Increase in invasive group A streptococcal disease among Australian children coinciding with northern hemisphere surges

An Australian Paediatric Retrieval Service Riding the Wave of Invasive Group A Streptococcal Disease From 2022 to 2024

BACKGROUND

From late 2022, there was an increase in cases of invasive group A streptococcus (iGAS) reported in the Northern Hemisphere and there was a similar increase noted in the referrals to the Newborn and Paediatric Emergency Transport service (NETS NSW), in the state of New South Wales (NSW), Australia. This study describes the clinical characteristics and outcomes of children referred to NETS NSW with iGAS disease.

METHODS

A retrospective cohort of children referred to NETS NSW for management of iGAS disease between 1st November 2022 to 29th February 2024. Patients included had a confirmed diagnosis of iGAS disease (i.e., on detection of S. pyogenes from a sterile site). Clinical characteristics and outcome data were collected from the medical record.

RESULTS

Seventy-seven cases were referred to NETS NSW of children with confirmed iGAS disease and seventy were retrieved by NETS NSW. Three patients died in the referring hospital; one was retrieved by an interstate service and three improved and stayed locally. A male predominance of 44/77 (57%) was noted, most were children of preschool age (median 4.2 years QR 1.95-8.05), presenting with pneumonia (52/77, 67.5%), septic arthritis (12/77, 16%), or rash 37/68 (54%). There were high rates of bacteraemia (38/77, 49%) and increased mean serum lactate (4.8 mmol/L ± 3.3). High clinical acuity was seen, with most cases retrieved to paediatric intensive care unit (52/77, 68%), often managed with mechanical ventilation (36/77, 47%), effusion drainage (50/77, 65%) and 24/77 (27%) referred via NETS NSW for the Kids ECMO Referral Service (KERS). IVIg was added for 31/64 cases (48%) as supportive care, along with antibiotic therapy. Four children did not survive.

CONCLUSION

The prevalence of iGAS disease referrals to NETS NSW significantly increased from late 2022 to early 2024. There was a high service demand for NETS NSW to retrieve critically unwell preschool-aged children requiring critical stabilisation and transfer to a paediatric intensive care unit (PICU).

Group A Streptococcal Disease in Sudden Unexpected Death in Youth in the Pre- and Post-COVID-19 Era

BACKGROUND

An upsurge in pediatric invasive group A streptococcal infection (iGAS) has been observed in the Netherlands along with a suspected increase in iGAS-related sudden death. Sudden unexplained deaths in youth (SUDY) are investigated nationally through a standardized procedure [(Postmortem Evaluation of Sudden Unexplained Death in Youth (PESUDY)]. We investigate epidemiological differences between pediatric iGAS-related sudden deaths (iGAS-PESUDY) and surviving iGAS cases.

METHODS

This observational study used data from the COPP-iGAS study on pediatric iGAS infections in Dutch hospitals and the PESUDY database. Children 0-18 years of age were included between August 2016 and December 2022.

RESULTS

Twenty-one iGAS-PESUDY cases and 156 iGAS survivors were included. iGAS-PESUDY cases tended to be older compared to survivors. iGAS-PESUDY cases significantly increased in 2022 compared to the pre-COVID period. Pre- and/or coinciding infections were present in 66% of iGAS-PESUDY cases, predominantly varicella zoster (19%) and influenza (24%). In survivors, 13% had varicella zoster virus and 3% had influenza virus ( P ≤ 0.001). C-reactive protein levels tended to be lower in iGAS-PESUDY cases (81 mg/L; interquartile range, 26.8-307.5) compared to survivors (266 mg/L; interquartile range, 218.0-302.0).

CONCLUSION

iGAS is currently a prevalent cause of SUDY. The finding of moderately elevated C-reactive protein levels compared to high levels in survivors might suggest children dying suddenly of iGAS have a rapid and fulminant disease course. Children with a pre- and/or coinciding infection of varicella zoster or influenza virus may be at greater risk of succumbing to iGAS infections.

Comparison of pharyngeal and invasive isolates of Streptococcus pyogenes by whole-genome sequencing in Toronto, Canada

Invasive Group A streptococcal (iGAS) infections are rising in Canada and wordwide. The 2022-2023 Ontario iGAS season was among the highest recorded, a trend continuing in 2023-2024. We sequenced 38 invasive (blood) and 117 non-invasive (pharyngeal) Streptococcus pyogenes clinical isolates from Toronto (January-May 2023) to compare between the two cohorts and against published sequences to determine if any genomic changes accounted for the trend. Results demonstrated limited clustering with one small totally invasive cluster (emm49) with both invasive and non-invasive isolates represented across a diverse set of lineages. Non-invasive isolates were predominantly emm12 (70.1%), whereas invasive isolates included emm12 (26.32%), emm49 (23.68%), and emm1 (13.16%) with most emm1 strains containing the 27 SNPs that define the hypervirulent M1UK clone (58.33%). Although there were no differences in the presence of overall virulence factors/adhesin genes between cohorts, there were statistically more superantigen and DNase genes in non-invasive isolates and a rare phage gene was significantly associated with invasiveness across three emm-types. The prevalence of individual virulence factor/adhesin genes also differed between our cohorts, including a higher likelihood of speA, enn, mrp, ideS/Mac, fbaA, and fbaB in invasive isolates. There were also no significant differences across the 11 antimicrobial resistance genes identified. Finally, pharyngeal isolates had larger hydrolysis and hemolysis zones, and covS deletions were observed in only seven invasive strains. Despite there being no genetic signature that differentiated our isolates, we observed several features that were predominant in invasive strains which provides further insights into the factors that contribute to GAS invasiveness.IMPORTANCEIncreasing rates of invasive Group A streptococcal (iGAS) infections are being seen both in Canada and worldwide, which is leading to a greater disease burden caused by this pathogen. Leveraging whole-genome sequencing gives us an opportunity to better understand the underlying genetic mechanisms of streptococcal disease. By utilizing this technique, we shed light on the circulating invasive and non-invasive strains of Streptococcus pyogenes in the largest urban area in Canada from January to May 2023. GAS strains causing non-invasive disease were found to have a higher abundance of superantigen and DNase genes, whereas invasive isolates were more likely to contain M-like protein genes, the superantigen speA, the protease ideS/Mac, and/or the fibronectin-binding proteins fbaA and fbaB. This work provides valuable insights into iGAS disease which will help with surveillance, epidemiology as well as developing treatment and preventative modalities to help curb the disease burden caused by this globally important pathogen.

Invasive Group A Streptococcal Infection in Children, 1992-2023

Importance

The resurgence of invasive group A streptococcal (iGAS) infections and progress in GAS vaccine development emphasize the importance of understanding current trends in the epidemiology of iGAS.

Objective

To describe the epidemiology of pediatric iGAS over a 32-year period.

Design, Setting, and Participants

This case series uses population-based surveillance data for iGAS in Toronto and Peel Region, Canada, including emm typing from Canada's National Microbiology Laboratory and population data from Statistics Canada. All children (age <18 years) with iGAS from January 1, 1992, to December 31, 2023, were included. Data were analyzed from July 15, 2023, to September 1, 2024.

Main Outcomes and Measures

Outcomes of interest were disease incidence over time and by age; variation in clinical presentation, disease severity, outcomes and infecting emm types; and antimicrobial resistance.

Results

Overall, 498 iGAS cases (300 [60.2%] male; median [IQR] age, 5.1 [2.7-8.6] years) occurred, including 151 (30.7%) in children with comorbidities. The most common presentations were soft tissue infection (140 cases [28.1%]) and bacteremia without focus (131 cases [26.3%]). iGAS incidence increased from 1.8 events per 100 000 population per year in 1992 to 2011 to 2.4 events per 100 000 population per year in 2012 to 2019 (incidence rate ratio, 1.3 [95% CI, 1.1-1.6]), with the increase occurring in GAS infections of the respiratory tract. Incidence declined to 1.2 events per 100 000 population per year in 2020 and 0.5 events per 100 000 population per year in 2021 before increasing to 6.0 events per 100 000 population per year in 2023. In 2022 to 2023, 18 of 56 children with iGAS (32.0%) had a viral respiratory coinfection. Varicella-associated iGAS cases declined from 23 of 137 children (16.8%) in 1992 to 2001 to 2 of 223 children (0.9%) in 2012 to 2023 (P < .001), after routine varicella vaccination implementation in 2004. Streptococcal toxic shock syndrome occurred in 29 children (5.8%), necrotizing fasciitis in 12 children (2.4%); 10 children (2.0%) died. The most common emm types were emm1 (182 of 471 isolates [38.6%]), emm12 (75 isolates [15.9%]), and emm4 (31 isolates [6.6%]). The M1UK subtype was first identified in 2019 and comprised 32 of 46 emm1 isolates (70.0%) from 2019 to 2023. Compared with other emm types, emm1 was more likely to be associated with pneumonia (odds ratio [OR], 1.99 [95% CI, 1.16-3.40]), bone and joint infections (OR, 1.70 [95% CI, 1.08-2.68]), and intensive care unit admission (OR, 1.67 [95% CI, 1.03-2.68]); emm4 was more likely to be associated with bacteremia without focus (OR, 6.10 [95% CI, 2.83-13.16]). Overall, 437 isolates (92.8%) were of emm types included in the 30-valent GAS vaccine.

Conclusions and Relevance

This case series found that pediatric iGAS incidence increased in south-central Ontario prior to and after the COVID-19 pandemic in association with increased iGAS infections of the respiratory tract. Respiratory viral coinfections were common. Different emm types were associated with differing presentations and severity.

Impact of an evidence-based sepsis pathway on paediatric hospital clinical practice: A quality improvement study

OBJECTIVES

To assess the impact of implementing a sepsis pathway and education program on key sepsis outcomes and performance targets in a tertiary paediatric hospital.

METHODS

A quality improvement study using a multi-modal screening process and pragmatic clinical definitions. Treatment of all children with septic shock and sepsis without shock 4 months prior to pathway/education package launch was compared with those meeting definitions 8 months post-launch.

RESULTS

Over the study period, 1483 episodes were screened; 517 episodes met study definitions (171 pre-launch; 346 post-launch). Eighty-two episodes met septic shock definitions (15.9%) and 435 met sepsis without shock definitions (84.1%). A total of 143 episodes pre-launch and 271 episodes post-launch were managed exclusively at Perth Children's Hospital (PCH). Post intervention, the pathway form was utilised in 146 of 271 episodes (53.9%). Pathway/education package introduction was associated with a reduction in the median time from recognition to antibiotic administration (60 [IQR: 26; 115] to 45 min [IQR: 16; 75] for those with septic shock and/or sepsis without shock treated exclusively at PCH; P < 0.001). The proportion receiving antibiotic therapy within recommended timeframes significantly increased (septic shock within 60 min: 70.0% to 92.5%, P < 0.03; sepsis without shock within 180 min; 86.2% to 94.8%, P = 0.005). No statistically significant change in length of stay, intensive care admission, mortality or antibiotic consumption was observed following pathway launch.

CONCLUSIONS

Paediatric sepsis pathway and education package implementation can reduce time to antibiotics in sepsis and aid local data collection and surveillance of patients treated for sepsis.

Characterization of a novel covS SNP identified in Australian group A Streptococcus isolates derived from the M1UK lineage

Group A Streptococcus (GAS) is a human-adapted pathogen responsible for a variety of diseases. The GAS M1UK lineage has contributed significantly to the recently reported increases in scarlet fever and invasive infections. However, the basis for its evolutionary success is not yet fully understood. During the transition to systemic disease, the M1 serotype is known to give rise to spontaneous mutations in the control of virulence two-component regulatory system (CovRS) that confer a fitness advantage during invasive infections. Mutations that inactivate CovS function result in the de-repression of key GAS virulence factors such as streptolysin O (SLO), a pore-forming toxin and major trigger of inflammasome/interleukin-1β-dependent inflammation. Conversely, expression of the streptococcal cysteine protease SpeB, which is required during initial stages of colonization and onset of invasive disease, is typically lost in such mutants. In this study, we identified and characterized a novel covS single nucleotide polymorphism detected in three separate invasive M1UK isolates. The resulting CovSAla318Val mutation caused a significant upregulation of SLO resulting in increased inflammasome activation in human THP-1 macrophages, indicating an enhanced inflammatory potential. Surprisingly, SpeB production was unaffected. Site-directed mutagenesis was performed to assess the impact of this mutation on virulence and global gene expression. We found that the CovSAla318Val mutation led to subtle, virulence-specific changes of the CovRS regulon compared to previously characterized covS mutations, highlighting an unappreciated level of complexity in CovRS-dependent gene regulation. Continued longitudinal surveillance is warranted to determine whether this novel covS mutation will expand in the M1UK lineage.IMPORTANCEThe M1UK lineage of GAS has contributed to a recent global upsurge in scarlet fever and invasive infections. Understanding how GAS can become more virulent is critical for infection control and identifying new treatment approaches. The two-component CovRS system, comprising the sensor kinase CovS and transcription factor CovR, is a central regulator of GAS virulence genes. In the M1 serotype, covRS mutations are associated with an invasive phenotype. Such mutations have not been fully characterized in the M1UK lineage. This study identified a novel covS mutation in invasive Australian M1UK isolates that resulted in a more nuanced virulence gene regulation compared to previously characterized covS mutations. A representative isolate displayed upregulated SLO production and triggered amplified interleukin-1β secretion in infected human macrophages, indicating an enhanced inflammatory potential. These findings underscore the need for comprehensive analyses of covRS mutants to fully elucidate their contribution to M1UK virulence and persistence.

Severe Parapneumonic Effusion in a Child With Respiratory Syncytial Virus and Streptococcus pyogenes Coinfection

A four-year-old boy with respiratory syncytial virus (RSV) infection and suspected bacterial coinfection deteriorated despite antibiotic treatment. Intensive care and thoracoscopic debridement were required due to parapneumonic effusion. Despite negative pleural fluid cultures, next-generation sequencing detected group A streptococcus (GAS). Even in healthy children without risk factors, RSV infection preceding invasive GAS infection can rapidly deteriorate, making diagnosis difficult.

Invasive group A Streptococcus infection (Streptococcus pyogenes): Current situation in Spain

Group A ß-hemolytic Streptococcus (S. pyogenes), also known as GAS, is a Gram-positive bacterium. It can be easily identified in the microbiology laboratory by its ability to hemolyse blood in culture media. This bacterium is highly virulent due to its production of enzymes and toxins, and its ability to cause immunologically mediated diseases such as rheumatic fever and post-streptococcal glomerulonephritis. GAS is the primary cause of bacterial pharyngotonsillitis, although it is typically a benign and non-invasive disease. However, it also has the potential to cause severe skin and soft tissue infections, necrotising fasciitis, bacteraemia and endocarditis, pneumonia and empyema, and streptococcal toxic shock syndrome, without any age or predisposition limits. The term invasive GAS disease (iGAS) is used to refer to this group of conditions. In more developed countries, iGAS disease has declined thanks to improved hygiene and the availability of antibiotics. For example, rheumatic fever has practically disappeared in countries such as Spain. However, recent data suggests a potential increase in some iGAS diseases, although the accuracy of this data is not consistent. Because of this, the COVID and Emerging Pathogens Committee of the Illustrious Official College of Physicians of Madrid (ICOMEM) has posed several questions about invasive GAS infection, especially its current situation in Spain. The committee has enlisted the help of several experts in the field to answer these questions. The following lines contain the answers that we have collaboratively produced, aiming to assist not only the members of ICOMEM but also anyone interested in this topic.

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

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

Invasive Group A Streptococcal Infections in Europe After the COVID-19 Pandemic

BACKGROUND

The incidence of airborne respiratory infections fell as a result of the protective measures taken during the COVID-19 pandemic and rose again when these were stopped. In 2022, there was a notable rise in invasive group A streptococcal (iGAS) infections in many countries, including Germany. This rise was also reflected in the data of the university otorhinolaryngology department in Ulm, Germany.

METHODS

This review is based on publications retrieved by a selective literature search on the rise of iGAS infections in Europe, with particular attention to the timing of disease onset, clinical presentation, pathogenic strains, and potential causes and risk factors.

RESULTS

The rise in infections after the pandemic was especially marked among children up to age 10 and in older adults; in Germany, it affected all age groups equally, but predominantly persons older than 65. Rising prevalence figures were seen in Germany and elsewhere as early as the fall of 2022, outside the usual season, and peaked mainly in the first and second quarters of 2023. The increased incidence of iGAS-associated pneumonia was paralleled by that of viral airway infections and led to greater use of intensivecare measures for children. The main bacterial strain identified was emm1; a new variant (M1DK) played a role in Denmark, and an emm4 variant (M4NL22) became increasingly important in the Netherlands. In Germany, initial evidence suggested the predominance of M1UK. Increased antibiotic resistance was not found.

CONCLUSION

The reduced confrontation of the immune system with pathogens during the pandemic, along with the increased incidence of viral airway infections immediately after it, apparently accounted for the exceptionally high post-pandemic rise in iGAS infections and the increase in invasive pulmonary diseases in Europe. Consistent vaccination programs against coincident respiratory viruses could reduce the burden of iGAS infections. The further extension of multinational surveillance programs with obligatory participation could aid in the detection of factors affecting the course of disease and the spread of new bacterial strains.

Epidemiology of scarlet fever in Victoria, Australia, 2007-2017

In the last 10-15 years, there has been a global resurgence of scarlet fever, an infection historically associated with significant morbidity and mortality. It is unknown whether scarlet fever incidence has increased in Australia. We aimed to examine the incidence, predictors and severity of scarlet fever in the state of Victoria, Australia from 2007 to 2017, analyzing scarlet fever emergency department (ED) presentations, hospitalizations and deaths. Of the 1 578 scarlet fever cases during the study period, most occurred in children aged <10 years (1 344, 85%), in males (882, 56%), and during winter and spring months (918, 57%). There were no deaths with scarlet fever, however, 374 cases (24%) were admitted to hospital. The annual incidence of scarlet fever was stable during the study period (mean, 2.5; range, 1.9-3.1 cases per 100 000). Annual incidence was highest in children aged <5 years (19.3 per 100 000), and was 21% higher in males than females, adjusting for age and year (incidence rate ratio, 1.21, 95%CI 1.09-1.34). Whilst scarlet fever ED presentations and hospitalizations were stable in Victoria from 2007 to 2017, the recent identification of a Streptococcus pyogenes variant in Australia associated with epidemic scarlet fever overseas highlights the risk of future outbreaks.

Ongoing Excess Hospitalizations for Severe Pediatric Group A Streptococcal Disease in 2023-2024-A Single-Center Report

A Europe-wide outbreak of invasive pediatric group A streptococcal infections (iGAS) began in fall 2022. Here, we report the evolution of GAS hospitalizations in children and adolescents during the second outbreak year in 2023-2024 at a tertiary center in Switzerland. Using prospective monitoring of all in-patient GAS cases below 16 years of age, including those with iGAS, we compared case frequencies and clinical characteristics in three time periods (2013-2020; 2022-2023; 2023-2024). Annual GAS hospitalizations increased from a median of 25 cases (range 11-28) in 2013-2020 to 89 and 63 cases, respectively, in 2022-2023 and 2023-2024. iGAS cases evolved similarly (2013-2020, 4 cases (3-8); 2022-2023, 32 cases; 2023-2024, 21 cases). The decline in cases from 2022-2023 to 2023-2024 included all types of GAS organ involvement, except suppurative infections in the head area, which remained largely unchanged (48 vs. 45 cases). Pleural empyema declined from 13 to 7 cases, possibly explained by a poor overlap of the GAS and influenza curves, respectively, in 2023-2024 compared to 2022-2023. These data document the prolongation of the GAS outbreak into its second winter season in 2023-2024.

Two Cases of Group A Streptococcus-Induced Right Empyema: Rare Occurrences in Adult Medicine

Group A Streptococcus (GAS) empyema, though rare in adults, poses serious clinical challenges. We present two cases of GAS-induced right empyema in immunocompetent patients. Case 1 involved a 45-year-old female Chinese healthcare worker with persistent pleural effusion despite antibiotic therapy. GAS was isolated from her sputum and bronchoalveolar lavage, necessitating a treatment shift to clindamycin and co-amoxiclav. Case 2 featured a 55-year-old Filipino domestic helper exhibiting right lower chest consolidation and effusion. Thoracocentesis confirmed empyema, prompting intrapleural fibrinolytic administration. Both cases highlight the diagnostic complexity and therapeutic intricacies of adult GAS empyema, underscoring the importance of early recognition and tailored management strategies for optimal patient outcomes.

Bacteraemia in Tropical Australia: A Review

Purpose of Review

This review discusses the trends of bacteraemia and their outcomes in tropical regions of Australia. Bacteraemia can frequently lead to severe sepsis and potentially life-threatening consequences. Epidemiology of bacteraemia is ever evolving.

Recent Findings

This review outlines the current patterns of bacteraemia in tropical regions of Australia, focusing on their outcomes and associated risk factors. The most frequently reported causes of bacteraemia were Staphylococcus aureus and Escherichia coli. There has been an increase in published incidence of Group A Streptococcus, methicillin-resistant Staphylococcus aureus and Burkholderia pseudomallei bacteraemia cases, while Streptococcus pneumoniae bacteraemia exhibited a declining trend. Factors specific to tropical environments and the higher representation of Indigenous populations in these areas were identified as contributing to the elevated incidence rates.

Summary

Bacteraemia was found to be an increasing healthcare burden to the Australian tropical regions. Ideally, linkage of existing data from healthcare settings could be utilised to obtain more accurate, comprehensive and up to date information of trends and patterns of bacteraemia.

Group A Streptococcal meningitis in children: a short case series and systematic review

BACKGROUND

Group A streptococcal(GAS) meningitis is a severe disease with a high case fatality rate. In the era of increasing GAS meningitis, our understanding about this disease is limited.

PURPOSE

To gain a better understanding about GAS meningitis.

METHODS

Five new cases with GAS meningitis were reported. GAS meningitis related literatures were searched for systematic review in PUBMED and EMBASE. Case reports and case series on paediatric cases were included. Information on demographics, risk factors, symptoms, treatments, outcomes, and emm types of GAS was summarized.

RESULTS

Totally 263 cases were included. Among 100 individuals, 9.9% (8/81) had prior varicella, 11.1% (9/81) had anatomical factors, and 53.2% (42/79) had extracranial infections. Soft tissue infections were common among infants (10/29, 34.5%), while ear/sinus infections were more prevalent in children ≥ 3 years (21/42, 50.0%). The overall case fatality rate (CFR) was 16.2% (12/74). High risk of death was found in patients with shock or systemic complications, young children(< 3 years) and cases related to hematogenic spread. The predominate cause of death was shock(6/8). Among the 163 patients included in case series studies, ear/sinus infections ranged from 21.4 to 62.5%, while STSS/shock ranged from 12.5 to 35.7%, and the CFR ranged from 5.9 to 42.9%.

CONCLUSIONS

A history of varicella, soft tissue infections, parameningeal infections and CSF leaks are important clinical clues to GAS in children with meningitis. Young children and hematogenic spread related cases need to be closely monitored for shock due to the high risk of death.

Group A Streptococcal Infections in Pediatric Age: Updates about a Re-Emerging Pathogen

Group A Streptococcus (GAS) presents a significant global health burden due to its diverse clinical manifestations ranging from mild infections to life-threatening invasive diseases. While historically stable, the incidence of GAS infections declined during the COVID-19 pandemic but resurged following the relaxation of preventive measures. Despite general responsiveness to β-lactam antibiotics, there remains an urgent need for a GAS vaccine due to its substantial global disease burden, particularly in low-resource settings. Vaccine development faces numerous challenges, including the extensive strain diversity, the lack of suitable animal models for testing, potential autoimmune complications, and the need for global distribution, while addressing socioeconomic disparities in vaccine access. Several vaccine candidates are in various stages of development, offering hope for effective prevention strategies in the future.

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

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

Clinical, microbiological, and molecular characterization of pediatric invasive infections by Streptococcus pyogenes in Spain in a context of global outbreak

In December 2022, an alert was published in the UK and other European countries reporting an unusual increase in the incidence of Streptococcus pyogenes infections. Our aim was to describe the clinical, microbiological, and molecular characteristics of group A Streptococcus invasive infections (iGAS) in children prospectively recruited in Spain (September 2022-March 2023), and compare invasive strains with strains causing mild infections. One hundred thirty isolates of S. pyogenes causing infection (102 iGAS and 28 mild infections) were included in the microbiological study: emm typing, antimicrobial susceptibility testing, and sequencing for core genome multilocus sequence typing (cgMLST), resistome, and virulome analysis. Clinical data were available from 93 cases and 21 controls. Pneumonia was the most frequent clinical syndrome (41/93; 44.1%), followed by deep tissue abscesses (23/93; 24.7%), and osteoarticular infections (11/93; 11.8%). Forty-six of 93 cases (49.5%) required admission to the pediatric intensive care unit. iGAS isolates mainly belonged to emm1 and emm12; emm12 predominated in 2022 but was surpassed by emm1 in 2023. Spread of M1UK sublineage (28/64 M1 isolates) was communicated for the first time in Spain, but it did not replace the still predominant sublineage M1global (36/64). Furthermore, a difference in emm types compared with the mild cases was observed with predominance of emm1, but also important representativeness of emm12 and emm89 isolates. Pneumonia, the most frequent and severe iGAS diagnosed, was associated with the speA gene, while the ssa superantigen was associated with milder cases. iGAS isolates were mainly susceptible to antimicrobials. cgMLST showed five major clusters: ST28-ST1357/emm1, ST36-ST425/emm12, ST242/emm12.37, ST39/emm4, and ST101-ST1295/emm89 isolates.

IMPORTANCE

Group A Streptococcus (GAS) is a common bacterial pathogen in the pediatric population. In the last months of 2022, an unusual increase in GAS infections was detected in various countries. Certain strains were overrepresented, although the cause of this raise is not clear. In Spain, a significant increase in mild and severe cases was also observed; this study evaluates the clinical characteristics and the strains involved in both scenarios. Our study showed that the increase in incidence did not correlate with an increase in resistance or with an emm types shift. However, there seemed to be a rise in severity, partly related to a greater rate of pneumonia cases. These findings suggest a general increase in iGAS that highlights the need for surveillance. The introduction of whole genome sequencing in the diagnosis and surveillance of iGAS may improve the understanding of antibiotic resistance, virulence, and clones, facilitating its control and personalized treatment.

Recent Scientific Advancements towards a Vaccine against Group A Streptococcus

Group A Streptococcus (GAS), or Streptococcus pyogenes, is a gram-positive bacterium that extensively colonises within the human host. GAS is responsible for causing a range of human infections, such as pharyngitis, impetigo, scarlet fever, septicemia, and necrotising fasciitis. GAS pathogens have the potential to elicit fatal autoimmune sequelae diseases (including rheumatic fever and rheumatic heart diseases) due to recurrent GAS infections, leading to high morbidity and mortality of young children and the elderly worldwide. Antibiotic drugs are the primary method of controlling and treating the early stages of GAS infection; however, the recent identification of clinical GAS isolates with reduced sensitivity to penicillin-adjunctive antibiotics and increasing macrolide resistance is an increasing threat. Vaccination is credited as the most successful medical intervention against infectious diseases since it was discovered by Edward Jenner in 1796. Immunisation with an inactive/live-attenuated whole pathogen or selective pathogen-derived antigens induces a potent adaptive immunity and protection against infectious diseases. Although no GAS vaccines have been approved for the market following more than 100 years of GAS vaccine development, the understanding of GAS pathogenesis and transmission has significantly increased, providing detailed insight into the primary pathogenic proteins, and enhancing GAS vaccine design. This review highlights recent advances in GAS vaccine development, providing detailed data from preclinical and clinical studies across the globe for potential GAS vaccine candidates. Furthermore, the challenges and future perspectives on the development of GAS vaccines are also described.

Antibiotics to eradicate Streptococcus pyogenes pharyngeal carriage in asymptomatic children and adults: A systematic review

Streptococcus pyogenes (S. pyogenes) is a Gram-positive bacteria which causes a spectrum of diseases ranging from asymptomatic infection to life-threatening sepsis. Studies report up to 2000 times greater risk of invasive S. pyogenes disease in close contacts of index cases within 30-days of symptom onset. Despite this, there is variability in the management of asymptomatic carriage of S. pyogenes and those at risk of secondary cases of invasive S. pyogenes infection.

OBJECTIVE

Our systematic review assessed the efficacy of different antibiotic regimens used for eradication of S. pyogenes from the pharynx in asymptomatic individuals.

METHODS

We searched Pubmed, EMBASE (1974-), OVID Medline (1948-) and the Cochrane CENTRAL registry. We included randomised controlled trials (RCTs) with asymptomatic participants with >50% with pharyngeal cultures positive with S. pyogenes at baseline. Only studies with microbiological methods including culture (+/- polymerase chain reaction, PCR) were included. We included studies published in English. Each included study was assessed by two independent reviewers for data extraction and risk of bias.

RESULTS

Of 1166 unique records identified, three RCTs were included in the review. Two of the three included RCTs found oral clindamycin for 10-days was the most efficacious regimen, compared to intramuscular benzathine penicillin G followed by 4 days of oral rifampicin, or monotherapy using benzathine penicillin, phenoxymethylpenicillin or erythromycin. Two RCTs were assessed as being at high risk of bias, with the third study demonstrating low/some risk of bias.

CONCLUSIONS

Current available evidence for the optimal antibiotic in eradicating pharyngeal S. pyogenes carriage is limited. Future RCTs should include penicillin, first-generation cephalosporins, rifampicin, macrolides (such as azithromycin) and clindamycin.