Epidemiology of invasive Streptococcus pyogenes infections in France in 2007

Skin and systemic infections in children with atopic dermatitis: review of the current evidence

Atopic dermatitis is a chronic, pruritic inflammatory skin disorder that affects approximately 2%-42% of children worldwide. Its course is frequently complicated by secondary bacterial, viral, and fungal infections, which can exacerbate disease severity and hinder treatment outcomes. These infections are thought to arise due to a disrupted skin barrier, reduced antimicrobial peptide production, alterations in the skin microbiome, and Th2-dominant inflammatory response. Identifying the most prevalent and pathogenic microorganisms in patients with AD is critical for early diagnosis, effective management, and prevention of complications. This review provides an updated synthesis of current knowledge on the infectious agents implicated in AD pathogenesis, summarizing recent findings on the epidemiology, microbial interactions, and immune mechanisms involved. Furthermore, it provides an overview of the latest therapeutic strategies for managing AD and its associated infections. By integrating recent insights into pathogenesis and treatment, this study offers a comprehensive perspective on the evolving landscape of AD management in children.

Antibiotic chemoprophylaxis for close contacts of invasive group A streptococcus in community settings: Evidence review

OBJECTIVES

Revised UK guidelines for the management of contacts of invasive group A Streptococcus (iGAS) infection in community settings were published in December 2022. We present the findings of a narrative review which informed the public health recommendations around the provision of antibiotic chemoprophylaxis detailed in the updated guidelines.

METHODS

We conducted a literature review of studies reporting the risk of iGAS infection associated with specific risk factors.

RESULTS

There was strong epidemiological evidence for an increased risk of iGAS infection in contacts who are older individuals, post-partum women, neonates and individuals with chickenpox infection; evidence on the impact of influenza co-infection, injecting drug use or being homeless in increasing risk of iGAS infection was less robust.

CONCLUSIONS

The guidelines made recommendations to offer chemoprophylaxis to close contacts of iGAS cases who are aged ≥75 years, pregnant ≥37 weeks gestation, post-partum, neonates or those with a recent history of, or current chickenpox infection. Systematic data collection evaluating the use of chemoprophylaxis and other control measures is recommended.

Group A streptococcus isolated in Guyana with reduced susceptibility to β-lactam antibiotics

Introduction. Streptococcus pyogenes [group A streptococci (GAS)] is the causative agent of pharyngitis and various other syndromes involving cellulitis, streptococcal toxic shock syndrome (STSS), and necrotising fasciitis. Although the prevalence of GAS infections globally remains high, necessitating the widespread use of β-lactam antibiotics, GAS have remained largely susceptible to these agents. However, there have been several reports of GAS with reduced susceptibility harbouring mutations in genes for penicillin-binding proteins (PBPs). The objectives of this study were to examine the in vitro β-lactam susceptibility patterns of group A streptococci, determine the prevalence of drug resistance, and ascertain whether such resistance could be attributed to mutations in specific PBP genes. Methods. In this study, we sought to use Sanger sequencing to identify mutations in PBP genes of Streptococcus pyogenes isolated from patients that required inpatient and outpatient care that could confer reduced PBP affinity for penicillin and/or cephalosporin antibiotics. All isolates were screened for susceptibility to penicillin, amoxicillin, and cefazolin using E-test strips. Results. While there were no documented cases of reduced susceptibility to penicillin or amoxicillin, 13 isolates had reduced susceptibility to cefazolin. Examination of pbp1a by Sanger sequencing revealed several isolates with single amino acid substitutions, which could potentially reduce the affinity of PBP 1A for cefazolin and possibly other first-generation cephalosporins. Conclusion. Penicillin and penicillin-derived antibiotics remain effective treatment options for GAS infections, but active surveillance is needed to monitor for changes to susceptibility patterns against these and other antibiotics and understand the genetic mechanisms contributing to them.

The Thousand Faces of Invasive Group A Streptococcal Infections: Update on Epidemiology, Symptoms, and Therapy

Invasive infections caused by Streptococcus pyogfenes (iGAS), commonly known as Group A Streptococcus, represent a significant public health concern due to their potential for rapid progression and life-threatening complications. Epidemiologically, invasive GAS infections exhibit a diverse global distribution, affecting individuals of all ages with varying predisposing factors. The pathogenesis of invasive GAS involves an array of virulence factors that contribute to tissue invasion, immune evasion, and systemic dissemination. In pediatrics, in the last few years, an increase in iGAS infections has been reported worldwide becoming a challenging disease to diagnose and treat promptly. This review highlights the current knowledge on pathogenesis, clinical presentations, and therapeutic approaches for iGAS in children.

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 Streptococcal Infection in Children: Report on Two Cases with Uncharacteristic Course of Scarlet Fever

Introduction: Scarlet fever is usually a mild childhood disease caused by type A streptococci. This disease is spread by droplets, mainly through direct contact with an infected person or the objects they have used. In pediatrics, these are significant risk factors for the transmission of infectious diseases. However, it is important to remember the possibility of serious complications in the course of scarlet fever. Aim: This paper provides a discussion of two pediatric cases in order to determine the possibilities of diagnosis, differentiation, and treatment of patients with severe, non-obvious courses of scarlet fever. Methods: The case reports of two patients hospitalized in a pediatric department due to Streptococcus pyogenes infection were examined. Results: The patients were admitted to the emergency room with symptoms not directly indicative of type A streptococcal infection, which required further diagnosis. Both patients complained of weakness at the time of presentation. They had an elevated temperature, were dehydrated during the course of gastroenteritis, and passed liquid stools without pathological admixtures. Further stages of diagnosis and treatment required hospitalization in the pediatric department. Therapeutic benefit from the implemented treatment was obtained, and the patients were discharged in good general condition with further recommendations. Conclusions: Medical history, which is often very detailed, can be the key to making the final diagnosis and can supplement the data collected on the basis of laboratory tests. Scarlet fever does not always occur with a mild course, and sometimes its course can be quite non-specific and may require a thorough diagnosis.

Incidence and clinical and microbiological features of invasive and probable invasive streptococcal group A infections in children and adults in the Brussels-Capital Region, 2005-2020

Assess the incidence, risk factors, clinical and microbiological features, and outcome of both probable invasive and invasive group A Streptococcus (GAS) infections in children and adults in the BrusselsCapital Region between 2005 and 2020. A retrospective, multicentric study was performed in three university hospitals in Brussels. Patients were identified through the centralized laboratory information system. Epidemiological and clinical data were collected from patients' hospital records. A total of 467 cases were identified. Incidence has increased from 2.1 to 10.9/100,000 inhabitants between 2009 and 2019 in non-homeless adults while it was above 100/100,000 on homeless in years with available denominators. Most of GAS were isolated from blood (43.6%), and the most common clinical presentation was skin and soft tissue infections (42.8%). A third of all the patients needed surgery, a quarter was admitted to the intensive care unit, and 10% of the adult patients died. Wounds and chickenpox disease were the main risk factors for children. Tobacco, alcohol abuse, wounds or chronic skin lesion, being homeless, and diabetes were identified as major predisposing factors for adults. The most common emm clusters were D4, E4, and AC3; 64% of the isolates were theoretically covered by the 30-valent M-protein vaccine. The burden of invasive and probable invasive GAS infections is on the rise in the studied adult population. We identified potential interventions that could contribute to decrease this burden: appropriate care of wounds, specifically among homeless and patients with risk factors such as diabetes and systematic chickenpox vaccination for children.

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.

Outcomes and management of pregnancy and puerperal group A streptococcal infections: A systematic review

INTRODUCTION

Group A streptococcus (Streptococcus pyogenes) is one of the most lethal bacterial pathogens of humans, with increased risk of progression to septic shock and multiorgan failure in the pregnant population. The objective of this study is to systematically review the outcomes and management strategies for pregnancy and puerperal group A streptococcus infections in an effort to provide further guidance for prevention and treatment of a rare but lethal infection worldwide.

MATERIAL AND METHODS

A comprehensive search using puerperium and streptococcus pyogenes terms was completed across several registered databases. A total of 902 articles investigating pregnancy and puerperal group A streptococcus infection were identified, with 40 studies fulfilling inclusion criteria of original research articles in humans published from 1990 onwards reporting four or more unique cases of group A streptococcus in pregnancy or postpartum. This study was registered in PROSPERO: CRD42020198983.

RESULTS

A total of 1160 patients with pregnancy and puerperal group A streptococcus infection were identified. Most infections occurred postpartum (91.9%), with 4.7% reported antepartum and 0.6% intrapartum. Bacteremia was present in 49.0% of patients and endometritis in 45.9%. Puerperal sepsis was described in 28.2% of cases and progressed to streptococcal toxic shock syndrome in one-third of such cases. Overall, the case fatality ratio was 2.0%, with one-third of the deaths from antenatal cases including 3/22 (13.6%) cases of septic abortion and 10/46 (21.7%) antenatal cases of group A streptococcus infection.

CONCLUSIONS

Group A streptococcus infection remains an important contributor to pregnancy and puerperal morbidity and mortality. Early recognition, diagnosis and aggressive management are important for favorable outcomes given the serious risk of sepsis and streptococcal toxic shock syndrome.

Impact of Phosphorylcholine Expression on the Adherence and Invasion of Streptococcus pyogenes to Epithelial Cells

Phosphorylcholine (PC) is a structural component of various pathogens and is involved in bacterial adhesion via the platelet-activating factor receptor (PAF-R). In this study, we investigated how PC expression affects cell adhesion and invasion of Streptococcus pyogenes (S. pyogenes). Eight clinical strains of S. pyogenes were cultured, and PC expression was measured using fluorescence-activated cell sorting. Bacterial adherence and invasion were examined using Detroit 562 cells. An anti-PC-specific monoclonal antibody (TEPC-15) was used to inhibit bacterial PC, and a PAF-R antagonist (ABT-491) was used to inhibit cellular PAF-R. The emm gene was amplified by the polymerase chain reaction with the standard primers. The level of PC expressed on the S. pyogenes surfaces differed in each strain and differed even in the same emm genotype. Adherence assay experiments showed a significant negative correlation between TEPC-15 and ABT-491 inhibitory effects and PC expression in S. pyogenes. Similarly, intracellular invasion assay experiments showed a significant negative correlation between TEPC-15 and ABT-491 inhibitory effects and PC expression in S. pyogenes. This study suggests that S. pyogenes is involved in cell adhesion and invasion by PC.

Incidence and mortality of necrotizing fasciitis in The Netherlands: the impact of group A Streptococcus

BACKGROUND

Little is known about the exact incidence of necrotizing soft tissue infections. The few incidences reported in international literature are not directly relatable to the Netherlands, or other European countries, due to geographic heterogeneity in causative micro-organisms involved. This resulted in the aim of this study to map the incidence, mortality rate and hospital course of necrotizing fasciitis infections in the Netherlands to gain insight in the incidence of necrotizing fasciitis in the Netherlands and the associated mortality and health care burden.

METHODS

This nationwide retrospective database study used three distinct data sources to map the incidence of necrotizing fasciitis in the Netherlands between 2014 and 2019, being data from the Dutch Hospital Data (DHD) foundation, data from Osiris-AIZ, which is a database of notifiable diseases managed by regional Public Health Services (GGD) and the National Institute for Public Health and the Environment (RIVM), and previously published studies on necrotizing fasciitis conducted in the Netherlands.

RESULTS

The incidence of necrotizing fasciitis in the Netherlands is estimated to be approximately 1.1 to 1.4 cases per 100,000 person years, which corresponds to 193-238 patients per year. Of all necrotizing fasciitis infections, 34 to 42% are caused by the group A Streptococcus. Annually, 56 patients die as a result of a necrotizing fasciitis infection (mortality of 23-29%) and 26 patients undergo an amputation for source control (11-14%). Patients stay a mean of 6 to 7 days at the intensive care unit and have a mean hospital length of stay of 24 to 30 days.

CONCLUSION

The combination of nationwide databases provides reliable insight in the epidemiology of low-incidence and heterogenic diseases. In the Netherlands, necrotizing fasciitis is a rare disease with group A Streptococcus being the most common causative micro-organism of necrotizing fasciitis. The prior Dutch cohort studies on necrotizing fasciitis report slightly higher sample mortality rates, compared to the population mortality. However, necrotizing fasciitis remain associated with substantial morbidity and mortality, risk at amputation and health care burden characterized by prolonged ICU and hospital stay.

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.

Severe acute otitis media and mastoiditis caused by group A beta-hemolytic streptococcus

OBJECTIVE

To describe the characteristics, diagnostics, treatment, and outcome of severe acute otitis media (AOM) and acute mastoiditis (AM) caused by group A beta-hemolytic streptococcus (GAS).

STUDY DESIGN

A retrospective cohort study.

METHODS

The yearly incidence of inpatient care-needing GAS AOM/AM patients in our hospital catchment area between 2002 and 2018 was investigated. A detailed analysis was performed for cases treated during the last GAS epidemic in 2017-2018. Anamnesis, signs and symptoms, pure-tone audiometry results, treatment, complications, and outcome were collected from medical charts. Patients responded to an otology-specific health-related quality of life survey (EOS-16) 1.5 to 3 years after their treatment.

RESULTS

The number of GAS infections peaks at approximately 7-year intervals. During 2017 and 2018, altogether 37 patients (29 adults and 8 children) were hospitalized due to GAS AOM/AM. AM was diagnosed in 14 (38%) patients. The disease progression was typically very rapid. At presentation, all patients had severe ear pain, 68% tympanic membrane perforation and discharge, 43% fever, and 43% vertigo. In pure-tone audiometry, there was usually a marked mixed hearing loss at presentation. There was a significant recovery in both air and bone conduction thresholds; the pure tone average improvement from presentation was 32.3 ± 14.8 dB. Rapid strep tests (RST) proved to be more sensitive than bacterial culture in identifying GAS as a cause of AOM/AM.

CONCLUSION

GAS AOM/AM has a rapid onset. Hearing loss usually includes a sensorineural component, which is usually reversible with adequate treatment. RST seems to be useful in detecting GAS from middle ear discharge.

LEVEL OF EVIDENCE

4.

The Mobile Genetic Element RD2 Affects Colonization Potential of Different GAS Serotypes

M-type 28 (M28) Streptococcus pyogenes (group A Streptococcus [GAS]) strains are highly associated with life-threatening puerperal infections. Genome sequencing has revealed a large mobile genetic element, RD2, present in most M28 GAS isolates but not found widely in other serotypes. Previous studies have linked RD2 to the ability of M28 GAS to colonize the vaginal tract. A new study by Roshika and colleagues (R. Roshika, I. Jain, J. Medicielo, J. Wächter, J. L. Danger, P. Sumby, Infect Immun 89:e00722-20, 2021, https://doi.org/10.1128/IAI.00722-20) used gain-of-function mutants in three different GAS serotypes to help determine why RD2 appears to have a serotype preference and what that could mean for GAS mucosal colonization and pathogenesis.

The Place of Group A Streptococci in Moroccan Children with Pharyngitis and Emm Type Distribution

Background: Streptococcus pyogenes is responsible for a wide variety of diseases, including noninvasive and severe invasive infections. The emm gene encodes the M protein that is the virulence factor and immunological determinant of group A streptococci. Emm typing is the group A Streptococci (GAS) standard molecular typing method based on the amplification of the N terminal hypervariable region of the emm gene. Objectives: The aim of the present study was to determine the prevalence of GAS in children with pharyngitis and determine different types of emm gene in the GAS isolates using emm typing. Methods: The study was carried out over a period of 14 months (from February 2017 to March 2018). Throat samples were collected from cases aged ≤ 18 years with pharyngitis referring to a primary health care center in Fez, Morocco. GAS isolates were subjected to conventional tests to confirm species identification. Antimicrobial susceptibility testing was performed using the standard disk diffusion method. We researched emm gene by a polymerase chain reaction (PCR). Emm types were determined by a sequence-based protocol. Demographic and clinical data were recorded from each patient. Results: From a total of 177 throat samples, 11 isolates (6.2%) were identified as GAS in children with pharyngitis. Antibiotic sensitivity testing revealed that all the GAS isolates were sensitive to penicillin. The sequencing of the PCR products of the emm gene revealed that emm90 was the most obtained emm type (30,77%); while emm75 was the least type observed (7.7%). Conclusions: The emm90 is the most prevalent type detected from patients with tonsillitis. Penicillin and erythromycin are still the foremost effective antibiotics to treat GAS pharyngitis.

Group A streptococcal bacteraemia at a tertiary hospital in Melbourne: concern of an under-reported risk group in Australia

BACKGROUND

Invasive group A streptococcal (iGAS) infections are increasing worldwide with at-risk groups being children, pregnant women and the elderly. In 2017, there was a rise in iGAS cases in Victoria, prompting a Chief Health Officer advisory.

AIMS

To describe the characteristics of patients with GAS bacteraemia admitted to a tertiary hospital. To compare at-risk groups in our population with those identified in the Victorian Government health alert.

METHODS

Retrospective review of patients with GAS bacteraemia admitted between June 2014 and December 2017 at a tertiary hospital in Melbourne, Victoria.

RESULTS

Forty-three cases of GAS bacteraemia occurred. Average age was 52 years (range 15-88 years) with 63% male. Average length of stay was 14 days (range 0-72 days) and all-cause mortality occurred in two (5%) cases. Twelve (28%) patients presented with shock, 11 (26%) required intensive care unit admission and 13 (30%) surgical intervention. A history of intravenous drug use was documented in 18 (42%) cases and was commonly complicated by bone or joint involvement or thrombosis. Typing of GAS samples identified 22 different emm-types.

CONCLUSION

GAS bacteraemia resulted in significant morbidity and prolonged hospitalisation. In contrast to the at-risk groups identified in the Victorian Government health advisory, the commonest risk group in this series were people who inject drugs and most commonly middle-aged men. Invasive GAS should be considered if a person who injects drugs presents with acute severe sepsis.

Invasive Streptococcus pyogenes disease in Spain: a microbiological and epidemiological study covering the period 2007-2019

The aim of this study is to present the first nationwide microbiological and epidemiological study of invasive group A Streptococcus (iGAS) disease in Spain. One thousand eight hundred ninety-three iGAS isolates were analyzed over 2007-2019. emm typing was performed by sequencing the gene's variable 5' end, exotoxin genes were identified by PCR, and antimicrobial susceptibility explored via the E test and disk diffusion. Five hundred twenty-three isolates were associated with sepsis, 292 with cellulitis, 232 with scarlet fever, 153 with pneumonia, 141 with streptococcal toxic shock syndrome, and 94 with necrotizing fasciitis. The most prevalent emm types were emm1 (449/1893 isolates), emm89 (210/1893), emm3 (208/1893), emm4 (150/1893), emm12 (112/1893) emm6 (107/1893), emm87 (89/1893), emm28 (88/1893), emm75 (78/1893), emm77 (78/1893), emm11 (58/1893), and emm22 (35/1893). emm1, emm3, emm4, and emm6 were the predominant types affecting children (mostly respiratory infections), while emm11, emm77, and emm89 prevailed in the elderly (mostly skin infections). Each emm type was associated with one or more exotoxin gene (spe, sme, and ssa) profiles. speA was detected in 660 isolates, speB in 1829, speC in 1014, speF in 1826, speG in 1651, speJ in 716, speH in 331, smeZ in 720, and ssa in 512. Isolates with speA were associated with the most severe infections. Penicillin susceptibility was universal. Two hundred twenty-four isolates were resistant to tetracycline, 169 to erythromycin, and 81 to clindamycin. Tetracycline, erythromycin, and clindamycin resistance rates declined over the study period. The above information could serve as the basis for continued surveillance efforts designed to control disease cause by this bacterium.

Challenges in Surveillance for Streptococcal Toxic Shock Syndrome: Active Bacterial Core Surveillance, United States, 2014-2017

OBJECTIVES

Routine surveillance for streptococcal toxic shock syndrome (STSS), a severe manifestation of invasive group A Streptococcus (GAS) infections, likely underestimates its true incidence. The objective of our study was to evaluate routine identification of STSS in a national surveillance system for invasive GAS infections.

METHODS

Active Bacterial Core surveillance (ABCs) conducts active population-based surveillance for invasive GAS disease in selected US counties in 10 states. We categorized invasive GAS cases with a diagnosis of STSS made by a physician as STSS-physician and cases that met the Council of State and Territorial Epidemiologists (CSTE) clinical criteria for STSS based on data in the medical record as STSS-CSTE. We evaluated agreement between the 2 methods for identifying STSS and compared the estimated national incidence of STSS when applying proportions of STSS-CSTE and STSS-physician among invasive GAS cases from this study with national invasive GAS estimates for 2017.

RESULTS

During 2014-2017, of 7572 invasive GAS cases in ABCs, we identified 1094 (14.4%) as STSS-CSTE and 203 (2.7%) as STSS-physician, a 5.3-fold difference. Of 1094 STSS-CSTE cases, we identified only 132 (12.1%) as STSS-physician cases. Agreement between the 2 methods for identifying STSS was low (κ = 0.17; 95% CI, 0.14-0.19). Using ABCs data, we estimated 591 cases of STSS-physician and 3618 cases of STSS-CSTE occurred nationally in 2017.

CONCLUSIONS

We found a large difference in estimates of incidence of STSS when applying different surveillance methods and definitions. These results should help with better use of currently available surveillance data to estimate the incidence of STSS and to evaluate disease prevention efforts, in addition to guiding future surveillance efforts for STSS.

Molecular epidemiology of nonpharyngeal group A streptococci isolates in northern Lebanon

Aim: To characterize the epidemiology of group A Streptococcus (GAS) involved in nonpharyngeal infections sparingly addressed in Lebanon. Materials & methods: A collection of 63 nonpharyngeal GAS isolates recovered between 2010 and 2019 from northern Lebanon were analyzed through emm typing, virulence gene profiling, FCT typing and antibiotic susceptibility analysis. Results & conclusion: A total of 29 emm subtypes was detected, with emm1 being the most dominant. A great intraclonal divergence driven by the loss and gain of superantigens or by the structural variability within the FCT regions was unraveled. The resistance rates for erythromycin and tetracycline were 8 and 20.6%, respectively. The 30-valent vaccine coverage was 76%. This study evidences the complexity of the neglected GAS pathogen in Lebanon.

Beta-Hemolytic Streptococci and Necrotizing Soft Tissue Infections

β-hemolytic streptococci are major causes of necrotizing soft tissue infections (NSTIs), Streptococcus pyogenes (group A streptococcus; GAS) in particular. NSTIs caused by Streptococcus dysgalactiae (SD) have also been reported. In the INFECT cohort of 409 NSTIs patients, more than a third of the cases were caused by GAS (31%) or SD (7%). Risk factors of streptococcal NSTIs compared to streptococcal cellulitis have previously been largely unknown. The INFECT study confirmed blunt trauma as an important risk factor. In addition, absence of pre-existing skin lesions and a lower BMI were associated with NSTIs. The study also confirmed that septic shock is more frequent in GAS cases than in other types of NSTIs. Septic shock was also among several predictors of mortality. The role of intravenous immunoglobulin (IVIG) in streptococcal NSTIs has been unclear. In the INFECT cohort, IVIG treatment was associated with increased survival. As in other studies, a significant microbial diversity was observed, but with predominance of a few emm types. Overall, the INFECT study gives a comprehensive and contemporary picture of the clinical characteristics and the microbes involved in streptococcal NSTIs. The reported severity of disease underscores the need for new efforts aimed at identifying novel diagnostic measures and improved treatment.

Molecular Characterization of Streptococcus pyogenes Causing Invasive Disease in Pediatric Population in Spain A 12-year Study

OBJECTIVES

To perform a comprehensive description of the epidemiology of Streptococcus pyogenes invasive disease in the pediatric population in 2 regions of Spain (Catalonia and Gipuzkoa) through 12 years.

METHODS

All S. pyogenes isolates causing invasive disease in pediatric patients between 2005 and 2016 were included. The emm-type and the presence of 13 exotoxin genes (speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, smeZ, ssa and slo) were determined in all 93 available isolates and the Multi Locus Sequece Typing in 10% of isolates of each different emm-type.

RESULTS

Overall, 103 cases of S. pyogenes invasive infections were detected: 77 in Catalonia and 26 in Gipuzkoa, being 50.5% females. The incidence rate per 100,000 children was 2.5 for Gipuzkoa and 2.6 for Catalonia, with no significant temporal trends. The median age was 30 months. The most frequent clinical presentations were: pneumonia (26.2%), bacteremia/sepsis (23.3%), septic arthritis/osteomyelitis (22.3%), cellulitis/mastoiditis (12.6%) and meningitis (6.8%). Eight children developed streptococcal toxic shock syndrome. Nine cases were preceded by varicella infection. The associated mortality rate was 3.9%. Three isolates were resistant to erythromycin, being one of them also resistant to clindamycin and 4 isolates were resistant to levofloxacine. Forteen different emm-types were detected being emm1/ST28 (40.9%) the most frequent clone in both regions followed by emm12/ST36-ST242, emm6/ST382, emm3/ST15, emm75/ST150 and emm4/ST38-39. speA gene was only detected in emm1 and emm3 isolates. Eight exotoxins were enough to assign an emm-type with a very high degree of accuracy (95%). The 30-valent vaccine would include 96.8% of isolates.

[Invasive disease due to Streptococcus pyogenes: Changes in incidence and prognostic factors]

INTRODUCTION

Invasive group A streptococcal disease (iGASD) is a serious infection in children. Several studies have shown an increased incidence in the past years.

OBJECTIVE

To evaluate the characteristics and outcome of iGASD in children, and to determine changes in incidence or severity.

MATERIAL AND METHODS

A retrospective study was conducted on children≤16 years evaluated in a tertiary paediatric hospital in Madrid, and diagnosed with iGASD (June 2005-July 2013). An analysis was made of the demographics, symptomatology, microbiology, and treatment. The changes throughout the period studied were evaluated, as well as parameters associated with disease severity.

RESULTS

The study included a total of 55 children with iGASD, with 33 (60%) females, and a median age of 48.5 (20.5-88.9) months. The most frequent clinical syndromes were cellulitis/subcutaneous abscess (21.8%), ENT abscess (20%), pneumonia (16.4%), osteoarticular infection (16.4%), and mastoiditis (12.7%). The incidence of iGASD (cases/10⁵ emergencies/year) increased from 5.6 (4.2-7.2) between June 2005-May 2009 to 18.9 (15.1-26) between June 2009-May 2013; P=.057. Surgery and admission to PICU was required by 35 (63.6%) and 10 (18.2%) patients, respectively. Children in PICU were younger (26.5 vs 52.6 months, P=.116), had a higher C-reactive protein (24.5 vs 10.7mg/dl, P<.001) and higher frequency of pneumonia (60 vs 7%, P<.001). In the multivariate analysis, only C-reactive protein was a risk factor for admission to PICU (OR: 1.14 [1.004-1.286], P=.04). There were no sequelae.

CONCLUSIONS

An increased incidence of iGASD was observed in the children in this study. Lower age, pneumonia, and higher C-reactive protein were associated with disease severity in this series.

Gene fitness landscape of group A streptococcus during necrotizing myositis

Necrotizing fasciitis and myositis are devastating infections characterized by high mortality. Group A streptococcus (GAS) is a common cause of these infections, but the molecular pathogenesis is poorly understood. We report a genome-wide analysis using serotype M1 and M28 strains that identified GAS genes contributing to necrotizing myositis in nonhuman primates (NHP), a clinically relevant model. Using transposon-directed insertion-site sequencing (TraDIS), we identified 126 and 116 GAS genes required for infection by serotype M1 and M28 organisms, respectively. For both M1 and M28 strains, more than 25% of the GAS genes required for necrotizing myositis encode known or putative transporters. Thirteen GAS transporters contributed to both M1 and M28 strain fitness in NHP myositis, including putative importers for amino acids, carbohydrates, and vitamins and exporters for toxins, quorum-sensing peptides, and uncharacterized molecules. Targeted deletion of genes encoding 5 transporters confirmed that each isogenic mutant strain was significantly (P < 0.05) impaired in causing necrotizing myositis in NHPs. Quantitative reverse-transcriptase PCR (qRT-PCR) analysis showed that these 5 genes are expressed in infected NHP and human skeletal muscle. Certain substrate-binding lipoproteins of these transporters, such as Spy0271 and Spy1728, were previously documented to be surface exposed, suggesting that our findings have translational research implications.

Interventions for necrotizing soft tissue infections in adults

BACKGROUND

Necrotizing soft tissue infections (NSTIs) are severe and rapidly spreading soft tissue infections of the subcutaneous tissue, fascia, or muscle, which are mostly caused by bacteria. Associated rates of mortality and morbidity are high, with the former estimated at around 23%, and disability, sequelae, and limb loss occurring in 15% of patients. Standard management includes intravenous empiric antimicrobial therapy, early surgical debridement of necrotic tissues, intensive care support, and adjuvant therapies such as intravenous immunoglobulin (IVIG).

OBJECTIVES

To assess the effects of medical and surgical treatments for necrotizing soft tissue infections (NSTIs) in adults in hospital settings.

SEARCH METHODS

We searched the following databases up to April 2018: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers, pharmaceutical company trial results databases, and the US Food and Drug Administration and the European Medicines Agency websites. We checked the reference lists of included studies and reviews for further references to relevant randomised controlled trials (RCTs).

SELECTION CRITERIA

RCTs conducted in hospital settings, that evaluated any medical or surgical treatment for adults with NSTI were eligible for inclusion. Eligible medical treatments included 1) comparisons between different antimicrobials or with placebo; 2) adjuvant therapies such as intravenous immunoglobulin (IGIV) therapy compared with placebo; no treatment; or other adjuvant therapies. Eligible surgical treatments included surgical debridement compared with amputation, immediate versus delayed intervention, or comparisons of number of interventions.RCTs of hyperbaric oxygen (HBO) therapy for NSTI were ineligible because HBO is the focus of another Cochrane Review.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome measures were 1) mortality within 30 days, and 2) proportion of participants who experience a serious adverse event. Secondary outcomes were 1) survival time, and 2) assessment of long-term morbidity. We used GRADE to assess the quality of the evidence for each outcome.

MAIN RESULTS

We included three trials randomising 197 participants (62% men) who had a mean age of 55 years. One trial compared two antibiotic treatments, and two trials compared adjuvant therapies with placebo. In all trials, participants concomitantly received standard interventions, such as intravenous empiric antimicrobial therapy, surgical debridement of necrotic tissues, intensive care support, and adjuvant therapies. All trials were at risk of attrition bias and one trial was not blinded.Moxifloxacin versus amoxicillin-clavulanate One trial included 54 participants who had a NSTI; it compared a third-generation quinolone, moxifloxacin, at a dose of 400 mg given once daily, against a penicillin, amoxicillin-clavulanate, at a dose of 3 g given three times daily for at least three days, followed by 1.5 g three times daily. Duration of treatment varied from 7 to 21 days. We are uncertain of the effects of these treatments on mortality within 30 days (risk ratio (RR) 3.00, 95% confidence interval (CI) 0.39 to 23.07) and serious adverse events at 28 days (RR 0.63, 95% CI 0.30 to 1.31) because the quality of the evidence is very low.AB103 versus placebo One trial of 43 randomised participants compared two doses, 0.5 mg/kg and 0.25 mg/kg, of an adjuvant drug, a CD28 antagonist receptor (AB103), with placebo. Treatment was given via infusion pump for 10 minutes before, after, or during surgery within six hours after the diagnosis of NSTI. We are uncertain of the effects of AB103 on mortality rate within 30 days (RR of 0.34, 95% CI 0.05 to 2.16) and serious adverse events measured at 28 days (RR 1.49, 95% CI 0.52 to 4.27) because the quality of the evidence is very low.Intravenous immunoglobulin (IVIG) versus placebo One trial of 100 randomised participants assessed IVIG as an adjuvant drug, given at a dose of 25 g/day, compared with placebo, given for three consecutive days. There may be no clear difference between IVIG and placebo in terms of mortality within 30 days (RR 1.17, 95% CI 0.42 to 3.23) (low-certainty evidence), nor serious adverse events experienced in the intensive care unit (ICU) (RR 0.73 CI 95% 0.32 to 1.65) (low-certainty evidence).Serious adverse events were only described in one RCT (the IVIG versus placebo trial) and included acute kidney injury, allergic reactions, aseptic meningitis syndrome, haemolytic anaemia, thrombi, and transmissible agents.Only one trial reported assessment of long-term morbidity, but the outcome was not defined in the way we prespecified in our protocol. The trial used the Short Form Health Survey (SF36). Data on survival time were provided upon request for the trials comparing amoxicillin-clavulanate versus moxifloxacin and IVIG versus placebo. However, even with data provided, it was not possible to perform survival analysis.

AUTHORS' CONCLUSIONS

We found very little evidence on the effects of medical and surgical treatments for NSTI. We cannot draw conclusions regarding the relative effects of any of the interventions on 30-day mortality or serious adverse events due to the very low quality of the evidence.The quality of the evidence is limited by the very small number of trials, the small sample sizes, and the risks of bias in the included trials. It is important for future trials to clearly define their inclusion criteria, which will help with the applicability of future trial results to a real-life population.Management of NSTI participants (critically-ill participants) is complex, involving multiple interventions; thus, observational studies and prospective registries might be a better foundation for future research, which should assess empiric antimicrobial therapy, as well as surgical debridement, along with the placebo-controlled comparison of adjuvant therapy. Key outcomes to assess include mortality (in the acute phase of the condition) and long-term functional outcomes, e.g. quality of life (in the chronic phase).

Genomic sequence investigation Streptococcus pyogenes clusters in England (2010-2015)

OBJECTIVES

To analyse genomic sequence data of referred Streptococcus pyogenes isolates and those pertaining to selected elderly/nursing care or maternity clusters from 2010 to 2015 to ascertain genomic differences between epidemiologically related isolates and unrelated isolates from outbreaks of disease.

METHODS

The genomic sequences of 134 S. pyogenes isolates from 21 clusters of infection in elderly care or maternity settings from 2010 to 2015 were analysed using bioinformatics to ascertain genomic phylogeny, single nucleotide polymorphism (SNP) differences and statistical outliers from epidemiologically defined outbreaks. Analysis was undertaken within clusters and compared with sporadic isolates from geographically distinct outbreaks of S. pyogenes infection.

RESULTS

Genomic sequence analysis of 21 outbreaks of S. pyogenes infection ranged in size from a single patient (with colonized healthcare worker link) to 18 patient cases of group A streptococcus (GAS) infection in a single setting. Seventeen healthcare workers were identified in 8 of 21 outbreaks with the associated outbreak strain, with multiple staff in 2 of 21 outbreaks. Genomic sequences from epidemiologically linked isolates from patients, staff and healthcare environmental settings were highly conserved, differing by 0-1 SNP in some cases and mirrored geographical data. Four of 21 outbreaks had environmental contamination with the outbreak strain, indistinguishable or of limited SNP difference to the patient isolates. Genomic SNP analysis enabled exclusion of ten isolates from epidemiological outbreaks.

CONCLUSIONS

Genomic discrimination can be applied to assist outbreak investigation. It enabled confirmation or exclusion of GAS cases from epidemiologically defined outbreaks. Colonization of healthcare workers and environmental contamination with the outbreak strain was demonstrated for several outbreaks.

Human Streptococcal Necrotizing Fasciitis Histopathology Mirrored in a Murine Model

Streptococcal necrotizing fasciitis (NF) causes high morbidity and mortality despite state-of-the-art therapy. Low incidence and rapid disease progression, necessitating immediate initiation of therapy, have proven challenging aspects for setting up prospective randomized trials. This has resulted in little therapeutic progress over the past decade. The validation of reliable murine NF models to study both pathogenesis and optimized therapeutic regimens of streptococcal NF are thus essential. In this study, we characterized a murine NF model and compared the pathology with an in-depth tissue analysis of streptococcal NF in patients. We found that the streptococcal murine NF model closely reflected all histologic characteristics encountered in human streptococcal NF. This murine NF model helps understanding of human NF pathology better in a time-dependent manner and will allow studying novel therapeutic options in the future.

Prevalent emm Types among Invasive GAS in Europe and North America since Year 2000

BACKGROUND

Streptococcus pyogenes or group A streptococcus (GAS) is an important human pathogen responsible for a broad range of infections, from uncomplicated to more severe and invasive diseases with high mortality and morbidity. Epidemiological surveillance has been crucial to detect changes in the geographical and temporal variation of the disease pattern; for this purpose the M protein gene (emm) gene typing is the most widely used genotyping method, with more than 200 emm types recognized. Molecular epidemiological data have been also used for the development of GAS M protein-based vaccines.

METHODS

The aim of this paper was to provide an updated scenario of the most prevalent GAS emm types responsible for invasive infections in developed countries as Europe and North America (US and Canada), from 1st January 2000 to 31st May 2017. The search, performed in PubMed by the combined use of the terms ("emm") and ("invasive") retrieved 264 articles, of which 38 articles (31 from Europe and 7 from North America) met the inclusion criteria and were selected for this study. Additional five papers cited in the European articles but not retrieved by the search were included.

RESULTS

emm1 represented the dominant type in both Europe and North America, replaced by other emm types in only few occasions. The seven major emm types identified (emm1, emm28, emm89, emm3, emm12, emm4, and emm6) accounted for approximately 50-70% of the total isolates; less common emm types accounted for the remaining 30-50% of the cases. Most of the common emm types are included in either one or both the 26-valent and 30-valent vaccines, though some well-represented emm types found in Europe are not.

CONCLUSION

This study provided a picture of the prevalent emm types among invasive GAS (iGAS) in Europe and North America since the year 2000 onward. Continuous surveillance on the emm-type distribution among iGAS infections is strongly encouraged also to determine the potential coverage of the developing multivalent vaccines.

Can necrotizing soft tissue infection be reliably diagnosed in the emergency department?

Necrotizing soft tissue infections (NSTIs) are associated with a high mortality and require prompt recognition and treatment, consisting of aggressive surgical debridement and critical care support. Diagnosis is a key step, which is generally made in the operating room (OR), but the decision to debride requires guidance. This is frequently made on clinical grounds, but NSTI can be occult in presentation and several other infective processes can mimic NSTI. It is unknown whether the various scoring systems described in the literature can enable clinicians to reliably diagnose NSTI in the emergency department, rather than the OR. The topic was debated at the 36thAnnual Point/Counterpoint Acute Care Surgery Conference and the following article summarizes the discussants points of view along with a summary of the evidence.

Integration of Genomic and Other Epidemiologic Data to Investigate and Control a Cross-Institutional Outbreak of Streptococcus pyogenes

Single-strain outbreaks of Streptococcus pyogenes infections are common and often go undetected. In 2013, two clusters of invasive group A Streptococcus (iGAS) infection were identified in independent but closely located care homes in Oxfordshire, United Kingdom. Investigation included visits to each home, chart review, staff survey, microbiologic sampling, and genome sequencing. S. pyogenes emm type 1.0, the most common circulating type nationally, was identified from all cases yielding GAS isolates. A tailored whole-genome reference population comprising epidemiologically relevant contemporaneous isolates and published isolates was assembled. Data were analyzed independently using whole-genome multilocus sequencing and single-nucleotide polymorphism analyses. Six isolates from staff and residents of the homes formed a single cluster that was separated from the reference population by both analytical approaches. No further cases occurred after mass chemoprophylaxis and enhanced infection control. Our findings demonstrate the ability of 2 independent analytical approaches to enable robust conclusions from nonstandardized whole-genome analysis to support public health practice.

Genome sequence analysis of emm89 Streptococcus pyogenes strains causing infections in Scotland, 2010-2016

Purpose

Strains of type emm89 Streptococcus pyogenes have recently increased in frequency as a cause of human infections in several countries in Europe and North America. This increase has been molecular epidemiologically linked with the emergence of a new genetically distinct clone, designated clade 3. We sought to extend our understanding of this epidemic behavior by the genetic characterization of type emm89 strains responsible in recent years for an increased frequency of infections in Scotland.

Methodology

We sequenced the genomes of a retrospective cohort of 122 emm89 strains recovered from patients with invasive and noninvasive infections throughout Scotland during 2010 to 2016.

Results

All but one of the 122 emm89 infection isolates are of the recently emerged epidemic clade 3 clonal lineage. The Scotland isolates are closely related to and not genetically distinct from recent emm89 strains from England, they constitute a single genetic population.

Conclusions

The clade 3 clone causes virtually all-contemporary emm89 infections in Scotland. These findings add Scotland to a growing list of countries of Europe and North America where, by whole genome sequencing, emm89 clade 3 strains have been demonstrated to be the cause of an ongoing epidemic of invasive infections and to be genetically related due to descent from a recent common progenitor.

[Streptococcus pyogenes infection in paediatrics: from pharyngotonsillitis to invasive infections]

BACKGROUND

Streptococcus pyogenes or Group A Streptococci (GAS) cause many infections in infancy. Changes in its epidemiology have been described in recent years, including an increase in invasive infections (iGAS).

METHODS

A retrospective-descriptive study was conducted on children less than 15 years old, with GAS infections, in particular iGAS, and their complications from February 2004-April 2014.

RESULTS

A total of 2,192 positive cultures were obtained of which 92.7% were pharyngeal cultures. Twenty-nine patients were admitted to hospital: 4 with suppurative complications, 7 post-infective, 14 iGAS, and 4 probable iGAS cases. There were no differences in the frequency of GAS isolations/year. Non-invasive isolates were more frequent in winter and spring (P<.001), and 68.3% were in patients younger than 5 years. The incidence of iGAS was 2.1/100,000 children/year. There was no seasonality, and it was more frequent in younger children (P=.039). The most common diagnosis was pneumonia (6/14). Eight patients required intensive care. They were treated empirically with second or third-generation cephalosporin or with intravenous penicillin, and pneumonia required longer treatment times (P=.016). All GAS isolates were sensitive to penicillin, and 10.6% were resistant to erythromycin. The time spent in hospital was longer for iGAS than other cases (P=.028). No patients died.

CONCLUSIONS

Pharyngotonsillitis caused by GAS is common in childhood, and its incidence is increasing in children younger than 5 years. At the moment, post-infectious complications are rare. Invasive infections are the most severe forms of presentation, and are more common in younger children.

Epidemiology of Invasive Group A Streptococcal Infections in the United States, 2005-2012

BACKGROUND

Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance.

METHODS

From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data.

RESULTS

We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates.

CONCLUSIONS

The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

When should clinicians suspect group A streptococcus empyema in children? A multicentre case-control study in French tertiary care centres

BACKGROUND

The incidence of invasive group A streptococcus (GAS) infections is increasing worldwide, whereas there has been a dramatic decrease in pneumococcal invasive diseases. Few data describing GAS pleural empyema in children are available.

OBJECTIVE

To describe the clinical and microbiological features, management and outcome of GAS pleural empyema in children and compare them with those of pneumococcal empyema.

DESIGN, SETTING AND PATIENTS

Fifty children admitted for GAS pleural empyema between January 2006 and May 2013 to 8 hospitals participating in a national pneumonia survey were included in a descriptive study and matched by age and centre with 50 children with pneumococcal empyema.

RESULTS

The median age of the children with GAS pleural empyema was 2 (range 0.1-7.6) years. Eighteen children (36%) had at least one risk factor for invasive GAS infection (corticosteroid use and/or current varicella). On admission, 37 patients (74%) had signs of circulatory failure, and 31 (62%) had a rash. GAS was isolated from 49/50 pleural fluid samples and from one blood culture. The commonest GAS genotype was emm1 (n=17/22). Two children died (4%). Children with GAS empyema presented more frequently with a rash (p<0.01), signs of circulatory failure (p=0.01) and respiratory disorders (p=0.02) and with low leucocyte levels (p=0.04) than children with pneumococcal empyema. Intensive care unit admissions (p<0.01), drainage procedures (p=0.04) and short-term complications (p=0.01) were also more frequent in patients with GAS empyema.

CONCLUSIONS

Pleural empyema following varicella or presenting with rash, signs of circulatory failure and leucopenia may be due to GAS. These features should prompt the addition to treatment of an antitoxin drug, such as clindamycin.

Group A streptococcal meningitis: emm type distribution and theoretical vaccine coverage in children

As group A Streptococcus (GAS) meningitis is seldom reported in children, emm-type distribution data are scare. We report eight cases of GAS meningitis in Belgium (2008-2013) and compare molecular characteristics of our strains with a further 55 cases previously reported with their corresponding emm-types. emm1 type was the most frequent (24%) followed by emm6 (11%), emm12 (11%) and emm3 (6%). Together these four emm-types accounted for 52% of the cases, while the rest of the cases are due to 24 different emm-types. These 28 emm-types associated with GAS meningitis belonged to 16 different emm-clusters suggesting that there is no propensity for particular emm-types or emm-cluster to cause meningitis. Theoretical coverage of the 30-valent vaccine candidate would be 77.8% (49/63 isolates) among children with GAS meningitis.

Epidemiology of Invasive Group A Streptococcal Infections in the United States, 2005-2012

BACKGROUND

Invasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance.

METHODS

From January 2005 through December 2012, we collected data from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data.

RESULTS

We identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates.

CONCLUSIONS

The burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

Epidemiology of invasive group A Streptococcus infections in Sydney, Australia

There is concern of global resurgence of invasive group A Streptococcus (iGAS) infections. We compared the clinical and molecular epidemiology of patients admitted with iGAS over two time periods, 2008 and 2010, in Western Sydney, Australia. The annual incidence was 19 cases per 100,000 admissions in 2008, compared to 33 per 100,000 in 2010. An increasing proportion of patients died (0% versus 13%), had an APACHE II score ≥30 (0% versus 19%), and had no known risk-factors (12% versus 25%). A potential skin source was identified as a trigger in fewer cases in 2010 (36% versus 11%). In total, there were 27 different emm types and 11 different emm clusters. There were some new emm types/clusters in 2010 that were not present in 2008. However, the study was not adequately powered to detect statistically significant differences in the distribution of emm types (p = 0.06) and emm clusters (p = 0.16) between the two years. There were also no clear associations between emm types/clusters and severity and clinical manifestations of iGAS infections. Although the proposed 30-valent M protein vaccine encompasses only 47% of our isolates, it will likely provide coverage for at least 71% of iGAS infections due to cross-opsonisation.

Superoxide anions produced by Streptococcus pyogenes group A-stimulated keratinocytes are responsible for cellular necrosis and bacterial growth inhibition

Gram-positive Streptococcus pyogenes (group A Streptococcus or GAS) is a major skin pathogen and interacts with keratinocytes in cutaneous tissues. GAS can cause diverse suppurative and inflammatory infections, such as cellulitis, a common acute bacterial dermo-hypodermitis with a high morbidity. Bacterial isolation yields from the lesions are low despite the strong local inflammation observed, raising numerous questions about the pathogenesis of the infection. Using an in vitro model of GAS-infected keratinocytes, we show that the major ROS produced is the superoxide anion ([Formula: see text]), and that its production is time- and dose-dependent. Using specific modulators of ROS production, we show that [Formula: see text] is mainly synthesized by the cytoplasmic NADPH oxidase. Superoxide anion production leads to keratinocyte necrosis but incomplete inhibition of GAS growth, suggesting that GAS may be partially resistant to the oxidative burst. In conclusion, GAS-stimulated keratinocytes are able to develop an innate immune response based on the production of ROS. This local immune response limits GAS development and induces keratinocyte cell death, resulting in the skin lesions observed in patients with cellulitis.