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.

GPR97 deficiency ameliorates renal interstitial fibrosis in mouse hypertensive nephropathy.

Hypertensive nephropathy (HTN) ranks as the second-leading cause of end-stage renal disease (ESRD). Accumulating evidence suggests that persistent hypertension injures tubular cells, leading to tubulointerstitial fibrosis (TIF), which is involved in the pathogenesis of HTN. G protein-coupled receptors (GPCRs) are implicated in many important pathological and physiological processes and act as important drug targets. In this study, we explored the intrarenal mechanisms underlying hypertension-associated TIF, and particularly, the potential role of GPR97, a member of the adhesion GPCR subfamily, in TIF. A deoxycorticosterone acetate (DOCA)/salt-induced hypertensive mouse model was used. We revealed a significantly upregulated expression of GPR97 in the kidneys, especially in renal tubules, of the hypertensive mice and 10 patients with biopsy-proven hypertensive kidney injury. GPR97-/- mice showed markedly elevated blood pressure, which was comparable to that of wild-type mice following DOCA/salt treatment, but dramatically ameliorated renal injury and TIF. In NRK-52E cells, we demonstrated that knockdown of GPR97 suppressed the activation of TGF-ß signaling by disturbing small GTPase RhoA-mediated cytoskeletal reorganization, thus inhibiting clathrin-mediated endocytosis of TGF-ß receptors and subsequent Smad activation. Collectively, this study demonstrates that GPR97 contributes to hypertension-associated TIF at least in part by facilitating TGF-ß signaling, suggesting that GPR97 is a pivotal intrarenal factor for TIF progression under hypertensive conditions, and therapeutic strategies targeting GPR97 may improve the outcomes of patients with HTN.

Fever of unknown origin (FUO) in children: a single-centre experience from Beijing, China.

OBJECTIVE: To date, there is no standard diagnostic practice to identify the underlying disease-causing mechanism for paediatric patients suffering from chronic fever without any specific diagnosis, which is one of the leading causes of death in paediatric patients. Therefore, we aimed this retrospective study to analyse medical records of paediatric patients with fever of unknown origin (FUO) to provide a preliminary basis for improving the diagnostic categories and facilitate the treatment outcomes. DESIGN: A retrospective study. SETTING: Beijing Children's Hospital. PARTICIPANTS: Clinical data were collected from 1288 children between 1 month and 18 years of age diagnosed with FUO at Beijing Children's Hospital between January 2010 and December 2017. INTERVENTIONS: According to the aetiological composition, age, duration of fever and laboratory examination results, the diagnostic strategies were analysed and formulated. PRIMARY AND SECONDARY OUTCOME MEASURES: The statistical analyses were carried out using SPSS V.24.0 platform along with the χ2 test and analysis of variance (p<0.05). RESULTS: The duration of fever ranged from 2 weeks to 2 years, with an average of 6 weeks. There were 656 cases (50.9%) of infectious diseases, 63 cases (4.9%) of non-infectious inflammatory diseases (NIIDs), 86 cases (6.7%) of neoplastic diseases, 343 cases (26.6%) caused by miscellaneous diseases and 140 cases (10.9%) were undiagnosed. With increasing age, the proportion of FUO from infectious diseases gradually decreased from 73.53% to 44.21%. NIID was more common in children over 3 years old, and neoplastic diseases mainly occurred from 1 to 6 years of age. Among miscellaneous diseases, the age distribution was mainly in school-aged children over 6 years. Respiratory tract infection was the most common cause of FUO in children, followed by bloodstream infections. Bacterial infection was the most common cause in children with less than 1 year old, while the virus was the main pathogen in children over 1 year old. CONCLUSIONS: The diagnosis of neoplastic diseases and miscellaneous diseases-related diseases still depends mainly on invasive examination. According to our clinical experience, the diagnostic process was formulated based on fever duration and the type of disease. This process can provide a guide for the diagnosis and treatment of paediatric FUO in the future.

Characteristics of Pediatric Recurrent Bacterial Meningitis in Beijing Children's Hospital, 2006-2019.

BACKGROUND: Few data on recurrent bacterial meningitis (RBM) in children are available. Here, we estimated the frequency of RBM in children and investigated the predisposing conditions, etiology, and clinical characteristics of RBM in children. METHODS: Cases of RBM in the Beijing Children's Hospital medical record database between January 2006 and December 2019 were collected. RESULTS: In total, 1905 children with bacterial meningitis (BM) were documented in the Beijing Children's Hospital medical record database. A total of 43 patients had RBM. The rate of RBM in children was 2.3% (43/1905). Forty (93.0%) patients had predisposing conditions, including 15 (34.9%) cases of inner ear malformations, 5 (11.6%) cases of dermal sinus tracts, 9 (20.9%) cases of head injury, 5 (11.6%) cases of congenital cranial meningocele, 3 (7.0%) cases of congenital skull base defects, 3 (7.0%) cases of immunodeficiency, and other 3 (7.0%) cases of unknown reason. Among all the 121 BM episodes, a total of 64 episodes were etiologically confirmed BM and the other 57 episodes were probable BM. Streptococcus pneumoniae (n = 52) was accounted for 81.3% of confirmed BM episodes. Thirty-four of the 37 patients with congenital or acquired anatomical defects were available to follow up after surgeries, and all of them had no BM after surgeries. Three patients with antibody deficiencies got intravenous immunoglobulin therapy and they did not suffer BM anymore. CONCLUSIONS: RBM is rare in children. The majority of children with RBM had predisposing conditions including congenital/acquired anatomical defects and immunodeficiency. Interventions should be implemented to solve the underlying conditions to avoid RBM.

Clinical Characteristics and Outcome Analysis of 94 Children With Brain Abscess in Beijing: A Single-center Retrospective Study.

BACKGROUND: There are limit studies about pediatric brain abscess in China. The aim of this study was to analyze clinical characteristics and outcomes of pediatric brain abscess in recent years in China. METHODS: The clinical information of children with brain abscess hospitalized in Beijing Children's Hospital between January 1, 2007 and December 31, 2016 were retrospectively reviewed. RESULTS: Ninety-four children were enrolled in this study. A Streptococcus milleri group (13.8%) was identified as the most common causative organisms, followed by Staphylococcus aureus (6.4%). The overall mortality was 21.6%, with 50.0% of deaths happening in the first week after diagnosis. Long-term outcomes of 74 patients were assessed with Glasgow Outcome Scale-Extended Pediatric Reversion: 50 patients with a score of 1-2 (favorable outcome) and 24 patients with a score of 3-8 (unfavorable outcome). Patients with multiple abscesses (P = 0.029) and intraventricular rupture of brain abscess/hydrocephalus (P = 0.024) had higher risk of unfavorable outcomes. CONCLUSIONS: Brain abscess is a serious disease with high mortality in children; more aggressive treatments should be considered in the first week of diagnosis because of high risk of death, and for patients with multiple brain abscesses and intraventricular rupture of brain abscess/hydrocephalus because of their higher risk of unfavorable.

In vitro expansion of pancreatic islet clusters facilitated by hormones and chemicals.

Tissue regeneration, such as pancreatic islet tissue propagation in vitro, could serve as a promising strategy for diabetes therapy and personalised drug testing. However, such a strategy has not been realised yet. Propagation could be divided into two steps, in vitro expansion and repeated passaging. Even the first step of the in vitro islet expansion has not been achieved to date. Here, we describe a method that enables the expansion of islet clusters isolated from pregnant mice or wild-type rats by employing a combination of specific regeneration factors and chemical compounds in vitro. The expanded islet clusters expressed insulin, glucagon and somatostatin, which are markers corresponding to pancreatic ß cells, α cells and δ cells, respectively. These different types of cells grouped together, were spatially organised and functioned similarly to primary islets. Further mechanistic analysis revealed that forskolin in our recipe contributed to renewal and regeneration, whereas exendin-4 was essential for preserving islet cell identity. Our results provide a novel method for the in vitro expansion of islet clusters, which is an important step forward in developing future protocols and media used for islet tissue propagation in vitro. Such method is important for future regenerative diabetes therapies and personalised medicines using large amounts of pancreatic islets derived from the same person.

The diagnostic value of metagenomic next-generation sequencing for identifying Streptococcus pneumoniae in paediatric bacterial meningitis.

BACKGROUND: There is currently no research on the diagnostic value of metagenomic next-generation sequencing (mNGS) for a single pathogens in CSF. The aim of this study was to analyse the value of mNGS for identifying Streptococcus pneumoniae (S. pneumoniae) in paediatric bacterial meningitis. METHODS: Bacterial meningitis (BM) cases from October 23, 2014, to December 31, 2016, and December 1, 2017, to July 31, 2018 at Beijing Children's Hospital were reviewed. Clinical features and pathogens were analysed. RESULTS: We diagnosed 135 patients with BM in this study. A total of 43 S. pneumoniae were identified by combination methods. 26/135 (19.3%) patients had positive results in S. pneumoniae by blood and/or cerebrospinal fluid (CSF) culture. Alere BinaxNow®Streptococcus pneumoniae Antigen test was positive in 35/135(25.9%) cases. 32/135 (23.7%) S. pneumoniae were identified by mNGS. Six CSF samples were identified as S. pneumoniae only by mNGS technology. Taking culture as the gold standard, the sensitivity and specificity of mNGS for diagnosing S. pneumoniae meningitis were 73.1 and 88.1%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of diagnosing S. pneumoniae meningitis by mNGS were 59.4 and 93.2%, respectively. When comparison between mNGS and combined tests (culture and Alere BinaxNow®Streptococcus pneumoniae Antigen test), the sensitivity and specificity of mNGS for S. pneumoniae identification were 70.3 and 93.9%, the PPV and NPV in the identification of S. pneumoniae by mNGS were 81.4 and 89.3%, respectively. The difference in number of unique reads of S. pneumoniaein from CSF sample (< 14 days onset) and CSF sample (> 14 days from onset) was statistically significant (170.5 VS. 13, P = 0.019). The difference in the collected time of CSF for culture and mNGS was statistically significant (4 days VS. 14 days, P < 0.001). CONCLUSIONS: mNGS has high sensitivity and specificity for S. pneumoniae identification. The pathogen load (number of unique reads) of S. pneumonia is related to the CSF collection time. mNGS was less affected than culture by the use of antibiotics before CSF collection.

Evaluation of next-generation sequencing for the pathogenic diagnosis of children brain abscesses.

In this study, we applied metagenomic next-generation sequencing (mNGS) to detect the causative pathogens in brain abscess samples from 4 pediatric patients. NGS could offer unbiased sequencing and rapid diagnosis of causative pathogens, moreover, it could detect multiple pathogenic microorganisms from abscess samples. In our study, Fusobacterium nucleatum, and Streptococcus intermedius or combinations of them were found in 3/4 of polymicrobial brain abscesses. Internal organ abscesses are illustrative of the shortcomings of bacterial culture. NGS has the ability to identify both common and rare pathogens without any prior suspicious needed, and is able to offer a new platform for quantification of all detected microorganisms. Our study displayed the possible potential that NGS is about to provide the diagnostic tools that can characterize even the most complex microbial communities during brain abscesses and is less affected by prior antibiotic exposure.

A systematic review about Streptococcus Pneumoniae serotype distribution in children in mainland of China before the PCV13 was licensed.

INTRODUCTION: Streptococcus pneumoniae (S. pneumoniae) is a major pathogen of infectious diseases in children. Surveillance of the distribution of pneumococcus serotypes is important for immunization strategies of pneumococcal polysaccharide conjugate vaccines (PCVs). Areas covered: This article is a systematic review of studies conducted from 2006 to 2016 that document serotypes of S. pneumoniae isolated from children less than 14 years old in the mainland of China. A total of 40 studies were included in this review. Serotypes 19F, 19A, 23F, 14 and 6B were the most common. Serotype prevalence and percentage varied by region and associated strains. The serotype coverage rate of PCV13 was higher than that of PCV10 due to the prevalence of serotype 19A, and there were no significant difference between the coverage rate of PCV13 and PPSV23. Expert commentary: To prevent Chinese children from S. pneumoniae infection, it is necessary for the universal immunization of PCV13 or develop new vaccines that include all the prevalent serotypes in China.

[Clinical value of cranial MRI in the diagnosis and treatment of central nervous system candidiasis].

OBJECTIVE: To study the clinical value of cranial magnetic resonance imaging (MRI) in the diagnosis and treatment of central nervous system candidiasis (CNSC), which has no specific clinical manifestations and has no rapid and specific diagnostic tools. METHODS: A retrospective analysis was performed on the clinical data of 10 children who were diagnosed with CNSC in Beijing Children's Hospital Affiliated to Capital Medical University between 2009 and 2013. RESULTS: Nine of the 10 children underwent cranial MRI within 8 days after admission, and 5 of the 9 children underwent contrast-enhanced MRI at the same time. Eight of the 9 children showed the features of meningoencephalitis, and 6 cases were accompanied by varying degrees of brain atrophy; one case showed hydrocephalus and cerebral abscess, and another case showed leukoencephalopathy. Six cases were found to have the features of cerebral vasculitis after infection in the first MRI after admission, including cerebral infarction (2 cases), venous sinus thrombosis (3 cases), and Moyamoya disease (1 case). Infectious granulomatous lesions were confirmed by contrast-enhanced MRI in 3 cases. Given the clinical manifestations, 8 of the 9 cases were diagnosed as suspected CNSC after MRI, and 7 of these cases received antifungal therapy before the pathogen test results were returned. The lesions on MRI were improved in 6 cases after 3-4 weeks of antifungal treatment. All the 10 children were diagnosed with CNSC by positive cerebrospinal fluid culture results. CONCLUSIONS: Cranial MRI, especially contrast-enhanced MRI, is of great significance for the diagnosis and treatment of CNSC. To confirm the guidance of MRI in the diagnosis and treatment of CNSC, further case-control studies are needed.

[Detection of group B streptococcus in the cases died of neonatal pneumonia].

OBJECTIVE: From the 1970s, group B streptococci (GBS) have been widely recognized as an important pathogen in neonatal infectious disease, and it emerged as the leading cause of neonatal morbidity and mortality in the Western world. However, there are few data on the prevalence of neonatal GBS infections in China. The aim of this retrospective study was to estimate whether GBS is an important pathogen in severe neonatal pneumonia, and to develop a method for detection of GBS infections in fatal neonatal pneumonia. METHODS: A total of 234 neonatal cases (0 - 28 days) died in Beijing Children's Hospital from 1953 to 2004 were enrolled in this study. They were divided into two groups. Two hundred cases diagnosed as neonatal pneumonia were assigned to study group and the remaining 34 cases died of neonatal hemolysis or surgical operation without any confirmed infectious diseases were designated as control group. Formalin-fixed, paraffin-embedded lung tissues were used as source for total genomic DNA extraction. PCR and Southern blot analyses were applied to detect GBS specific cfb gene target sequence. And the clinical data of these cases were reviewed as well. RESULTS: In the study group, 52 cases were detected positive for GBS DNA by PCR (26%), 130 cases were positive by Southern blot (65%). In the control group, 1 case was detected positive GBS DNA by PCR (3%), and 6 cases were positive by Southern blot (18%). The positive rate was significantly lower in the control group than that in the study group (PCR, chi(2) = 8.82, P < 0.01; Southern blot, chi(2) = 26.77, P < 0.01). The positive rate in the neonates younger than 7 days (early-onset) was significantly higher than that in neonates older than 7 days (late-onset) (PCR: 37% vs. 13%, chi(2) = 15.537, P < 0.01; Southern blot: 72% vs. 52%, chi(2) = 4.37, P < 0.05). In the positive early-onset cases, 39% of whom were born prematurely (29/74). Out of the 200 cases, 75 had complete clinical data. Neither blood nor lung culture for GBS was performed in any of these cases. But risk factors were identified for 35 cases, such as premature delivery, low birth weight, premature rupture of the membrane and abnormal amniotic fluid. GBS was positive in all these cases. Severe apnea appeared to be a common symptom and was present in most of the early-onset GBS-positive cases, while cough and wheezing were found in most of the late-onset GBS-positive cases. In the control group, one PCR positive case was suffered from malignant teratoma. The other 5 positive cases confirmed by Southern blot were diagnosed as kernicterus, hepatoma, aproctia complicating with cysti-urethral fistula, neonatal physio logical bleeding and aproctia complicated with archo-perineal fistula. CONCLUSION: Group B Streptococcus is an important pathogen in fatal neonatal pneumonia, especially in early-onset cases. southern blot may be a sensitive method to detect GBS infection in archival tissues. In the clinical work, more attention should be paid to the neonates with GBS risk factors. And GBS detection and prevention in neonates should be put into clinical practice.

[Study on Haemophilus influenzae type b: data from autopsy of community acquired pneumonia among children].

OBJECTIVE: To evaluate the status of Haemophilus influenza type b(Hib) on death cases of children from community-acquired pneumonia (CAP) and to estimate the value of direct in-situ polymerase chain reaction (ISPCR) on diagnosis of children CAP, pathogenically. METHODS: Ordinary PCR, Southern blot and direct ISPCR were applied and compared in detecting Hib in 100 paraffin-embedded lung tissues of autopsy children died of CAP. RESULTS: No major difference on the detection rate of Hib between 50-60s and 80s-2002 was found. The detection rate of Hib by direct ISPCR was higher than the other two methods. By Southern blot, Hib was identified from 8 out of 100 samples (8%), including 4 out of 56 in 1950-60s (7.1%) and 4 out of 44 (9.1%) (chi2 = 0.084, P>0.05) in 1980s-2002. By ISPCR, Hib was identified from 17 out of 100 samples (17%), including 8 out of 56 in 1950-60s (14.3%) and 9 out of 44 (20.5%) with chi2 = 0.665, P > 0.05, in 1980s-2002. Positive cases diagnosed by both Southern blot and ISPCR were 7%. CONCLUSION: Hib was one of the main bacterial pathogens causing CAP and deaths among children. Direct ISPCR was prefertable to be used in pathogenic diagnosis on children pneumonia, in terms of its sensitivity, specificity and localization.

[Study on MYCN gene amplification and CD44 expression in neuroblastoma].

OBJECTIVE: To assess the relationship between MYCN amplification in neuroblastoma (NB), tumor stage and prognosis; and to evaluate the usefulness of CD44 in predicting prognosis of NB. METHODS: Differential polymerase chain reaction (D-PCR) with serial dilution assay was used to quantify the MYCN gene copy number in 33 paraffin-embedded tissue samples of NB. All the samples were also studied by immunohistochemistry for CD44. The results were correlated with various prognostic factors of NB, including patient age, tumor stage, pathologic type and MYCN gene amplification. RESULTS: MYCN amplification was identified in 10 of the 33 samples studied (30.3%), which all were in high clinical stage (stage III or IV) and occurred in patients older than 1 year of age. MYCN amplification also significantly correlated with poor clinical outcome (P < 0.01). CD44 was positive in 21 cases and often occurred in patients below 1 year of age, in low clinical stage, with favorable histology and without MYCN gene amplification. The two-year survival rate of CD44-positive group (57.1%) was higher than that of CD44-negative group (8.3%, P < 0.01). Stronger CD44 expression was also associated with better prognosis (P < 0.01). CONCLUSIONS: MYCN gene amplification is significantly associated with advanced tumor stage and poor prognosis in patients with NB. CD44 expression is a reliable marker for better prognosis and is complementary to MYCN amplification assay. D-PCR with serial dilution assay is also suitable for clinical use in quantifying MYCN copy number in NB.