Interpretation of Chinese experts′ consensus statement on diagnosis, treatment, and prevention of Group A Streptococcus infection related diseases in children / 中华实用儿科临床杂志

Group A Streptococcus (GAS) is a very important pathogenic organism, especially for children.Chinese experts′consensus statement on diagnosis, treatment, and prevention of Group A Streptococcus infection related diseases in children was developed in November 2022 by pediatric experts in the fields of respiration, infection, immunology, testing, cardiovascular, kidney, critical care and prevention in China, aiming to further standardize the prevention and treatment of diseases associated with GAS infections and to promote and maintain the health of children.Its main contents are now explained, including disease burden, prevention, diagnosis, antimicrobial resistance and therapy.

Application of the emm cluster typing system in related studies of Group A Streptococcus / 中华实用儿科临床杂志

Group A Streptococcus (GAS) is one of the most important pathogens leading to children deaths all over the world.Bacterial typing is the commonest approach to analyzing the epidemiological characteristics of pathogenic microorganisms.The emm typing is frequently adopted to study GAS.The emm cluster typing is a recently proposed typing method based on the amino acid sequence homology of M proteins and the ability to bind to the host serum protein.This typing system has been extensively used for epidemiological investigation, strain selection and vaccine deve-lopment in foreign countries.However, it has not been applied in China yet. emm typing is based on a small variable region of emm genes, while the emm cluster typing system defines GAS types according to nearly intact sequences of emm genes.Besides, the emm cluster grouping system is acquired directly by emm typing comparison, so it is simple and feasible.Furthermore, the emm cluster typing can provide more information regarding the functional and structural properties of M proteins in different emm types of GAS.In this review, the methods, principles and applications of the emm cluster typing system in GAS research were summarized, in order to promote its application in China.

Analysis of emm typing and genomic polymorphism of Group A Streptococcus from children with scarlet fever in Shenzhen 2016-2018 / 中华实用儿科临床杂志

Objective:To identify the epidemic types of Group A Streptococcus (GAS)causing scarlet fever, to compare the gene structure and variability of GAS with different emm types, and to elucidate the epidemiological pattern of scarlet fever pathogens in Shenzhen. Methods:Pharyngeal swab samples were collected and analyzed retrospectively from children diagnosed with scarlet fever in Shenzhen Children′s Hospital from January 1, 2016 to May 31, 2018.The GAS strains were preserved for emm genotyping analysis.The strains of representative emm types were selected for whole-genome sequencing.The genomic polymorphism of GAS strains was described by comparative genomic analysis.Moreover, a phylogenetic tree was constructed based on the whole genome core-gene single nucleotide polymorphisms(SNPs) to clarify the evolutionary relationship between strains.Data between groups were compared by Rank sum test. Results:Among 176 GAS isolates that caused scarlet fever in children, 8 emm types were detected.The most common genotype was emm12.0 and its subtype(108/176 strains, 61.4%), followed by emm1.0 and its subtype(53/176 strains, 30.1%). These two genotypes accounted for 91.5% of all isolates collected.Comparative genome analysis was made taking GCA-900984775 as a reference sequence, and the results showed that the genomes of GAS strains had high levels of SNP and insertion or deletion (InDel) polymorphisms.There were more SNPs in emm12.0 strains[183(163, 213)] than those in emm1.0 strains[63 (54, 75)], and the difference was statistically significant ( P<0.05). As for InDel, more insertions and deletions [4(3, 6), 8(6, 10)] were observed in emm12.0 strains than those [1(0, 2), 5(3, 7)] in emm1.0 strains.According to the phylogenetic tree built by taking MGAS5005 as the reference sequence based on the whole genome core-gene SNPs, 18 strains and reference strains formed two clades. Conclusions:The emm12.0 and emm1.0 types are the most common GAS strains leading to scarlet fever in children.There are differences in the genome composition of different GAS strains.The emm12.0 strains have higher genetic diversity.

Epidemiology, prevention and control strategy of Group A Streptococcus infection / 中华实用儿科临床杂志

As a pathogen of public health significance, group A Streptococcus (GAS) infects 18.1 million people and leads to 500 000 deaths all over the world every year.GAS is often transmitted through respiratory droplets and contact with damaged skin.Children, the elderly and immunocompromised people are highly susceptible to GAS infection.Schools, kindergartens, hospitals, nursing homes and other densely populated areas are high-risk areas for GAS transmission.Prevention and control measures should highlight the improvement of living conditions and hand hygiene.Adherence to infection prevention and control measures should be emphasized in high-risk environments.In this paper, the risk factors, prevention and control strategies of GAS infection and transmission were summarized, so as to provide basis for the prevention and control of GAS.

Chinese experts′ consensus statement on diagnosis, treatment and prevention of Group A Streptococcus infection related diseases in children / 中华实用儿科临床杂志

Group A Streptococcus (GAS) is a very important pathogen, especially for children.On a global scale, GAS is an important cause of morbidity and mortality.But the burden of disease caused by GAS is still unknown in China and also has not obtained enough attention.For this purpose, the expert consensus is comprehensively described in diagnosis, treatment and prevention of GAS diseases in children, covering related aspects of pneumology, infectiology, immunology, microbiology, cardiology, nephrology, critical care medicine and preventive medicine.Accordingly, the consensus document was intended to improve management strategies of GAS disease in Chinese children.

Multilocus sequence typing of Streptococcus pyogenes isolated from children in Shenzhen / 中华实用儿科临床杂志

Objective:To explore the epidemiological characteristics of Streptococcus pyogenes, namely β-hemolytic Group A Streptococcus (GAS) in children in Shenzhen. Methods:Multilocus sequence typing (MLST) data on the epidemic clonal population of GAS infection in children in Shenzhen Children′s Hospital from January 2016 to December 2018 were retrospectively analyzed.In the present study, 32 GAS strains belonging to 7 different emm types were from 32 children′s with impetigo, cellulitis, scarlet fever, sepsis, pneumonia, obstructive sleep apnea hypopnea syndrome, bronchitis, allergy with rhinitis, buttock abscess, allergic purpura or pharyngeal tonsillitis, which were isolated from 23 throat swabs, 5 sputum samples, 3 pus and 1 blood.Using polymerase chain reaction technology, 7 pairs of allelic housekeeping genes ( gki, gtr, murI, mutS, recP, xpt and yqiL) of 32 GAS isolates were analyzed, and the target gene products were subjected to sequencing.Then the obtained gene sequences of each allele were submitted to the MLST database to obtain the allele profile.Finally, the allele profiles were introduced in the MLST database again to confirm the sequence typing (ST). Results:The GAS clone groups of emm 1.00 and its subtypes, emm 4.00, emm 12.00 and its subtypes, emm 22.00, emm 28.00, emm 75.00, and emm 89.00 belonged to the sequence typing ST28, ST39, ST36, ST46, ST52, ST49, and ST921, respectively. Conclusions:From 2016 to 2018, the MLST clone populations of GAS isolates causing infections in children in Shenzhen are classified as ST28, ST39, ST36, ST46, ST52, ST49 and ST921.

Integrated functional neuronal network analysis of 3D silk-collagen scaffold-based mouse cortical culture.

Bioengineered 3D tunable neuronal constructs are a versatile platform for studying neuronal network functions, offering numerous advantages over existing technologies and providing for the discovery of new biological insights. Functional neural networks can be evaluated using calcium imaging and quantitatively described using network science. This protocol includes instructions for fabricating protein-based composite scaffolds, 3D in vitro culture of embryonic mouse cortical neurons, virally induced expression of GCaMP6f, wide-field calcium imaging, and computational analysis with open-source software and custom MATLAB code. For complete details on the use and execution of this protocol, please refer to Dingle et al. (2020).

Functional Characterization of Three-Dimensional Cortical Cultures for In Vitro Modeling of Brain Networks.

Three-dimensional (3D) in vitro cultures recapitulate key features of the brain including morphology, cell-cell and cell-extracellular matrix interactions, gradients of factors, and mechanical properties. However, there remains a need for experimental and computational tools to investigate network functions in these 3D models. To address this need, we present an experimental system based on 3D scaffold-based cortical neuron cultures in which we expressed the genetically encoded calcium indicator GCaMP6f to record neuronal activity at the millimeter-scale. Functional neural network descriptors were computed with graph-theory-based network analysis methods, showing the formation of functional networks at 3 weeks of culture. Changes to the functional network properties upon perturbations to glutamatergic neurotransmission or GABAergic neurotransmission were quantitatively characterized. The results illustrate the applicability of our 3D experimental system for the study of brain network development, function, and disruption in a biomimetic microenvironment.

Innovations in 3-Dimensional Tissue Models of Human Brain Physiology and Diseases.

3-dimensional (3D) laboratory tissue cultures have emerged as an alternative to traditional 2-dimensional (2D) culture systems that do not recapitulate native cell behavior. The discrepancy between in vivo and in vitro tissue-cell-molecular responses impedes understanding of human physiology in general and creates roadblocks for the discovery of therapeutic solutions. Two parallel approaches have emerged for the design of 3D culture systems. The first is biomedical engineering methodology, including bioengineered materials, bioprinting, microfluidics and bioreactors, used alone or in combination, to mimic the microenvironments of native tissues. The second approach is organoid technology, in which stem cells are exposed to chemical and/or biological cues to activate differentiation programs that are reminiscent of human (prenatal) development. This review article describes recent technological advances in engineering 3D cultures that more closely resemble the human brain. The contributions of in vitro 3D tissue culture systems to new insights in neurophysiology, neurological diseases and regenerative medicine are highlighted. Perspectives on designing improved tissue models of the human brain are offered, focusing on an integrative approach merging biomedical engineering tools with organoid biology.

Study progress of chronic granulomatous disease in children / 中华实用儿科临床杂志

Chronic granulomatous disease(CGD)is a rare primary immunodeficiency disease with X-linked or autosomal pattern of inheritance, which belongs to monogenic disorders, mainly manifested in repeated infection, granuloma formation caused by inflammatory response disorder and other inflammatory diseases.Detection of neutrophil respiratory burst function can screen the disease, and gene sequence analysis can identify the pathogenic genes.Now, the latest research on gene therapy was updated, and the clinical manifestations, diagnosis, routine treatment and hemato-poietic stem cell transplantation(HSCT)were summarized in order to strengthen the clinicians′ understanding of CGD.

Three-Dimensional Neural Spheroid Culture: An In Vitro Model for Cortical Studies.

There is a high demand for in vitro models of the central nervous system (CNS) to study neurological disorders, injuries, toxicity, and drug efficacy. Three-dimensional (3D) in vitro models can bridge the gap between traditional two-dimensional culture and animal models because they present an in vivo-like microenvironment in a tailorable experimental platform. Within the expanding variety of sophisticated 3D cultures, scaffold-free, self-assembled spheroid culture avoids the introduction of foreign materials and preserves the native cell populations and extracellular matrix types. In this study, we generated 3D spheroids with primary postnatal rat cortical cells using an accessible, size-controlled, reproducible, and cost-effective method. Neurons and glia formed laminin-containing 3D networks within the spheroids. The neurons were electrically active and formed circuitry through both excitatory and inhibitory synapses. The mechanical properties of the spheroids were in the range of brain tissue. These in vivo-like features of 3D cortical spheroids provide the potential for relevant and translatable investigations of the CNS in vitro.

Unique insights into the intestinal absorption, transit, and subsequent biodistribution of polymer-derived microspheres.

Polymeric microspheres (MSs) have received attention for their potential to improve the delivery of drugs with poor oral bioavailability. Although MSs can be absorbed into the absorptive epithelium of the small intestine, little is known about the physiologic mechanisms that are responsible for their cellular trafficking. In these experiments, nonbiodegradable polystyrene MSs (diameter range: 500 nm to 5 µm) were delivered locally to the jejunum or ileum or by oral administration to young male rats. Following administration, MSs were taken up rapidly (≤ 5 min) by the small intestine and were detected by transmission electron microscopy and confocal laser scanning microscopy. Gel permeation chromatography confirmed that polymer was present in all tissue samples, including the brain. These results confirm that MSs (diameter range: 500 nm to 5 µm) were absorbed by the small intestine and distributed throughout the rat. After delivering MSs to the jejunum or ileum, high concentrations of polystyrene were detected in the liver, kidneys, and lungs. The pharmacologic inhibitors chlorpromazine, phorbol 12-myristate 13-acetate, and cytochalasin D caused a reduction in the total number of MSs absorbed in the jejunum and ileum, demonstrating that nonphagocytic processes (including endocytosis) direct the uptake of MSs in the small intestine. These results challenge the convention that phagocytic cells such as the microfold cells solely facilitate MS absorption in the small intestine.

Navigating neurites utilize cellular topography of Schwann cell somas and processes for optimal guidance.

The path created by aligned Schwann cells (SCs) after nerve injury underlies peripheral nerve regeneration. We developed geometric bioinspired substrates to extract key information needed for axon guidance by deconstructing the topographical cues presented by SCs. We have previously reported materials that directly replicate SC topography with micro- and nanoscale resolution, but a detailed explanation of the means of directed axon extension on SC topography has not yet been described. Here, using neurite tracing and time-lapse microscopy, we analyzed the SC features that influence axon guidance. Novel poly(dimethylsiloxane) materials, fabricated via photolithography, incorporated bioinspired topographical components with the shapes and sizes of aligned SCs, namely somas and processes, where the lengths of the processes were varied but the soma geometry and dimensions were kept constant. Rat dorsal root ganglia neurites aligned to all materials presenting bioinspired topography after 5days in culture and aligned to bioinspired materials presenting soma and process features after only 17h in culture. The key findings of this study were: neurite response to underlying bioinspired topographical features was time dependent, with neurites aligned most strongly to materials presenting combinations of soma and process features at 5days, with higher than average density of either process or soma features, but at 17h they aligned more strongly to materials presenting average densities of soma and process features and to materials presenting process features only. These studies elucidate the influence of SC topography on axon guidance in a time-dependent setting and have implications for the optimization of nerve regeneration strategies.