At the end of 2022, the World Health Organization reported an increase in group A Streptococcus (GAS) infections, such as scarlet fever, in multiple countries. The outbreak primarily affected children under 10 years old, and the number of deaths was higher than anticipated, causing international concern. This paper reviews the current state of the GAS disease outbreak, its causes, and response measures. The authors aim to draw attention from clinical workers in China and increase their awareness and vigilance regarding this epidemic. Healthcare workers should be aware of the potential epidemiological changes in infectious diseases that may arise after the optimization of control measures for coronavirus disease 2019 to ensure children's health.
Child ; Humans ; Streptococcus pyogenes ; COVID-19/epidemiology* ; Streptococcal Infections/epidemiology* ; Scarlet Fever/epidemiology* ; Epidemics ; Disease Outbreaks

The application of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) can be limited due to a lack of compatible protospacer adjacent motif (PAM) sequences in the DNA regions of interest. Recently, SpRY, a variant of Streptococcus pyogenes Cas9 (SpCas9), was reported, which nearly completely fulfils the PAM requirement. Meanwhile, PAMs for SpRY have not been well addressed. In our previous study, we developed the PAM Definition by Observable Sequence Excision (PAM-DOSE) and green fluorescent protein (GFP)‍-reporter systems to study PAMs in human cells. Herein, we endeavored to identify the PAMs of SpRY with these two methods. The results indicated that 5'-NRN-3', 5'-NTA-3', and 5'-NCK-3' could be considered as canonical PAMs. 5'-NCA-3' and 5'-NTK-3' may serve as non-priority PAMs. At the same time, PAM of 5'-NYC-3' is not recommended for human cells. These findings provide further insights into the application of SpRY for human genome editing.
CRISPR-Associated Protein 9/metabolism* ; CRISPR-Cas Systems ; DNA ; Gene Editing/methods* ; Humans ; Streptococcus pyogenes/metabolism*

Streptococcus pyogenes Cas9 (SpCas9) has become a powerful genome editing tool, but has a limited range of recognizable protospacer adjacent motifs (PAMs) and shows off-target effects. To address these issues, we present a rational approach to optimize the xCas9 mutant derived from SpCas9 by directed evolution. Firstly, energy minimization with the Rosetta program was applied to optimize the three-dimensional structure of Cas9 to obtain the lowest energy conformation. Subsequently, combinatorial mutations were designed based on the mutations sites of xCas9 acquired during the directed evolution. Finally, optimal mutants were selected from the designed mutants by free energy ranking and subjected to experimental verification. A new mutant yCas9 (262A/324R/409N/480K/543D/694L/1219T) with multiple PAM recognition ability and low off-target effects was obtained and verified by DNA cleavage experiments. This mutant recognizes the NG, GAA and GAT PAMs and shows low off-target DNA cleavage activity guided by mismatched sgRNA, thus provides a gene editing tool with potential applications in biomedical field. Furthermore, we performed molecular dynamics simulations on the structures of SpCas9, xCas9 and yCas9 to reveal the mechanisms of their PAM recognition and off-target effects. These may provide theoretical guidance for further optimization and modification of CRISPR/Cas9 proteins.
CRISPR-Associated Protein 9/metabolism* ; CRISPR-Cas Systems/genetics* ; Clustered Regularly Interspaced Short Palindromic Repeats ; Gene Editing ; RNA, Guide/genetics* ; Streptococcus pyogenes/metabolism*

Postinfectious glomerulonephritis (PIGN) is most commonly caused by Streptococcus pyogenes in children, but PIGN associated with other pathogens has been described in the literature. A previously healthy 6-year-old boy was admitted with complaints of cough, fever, and right chest pain. The patient was diagnosed with pneumococcal bacteremia and influenza A virus infection and treated with antibiotics and antiviral agent. During hospitalization, generalized edema, hematuria, proteinuria, and increased blood pressure were observed; therefore, we started administering diuretics. The boy was discharged with gross hematuria, and even microscopic hematuria disappeared 14 weeks after discharge. We report a case of PIGN associated with bacteremic pneumococcal pneumonia and influenza A virus infection in children. A urine test and blood pressure measurement should be considered for the early detection of PIGN in children with pneumococcal or influenza A virus infection when they present with nephritic symptoms.
Anti-Bacterial Agents ; Bacteremia ; Blood Pressure ; Chest Pain ; Child ; Cough ; Diuretics ; Edema ; Fever ; Glomerulonephritis ; Hematuria ; Hospitalization ; Humans ; Influenza A virus ; Influenza, Human ; Male ; Pneumonia ; Pneumonia, Pneumococcal ; Proteinuria ; Streptococcus pneumoniae ; Streptococcus pyogenes

OBJECTIVES: Outbreaks of scarlet fever in Mexico in 1999, Hong Kong and mainland China in 2011, and England in 2014-2016 have received global attention, and the number of notified cases in Korean children, including in Jeju Province, has also increased since 2010. To identify relevant hypotheses regarding this emerging outbreak, an age-period-cohort (APC) analysis of scarlet fever incidence was conducted among children in Jeju Province, Korea. METHODS: This study analyzed data from the nationwide insurance claims database administered by the Korean National Health Insurance Service. The inclusion criteria were children aged ≤14 years residing in Jeju Province, Korea who received any form of healthcare for scarlet fever from 2002 to 2016. The age and year variables were categorized into 5 groups, respectively. After calculating the crude incidence rate (CIR) for age and calendar year groups, the intrinsic estimator (IE) method was applied to conduct the APC analysis. RESULTS: In total, 2345 cases were identified from 2002 to 2016. Scarlet fever was most common in the 0-2 age group, and boys presented more cases than girls. Since the CIR decreased with age between 2002 and 2016, the age and period effect decreased in all observed years. The IE coefficients suggesting a cohort effect shifted from negative to positive in 2009. CONCLUSIONS: The results suggest that the recent outbreak of scarlet fever among children in Jeju Province might be explained through the cohort effect. As children born after 2009 showed a higher risk of scarlet fever, further descriptive epidemiological studies are needed.
Child ; China ; Cohort Effect ; Delivery of Health Care ; Disease Outbreaks ; England ; Epidemiologic Studies ; Exotoxins ; Female ; Hong Kong ; Humans ; Incidence ; Insurance ; Korea ; Methods ; Mexico ; National Health Programs ; Scarlet Fever ; Streptococcus pyogenes

No abstract available.
Dermatitis* ; Streptococcus pyogenes

BACKGROUND AND OBJECTIVES: This study aims to verify the usefulness of Centor scores to diagnose the Group A Streptococcal pharyngitis. SUBJECTS AND METHOD: The subjects of this study were 379 patients who had been examined by the rapid antigen detection test (RADT) for Group A Streptococcus. We analyzed their medical records and laboratory test results retrospectively and compared the results of Centor symptom scores with those of RADT. Then we analyzed the association of RADT, the Centor score and the laboratory test results statistically. RESULTS: There were no correlation between the RADT results and fever, cough, tonsillar enlargement, nasal symptoms, myalgia or chilling (p>0.05). In the RADT positive group, there were more patients with tonsillar exudate, neck lymph node enlargement, tenderness and pharyngeal abscess formation significantly (p<0.05). The Centor score and C-reactive protein were significantly higher in the RADT positive group (p<0.05). CONCLUSION: The results of this study suggest that Centor symptom scores can be used to determine which antibiotics to use. The Centor score system can help reduce medical costs and detect the problematic Group A Streptococcal pharyngitis.
Abscess ; Anti-Bacterial Agents ; C-Reactive Protein ; Cough ; Decision Making ; Diagnosis ; Exudates and Transudates ; Fever ; Humans ; Lymph Nodes ; Medical Records ; Methods ; Myalgia ; Neck ; Pharyngitis ; Retrospective Studies ; Streptococcus ; Streptococcus pyogenes

Objective: To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS), isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. Methods: Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS. Eleven currently known SAg genes including SpeA, speC, speG, speH, speI, speJ, speK, speL, speM, smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR. Results: A total of 377 GAS were isolated from 6 801 throat swab specimens, with the positive rate as 5.5%. There were obvious changes noticed among speC, speG, speH and speK in three years. A total of 45 SAg genes profiles were observed, according to the SAgs inclusion. There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emm1 and emm12 strains (χ(2)=38.196, P<0.001; χ(2)=72.310, P<0.001). There also appeared significant differences in the frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (χ(2)=146.154, P<0.001; χ(2)=52.31, P<0.001; χ(2)=58.43, P<0.001; χ(2)=144.70, P<0.001). Conclusions: Obvious changes were noticed among SAg genes including speC, speG, speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. SAg genes including speA, speH, speI and speJ appeared to be associated with the emm 1 and emm 12 strains. More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles, during the epidemic period.
Antigens, Bacterial/genetics* ; Bacterial Outer Membrane Proteins ; Bacterial Proteins ; Beijing/epidemiology* ; China/epidemiology* ; Exotoxins ; Female ; Humans ; Membrane Proteins ; Pharyngitis/microbiology* ; Pharynx/microbiology* ; Pregnancy ; Pregnancy Complications, Infectious/microbiology* ; Real-Time Polymerase Chain Reaction ; Scarlet Fever/microbiology* ; Streptococcal Infections ; Streptococcus pyogenes/isolation & purification* ; Superantigens/genetics*

Group A streptococcus is a common cause of upper respiratory infection in children; however, it is a rare cause of pseudoaneurysm in pediatrics with only limited reports of cases associated with cardiac surgery and underlying disease. We report a case of infectious pseudoaneurysm of the right internal iliac artery caused by group A streptococcus in a previously healthy 5-year-old boy who presented with scarlet fever and group A streptococcal bacteremia. He was admitted to the hospital with fever, rash on the whole body, and sore throat, accompanied by severe leg pain. He was treated with surgical removal and antibiotics. Because a pseudoaneurysm may develop in children without vascularrelated underlying diseases, we should consider the possibility of this important clinical diagnosis in patients with scarlet fever.
Aneurysm, False* ; Aneurysm, Infected ; Anti-Bacterial Agents ; Bacteremia ; Child* ; Child, Preschool ; Diagnosis ; Exanthema ; Fever ; Humans ; Iliac Artery ; Leg ; Male ; Pediatrics ; Pharyngitis ; Scarlet Fever ; Streptococcus pyogenes ; Streptococcus* ; Thoracic Surgery

PURPOSE: There is a need to broaden protective coverage of M protein–based vaccines against group A streptococci (GAS) because coverage of the current 30-valent M protein vaccine does not extend to all emm types. An additional GAS antigen and virulence factor that could potentially extend vaccine coverage is M-related protein (Mrp). Previous work indicated that there are three structurally related families of Mrp (MrpI, MrpII, and MrpIII) and peptides of all three elicited bactericidal antibodies against multiple emm types. The purpose of this study was to determine if a recombinant form containing Mrp from the three families would evoke bactericidal antiserum and to determine if this antiserum could enhance the effectiveness of antisera to the 30-valent M protein vaccine. MATERIALS AND METHODS: A trivalent recombinant Mrp (trMrp) protein containing N-terminal fragments from the three families (trMrp) was constructed, purified and used to immunize rabbits. Anti-trMrp sera contained high titers of antibodies against the trMrp immunogen and recombinant forms representing MrpI, MrpII, and MrpIII. RESULTS: The antisera opsonized emm types of GAS representing each Mrp family and also opsonized emm types not covered by the 30-valent M protein–based vaccine. Importantly, a combination of trMrp and 30-valent M protein antiserum resulted in higher levels of opsonization of GAS than either antiserum alone. CONCLUSION: These findings suggest that trMrp may be an effective addition to future constructs of GAS vaccines.
Antibodies ; Humans ; Immune Sera ; Peptides ; Rabbits ; Staphylococcal Protein A* ; Streptococcal Vaccines* ; Streptococcus pyogenes ; Vaccines ; Virulence ; Virulence Factors