Ga-DFO-Cip and Ga-LDFC-Cip effectively disrupt iron-siderophore biosynthesis and uptake machinery. We affirm our results with the radioactive surrogate 67/68Ga-DFO-Cip and demonstrate that the bacterial uptake in Ga-DFO-Cip-resistant S. aureus strains is impaired, leading to diminished compound accumulation in vitro and in vivo.

How AI can help us beat AMR

Antimicrobial resistance (AMR) is an urgent public health threat. Advancements in artificial intelligence (AI) and increases in computational power have resulted in the adoption of AI for biological tasks. This review explores the application of AI in bacterial infection diagnostics, AMR surveillance, and antibiotic discovery. We summarize contemporary AI models applied to each of these domains, important considerations when applying AI across diverse tasks, and current limitations in the field.

Proinflammatory synergy between protease and superantigen streptococcal pyogenic exotoxins

Streptococcal pyogenic exotoxins (Spe proteins) secreted by Streptococcus pyogenes (group A Streptococcus, GAS) are responsible for scarlet fever and streptococcal toxic shock syndrome. Most Spes are superantigens that cause excessive inflammation by activating large numbers of T cells. However, Streptococcal pyogenic exotoxin B (SpeB) is an exception, which is pro-inflammatory through its protease activity. Prior work shows that SpeB has the potential to cleave bacterial proteins. If cleavage of superantigens results in their inactivation, this gives the possibility that these two classes of exotoxins work at cross-purposes. We examined SpeB cleavage of the 11 major GAS superantigens and found that lability was not specific to structure, conservation, or, when compared to orthologous superantigens from Staphylococcus aureus, species of origin. We further show that rather than strictly antagonizing superantigen activity through degradation, SpeB can synergistically enhance superantigen-induced inflammation. For SpeB-labile superantigens, such as SmeZ, this is limited due to degradation, but for protease-resistant superantigens like SpeA, activity remains synergistic even at high protease concentrations. These findings suggest two modes by which proteases like SpeB may post-translationally regulate superantigens: positively, as a force amplifier that cooperatively increases inflammation, and negatively, through degradation that could act as a rheostat-like mechanism to limit excessive immune activation. Both mechanisms may contribute to the pathogenesis of GAS and other superantigen-producing pathogens.IMPORTANCEStreptococcus pyogenes produces both superantigen and protease virulence factors to subvert host immunity. However, its major protease is highly promiscuous and would potentially limit superantigen activity through its degradation. We profile the sensitivity of the streptococcal superantigens to degradation by the protease SpeB, providing evidence that many are highly resistant. Furthermore, we show that these important toxins can have synergistic proinflammatory activity. This provides insight into diseases like scarlet fever and toxic shock syndrome caused by these toxins and suggests anti-inflammatories that may be therapeutically useful.

Toxic shock syndrome secondary to Group A Streptococcus infection: A case report

Toxic shock syndrome secondary to Group A Streptococcus infection is a rare but serious cause of women's morbidity and mortality which can easily be misdiagnosed. A 37-year-old woman presented to the emergency department in a state of shock after a two-day history of abdominal pain, fever, diarrhoea and green vaginal discharge. Following extensive investigations, she was proved to have septic shock secondary to Group A Streptococcus pyogenes. Despite receiving intravenous antibiotics, she required explorative laparotomy, which proceeded to subtotal hysterectomy and bilateral salpingectomy. Subsequently, she developed multi-organ failure, disseminated intravascular coagulation, and limb ischemia requiring below-knee amputation of the right limb. She was discharged home. The aim of this report is to raise the awareness about toxic shock syndrome from Streptococcus pyogenes. A high index of suspicion is required to promptly diagnose this rare yet potentially fatal infection.

Clinical outcomes and severe complications of hospitalised children and adolescents with varicella in central Switzerland: a retrospective observational study

AIM

Recent data on clinical complications and mortality among hospitalised children and adolescents due to varicella are unavailable in Switzerland. The aim of the study was to explore data on severe varicella complications in hospitalised children before the introduction of a universal varicella vaccination recommendation, which the Swiss Federal Office of Public Health implemented in January 2023.

METHODS

This was a retrospective observational study of children hospitalised with varicella between 01.01.2010 and 31.03.2020 at a tertiary children's hospital in central Switzerland serving approximately 10% of the Swiss population. The inclusion criteria were acute varicella and/or related complications.

RESULTS

A total of 95 patients were identified. The median age at onset was 4 years (range: 2 months to 13 years) and the peak age of patients was between 1 and 4 years. 53 had mild and 42 patients had severe varicella-associated complications (8 had >1 severe complication). The most common severe complications were bacterial skin and soft tissue infections (n = 28), invasive secondary bacterial infections (n = 18), and central nervous system-related complications (n = 12). Admission to the paediatric intensive care unit and surgical intervention were required in 11 (12%) and 16 (17%) patients, respectively. Two previously healthy school-age children died because of secondary bacterial infections.

CONCLUSION

Our results demonstrate that varicella can cause severe and even fatal complications in children living in a highly developed country. This study provides valuable clinical data on severe varicella complications in hospitalised children from a large catchment area of Switzerland, facilitating future data comparison of the disease burden before and after the introduction of universal varicella vaccination in Switzerland.

Sesamol hinders the proliferation of intracellular bacteria by promoting fatty acid metabolism and decreasing excessive inflammation

The extraintestinal pathogenic Escherichia coli (ExPEC) is a significant zoonotic bacterial pathogen that can cause severe infections and potentially cross-transmit between different hosts. The treatment of clinical bacterial infections is challenging because of the increasingly severe problem of drug resistance. The development of new strategies for managing bacterial infections is essential. Host-acting antibacterial compound (HAC)-based host-directed therapy (HDT) has emerged as a promising approach to combat bacterial infections by targeting host-pathogen interactions and bacterial intracellular survival strategies. In this study, we conducted a cell-based screening to identify compounds that can inhibit the survival and proliferation of ExPEC within host cells. Our screening revealed that sesamol effectively inhibited ExPEC proliferation but had no effect on the natural growth of bacteria. Analysis of the transcriptome data revealed that sesamol has the ability to increase the metabolism of host fatty acids while also suppressing excessive inflammation. Mechanistic studies have shown that sesamol-induced PPAR-β activation is crucial for increased fatty acid metabolism and clearance of intracellular bacteria. Furthermore, sesamol treatment demonstrated protective effects against ExPEC infection in both Galleria mellonella and mouse models, suggesting its potential use for treating diseases caused by intracellular bacterial pathogens and as a lead compound for further development of anti-infection drugs on the basis of the HDT strategy.

Primary Bacterial Peritonitis in a Young Man: A Rare Manifestation of Invasive Group A Streptococcal Infection

Group A Streptococcus (GAS) is a ubiquitous pathogen responsible for a wide range of infections, from superficial to severe invasive forms (iGAS). Among these, primary bacterial peritonitis (PBP) due to GAS is a rare but severe presentation. Recent epidemiological data indicate a significant rise in iGAS cases globally, which may be linked to changes in post-pandemic pathogen circulation. This report describes a case of PBP and streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes in a young man with no known risk factors. To our knowledge, this is one of only 10 cases of PBP in men reported in the literature. In this article, we review the epidemiology, risk factors, clinical manifestations, and management of iGAS, especially in the case of peritoneal involvement. Further research is needed to better understand the pathogenesis and optimize treatment strategies for this severe infection.

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.

Fever and Rash

Infectious causes of fever and rash pose a diagnostic challenge for the emergency provider. It is often difficult to discern rashes associated with rapidly progressive and life-threatening infections from benign exanthems, which comprise the majority of rashes seen in the emergency department. Physicians must also consider serious noninfectious causes of fever and rash. A correct diagnosis depends on an exhaustive history and head-to-toe skin examination as most emergent causes of fever and rash remain clinical diagnoses. A provisional diagnosis and immediate treatment with antimicrobials and supportive care are usually required prior to the return of confirmatory laboratory testing.

Necrotizing Fasciitis of the Serratus Anterior in a Patient Treated With Infliximab and Prednisolone for Ulcerative Colitis and Rheumatoid Arthritis

Necrotizing fasciitis (NF) is a rapidly progressive bacterial infection with high mortality. Invasive group A Streptococcus (GAS) infection is the leading cause of NF. Our understanding regarding clinicopathological features and pathogenesis of invasive GAS infection is expanding as the incidence of NF in healthy individuals increases. However, clinicopathological features of NF in the presence of autoimmune diseases have been poorly defined. We experienced NF in a patient treated with infliximab and prednisolone for ulcerative colitis and rheumatoid arthritis. Herein, we present time kinetics findings of clinical symptoms and laboratory data of GAS-associated NF in the presence of immunosuppressant-treated immune disorders.

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.

Toxic Shock Syndrome: Eighteen Years of Experience in a Pediatric Intensive Care Unit

Introduction Toxic shock syndrome (TSS) is a life-threatening disease usually caused by a Staphylococcus aureus or group Aβ-hemolytic Streptococcus infection. Methods In this retrospective study, we included patients with TSS admitted to a tertiary hospital's pediatric intensive care unit (PICU) over the last 18 years. We compared the staphylococcal TSS (Staph-TSS) and streptococcal TSS (Strep-TSS) groups. Results We included 17 patients (64.7% male), with a median age of 6.1 years (3.0 years for streptococcal TSS versus 13.3 years for staphylococcal TSS, p = 0.040), a median of 3.0 days from symptom onset to diagnosis, and a median of 6.0 days of hospitalization. Ten patients met the Centers for Disease Control and Prevention (CDC) criteria for staphylococcal TSS (one menstrual-related) and seven met the criteria for streptococcal TSS (four of them occurring since the COVID-19 pandemic was declared). Fifteen patients had identified risk factors, primarily cutaneous lesions (29.4%). In 15 patients, at least three organs or systems were affected, with fever, rash, and hypotension as universal findings. Mucous membrane hyperemia was present in 16 patients, gastrointestinal symptoms in 14 patients, and desquamation in nine. Muscular involvement was present in seven patients, all with staphylococcal TSS (p = 0.010). All patients received two or more antibiotics, including a protein synthesis inhibitor (except for one), and required fluid resuscitation and vasoactive amines (median three days). Six patients needed invasive mechanical ventilation (median seven days). Albumin infusion was necessary in six patients, significantly more frequently in patients with streptococcal TSS (p = 0.035). Two patients with staphylococcal TSS died, while the seven patients with streptococcal TSS survived hospital discharge. There were no recurrent cases. Conclusions Our study revealed TSS severity and multiorgan involvement, emphasizing the importance of early diagnosis and intervention. Risk factors were prevalent, and we noted an increased frequency of group A streptococcal (GAS) TSS post-COVID-19 pandemic.

Comparison of Adjuvant Clindamycin vs Linezolid for Severe Invasive Group A Streptococcus Skin and Soft Tissue Infections

Background

Linezolid may be an option for severe group A Streptococcus (GAS) infections based on its potent in vitro activity and antitoxin effects, but clinical data supporting its use over clindamycin are limited. This study evaluated treatment outcomes in patients with severe GAS skin and soft tissue infections who received either linezolid or clindamycin.

Methods

This retrospective single-center cohort study examined patients with GAS isolated from blood and/or tissue cultures with invasive soft tissue infection or necrotizing fasciitis who underwent surgical debridement and received linezolid or clindamycin for at least 48 hours. The primary outcome was percentage change in Sequential Organ Failure Assessment (SOFA) score from baseline through 72 hours of hospitalization.

Results

After adjustment for time to first surgical intervention among patients with a baseline SOFA score >0 (n = 23 per group), there was no difference in reduction of SOFA score over the first 72 hours in patients receiving clindamycin vs linezolid. In the entire cohort (n = 26, clindamycin; n = 29, linezolid), there was no difference in inpatient mortality (2% vs 1%) or any secondary outcomes, including duration of vasopressor therapy, intensive care unit length of stay, and antibiotic-associated adverse drug events.

Conclusions

There was no difference in reduction of critical illness as measured by SOFA score between baseline and 72 hours among patients treated with clindamycin vs linezolid. Given its more favorable side effect profile, linezolid may be a viable option for the treatment of serious GAS infections and should be further studied.

Cytotoxic dermatitis: Review of the interface dermatitis pattern in veterinary skin diseases

Interface dermatitis or lichenoid interface dermatitis refers to a cutaneous inflammatory pattern in which keratinocyte cell death is the essential feature. These terms have evolved from the originally described lichenoid tissue reaction. These lesions are the basis for an important group of skin diseases in animals and people where cytotoxic T-cell-mediated epidermal damage is a major pathomechanism. Yet, for largely historical reasons these commonly used morphological diagnostic terms do not reflect the essential nature of the lesion. An emphasis on subsidiary lesions, such as the presence of a lichenoid band, and definitions based on anatomical features, such as location at the dermo-epidermal location, may cause confusion and even misdiagnosis. This review covers historical aspects of the terminology, including the origin of terms such as "lichenoid." The types of cell death involved and the histopathologic lesions are described. Etiopathogenesis is discussed in terms of aberrations of immune/inflammatory mechanisms focusing on cutaneous lupus erythematosus, erythema multiforme, and Stevens-Johnson syndrome/toxic epidermal necrolysis. Mechanisms have most extensively been studied in humans and laboratory animals and the discussion is centered on these species. As interface dermatitis is firmly entrenched in dermatological parlance, rather than using "cytotoxic" as its substitute, the terminologies "interface cytotoxic dermatitis" and "panepidermal cytotoxic dermatitis" are recommended, based on location and extent of epithelium affected.

Toxin exposure and HLA alleles determine serum antibody binding to toxic shock syndrome toxin 1 (TSST-1) of Staphylococcus aureus

Life-threatening toxic shock syndrome is often caused by the superantigen toxic shock syndrome toxin-1 (TSST-1) produced by Staphylococcus aureus. A well-known risk factor is the lack of neutralizing antibodies. To identify determinants of the anti-TSST-1 antibody response, we examined 976 participants of the German population-based epidemiological Study of Health in Pomerania (SHIP-TREND-0). We measured anti-TSST-1 antibody levels, analyzed the colonization with TSST-1-encoding S. aureus strains, and performed a genome-wide association analysis of genetic risk factors. TSST-1-specific serum IgG levels varied over a range of 4.2 logs and were elevated by a factor of 12.3 upon nasal colonization with TSST-1-encoding S. aureus. Moreover, the anti-TSST-1 antibody levels were strongly associated with HLA class II gene loci. HLA-DRB1*03:01 and HLA-DQB1*02:01 were positively, and HLA-DRB1*01:01 as well as HLA-DQB1*05:01 negatively associated with the anti-TSST-1 antibody levels. Thus, both toxin exposure and HLA alleles affect the human antibody response to TSST-1.

Staphylococcal toxic shock syndrome

Toxic Shock Syndrome (TSS) is a severe acute disease characterized by high fever, hypotension, rash, multiple organ dysfunction and desquamation during convalescence. TSS is caused by toxin-producing strains of Staphylococcus aureus or Streptococcus pyogenes. TSS remains a rare but severe disease. Early diagnosis is important because specific treatments with antitoxin effects must be started as soon as possible. This manuscript presents a set of images that illustrate the main findings in the peripheral blood film of a patient with TSS.

HM-chromanone alleviates hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance

This study was designed to investigate whether (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone alleviates inflammation and hyperglycemia in mice with endotoxin-induced insulin resistance. (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone (10, 30, and 50 mg/kg bodyweight) was orally pre-administered to C57BL/6 J mice. An hour later, lipopolysaccharides (20 mg/kg bodyweight) was administered intraperitoneally to induce endotoxins. Blood samples were collected from the tail vein of the mice every 0, 30, and 90 min. The results indicated that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone effectively regulated blood glucose levels in mice with endotoxin-induced insulin resistance. Furthermore, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone significantly reduced the phosphorylation of mammalian target of rapamycin, ribosomal protein S6 kinase 1, and protein kinase C θ. Additionally, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone suppressed the phosphorylation of c-Jun-NH2-terminal kinase and IkB kinase β, thereby decreasing the phosphorylation of inhibitor of nuclear factor kappa-B α and activating the nuclear factor-κB and activator protein-1 in the liver. Therefore, the expression of tumor necrosis factor-α, interleukin-6, and interleukin-1β was significantly reduced by suppressing the nuclear factor-κB and activator protein 1 activity. Suppression of mammalian target of rapamycin, S6 kinase 1, protein kinase C θ, c-Jun-NH2-terminal kinase, and IkB kinase β also ameliorated insulin resistance by reducing the phosphorylation of insulin receptor substrate-1 serine 307, thereby decreasing hyperglycemia. These findings suggest that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone can alleviate hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance.

A case of severe bilateral empyema due to Streptococcus pyogenes

Bilateral empyema is a rare and severe condition and deciding on a treatment is quite difficult. Additionally, infections caused by group A Streptococcus (GAS [Streptococcus pyogenes]) are known to be invasive. We successfully treated without surgery a previously healthy 59-year-old woman with bilateral empyema due to GAS, with repeated drainages, antibiotics, and fibrinolytic therapy. To our knowledge, there have not been any published reports on cases of bilateral empyema due to GAS infection. In rare, severe cases of bilateral empyema caused by organisms such as GAS, physicians managing the condition should consider the overall condition of the patient.

Alpha-Gal Bound Aptamer and Vancomycin Synergistically Reduce Staphylococcus aureus Infection In Vivo

Methicillin-resistant Staphylococcus aureus (MRSA) is a pervasive and persistent threat that requires the development of novel therapies or adjuvants for existing ones. Aptamers, small single-stranded oligonucleotides that form 3D structures and can bind to target molecules, provide one possible therapeutic route, especially when presented in combination with current antibiotic applications. BALB/c α-1, 3-galactosyltransferase (-/-) knockout (GTKO) mice were infected with MRSA via tail vein IV and subsequently treated with the αSA31 aptamer (n = 4), vancomycin (n = 12), or αSA31 plus vancomycin (n = 12), with split doses in the morning and evening. The heart, lungs, liver, spleen, and kidneys were harvested upon necropsy for histological and qPCR analysis. All mice treated with αSA31 alone died, whereas 5/12 mice treated with vancomycin alone and 7/12 mice treated with vancomycin plus αSA31 survived the course of the experiment. The treatment of MRSA-infected mice with Vancomycin and an adjuvant aptamer αSA31 reduced disease persistence and dispersion as compared to treatment with either vancomycin SA31 alone, indicating the combination of antibiotic and specifically targeted αSA31 aptamer could be a novel way to control MRSA infection. The data further indicate that aptamers may serve as a potential therapeutic option for other emerging antibiotic resistant pathogens.

Staphylococcal Enterotoxins Promote Virulence in Bacterial Keratitis

Purpose

Staphylococcus aureus is an important cause of corneal infections (keratitis). To better understand the virulence mechanisms mediating keratitis, a recent comparative genomics study revealed that a set of secreted enterotoxins were found with higher prevalence among ocular versus non-ocular S. aureus clinical infection isolates, suggesting a key role for these toxins in keratitis. Although well known to cause toxic shock syndrome and S. aureus food poisoning, enterotoxins have not yet been shown to mediate virulence in keratitis.

Methods

A set of clinical isolate test strains, including a keratitis isolate that encodes five enterotoxins (sed, sej, sek, seq, ser), its corresponding enterotoxin deletion mutant and complementation strain, a keratitis isolate devoid of enterotoxins, and the non-ocular S. aureus strain USA300 along with its corresponding enterotoxin deletion and complementation strains, were evaluated for cellular adhesion, invasion and cytotoxicity in a primary corneal epithelial model as well as with microscopy. Additionally, strains were evaluated in an in vivo model of keratitis to quantify enterotoxin gene expression and measure disease severity.

Results

We demonstrate that, although enterotoxins do not impact bacterial adhesion or invasion, they do elicit direct cytotoxicity in vitro toward corneal epithelial cells. In an in vivo model, sed, sej, sek, seq, ser were found to have variable gene expression across 72 hours of infection and test strains encoding enterotoxins resulted in increased bacterial burden as well as a reduced host cytokine response.

Conclusions

Our results support a novel role for staphylococcal enterotoxins in promoting virulence in S. aureus keratitis.

Clinical Profile, Intensive Care Needs, and Short-Term Outcome of Toxic Shock Syndrome Among Children: A 10-Year Single-Centre Experience from North India

OBJECTIVE

To describe the clinical and laboratory profile, management, intensive care needs, and outcome of children with toxic shock syndrome (TSS) admitted to the pediatric intensive care unit (PICU) of a tertiary care center in North India.

METHODS

This retrospective study was conducted in the PICU of a tertiary care hospital in North India over a period of 10 y (January 2011-December 2020) including children < 12 y with TSS (n = 63).

RESULTS

The median (interquartile range, IQR) age was 5 (2-9) y, 58.7% were boys, and Pediatric Risk of Mortality III (PRISM-III) score was 15 (12-17). The primary focus of infection was identified in 60.3% children, 44.5% had skin and soft tissue infections, and 17.5% (n = 11) had growth of Staphylococcus aureus. Common manifestations were shock (100%), rash (95.2%), thrombocytopenia (79.4%), transaminitis (66.7%), coagulopathy (58.7%), and acute kidney injury (AKI) (52.4%); and involvement of gastrointestinal (61.9%), mucus membrane (55.5%), respiratory (47.6%), musculoskeletal (41.3%), and central nervous system (CNS) (31.7%). The treatment included fluid resuscitation (100%), vasoactive drugs (92.1%), clindamycin (96.8%), intravenous immunoglobulin (IVIG) (92.1%), blood products (74.6%), mechanical ventilation (58.7%), and renal replacement therapy (31.7%). The mortality was 27% (n = 17). The duration of PICU and hopsital stay was 5 (4-10) and 7 (4-11) d, respectively. Higher proportion of nonsurvivors had CNS involvement, transaminitis, thrombocytopenia, coagulopathy, and AKI; required mechanical ventilation and blood products; and had higher vasoactive-inotropic score.

CONCLUSION

TSS is not uncommon in children in Indian setup. The management includes early recognition, intensive care, antibiotics, source control, and adjunctive therapy (IVIG and clindamycin). Multiorgan dysfunction and need for organ supportive therapies predicted mortality.

Staphylococcal Toxic Shock Syndrome in a Burned Child Treated with an Antimicrobial Foam Dressing: A Case Report

Staphylococcal toxic shock syndrome (TSS) is a severe systemic disease characterized by fever, hypotension, desquamating rash, and multiorgan dysfunction. Attributed to bacterial exotoxins, TSS has been a known, though rare, complication in the field of pediatric burns for decades. The adoption of new antimicrobial burn dressings has allowed for the management of small to medium sized burns with minimal discomfort or inconvenience to the patient. In this report, we discuss a 3-year-old male with burns wounds dressed using a silver-impregnated foam who went on to develop TSS.

Pathophysiological Considerations in Periorbital Necrotizing Fasciitis: A Case Report

BACKGROUND

Periorbital necrotizing fasciitis (PNF) is a rare complication of bacterial infection, associated with irreversible inflammatory destruction of soft tissues like subcutaneous tissue and superficial fascia. PNF can cause visual loss, septic shock and death within hours to days. Since the infection progresses rapidly from a local disease to septic shock, prompt identification and decisive interventions are mandatory.

AIM

Considering pathophysiology, differential diagnosis, and treatment options, we report a case of PNF and its outcome.

METHODS

A 69 years old male with febrile periorbital swelling had been diagnosed with bilateral PNF, caused by dual infection with Streptococcus pyogenes (S. pyogenes) and Staphylococcus aureus (S. aureus) based on conjunctival swabs.

RESULTS

The superantigens produced by S. pyogenes have been identified as key to the rapid dissemination of infection and severity of systemic manifestations.

CONCLUSION

A combination of intravenous antibiotics and regular surgical debridements resulted in a beneficial outcome in our patient.

The superantigens SpeC and TSST-1 specifically activate TRBV12-3/12-4+ memory T cells

Severe bacterial or viral infections can induce a state of immune hyperactivation that can culminate in a potentially lethal cytokine storm. The classic example is toxic shock syndrome, a life-threatening complication of Staphylococcus aureus or Streptococcus pyogenes infection, which is driven by potent toxins known as superantigens (SAgs). SAgs are thought to promote immune evasion via the promiscuous activation of T cells, which subsequently become hyporesponsive, and act by cross-linking major histocompatibility complex class II molecules on antigen-presenting cells to particular β-chain variable (TRBV) regions of αβ T cell receptors (TCRs). Although some of these interactions have been defined previously, our knowledge of SAg-responsive TRBV regions is incomplete. In this study, we found that CD4⁺ and CD8⁺ T cells expressing TRBV12-3/12-4⁺ TCRs were highly responsive to streptococcal pyrogenic exotoxin C (SpeC) and toxic shock syndrome toxin-1 (TSST-1). In particular, SpeC and TSST-1 specifically induced effector cytokine production and the upregulation of multiple coinhibitory receptors among TRBV12-3/12-4⁺ CD4⁺ and CD8⁺ memory T cells, and importantly, these biological responses were dependent on human leukocyte antigen (HLA)-DR. Collectively, these data provided evidence of functionally determinative and therapeutically relevant interactions between SpeC and TSST-1 and CD4⁺ and CD8⁺ memory T cells expressing TRBV12-3/12-4⁺ TCRs, mediated via HLA-DR.

Targeted Proteomics Analysis of Staphylococcal Superantigenic Toxins in Menstrual Fluid from Women with Menstrual Toxic Shock Syndrome (mTSS)

Menstrual toxic shock syndrome (mTSS) is a rare life-threatening febrile illness that occurs in women using intravaginal menstrual protection. It is caused by toxic shock syndrome toxin 1 (TSST-1) produced by Staphylococcus aureus, triggering a sudden onset of rash and hypotension, subsequently leading to multiple organ failure. Detecting TSST-1 and S. aureus virulence factors in menstrual fluid could accelerate the diagnosis and improve therapeutic management of mTSS. However, menstrual fluid is a highly complex matrix, making detection of bacterial toxins challenging. Here, we present a mass-spectrometry-based proteomics workflow for the targeted, quantitative analysis of four S. aureus superantigenic toxins in menstrual fluids (TSST-1, SEA, SEC, and SED). This method was applied to characterize toxin levels in menstrual fluids collected from patients with mTSS and healthy women. Toxins were detectable in samples from patients with mTSS and one healthy donor at concentrations ranging from 0 to 0.46 µg/mL for TSST-1, and 0 to 1.07 µg/mL for SEC. SEA and SED were never detected in clinical specimens, even though many S. aureus strains were positive for the corresponding genes. The method presented here could be used to explore toxin production in vivo in users of intravaginal devices to improve the diagnosis, understanding, and prevention of mTSS.

Acute heart failure associated with toxic shock syndrome due to methicillin-susceptible Staphylococcus aureus during the postpartum period: case report and systematic literature review

BACKGROUND

Toxic shock syndrome (TSS) caused by Staphylococcus aureus in the postpartum period is a rare but life-threatening disease. We present a case of acute heart failure as the initial presentation of TSS due to methicillin-susceptible Staphylococcus aureus (MSSA) and describe its clinical characteristics with a systematic literature review.

CASE PRESENTATION

A 34-year-old woman, 8 days after a normal vaginal delivery presented to our hospital with dyspnea and fever. She had jugular venous distension, bilateral leg edema, and erythema. Laboratory examinations revealed elevated NT-pro-BNP level of 3,233 pg/mL. Transthoracic echocardiography showed elevated tricuspid regurgitation peak gradient, with decreased respiratory variability of the inferior vena cava diameter and bilateral pleural effusions. The patient was hospitalized with suspicion of congestive heart failure. MSSA positive for toxic shock syndrome exotoxin-1 was detected in the culture of the perineal incision wound, and we diagnosed TSS caused by MSSA. Intravenous diuretics were administered, along with eventual cefazolin plus clindamycin. After 2 weeks of antimicrobial therapy, the patient showed improvement and was discharged. No recurrence was observed at the 24-month follow-up.

CONCLUSION

This is a rare case report of acute heart failure being the initial manifestation of TSS due to MSSA in the postpartum period. Clinicians should consider TSS as a possibility in postpartum patients with acute heart failure. This systematic review provides insights into its clinical features, treatment regimens, and prognosis of TSS by S. aureus in the postpartum period. TSS requires an appropriate, prompt diagnosis, because delayed treatment can be fatal.

Acute kidney injury in group A streptococcal bacteraemia: incidence, outcome and predictive value of C-reactive protein

BACKGROUND

A ubiquitous human pathogen, Streptococcus pyogenes (Group A Streptococcus, GAS) causes infections from mild pharyngitis to severe septic infections. Acute kidney injury (AKI) is a condition of prompt decline of renal function. The aim of the present study was to report the incidence and outcome of AKI in GAS bacteraemia and to evaluate the diagnostic value of serum C-reactive protein as an indicator of AKI.

METHODS

All adult patients with GAS bacteraemia treated at Turku University Hospital from 2007 to 2018 were identified and their patient records were scrutinised.

RESULTS

Of 195 included patients, 38 (19.5%) had AKI stage 1, 20 (10.3%) AKI stage 2 and 26 (13.3%) AKI stage 3 and 111 (56.9%) did not have AKI. The adjusted seven-day mortality was significantly higher in AKI stages 2 and 3 compared to the non-AKI group (15% and 19% vs. 3.6%; p = .046 and .006, respectively). Of the survivors, 95.8% met the criteria of renal recovery at discharge. The higher the AKI stage, the higher was the mean serum CRP level on admission. The optimal cut-off for CRP to identify patients with AKI stage 2 or 3 was ≥244 mg/l (sensitivity 82.6% and specificity 75.8%).

CONCLUSIONS

AKI is common in patients with GAS bacteraemia and the severity of AKI correlates with the CRP level on admission. The mortality of patients with GAS bacteraemia and AKI is significantly higher than of patients without AKI. Most survivors, however, show renal recovery.Key MessageAKI is common in group A Streptococcal bacteraemia and increases mortality compared to bacteraemia alone. However, renal recovery is also common. A high CRP level on admission correlates significantly positively with the degree of severity of AKI.

Nanoparticles application as a therapeutic strategy for diabetes mellitus management

The prevalence of diabetes, as reported by the World Health Organization and the International Diabetes Federation, has raised many eyebrows about the dangers of diabetes mellitus to society, leading to the development of various therapeutic techniques, including nanotechnological, in the management of this disease. This review discusses silver, gold, ceramic, alloy, magnetic, silica, polymeric nanoparticles and their various applications in diabetes management which may help to reduce the incidence of diabetes and its complication.

SARS-CoV-2-Specific Immune Response and the Pathogenesis of COVID-19

The review aims to consolidate research findings on the molecular mechanisms and virulence and pathogenicity characteristics of coronavirus disease (COVID-19) causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and their relevance to four typical stages in the development of acute viral infection. These four stages are invasion; primary blockade of antiviral innate immunity; engagement of the virus's protection mechanisms against the factors of adaptive immunity; and acute, long-term complications of COVID-19. The invasion stage entails the recognition of the spike protein (S) of SARS-CoV-2 target cell receptors, namely, the main receptor (angiotensin-converting enzyme 2, ACE2), its coreceptors, and potential alternative receptors. The presence of a diverse repertoire of receptors allows SARS-CoV-2 to infect various types of cells, including those not expressing ACE2. During the second stage, the majority of the polyfunctional structural, non-structural, and extra proteins SARS-CoV-2 synthesizes in infected cells are involved in the primary blockage of antiviral innate immunity. A high degree of redundancy and systemic action characterizing these pathogenic factors allows SARS-CoV-2 to overcome antiviral mechanisms at the initial stages of invasion. The third stage includes passive and active protection of the virus from factors of adaptive immunity, overcoming of the barrier function at the focus of inflammation, and generalization of SARS-CoV-2 in the body. The fourth stage is associated with the deployment of variants of acute and long-term complications of COVID-19. SARS-CoV-2's ability to induce autoimmune and autoinflammatory pathways of tissue invasion and development of both immunosuppressive and hyperergic mechanisms of systemic inflammation is critical at this stage of infection.

Post-surgical staphylococcal toxic shock syndrome in pediatrics: A case report

Introduction

Toxic shock syndrome (TSS) is a rare but serious, life-threatening medical condition and potentially lethal if not detected and treated early. It is mainly caused by a toxin called toxin-1 produced by Staphylococcus aureus, and characterized by fever, hypotension, rash, skin desquamation and multisystem involvement.

Case presentation

Herein, we describe a nine-month-old male patient who presented to the hospital complaining of fever, vomiting and hypoactivity on day one post-orchidopexy. During hospitalization, his condition began to deteriorate with signs and symptoms of multisystemic failure. Laboratory tests and radiological images were done, leading to the decision to reopen and drain the surgical wound. Wound and nasal swabs were cultured and showed S. aureus infection, and the diagnosis of toxic shock syndrome was confirmed.

Discussion

TSS is a systemic illness resulting from overwhelming host response to bacterial exotoxins, that cause T cells activation and the release of pro-inflammatory cytokines (IL-1 and TNF-α causing fever, hypotension, and tissue injury). Also, it can present with CNS signs that may be misdiagnosed with meningitis in pediatrics.

It requires early identification and treatment despite its rarity with mortality rate of 81% even with treatment.

The patient's presentation, examination and laboratories tests with the blood and wound cultures were highly suggestive for this condition.

Conclusion

Physicians must maintain a high index of suspicion for TSS, as early diagnosis and treatment make a difference. This condition shouldn't be excluded even in young age patients or after simple procedure as in our case in which TSS occurred after orchidopexy.

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Toxic shock syndrome is a life-threatening condition that can be highly mortal even with treatment.

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Post-surgical TSS is very rare and according to the literature this is the first reported case post-orchidopexy.

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Broad spectrum antibiotics with debridement of the necrotic tissue as management are the best option to treat this condition.

AR-12 Has a Bactericidal Activity and a Synergistic Effect with Gentamicin against Group A Streptococcus

Streptococcus pyogenes (group A Streptococcus (GAS) is an important human pathogen that can cause severe invasive infection, such as necrotizing fasciitis and streptococcal toxic shock syndrome. The mortality rate of streptococcal toxic shock syndrome ranges from 20% to 50% in spite of antibiotics administration. AR-12, a pyrazole derivative, has been reported to inhibit the infection of viruses, intracellular bacteria, and fungi. In this report, we evaluated the bactericidal activities and mechanisms of AR-12 on GAS infection. Our in vitro results showed that AR-12 dose-dependently reduced the GAS growth, and 2.5 μg/mL of AR-12 significantly killed GAS within 2 h. AR-12 caused a remarkable reduction in nucleic acid and protein content of GAS. The expression of heat shock protein DnaK and streptococcal exotoxins was also inhibited by AR-12. Surveys of the GAS architecture by scanning electron microscopy revealed that AR-12-treated GAS displayed incomplete septa and micro-spherical structures protruding out of cell walls. Moreover, the combination of AR-12 and gentamicin had a synergistic antibacterial activity against GAS replication for both in vitro and in vivo infection. Taken together, these novel findings obtained in this study may provide a new therapeutic strategy for invasive GAS infection.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America: 2021 Guideline on Diagnosis and Management of Acute Hematogenous Osteomyelitis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute hematogenous osteomyelitis (AHO) in children was developed by a multidisciplinary panel representing Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with AHO, including specialists in pediatric infectious diseases, orthopedics, emergency care physicians, hospitalists, and any clinicians and healthcare providers caring for these patients. The panel's recommendations for the diagnosis and treatment of AHO are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of AHO in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

Less-invasive Treatment for Group A Streptococcal Fasciitis with Rapid Antigen Detection Test and Collagen/Gelatin Sponge

Patients with severe group A Streptococcus (GAS) induced necrotizing soft tissue infection sometimes develop Streptococcal toxic shock syndrome, which is a life-threatening condition with an extremely high fatality rate. Obtaining survival is the most important goal; however, an early diagnosis for debridement surgery and quick granulation formation for skin grafting surgery can better preserve the extremity functions. The patient was a 47-year-old man with a history of atopic dermatitis who presented with GAS-induced necrotizing soft tissue infection in his left lower extremity. His vital signs indicated shock, and he was diagnosed with streptococcal toxic shock syndrome. Emergency surgery was performed with his body pressure maintained with noradrenaline. Intraoperatively, rapid antigen detection tests (RADTs) were negative in the medial thigh and positive in the lower leg, which helped in decision-making regarding the area of aggressive debridement surgery. The wound culture results matched the intraoperative rapid antigen detection test results. A collagen/gelatin sponge with the sustained release of basic fibroblast growth factor was used as an artificial dermis before skin grafting. Excellent granulation was obtained, and skin grafting surgery was performed on the 11th day after collagen/gelatin sponge placement. He was discharged home on the 42nd day with normal lower extremity functions. First, an intraoperative diagnosis using GAS-rapid antigen detection tests with an appropriate sampling method from small incisions avoided excessive surgical debridement. Second, collagen/gelatin sponge with the sustained release of basic fibroblast growth factor promoted quick granulation tissue formation for wound bed preparation. These efforts resulted in the successful less-invasive treatment of a patient with streptococcal toxic shock syndrome caused by GAS-induced necrotizing soft tissue infection.

A 24-Year-Old Woman Presenting With Altered Mental Status and Multiorgan Failure

A 24-year-old previously healthy woman was brought to the hospital for acute altered mental status. One week prior to presentation, she had developed a sore throat, nausea, and vomiting. At that time, SARS-CoV-2 polymerase chain reaction and rapid streptococcal pharyngitis test results were both negative. On the day prior to presentation, the patient had developed an erythematous painful rash on her left arm. The following day she was noted to be agitated, combative, and having trouble communicating, prompting ED evaluation. In the ED, the patient was tachycardic to 108 beats/min and tachypneic to 30 breaths/min but normotensive and afebrile. Her initial workup was notable for leukocytosis with bandemia, acute liver injury with coagulopathy, and acute renal failure. She was intubated, transferred to our hospital, and admitted to the MICU. The patient’s medical history was notable for obesity and oral contraceptive use. She had no family history of autoimmune, rheumatologic, or hematologic disorders. She was a student and worked part time in retail. She had no recent travel or outdoor exposure. The patient’s family was unaware of any tobacco or drug use but did report that she drank socially.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Clinical and laboratory characteristics of patients presenting to a tertiary care center emergency department with invasive group A streptococcal infections

OBJECTIVES

The aim of this study was to describe the clinical and laboratory characteristics of invasive group A streptococcal infections in a geographic area that sees a high volume of cases.

METHODS

We conducted a health records review of consecutive patients presenting to the Thunder Bay Regional Health Sciences Centre Emergency Department (ED) in 2016-2017 with a diagnosis of invasive group A streptococcal infection using ICD-10 codes. Patient demographics, host characteristics, triage vital signs, laboratory values, culture sites, and disposition were described using univariate and bivariate statistics.

RESULTS

Forty-four adult cases were identified over 2 years, with a median age of 44 years (interquartile range, 35-52). The most prevalent risk factors were diabetes mellitus (45%), current or previous alcohol abuse (39%), and current or previous intravenous drug use (34%). The two most abnormal triage vitals signs were a heart rate ≥ 100 beats per minute in 32 (73%) cases and a respiratory rate ≥ 20 breaths per minute in 27 (63%) cases. The temperature was ≥ 38°C in only 14 (32%) of cases. The C-reactive protein (CRP) was always elevated when measured, and greater than 150 mg/L in 20 (71%) of cases. One-third of patients had an ED visit in the preceding 7 days before the diagnosis of invasive group A Streptococcus.

CONCLUSIONS

Invasive group A streptococcal infections often present insidiously in adult patients with mild tachycardia and tachypnea at triage. The CRP was the most consistently abnormal laboratory investigation.

Playing With Fire: Proinflammatory Virulence Mechanisms of Group A Streptococcus

Group A Streptococcus is an obligate human pathogen that is a major cause of infectious morbidity and mortality. It has a natural tropism for the oropharynx and skin, where it causes infections with excessive inflammation due to its expression of proinflammatory toxins and other virulence factors. Inflammation directly contributes to the severity of invasive infections, toxic shock syndrome, and the induction of severe post-infection autoimmune disease caused by autoreactive antibodies. This review discusses what is known about how the virulence factors of Group A Streptococcus induce inflammation and how this inflammation can promote disease. Understanding of streptococcal pathogenesis and the role of hyper-immune activation during infection may provide new therapeutic targets to treat the often-fatal outcome of severe disease.

Toxic shock syndrome associated with menstrual cup use

Staphylococcal toxic shock syndrome is a rare but life-threatening condition. It occurs when Staphylococcus aureus bacteria colonizing the vagina of a healthy woman, produce toxic shock syndrome toxin 1 activating the immune system and leading to multiorgan failure. Menstrual cups also known as vaginal cups are usually used as alternatives to other intravaginal products for menstrual blood collection. In rare cases, they can also lead to toxic shock syndrome. We report a case of toxic shock syndrome associated with vaginal cup use in a healthy menstruating woman. The diagnosis was made based on the United States Centers for Disease Control and Prevention criteria of the syndrome and confirmed with a vaginal cultural growth of Staphylococcus aureus.

Activation of human γδ T cells and NK cells by Staphylococcal enterotoxins requires both monocytes and conventional T cells

Staphylococcal enterotoxins (SE) pose a great threat to human health due to their ability to bypass antigen presentation and activate large amounts of conventional T cells resulting in a cytokine storm potentially leading to toxic shock syndrome. Unconventional T- and NK cells are also activated by SE but the mechanisms remain poorly understood. In this study, the authors aimed to explore the underlying mechanism behind SE-mediated activation of MAIT-, γδ T-, and NK cells in vitro. CBMC or PBMC were stimulated with the toxins SEA, SEH, and TSST-1, and cytokine and cytotoxic responses were analyzed with ELISA and flow cytometry. All toxins induced a broad range of cytokines, perforin and granzyme B, although SEH was not as potent as SEA and TSST-1. SE-induced IFN-γ expression in MAIT-, γδ T-, and NK cells was clearly reduced by neutralization of IL-12, while cytotoxic compounds were not affected at all. Kinetic assays showed that unconventional T cell and NK cell-responses are secondary to the response in conventional T cells. Furthermore, co-cultures of isolated cell populations revealed that the ability of SEA to activate γδ T- and NK cells was fully dependent on the presence of both monocytes and αβ T cells. Lastly, it was found that SE provoked a reduced and delayed cytokine response in infants, particularly within the unconventional T and NK cell populations. This study provides novel insights regarding the activation of unconventional T- and NK cells by SE, which contribute to understanding the vulnerability of young children towards Staphylococcus aureus infections.

[COVID-19 in children: SARS-CoV-2-related inflammatory multisystem syndrome mimicking Kawasaki disease]

SARS-CoV-2 pandemics is characterized by a high level of infectivity and a high mortality among adults at risk (older than 65 years, obesity, diabetes, systemic hypertension). Following a common viral pneumonia, a multisystem inflammatory syndrome sometimes occurs, including an Acute Respiratory Distress Syndrome (ARDS) carrying a high mortality. Unlike most common respiratory viruses, children seem less susceptible to SARS-CoV-2 infection and generally develop a mild disease with low mortality. However, clusters of severe shock associated with high levels of cardiac biomarkers and unusual vasoplegia requiring inotropes, vasopressors and volume loading have been recently described. Both clinical symptoms (i.e., high and persistent fever, gastrointestinal disorders, skin rash, conjunctivitis and dry cracked lips) and biological signs (e.g., elevated CRP/PCT, hyperferritinemia) resembled Kawasaki disease. In most instances, intravenous immunoglobin therapy improved the cardiac function and led to full recovery within a few days. However, adjunctive steroid therapy and sometimes biotherapy (e.g., anti-IL-1Ra, anti-IL-6 monoclonal antibodies) were often necessary. Although almost all children fully recovered within a week, some of them developed coronary artery dilation or aneurysm. Thus, a new 'Multisystem Inflammatory Syndrome associated with SARS-CoV-2' has been recently described in children and helps to better understand Kawasaki disease pathophysiology.

Severe acute respiratory syndrome coronavirus 2-related multisystem inflammatory syndrome in children mimicking Kawasaki disease

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been characterized by high transmission rates and high mortality in adults with predisposing factors, including age > 70 years, obesity, diabetes, systemic hypertension and other underlying diseases. During the second week of viral pneumonia, acute respiratory distress syndrome can occur and carries high mortality. Unlike most common respiratory viruses, children seem to be less susceptible to SARS-CoV-2 infection, and generally develop mild disease with low mortality. However, clusters of severe shock associated with high levels of cardiac biomarkers and unusual vasoplegia requiring inotropes, vasopressors and volume loading have recently been described. Both the clinical symptoms (i.e. high and persistent fever, gastrointestinal disorders, skin rash, conjunctival injection and dry cracked lips) and the biological signs (e.g. elevated C-reactive protein/procalcitonin and high levels of ferritinaemia) mimicked Kawasaki disease. In most cases, intravenous immunoglobin therapy improved cardiac function and led to full recovery within a few days. Adjunctive steroid therapy and sometimes biotherapy (e.g. anti-interleukin 1Ra and anti-interleukin 6 monoclonal antibodies) were often necessary. Although almost all children fully recovered within a week, some of them later developed coronary artery dilation or aneurysm. Thus, a new “multisystem inflammatory syndrome in children” related to SARS-CoV-2 has recently been described. Similarities with Kawasaki disease and the physiopathology of this syndrome still need further exploration.