Group A streptococcal infections in children

Are Invasive Group A Streptococcal Infections Preventable by Antibiotic Therapy?: A Collaborative Retrospective Study

BACKGROUND

In winter 2022/2023, a resurgence of invasive group A streptococcal (iGAS) infections in children was observed in Europe, including Germany and Switzerland. While a simultaneous increase in consultations for scarlet fever and pharyngitis was reported in England, leading to the recommendation to treat any suspected GAS disease with antibiotics, guidelines in Germany and Switzerland remained unchanged. We aimed to investigate whether this policy was appropriate.

METHODS

We conducted a retrospective multicenter study of children hospitalized for invasive GAS disease between September 2022 and March 2023 in pediatric departments in Dresden and Berlin (Germany) and Basel (Switzerland). We reviewed medical records and conducted structured telephone interviews to analyze whether suspected GAS infections with or without antibiotic treatment were reported prehospitalization.

RESULTS

In total, 63 patients met the inclusion criteria (median age 4.2 years, 57% males); however, clinical information was not complete for all analyzed characteristics; 32/54 (59%) had ≥1 physician visit ≤4 weeks prehospitalization. In 4/32 (13%) patients, GAS disease, that is, tonsillitis or scarlet fever, was suspected; 2/4 of them received antibiotics, and a positive rapid antigen test for GAS was documented in 1 of them.

CONCLUSIONS

A small minority of patients had suspected GAS infection within 4 weeks before iGAS disease. These data suggest that there is little opportunity to prevent iGAS disease by antibiotic therapy, because in most patients-even if seen by a physician-there was either no evidence of GAS disease or when GAS disease was suspected and treated with antibiotics, consecutive invasive GAS disease was not prevented.

Deep learning from latent spatiotemporal information of the heart: Identifying advanced bioimaging markers from echocardiograms

A key strength of echocardiography lies in its integration of comprehensive spatiotemporal cardiac imaging data in real-time, to aid frontline or bedside patient risk stratification and management. Nonetheless, its acquisition, processing, and interpretation are known to all be subject to heterogeneity from its reliance on manual and subjective human tracings, which challenges workflow and protocol standardization and final interpretation accuracy. In the era of advanced computational power, utilization of machine learning algorithms for big data analytics in echocardiography promises reduction in cost, cognitive errors, and intra- and inter-observer variability. Novel spatiotemporal deep learning (DL) models allow the integration of temporal arm information based on unlabeled pixel echocardiographic data for convolution of an adaptive semantic spatiotemporal calibration to construct personalized 4D heart meshes, assess global and regional cardiac function, detect early valve pathology, and differentiate uncommon cardiovascular disorders. Meanwhile, data visualization on spatiotemporal DL prediction models helps extract latent temporal imaging features to develop advanced imaging biomarkers in early disease stages and advance our understanding of pathophysiology to support the development of personalized prevention or treatment strategies. Since portable echocardiograms have been increasingly used as point-of-care imaging tools to aid rural care delivery, the application of these new spatiotemporal DL techniques show the potentials in streamlining echocardiographic acquisition, processing, and data analysis to improve workflow standardization and efficiencies, and provide risk stratification and decision supporting tools in real-time, to prompt the building of new imaging diagnostic networks to enhance rural healthcare engagement.

Clinical profile of children with acute post-streptococcal glomerulonephritis

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is common in developing countries with a high hospitalization rate. Most patients have acute nephritic syndrome features, although some occasionally present with unusual clinical features. This study aims to describe and analyze clinical features, complications, and laboratory parameters in children diagnosed with APSGN at presentation, 4 and 12 weeks later, in a resource-limited setting.

METHODS

This cross-sectional study was conducted among children < 16 years with APSGN between January 2015 and July 2022. Hospital medical records and outpatient cards were reviewed for clinical findings, laboratory parameters, and kidney biopsy results. Descriptive analysis of multiple categorical variables was performed using SPSS version 16.0 and presented as frequencies and percentages.

RESULTS

The study included 77 patients. Most (94.8%) were older than five years, and age group 5-12 years had highest prevalence (72.7%). Boys were affected more frequently than girls (66.2% vs. 33.8%). Edema (93.5%), hypertension (87%), and gross hematuria (67.5%) were the most frequent presenting symptoms, and pulmonary edema (23.4%) was the most common severe complication. Anti-DNase B and anti-streptolysin O titers were positive in 86.9% and 72.7%, respectively, and 96.1% had C3 hypocomplementemia. Most clinical features resolved in three months. However, at 3 months, 6.5% of patients had persistent hypertension, impaired kidney function, and proteinuria alone or in combination. Most patients (84.4%) had an uncomplicated course; 12 underwent kidney biopsy, 9 required corticosteroids, and 1 required kidney replacement therapy. There was no mortality during the study period.

CONCLUSION

Generalized swelling, hypertension, and hematuria were most common presenting features. Persistent hypertension, impaired kidney function, and proteinuria persisted in a small proportion who had a significant clinical course and required kidney biopsy. A higher resolution version of the Graphical abstract is available as Supplementary information.

Infection-Related Glomerulonephritis in Children and Adults

Infection-related glomerulonephritis is an immunologically mediated glomerular injury after an infection. Glomerulonephritis may occur with the infection or after a variable latent period. Poststreptococcal glomerulonephritis (PSGN) is the prototype of infection-related glomerulonephritis. The streptococcal antigens, nephritis-associated plasmin-like receptor and streptococcal exotoxin B, have emerged as major players in the pathogenesis of PSGN. Although PSGN is the most common infection-related glomerulonephritis in children, in adults, glomerulonephritis is secondary to bacteria such as staphylococci, viruses such as hepatitis C, and human immunodeficiency virus, and, rarely, parasitic infections. Supportive therapy is the mainstay of treatment in most infection-related glomerulonephritis. Treatment of the underlying infection with specific antibiotics and antiviral medications is indicated in some infections. Parasitic infections, although rare, may be associated with significant morbidity. Poststreptococcal glomerulonephritis is a self-limiting condition with a good prognosis. However, bacterial, viral, and parasitic infections may be associated with significant morbidity and long-term consequences. Epidemiologic studies are required to assess the global burden of infection-related glomerulonephritis. A better understanding of the pathogenesis of infection-related glomerulonephritis may unravel more treatment options and preventive strategies.

Global economic burden per episode for multiple diseases caused by group A Streptococcus

Considering the lack of existing evidence on economic burden for diseases caused by group A Streptococcus, we estimated the economic burden per episode for selected diseases. Each cost component of direct medical costs (DMCs), direct non-medical costs (DNMCs), and indirect costs (ICs) was separately extrapolated and aggregated to estimate the economic burden per episode by income group as classified by the World Bank. Adjustment factors for DMC and DNMC were generated to overcome related data insufficiencies. To address uncertainty surrounding input parameters, a probabilistic multivariate sensitivity was carried out. The average economic burden per episode ranged from $22 to $392 for pharyngitis, $25 to $2,903 for impetigo, $47 to $2,725 for cellulitis, $662 to $34,330 for invasive and toxin-mediated infections, $231 to $6,332 for acute rheumatic fever (ARF), $449 to $11,717 for rheumatic heart disease (RHD), and $949 to $39,560 for severe RHD across income groups. The economic burden for multiple Group A Streptococcus diseases underscores an urgent need to develop effective prevention strategies including vaccines.

Exposure to Acyl Homoserine Lactone Enhances Survival of Streptococcus pyogenes in Murine Macrophages

Streptococcus pyogenes is an opportunistic pathogen causing infections of the skin and upper respiratory tract of the human host. Due to the polymicrobial community present in the human host, S. pyogenes comes across several interspecies signalling molecules. Among these molecules, N-(3-oxododecanoyl)-L-homoserine lactone (Oxo-C12) modulates the morphology, thereby enhancing virulence characteristics of S. pyogenes. After the initial attachment of the bacteria to the host cell, the pathogen needs to invade the host immune system for a successful infection to occur. The host immune system is activated upon infection, where macrophages engulf the pathogen, thereby killing the bacteria. However, S. pyogenes have evolved various strategies to evade the host immune response. In this study, we investigate the role of Oxo-C12 in enhancing the survival of S. pyogenes M3 in murine macrophages. The observed Oxo-C12-mediated increased survival in murine macrophages was through increased lysozyme and acid stress resistance. Moreover, Oxo-C12 increased the survival of S. pyogenes in normal human serum. Thus, understanding the role of interspecies signalling in enhancing the survival strategies of S. pyogenes in the host will further help fill the gap for therapeutics development.

Management and outcomes of acute post-streptococcal glomerulonephritis in children

Acute post-streptococcal glomerulonephritis (APSGN) is the major cause of acute glomerulonephritis among children, especially in low- and middle-income countries. APSGN commonly occurs following pharyngitis due to the activation of antibodies and complements proteins against streptococcal antigens through the immune-complex-mediated mechanism. APSGN can be presented as acute nephritic syndrome, nephrotic syndrome, and rapidly progressive glomerulonephritis, or it may be subclinical. The management of APSGN is mainly supportive in nature with fluid restriction, anti-hypertensives, diuretics, and renal replacement therapy with dialysis, when necessary, as the disease is self-limiting. Congestive heart failure, pulmonary edema, and severe hypertension-induced encephalopathy might occur during the acute phase of APSGN due to hypervolemia. APSGN generally has a favorable prognosis with only a small percentage of patients with persistent urinary abnormalities, persistent hypertension, and chronic kidney disease after the acute episode of APSGN. Decreased complement levels, increased C-reactive protein, and hypoalbuminemia are associated with disease severity. Crescent formations on renal biopsy and renal insufficiency on presentation may be the predictors of disease severity and poor outcomes in APSGN in children.

Standardization of Epidemiological Surveillance of Group A Streptococcal Pharyngitis

Pharyngitis, more commonly known as sore throat, is caused by viral and/or bacterial infections. Group A Streptococcus (Strep A) is the most common bacterial cause of pharyngitis. Strep A pharyngitis is an acute, self-limiting disease but if undertreated can lead to suppurative complications, nonsuppurative poststreptococcal immune-mediated diseases, and toxigenic presentations. We present a standardized surveillance protocol, including case definitions for pharyngitis and Strep A pharyngitis, as well as case classifications that can be used to differentiate between suspected, probable, and confirmed cases. We discuss the current tests used to detect Strep A among persons with pharyngitis, including throat culture and point-of-care tests. The type of surveillance methodology depends on the resources available and the objectives of surveillance. Active surveillance and laboratory confirmation is the preferred method for case detection. Participant eligibility, the surveillance population and additional considerations for surveillance of pharyngitis are addressed, including baseline sampling, community engagement, frequency of screening and season. Finally, we discuss the core elements of case report forms for pharyngitis and provide guidance for the recording of severity and pain associated with the course of an episode.

Standardization of Epidemiological Surveillance of Acute Poststreptococcal Glomerulonephritis

Acute poststreptococcal glomerulonephritis (APSGN) is an immune complex-induced glomerulonephritis that develops as a sequela of streptococcal infections. This article provides guidelines for the surveillance of APSGN due to group A Streptococcus (Strep A). The primary objectives of APSGN surveillance are to monitor trends in age- and sex-specific incidence, describe the demographic and clinical characteristics of patients with APSGN, document accompanying risk factors, then monitor trends in frequency of complications, illness duration, hospitalization rates, and mortality.

This document provides surveillance case definitions for APSGN, including clinical and subclinical APSGN based on clinical and laboratory evidence. It also details case classifications that can be used to differentiate between confirmed and probable cases, and it discusses the current investigations used to provide evidence of antecedent Strep A infection.

The type of surveillance recommended depends on the burden of APSGN in the community and the objectives of surveillance. Strategies for minimal surveillance and enhanced surveillance of APSGN are provided. Furthermore, a discussion covers the surveillance population and additional APSGN-specific surveillance considerations such as contact testing, active follow up of cases and contacts, frequency of reporting, surveillance visits, period of surveillance, and community engagement. Finally, the document presents core data elements to be collected on case report forms, along with guidance for documenting the course and severity of APSGN.

Luteolin Binds Streptolysin O Toxin and Inhibits Its Hemolytic Effects and Cytotoxicity

Group A streptococcus (GAS, Streptococcus pyogenes) is a common pathogen that can cause a variety of human diseases. Streptolysin O (SLO) is an exotoxin produced by GAS. It is a pore-forming toxin (PFT) that exhibits high in vivo toxicity. SLO enables GAS to evade phagocytosis and clearance by neutrophils, induces eukaryotic cell lysis, and activates inflammatory bodies. Luteolin is a natural compound that is produced by a wide range of plant species, and recent studies have shown that luteolin can inhibit the growth and alter the morphological of GAS. Here, we reported that luteolin can weaken the cytotoxicity and hemolytic activity of SLO in vitro. Briefly, luteolin bound SLO with high affinity, inhibited its dissolution of erythrocytes, affected its conformational stability and inhibited the formation of oligomers. To further verify the protective effect of luteolin, we used an in vitro SLO-induced human laryngeal carcinoma epithelial type-2 cells (HEp-2) model. Notably, our results showed luteolin protected HEp-2 cells from SLO induced cytotoxicity and changed in cell membrane permeability. In addition, we explored the role of luteolin in protecting mice from GAS-mediated injury using an aerosolized lung delivery model, and our results indicate that luteolin increases murine survival rate following inoculation with a lethal dose of GAS, and that survival was also associated with decreased pathological damage to lung tissue. Our results suggest that luteolin may be a novel drug candidate for the treatment of GAS infection.

Acute Post-Streptococcal Glomerulonephritis In Children: A Comprehensive Review

BACKGROUND

Acute post-streptococcal glomerulonephritis (APSGN) is an immune-complex (ICs) mediated glomerular disease triggered by group A β-hemolytic streptococcus (GAS) or Streptococcus pyogenes infections. APSGN represents a major cause of acquired kidney injury in children.

METHODS

This non-systematic review summarizes recent evidence on APSGN. We discuss the epidemiology, pathogenesis, clinical and laboratory findings, histopathology, treatment and prognosis of the disease.

RESULTS

The median APSGN incidence in children in developing countries is estimated at 24.3/100,000 per year, compared with 6.2/100,000 per year in developed countries. Nephritis-associated plasmin receptor, identified as glyceraldehyde-3-phosphate dehydrogenase, and the cationic cysteine proteinase streptococcal pyrogenic exotoxin B are thought to be two leading streptococcal antigens involved in the pathogenesis of APSGN, which activate the complement system, mainly via the alternative but also the lectin pathway. This process is critical for the generation of inflammation by the ICs deposited in the glomerulus. The classic phenotype is an acute diffuse proliferative glomerulonephritis leading to features of the nephritic syndrome including hematuria, oliguria, hypertension and edema. The histopathology shows that the glomeruli are diffused affected, mostly presenting enlarged glomerular tuffs due to hypercellularity. Proliferative endothelial and mesangial cells and inflammation are also observed. APSGN frequently has spontaneous recovery. There is no specific therapy, but its morbidity and mortality are drastically reduced by the prevention and/or treatment of complications.

CONCLUSION

Despite recent advances, the pathogenesis of APSGN is not fully understood. There is no specific treatment for APSGN. The prognosis is generally good. However some cases may evolve to chronic kidney disease.

OUP accepted manuscript

Background

Group A Streptococcus (GAS) causes superficial pharyngitis and skin infections as well as serious autoimmune sequelae such as acute rheumatic fever (ARF) and subsequent rheumatic heart disease. ARF pathogenesis remains poorly understood. Immune priming by repeated GAS infections is thought to trigger ARF, and there is growing evidence for the role of skin infections in this process.

Methods

We utilized our recently developed 8-plex immunoassay, comprising antigens used in clinical serology for diagnosis of ARF (SLO, DNase B, SpnA), and 5 conserved putative GAS vaccine antigens (Spy0843, SCPA, SpyCEP, SpyAD, Group A carbohydrate), to characterize antibody responses in sera from New Zealand children with a range of clinically diagnosed GAS disease: ARF (n = 79), GAS-positive pharyngitis (n = 94), GAS-positive skin infection (n = 51), and matched healthy controls (n = 90).

Results

The magnitude and breadth of antibodies in ARF was very high, giving rise to a distinct serological profile. An average of 6.5 antigen-specific reactivities per individual was observed in ARF, compared to 4.2 in skin infections and 3.3 in pharyngitis.

Conclusions

ARF patients have a unique serological profile, which may be the result of repeated precursor pharyngitis and skin infections that progressively boost antibody breadth and magnitude.

Serological Profiling of Group A Streptococcus Infections in Acute Rheumatic Fever

Rheumatic fever is a serious post-infectious sequela of group A Streptococcus (GAS). Prior GAS exposures were mapped in sera using a large panel of M-type specific peptides. Rheumatic fever patients had serological evidence of significantly more GAS exposures than matched controls suggesting immune priming by repeat infections contributes to pathogenesis.

A Comprehensive Review Study on Glomerulonephritis Associated With Post-streptococcal Infection

Post-streptococcal glomerulonephritis (PSGN) is an immune-complex mediated inflammation that used to be considered one of the commonest causes of acute nephritis amongst children. PSGN is characterized by the proliferation of cellular elements called nephritogenic M type as a result of an immunologic mechanism following an infection of the skin (impetigo) or throat (pharyngitis) caused by nephritogenic strains of group A beta-hemolytic streptococci, a gram-positive bacteria that enters the body across pores in the skin or mucus epithelia and is responsible for more than 500,000 deaths annually due to multiple subsequence diseases such as rheumatic heart disease, rheumatic fever, PSGN, and other invasive infections. After the infection, the formation of an immune complex of antigen-antibody and complement system will take place and will deposit in the glomeruli where the injury occurs and leads to inflammation. The manifestations of PSGN can be explained by nephritic syndrome manifestation. PSGN is diagnosed by laboratory tests like microscopy and urinalysis. The imaging studies in PSGN could be used to assess the possible complications of PSGN such as pulmonary congestion and chronic kidney disease. The management of PSGN is symptomatic. If PSGN is not treated, the patient may develop chronic kidney disease. The main way to prevent PSGN is to treat group A streptococcal (GAS) infections by giving good coverage of antibiotic therapy to a patient who has primary GAS infections to prevent the development of the complication.

Diagnosis and management of pharyngitis in children: a survey study in Ukraine

Introduction

The purpose of our study was to evaluate the knowledge of pediatricians in diagnosis and management of sore throat in children and to identify further ways to raise their awareness.

Methods

We conducted a survey among pediatricians on evaluation of diagnosis and management of pharyngitis in children. The study involved pediatricians of Ternopil region, Ukraine. Overall, 112 pediatricians participated in the study. Among the participants 79 (70.5%) were primary care physicians and 33 (29.5%) worked in the secondary and tertiary care hospitals.

Results

Overall, 70.5% of pediatricians prescribed a throat swab for patients with pharyngitis in selected cases. However, they rarely (20 %) used Centor or McIsaak criteria to choose management strategy of sore throat. Amoxicillin as a first-line antibiotic for streptococcal pharyngitis was chosen by 66.1% of respondents and primary care pediatricians prescribed it more often than pediatricians in hospitals (p<0.001), but antibiotic therapy was prescribed for 10 days only by 52.7% of respondents. Less than half of the correct answers were to the questions related to prescription of antibacterial therapy in healthy children, in which GAS is detected in throat swab (39.3%) and in cases of positive antistreptolysin O (ASL-O - 25.9%).

Conclusions

The study showed a wide range of knowledge of pediatricians about the diagnosis and management of GAS pharyngitis - from satisfactory responses concerning prescription of antibiotic therapy to low level of knowledge about the diagnosis and determination of strategies in healthy carriers. These data emphasize the need to improve knowledge about the strategies of GAS pharyngitis control.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2019: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is an Australian hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2019.

Methods

Specialist nurses screened hospital admissions, emergency department records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia, to identify children with the conditions under surveillance. Standardised protocols and case definitions were used across all sites. In 2019, the conditions under surveillance comprised: acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal and invasive Group A streptococcus diseases and two new conditions, Kawasaki disease and gram-negative bloodstream infections. An additional social research component continued to evaluate parental attitudes to influenza vaccination.

Results

PAEDS captured 2,701 cases for 2019 across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets for detection of poliomyelitis cases; demonstration of high influenza activity in 2019 and influenza-associated deaths in ACE cases; identification of key barriers to influenza vaccination of children hospitalised for acute respiratory illness; reporting of all IS cases associated with vaccine receipt to relevant state health department; and showing a further reduction nationally in varicella cases. Enhanced pertussis surveillance continued to capture controls to support vaccine efficacy estimation. Invasive meningococcal disease surveillance showed predominance of serotype B and a reduction in cases nationally. Surveillance for invasive group A streptococcus captured severe cases in children. Monitoring of Kawasaki disease incidence and gram-negative bloodstream infections commenced.

Conclusions

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using sentinel hospital-based enhanced surveillance. Keywords: paediatric, surveillance, child, hospital, vaccine preventable diseases, adverse event following immunisation, acute flaccid paralysis, encephalitis, influenza, intussusception, pertussis, varicella zoster virus, meningococcal, group A streptococcus, Kawasaki, bloodstream infections.

Towards automatic diagnosis of rheumatic heart disease on echocardiographic exams through video-based deep learning

OBJECTIVE

Rheumatic heart disease (RHD) affects an estimated 39 million people worldwide and is the most common acquired heart disease in children and young adults. Echocardiograms are the gold standard for diagnosis of RHD, but there is a shortage of skilled experts to allow widespread screenings for early detection and prevention of the disease progress. We propose an automated RHD diagnosis system that can help bridge this gap.

MATERIALS AND METHODS

Experiments were conducted on a dataset with 11 646 echocardiography videos from 912 exams, obtained during screenings in underdeveloped areas of Brazil and Uganda. We address the challenges of RHD identification with a 3D convolutional neural network (C3D), comparing its performance with a 2D convolutional neural network (VGG16) that is commonly used in the echocardiogram literature. We also propose a supervised aggregation technique to combine video predictions into a single exam diagnosis.

RESULTS

The proposed approach obtained an accuracy of 72.77% for exam diagnosis. The results for the C3D were significantly better than the ones obtained by the VGG16 network for videos, showing the importance of considering the temporal information during the diagnostic. The proposed aggregation model showed significantly better accuracy than the majority voting strategy and also appears to be capable of capturing underlying biases in the neural network output distribution, balancing them for a more correct diagnosis.

CONCLUSION

Automatic diagnosis of echo-detected RHD is feasible and, with further research, has the potential to reduce the workload of experts, enabling the implementation of more widespread screening programs worldwide.

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.

Interspecies signaling affects virulence related morphological characteristics of Streptococcus pyogenes M3

Streptococcus pyogenes is a Gram-positive human-specific pathogen that asymptomatically colonizes the human respiratory tract. The factors affecting the colonization to the host is not clearly understood. Adherence of the pathogen to host epithelial cell is the initial step for a successful colonization process. In the host, bacteria live in a polymicrobial community; thus, the signaling mediated between the bacteria plays a significant role in the colonization of the pathogen to the host. Thus, the effect of acyl-homoserine lactone, secreted by Gram-negative bacteria on the adhesion properties of S. pyogenes M3 strain was examined. N-(3-Oxododecanoyl)-L-homoserine lactone (Oxo-C12) increased the cell size as well as hydrophobicity of S. pyogenes. qPCR data revealed that the expression of sagA and hasA was negatively affected by Oxo-C12. Moreover, Oxo-C12 leads to changes in the morphological characteristic of S. pyogenes, further promoting adherence to host epithelia and biofilm formation on abiotic surface. The study demonstrates the role of Oxo-C12 as a factor that can promote virulence in S. pyogenes M3.

Descriptive analysis of group A Streptococcus in skin swabs and acute rheumatic fever, Auckland, New Zealand, 2010-2016

Background

Group A Streptococcus (GAS) can trigger an immune-mediated response resulting in acute rheumatic fever (ARF). Historically, ARF has been considered a consequence of preceding GAS pharyngitis, but increasing evidence suggests that GAS skin infections may be a driver. Data on the primary care burden of GAS skin infection are limited. This paper aims to describe and compare the prevalence and distribution of GAS detection in skin swabs and ARF rates in the Auckland population.

Methods

This cross-sectional study used all laboratory skin swab data from people who had a skin swab taken as a result of a consultation with a health professional in the Auckland region (2010–2016). Initial primary hospitalisations for ARF were identified and all data were linked using unique patient identifiers to patient's age, prioritised ethnicity, sex, and socio-economic status.

Findings

377,410 skin swabs from 239,494 individuals were included. 12·8% of swabs were GAS positive, an annual incidence of 4·8 per 1,000 person-years. Māori and Pacific Peoples under 20 years of age had markedly higher GAS detection in skin swabs (RR 4·0; 95% CI 3·9–4·2: RR 6·8; 95% CI 6·6–7·0) and significantly higher ARF rates (RR 30·3; 95% CI 19·5–46·9: RR 69·7 95% CI 45·8–106·1) compared with European/Other ethnicities.

Interpretation

The observation that GAS detection was markedly higher in Māori and Pacific Peoples provides a potential explanation for the marked ethnic differences in ARF. These findings support a greater focus on addressing the burden of skin infection in NZ, including as ARF prevention.

Funding

The first author received a training stipend from the New Zealand College of Public Health Medicine (NZCPHM) during her Masters of Public Health.

Intolerable Burden of Impetigo in Endemic Settings: A Review of the Current State of Play and Future Directions for Alternative Treatments

Impetigo (school sores) is a common superficial bacterial skin infection affecting around 162 million children worldwide, with the highest burden in Australian Aboriginal children. While impetigo itself is treatable, if left untreated, it can lead to life-threatening conditions, such as chronic heart and kidney diseases. Topical antibiotics are often considered the treatment of choice for impetigo, but the clinical efficacy of these treatments is declining at an alarming rate due to the rapid emergence and spread of resistant bacteria. In remote settings in Australia, topical antibiotics are no longer used for impetigo due to the troubling rise of antimicrobial resistance, demanding the use of oral and injectable antibiotic therapies. However, widespread use of these agents not only contributes to existing resistance, but also associated with adverse consequences for individuals and communities. These underscore the urgent need to reinvigorate the antibiotic discovery and alternative impetigo therapies in these settings. This review discusses the current impetigo treatment challenges in endemic settings in Australia and explores potential alternative antimicrobial therapies. The goals are to promote intensified research programs to facilitate effective use of currently available treatments, as well as developing new alternatives for impetigo.

Rheumatic heart disease: A review of the current status of global research activity

Rheumatic heart disease (RHD) is a serious and long-term consequence of acute rheumatic fever (ARF), an autoimmune sequela of a mucosal infection by Streptococcus pyogenes (Group A Streptococcus, Strep A). The pathogenesis of ARF and RHD is complex and not fully understood but involves host and bacterial factors, molecular mimicry, and aberrant host innate and adaptive immune responses that result in loss of self-tolerance and subsequent cross-reactivity with host tissues. RHD is entirely preventable yet claims an estimated 320 000 lives annually. The major burden of disease is carried by developing nations and Indigenous populations within developed nations, including Australia. This review will focus on the epidemiology, pathogenesis and treatment of ARF and RHD in Australia, where: streptococcal pyoderma, rather than streptococcal pharyngitis, and Group C and Group G Streptococcus, have been implicated as antecedents to ARF; the rates of RHD in remote Indigenous communities are persistently among the highest in the world; government register-based programs coordinate disease screening and delivery of prophylaxis with variable success; and researchers are making significant progress in the development of a broad-spectrum vaccine against Strep A.

Coexistence of acute poststreptococcal glomerulonephritis and acute rheumatic fever in a Japanese girl with primary Sjögren's syndrome

Although acute poststreptococcal glomerulonephritis (APSGN) and acute rheumatic fever (ARF) are well-known complications of group A streptococcus infection, concomitant occurrence of both diseases is rare. We report an 11-year-old Japanese girl with primary Sjögren's syndrome complicated by acute renal failure about 2 weeks after the onset of pharyngitis. Although histopathological findings of the kidney were not confirmative, APSGN was suggested by the spontaneous recovery of her renal function, typical latent period with high levels of antistreptolysin O and low serum levels of C3 but not of C4. In addition, cardiac hypomotility and regurgitation of the 4 valves progressed in the convalescent phase of APSGN, which was accompanied by elevation of serum C-reactive protein and plasma brain natriuretic peptide (BNP) levels. Myocarditis was suggested by delayed gadolinium-enhancement of cardiac walls on cardiac magnetic resonance imaging. She was diagnosed with APSGN and ARF and was treated with a combination of short course prednisolone and prophylactic penicillin G. There is no relapse of renal or cardiac symptoms during 6 years follow-up. Unexpected elevation of plasma BNP in a convalescent stage of APSGN suggests the development of ARF. Underlying Sjögren's syndrome (SS) may modify the histopathological findings and make it difficult to differentiate APSGN from CTD-associated nephritis such as lupus nephritis (LN) even by renal biopsy.

Impetigo Animal Models: A Review of Their Feasibility and Clinical Utility for Therapeutic Appraisal of Investigational Drug Candidates

Impetigo (school sores), a superficial skin infection commonly seen in children, is caused by the gram-positive bacteria Staphylococcus aureus and/or Streptococcus pyogenes. Antibiotic treatments, often topical, are used as the first-line therapy for impetigo. The efficacy of potential new antimicrobial compounds is first tested in in vitro studies and, if effective, followed by in vivo studies using animal models and/or humans. Animal models are critical means for investigating potential therapeutics and characterizing their safety profile prior to human trials. Although several reviews of animal models for skin infections have been published, there is a lack of a comprehensive review of animal models simulating impetigo for the selection of therapeutic drug candidates. This review critically examines the existing animal models for impetigo and their feasibility for testing the in vivo efficacy of topical treatments for impetigo and other superficial bacterial skin infections.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2017 and 2018: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine-preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2017 and 2018.

Methods

Specialist nurses screened hospital admissions, emergency department (ED) records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia to identify children with the conditions under surveillance. In 2017 and 2018 these included acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal, and invasive Group A streptococcus diseases. An additional social research component was added to evaluate parental attitudes to vaccination.

Results

PAEDS captured 1,580 and 925 cases for 2017 and 2018, respectively, across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets; identification of a third human parechovirus outbreak among other infectious diseases linked to ACE; demonstration of variable influenza activity between 2017 and 2018, with vaccine effectiveness (VE) analysis demonstrating that the protection offered through vaccination is season-dependent. All IS cases associated with vaccine receipt were reported to the relevant state health department. Varicella and herpes zoster case numbers remained unchanged, with vaccine uptake found to be suboptimal among eligible children under the NIP. Enhanced pertussis surveillance continues to capture controls for VE estimation. Surveillance for invasive meningococcal disease showed predominance for serotype B at 57% over 2 years among 77 cases where serotyping was available, and surveillance for invasive group A streptococcus captured severe disease in children.

Conclusion

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

Molecular Epidemiology of Noninvasive and Invasive Group A Streptococcal Infections in Cape Town

The development of a vaccine for group A streptococcus (GAS) is of paramount importance given that GAS infections cause more than 500,000 deaths annually across the world. This prospective passive surveillance laboratory study evaluated the potential coverage of the M protein-based vaccine currently under development. While a number of GAS strains isolated from this sub-Sahara African study were included in the current vaccine formulation, we nevertheless report that potential vaccine coverage for GAS infection in our setting was approximately 60%, with four of the most prevalent strains not included. This research emphasizes the need to reformulate the vaccine to improve coverage in areas where the burden of disease is high.

Group A streptococcus (GAS) is responsible for a wide range of noninvasive group A streptococcal (non-iGAS) and invasive group A streptococcal (iGAS) infections. Information about the emm type variants of the M protein causing GAS disease is important to assess potential vaccine coverage of a 30-valent vaccine under development, particularly with respect to how they compare and contrast with non-iGAS isolates, especially in regions with a high burden of GAS. We conducted a prospective passive surveillance study of samples from patients attending public health facilities in Cape Town, South Africa. We documented demographic data and clinical presentation. emm typing was conducted using CDC protocols. GAS was commonly isolated from pus swabs, blood, deep tissue, and aspirates. Clinical presentations included wound infections (20%), bacteremia (15%), abscesses (9%), and septic arthritis (8%). Forty-six different emm types were identified, including M76 (16%), M81 (10%), M80 (6%), M43 (6%), and M183 (6%), and the emm types were almost evenly distributed between non-iGAS and iGAS isolates. There was a statistically significant association with M80 in patients presenting with noninvasive abscesses. Compared to the 30-valent vaccine under development, the levels of potential vaccine coverage for non-iGAS and iGAS infection were 60% and 58%, respectively, notably lower than the coverage in developed countries; five of the most prevalent emm types, M76, M81, M80, M43, and M183, were not included. The emm types from GAS isolated from patients with invasive disease did not differ significantly from those from noninvasive disease cases. There is low coverage of the multivalent M protein vaccine in our setting, emphasizing the need to reformulate the vaccine to improve coverage in areas where the burden of disease is high.

IMPORTANCE The development of a vaccine for group A streptococcus (GAS) is of paramount importance given that GAS infections cause more than 500,000 deaths annually across the world. This prospective passive surveillance laboratory study evaluated the potential coverage of the M protein-based vaccine currently under development. While a number of GAS strains isolated from this sub-Sahara African study were included in the current vaccine formulation, we nevertheless report that potential vaccine coverage for GAS infection in our setting was approximately 60%, with four of the most prevalent strains not included. This research emphasizes the need to reformulate the vaccine to improve coverage in areas where the burden of disease is high.

Genetics of rheumatic fever and rheumatic heart disease

Rheumatic heart disease (RHD) is a complication of group A streptococcal infection that results from a complex interaction between the genetic make-up of the host, the infection itself and several other environmental factors, largely reflecting poverty. RHD is estimated to affect 33.4 million people and results in 10.5 million disability-adjusted life-years lost globally. The disease has long been considered heritable but still little is known about the host genetic factors that increase or reduce the risk of developing RHD. In the 1980s and 1990s, several reports linked the disease to the human leukocyte antigen (HLA) locus on chromosome 6, followed in the 2000s by reports implicating additional candidate regions elsewhere in the genome. Subsequently, the search for susceptibility loci has been reinvigorated by the use of genome-wide association studies (GWAS) through which millions of variants can be tested for association in thousands of individuals. Early findings implicate not only HLA, particularly the HLA-DQA1 to HLA-DQB1 region, but also the immunoglobulin heavy chain locus, including the IGHV4-61 gene segment, on chromosome 14. In this Review, we assess the emerging role of GWAS in assessing RHD, outlining both the advantages and disadvantages of this approach. We also highlight the potential use of large-scale, publicly available data and the value of international collaboration to facilitate comprehensive studies that produce findings that have implications for clinical practice.

Prospective Surveillance of Pediatric Invasive Group A Streptococcus Infection

BACKGROUND

Invasive group A Streptococcus (GAS) disease has an incidence in high-income countries of 3 to 5 per 100000 per annum and a case-fatality ratio of 10% to 15%. Although these rates are comparable to those of invasive meningococcal disease in Australia before vaccine introduction, invasive GAS disease currently requires reporting in only 2 jurisdictions.

METHODS

Data were collected prospectively through active surveillance at the Royal Children's Hospital, Melbourne (October 2014 to September 2016). Isolation of GAS from a sterile site was required for inclusion. Comprehensive demographic and clinical data were collected, and emm typing was performed on all isolates. Disease was considered severe if the patient required inotropic support or mechanical ventilation.

RESULTS

We recruited 28 patients. The median age of the patients was 3.5 years (range, 4 days to 11 years). Ten (36%) patients had severe disease. Fifteen (54%) children had presented to a medical practitioner for review in the 48 hours before their eventual admission, including 7 of the 10 patients with severe GAS infection. Complications 6 months after discharge persisted in 21% of the patients. emm1 was the most common emm type (29%).

CONCLUSION

We found considerable short- and longer-term morbidity associated with pediatric invasive GAS disease in our study. Disease manifestations were frequently severe, and more than one-third of the patients required cardiorespiratory support. More than one-half of the patients attended a medical practitioner for assessment but were discharged in the 48-hour period before admission, which suggests that there might have been a window for earlier diagnosis. Our methodology was easy to implement as a surveillance system.

High virulence gene diversity in Streptococcus pyogenes isolated in Central Italy

Globally, Streptococcus pyogenes poses a continuous burden on human health, causing both self-limiting and life-threatening diseases. Therefore, studying the profile of virulence genes and their combinations is essential to monitor the epidemiology and pathogenic potential of this important species. Thus, the aim of this study was to analyze related genetic features of clinical strains collected in Italy in 2012 in order to obtain a valid picture of their virulence profile that could be compared to similar studies made in other countries approximately in the same period. We conducted emm typing and fibronectin-collagen-T antigen (FCT) region typing in 122 Streptococcus pyogenes strains. Furthermore, several additional virulence genes were screened by polymerase chain reaction. We found correlations between emm types and FCT region profiles. emm1 strains were mainly associated with FCT2 and FCT6, while emm89 and emm12 strains were associated with FCT4. FCT5 was mainly represented in emm4, emm6, and emm75 strains. Significantly, we defined subtypes for each FCT type based on the differences in single and double loci compared to the reference scheme used for the classification of the FCT region. In addition, new FCT-region variants with differences in multiple loci were also recorded. Cluster analysis based on virulence gene profiling showed a non-random distribution within each emm type. This study added new data to existing studies conducted worldwide and revealed new variability scores in circulating Streptococcus pyogenes strains and new assortments in well-established virulence gene signatures.

Linear and branched polyacrylates as a delivery platform for peptide-based vaccines

AIM

Peptide-based vaccines are designed to carry the minimum required antigen to trigger the desired immune responses; however, they are usually poorly immunogenic and require appropriate delivery system.

RESULTS

Peptides, B-cell epitope (J14) derived from group A streptococcus M-protein and universal T-helper (PADRE) epitope, were conjugated to a variety of linear and branched polyacrylates. All produced conjugates formed submicron-sized particles and induced a high level of IgG titres in mice after subcutaneous immunization. These polymer-peptide conjugates demonstrated high opsonization capacity against group A streptococcus clinical isolates.

CONCLUSION

We have successfully demonstrated that submicron-sized polymer-peptide conjugates were capable of inducing strong humoral immune responses after single immunization.

Protocol for the systematic review of the prevention, treatment and public health management of impetigo, scabies and fungal skin infections in resource-limited settings

BACKGROUND

Impetigo, scabies, and fungal skin infections disproportionately affect populations in resource-limited settings. Evidence for standard treatment of skin infections predominantly stem from hospital-based studies in high-income countries. The evidence for treatment in resource-limited settings is less clear, as studies in these populations may lack randomisation and control groups for cultural, ethical or economic reasons. Likewise, a synthesis of the evidence for public health control within endemic populations is also lacking. We propose a systematic review of the evidence for the prevention, treatment and public health management of skin infections in resource-limited settings, to inform the development of guidelines for the standardised and streamlined clinical and public health management of skin infections in endemic populations.

METHODS

The protocol has been designed in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols statement. All trial designs and analytical observational study designs will be eligible for inclusion. A systematic search of the peer-reviewed literature will include PubMed, Excertpa Medica and Global Health. Grey literature databases will also be systematically searched, and clinical trials registries scanned for future relevant studies. The primary outcome of interest will be the clinical cure or decrease in prevalence of impetigo, scabies, crusted scabies, tinea capitis, tinea corporis or tinea unguium. Two independent reviewers will perform eligibility assessment and data extraction using standardised electronic forms. Risk of bias assessment will be undertaken by two independent reviewers according to the Cochrane Risk of Bias tool. Data will be tabulated and narratively synthesised. We expect there will be insufficient data to conduct meta-analysis. The final body of evidence will be reported against the Grades of Recommendation, Assessment, Development and Evaluation grading system.

DISCUSSION

The evidence derived from the systematic review will be used to inform the development of guidelines for the management of skin infections in resource-limited settings. The evidence derived will be intended for use by clinicians, public health practitioners and policy makers in the treatment of skin infections and the development of skin infection control programmes. The review will identify any gaps in the current evidence to provide direction for future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015029453.

Serological Evidence of Immune Priming by Group A Streptococci in Patients with Acute Rheumatic Fever

Acute rheumatic fever (ARF) is an autoimmune response to Group A Streptococcus (GAS) infection. Repeated GAS exposures are proposed to ‘prime’ the immune system for autoimmunity. This notion of immune-priming by multiple GAS infections was first postulated in the 1960s, but direct experimental evidence to support the hypothesis has been lacking. Here, we present novel methodology, based on antibody responses to GAS T-antigens, that enables previous GAS exposures to be mapped in patient sera. T-antigens are surface expressed, type specific antigens and GAS strains fall into 18 major clades or T-types. A panel of recombinant T-antigens was generated and immunoassays were performed in parallel with serum depletion experiments allowing type-specific T-antigen antibodies to be distinguished from cross-reactive antibodies. At least two distinct GAS exposures were detected in each of the ARF sera tested. Furthermore, no two sera had the same T-antigen reactivity profile suggesting that each patient was exposed to a unique series of GAS T-types prior to developing ARF. The methods have provided much-needed experimental evidence to substantiate the immune-priming hypothesis, and will facilitate further serological profiling studies that explore the multifaceted interactions between GAS and the host.

Genetic Diversity among Group A Streptococcus Isolated from Throats of Healthy and Symptomatic Children

BACKGROUND

Group A streptococcus (GAS) is the commonest bacterial cause of pharyngitis. Children in the age group of 5-15 years are most commonly affected. It can also colonize throats of healthy children in this age group. Both cases and carriers can transmit it in the community.

METHODS

Throat swab samples were collected from 1849 asymptomatic and 371 symptomatic children.

RESULTS

The rate of isolation of GAS was 1.41% among the asymptomatic group and 7.55% among the symptomatic group. Nine different emm types were encountered in the asymptomatic children and 14 among the symptomatic children.

CONCLUSION

Throat swab cultures must be used in all cases of pharyngitis. Early and appropriate antibiotic therapy will prevent complications. Asymptomatic throat carriage of GAS in children was low in our study. However, they can still act as reservoirs. Emm typing helps in understanding epidemiology and finding new types.

Rheumatic heart disease echocardiographic screening: approaching practical and affordable solutions

Rheumatic heart disease (RHD) affects at least 32.9 million people worldwide and ranks as a leading cause of death and disability in low-income and middle-income countries (LMICs). Echocardiographic screening has been demonstrated to be a powerful tool for early RHD detection, and holds potential for global RHD control. However, national screening programmes have not emerged. Major barriers to implementation include the lack of human and financial resources in LMICs. Here, we focus on recent research advances that could make echocardiographic screening more practical and affordable, including handheld echocardiography devices, simplified screening protocols and task shifting of echocardiographic screening to non-experts. Additionally, we highlight some important remaining questions before echocardiographic screening can be widely recommended, including demonstration of cost-effectiveness, assessment of the impact of screening on children and communities, and determining the importance of latent RHD. While a single strategy for echocardiographic screening in all high-prevalence areas is unlikely, we believe recent advancements are bringing the public health community closer to developing sustainable programmes for echocardiographic screening.

Prevalence of group A streptococcal disease in North and Sub-Saharan Africa: a systematic review protocol

INTRODUCTION

The true burden of group A streptococcal (GAS) disease in Africa is not known. GAS is a significant cause of mortality and morbidity on the global scale and in developing countries. According to Carapetis et al, the prevalence of severe GAS disease is at least 18.1 million cases with an incidence of at least 1.78 million cases per year.

METHODS AND ANALYSES

We aim to provide a systematic review of studies measuring the prevalence of GAS infection among people in North and Sub-Saharan African countries. A comprehensive literature search of a number of databases will be undertaken, using an African search filter, to identify GAS prevalence studies that have been published. Full copies of articles will be identified by a defined search strategy and will be considered for inclusion against predefined criteria. Statistical analysis will include two steps: (1) identification of data sources and documenting of estimates, and (2) the application of the random-effects and fixed-effects meta-analysis model to aggregate prevalence estimates, and to account for between study variability in calculating the overall pooled estimates and 95% CI for GAS prevalence. Heterogeneity will be evaluated using the I(2) statistic to determine the extent of variation in effect estimates that is due to heterogeneity rather than chance. This systematic review protocol was prepared according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses Protocols (PRISMA-P) 2015 Statement. This review will provide updated evidence of a review published in 2009. Our data will have implications for the development of a GAS vaccine.

ETHICS AND DISSEMINATION

Ethics approval is not required for this study given that this is a protocol for a systematic review of published studies. The results of this study will be disseminated through a peer-reviewed publication and conference presentation.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD4201401290 0. (http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014012900).

Clinical and bacteriological efficacy of twice daily topical retapamulin ointment 1% in the management of impetigo and other uncomplicated superficial skin infections

BACKGROUND

Cutaneous bacterial infections are common in children and adults and frequently are caused by Staphylococcus aureus (S. aureus). Treatment failures with topical agents are not uncommon and have been shown to be secondary to bacterial resistance.

OBJECTIVE

To determine clinical and bacteriological efficacy of retapamulin ointment 1% in treatment of patients with cutaneous bacterial infections caused by methicillin-resistant S. aureus (MRSA) and other bacteria.

METHODS

Prospective, nonrandomized, uncontrolled, open label, single center trial conducted between April 2008 and November 2012 that evaluated efficacy of retapamulin ointment 1% in the treatment of impetigo, folliculitis, and other minor soft tissue infections in children and adults. Fifty patients, who presented to a dermatology outpatient clinic and were clinically diagnosed with impetigo, folliculitis, or minor soft tissue infection suitable for treatment with a topical antibiotic, were screened. Thirty-eight patients were enrolled and received treatment: topical retapamulin ointment 1% twice daily for 5 days. Seven patients were MRSA positive and qualified for the primary efficacy population. One patient withdrew due to an adverse event. Clinical and microbiological exams were performed at baseline and follow-up 5 to 7 days later to assess clinical, microbiological, and therapeutic responses. Primary outcome was clinical response at follow-up in primary efficacy population with MRSA isolated as the baseline pathogen. Secondary outcomes included clinical, microbiologic, and therapeutic responses in patients who were culture positive for any species of bacteria.

RESULTS

Clinical response at follow-up in the primary efficacy population (MRSA-positive patients) was not sufficiently powered to demonstrate significance; however, outcomes were excellent, with 7 of 7 patients demonstrating clinical success (5 of 7) or clinical improvement (2 of 7) at follow-up. Barring lack of significance due to small total sample size for patients who were culture positive for any species of bacteria (n = 35), overall success rates were favorable for clinical, microbiologic, and therapeutic responses with values of 66%, 97%, and 69%, respectively. Adverse events (AEs) were mild or moderate in severity. No serious AEs were reported.

CONCLUSION

Safety profile appears favorable given the low number of AEs. Study design limits conclusions that can be drawn. Nevertheless, this study supports use of topical retapamulin 1% ointment in treatment of cutaneous bacterial infections, particularly those caused by S. aureus, including MRSA.

Indigenous child health: are we making progress?

We identified 244 relevant articles pertinent to indigenous health (4% of the total) with a steady increase in number since 1995. Most Australian publications in the journal (with a small Indigenous population) have focussed on conditions such as malnutrition, diarrhoeal disease, iron deficiency, rheumatic fever, acute glomerulonephritis and respiratory and ear infections, and in settings where nearly all affected children are Indigenous. In contrast, New Zealand publications (with a large Maori and Pacific Islander population) have addressed important health issues affecting all children but emphasised the over-representation of Maori and Pacific Islanders. Publications in the journal are largely descriptive studies with relatively few systematic reviews and randomised trials. Our review attempts to cover the important Indigenous health issues in our region as represented by articles published in the Journal. The studies do document definite improvements in indigenous child health over the last 50 years.

How to use antistreptolysin O titre

Group A streptococcus (GAS) is the cause of a wide range of acute suppurative and, following a latent period, non-suppurative diseases such as rheumatic fever and poststreptococcal glomerulonephritis. Diagnosis of the latter group requires evidence of preceding GAS infection. The bacteria produce a range of extracellular antigens, including streptolysin O, which induce an antibody response in the host. A rise in antistreptolysin O titre (ASOT) is indicative of preceding GAS infection. In clinical practice, often only a single ASOT measurement is available and its timing in relation to a possible GAS infection is unknown. Interpretation of the result in this context is liable to misdiagnosis. In order to optimise diagnosis of preceding GAS infection, at least two sequential ASOT measurements, together with simultaneous assay for anti-DNase B, a second antistreptococcal antibody, is recommended.

Management of invasive group A streptococcal infections

Invasive group A streptococcal (GAS) disease in children includes deep soft tissue infection, bacteraemia, bacteraemic pneumonia, meningitis and osteomyelitis. The expression of toxins and super antigens by GAS can complicate infection by triggering an overwhelming systemic inflammatory response, referred to as streptococcal toxic shock syndrome (STSS). The onset and progression of GAS disease can be rapid, and the associated mortality high. Prompt antibiotics therapy and early surgical debridement of infected tissue are essential. Adjunctive therapy with intravenous immunoglobulin and hyperbaric therapy may improve outcomes in severe disease. Nosocomial outbreaks and secondary cases in close personal contacts are not uncommon; infection control measures and consideration of prophylactic antibiotics to those at high risk are important aspects of disease control. To reduce a substantial part of the global burden of GAS disease, an affordable GAS vaccine with efficacy against a broad number of strains is needed.

Immune response against M protein-conserved region peptides from prevalent group A Streptococcus in a North Indian population

BACKGROUND

Group A streptococci (GAS) cause infections with a high prevalence in most developing countries. A GAS vaccine under trial that is based on the amino-terminus of the M protein provides type-specific immunity, and hence seems ineffective in India because of heterogeneous emm types. However, the conserved C-terminal region of the M protein protects against multiple serotypes. In this paper, the immune response generated against the conserved C-repeat region of the M protein was checked in an Indian population to establish their vaccine candidature.

METHODS

When screened for GAS, patients with pharyngitis, rheumatic fever/rheumatic heart disease (RF/RHD), and invasive disease showed heterogeneous emm types, out of which five prevalent types (1-2, 11, 49, 75 and 112) were selected for the study. The C-terminal region of their M proteins showed conserved C1-, C2-, and C3-repeats. The C1-repeat was more diverse and had two different J14-like sequences. Peptides to these C-terminal regions (J14.1 and J14-R6) were designed. Antibodies against these peptides were analyzed using the sera of 130 GAS-infected volunteers.

RESULTS

Serum antibodies were significantly higher in patients with acute rheumatic fever, RHD, and invasive disease than in patients with pharyngitis or the healthy controls. The serum antibodies to these peptides was higher in teenagers and adults than in children.

CONCLUSION

Results showed an association between streptococcal disease progression and the age-related development of immunity to the conserved regions. Hence, these peptides could be considered protective in impeding streptococcal infections worldwide.

Current practice about the evaluation of antibody to streptolysin O (ASO) levels by physicians working in Antananarivo, Madagascar

INTRODUCTION

The diagnosis of post streptococcal diseases is usually confirmed by immunological tests. Only the antistreptolysin O is usually prescribed by physician. This study aimed to describe the current practice of these requests in Antananarivo.

METHODS

It was a retrospective and descriptive study conducted at the Para clinic Unit of Immunology at the University Center Hospital of Antananarivo. We analyzed all requests during seven years, from January 2003 to December 2009. We looked at age, gender, and clinical symptoms which led to the request and the result for each request.

RESULTS

We retained 4143 requests for antistreptolysin O titration in our study. The mean age of the study participants was 32.9 years with 18.3% of participants being less than 15 years old. The main symptoms leading to the request of this analysis were rheumatologic (41%), followed by neurological (13.9%) and cardiologic symptoms (8.5%) and 19.4% were prescribed for various symptoms. Only 15% of all requests had a value more than 200 U/ml.

CONCLUSION

Our study found that in most of requests, ASO titre levels were not significant.

Disease manifestations and pathogenic mechanisms of Group A Streptococcus

Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.

Disease manifestations and pathogenic mechanisms of Group A Streptococcus

Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.