Objective: To investigate the clinical characteristics of pediatric methicillin-resistant Staphylococcus aureus (MRSA) infection and the antibiotic sensitivity of the isolates. Methods: The clinical data of children with MRSA infection and antibiotic sensitivity of the isolates from 11 children's hospitals in Infectious Diseases Surveillance of Paediatrics (ISPED) group of China between January 1, 2018 and December 31, 2018 were collected retrospectively. The children's general condition, high-risk factors, antimicrobial therapy and prognosis, differences in clinical disease and laboratory test results between different age groups, and differences of antibiotic sensitivity between community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA were analyzed. The t test and Wilcoxon rank sum test were used for statistical analysis of the quantitative data and Chi-square test were used for comparison of rates. Results: Among the 452 patients, 264 were males and 188 were females, aged from 2 days to 17 years. There were 233 cases (51.5%) in the ≤1 year old group, 79 cases (17.5%) in the>1-3 years old group, 29 cases (6.4%) in the >3-5 years old group, 65 cases (14.4%) in the >5-10 years old group, and 46 cases (10.2%) in the>10 years old group. The main distributions of onset seasons were 55 cases (12.2%) in December, 47 cases (10.4%) in February, 46 cases (10.2%) in November, 45 cases (10.0%) in January, 40 cases (8.8%) in March. There were 335 cases (74.1%) CA-MRSA and 117 (25.9%) cases HA-MRSA. Among all cases, 174 cases (38.5%) had basic diseases or long-term use of hormone and immunosuppressive drugs. During the period of hospitalization, 209 cases (46.2%) received medical interventions. There were 182 patients (40.3%) had used antibiotics (β-lactams, glycopeptides, macrolides, carbapenems, oxazolones, sulfonamides etc) 3 months before admission. The most common clinical disease was pneumonia (203 cases), followed by skin soft-tissue infection (133 cases), sepsis (92 cases), deep tissue abscess (42 cases), osteomyelitis (40 cases), and septic arthritis (26 cases), suppurative meningitis (10 cases). The proportion of pneumonia in the ≤1 year old group was higher than the >1-3 years old group,>3-5 years old group,>5-10 years old group,>10 years old group (57.5% (134/233) vs. 30.4% (24/79), 31.0% (9/29), 38.5% (25/65), 23.9% (11/46), χ(2)=17.374, 7.293, 7.410, 17.373, all P<0.01) The proportion of skin and soft tissue infections caused by CA-MRSA infection was higher than HA-MRSA (33.4% (112/335) vs. 17.9% (21/117), χ(2)=10.010, P=0.002), and the proportion of pneumonia caused by HA-MRSA infection was higher than CA-MRSA (53.0% (62/117) vs. 42.1% (141/335), χ(2)=4.166, P=0.041). The first white blood cell count of the ≤1 year old group was higher than that children > 1 year old ((15±8)×10(9)/L vs. (13±7)×10(9)/L, t=2.697, P=0.007), while the C-reactive protein of the ≤1 year old group was lower than the 1-3 years old group,>5-10 years old group,>10 years old group (8.00 (0.04-194.00) vs.17.00 (0.50-316.00), 15.20 (0.23-312.00), 21.79(0.13-219.00) mg/L, Z=3.207, 2.044, 2.513, all P<0.05), there were no significant differences in procalcitonin (PCT) between different age groups (all P>0.05). After the treatment, 131 cases were cured, 278 cases were improved, 21 cases were not cured, 12 cases died, and 10 cases were abandoned. The 452 MRSA isolates were all sensitive to vancomycin (100.0%), linezolid (100.0%), 100.0% resistant to penicillin, highly resistant to erythromycin (85.0%, 375/441), clindamycin (67.7%, 294/434), less resistant to sulfonamides (5.9%, 23/391), levofloxacin (4.5%, 19/423), gentamicin (3.2%, 14/438), rifampicin (1.8%, 8/440), minocycline (1.1%, 1/91). The antimicrobial resistance rates were not significantly different between the CA-MRSA and HA-MRSA groups (all P>0.05). Conclusions: The infection of MRSA is mainly found in infants under 3 years old. The prevalent seasons are winter and spring, and MRSA is mainly acquired in the community. The main clinical diseases are pneumonia, skin soft-tissue infection and sepsis. No MRSA isolate is resistant to vancomycin, linezolid. MRSA isolates are generally sensitive to sulfonamides, levofloxacin, gentamicin, rifampicin, minocycline, and were highly resistant to erythromycin and clindamycin. To achieve better prognosis. clinicians should initiate anti-infective treatment for children with MRSA infection according to the clinical characteristics of patients and drug sensitivity of the isolates timely and effectively.

Objective: To explore the predictive values of routine blood test results for iron deficiency (ID) screening in children. Methods: Routine blood test results and serum ferritin (SF) levels from 1 443 healthy children (862 boys, 581 girls) aged 6 months to 18 years, who were seen for well-child visits between June 2017 and May 2019 in Children's Hospital, Zhejiang University School of Medicine, were retrospectively analyzed. ID was defined as SF<20 μg/L, iron deficiency anemia (IDA) as ID with anemia (hemoglobin(Hb)<110 g/L at 6 months-5 years of age, Hb<120 g/L at 6-18 years of age), non-anemia ID as ID without anemia, non-ID anemia as SF≥20 μg/L with anemia, and healthy control subjects as those with SF≥20 μg/L but without anemia. The blood test results including Hb, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), and the percentage of low hemoglobin density (LHD) of healthy control, non-anemia ID, non-ID anemia, and IDA groups were compared by analysis of variance (ANOVA) or non-parametric test, quantitative data were described as x±s or M(interquartile range), and receiver operating characteristic curve (ROC) analysis was applied to assess predictive values of routine blood test results and LHD for detecting IDA and ID. Results: Among 1 443 children with median age of 2.1(3.3) years, 1 061 children were in healthy control group, 292 in non-anemia ID group, 43 in non-ID anemia group and 47 in IDA group. The prevalence of ID was much higher than that of anemia (23.5% (339/1 443) vs. 6.2% (90/1 443) , χ(2)=169.76, P<0.01). Compared with control group, non-anemia ID group showed higher LHD (0.088 (0.093) vs.0.073 (0.068), P<0.01) and RDW (0.131±0.013 vs. 0.126±0.008, P<0.01), lower MCV ((80±4) vs. (83±4) fl, P<0.01) and MCHC values ((326±9) vs. (329±8) g/L, P<0.01). IDA group showed higher LHD (0.322(0.544)) and RDW (0.151±0.018), lower MCV ((73±6) fl) and MCHC values((309±14) g/L) than non-anemia ID group (all P<0.01). The area under curve (AUC) values of MCHC, LHD, RDW and MCV for detecting ID were 0.63 (95%CI: 0.60-0.67), 0.63 (95%CI:0.60-0.67), 0.67 (95%CI: 0.63-0.70) and 0.73 (95%CI: 0.69-0.76) respectively. With cutoff limits (MCV<80.2 fl, RDW>0.131 or MCHC<322 g/L), MCV, RDW and MCHC showed higher sensitivity for screening ID than hemoglobin (0.540, 0.469 and 0.336 vs. 0.139, χ(2)=121.70, 87.47, 35.56, all P<0.01). Conclusion: MCV, RDW and MCHC can be used to screen ID in primary health care settings.

患儿 女，9岁，因"肢体无力2年3个月余，加重7个月"就诊。临床表现为逐渐进展的不对称性肌无力，病初因存在部分类似肌炎的表现而误诊为炎症性肌病，后根据免疫治疗反应欠佳考虑为遗传性肌病。基因检测发现FHL1基因c.311G>A，p.C104T，为已知杂合新生致病性变异，进一步对肌肉组织行甲萘醌-硝基四氮唑盐染色，发现胞质内蓝紫色包涵体，最终确诊还原体肌病。.

Objective: To summarize the clinical and genetic features of β-propeller protein-associated neurodegeneration (BPAN). Methods: The clinical data of 17 patients with BPAN with WDR45 gene variants were retrospectively collected at Children's Hospital of Fudan University, Peking University First Hospital, Capital Institute of Pediatrics, Shengjing Hospital of China Medical University and Shanghai Children's Hospital from June 2016 to December 2018, and their clinical manifestations, electroencephalogram, neuroimaging and genetics were analyzed. Results: Seventeen cases (13 females, 4 males), aged 1.1-8.8 years, were included. The median age of seizure onset was 14.5 months, from 3 months to 24 months of age, manifested with epileptic spasm in 6 cases and focal seizures in 5 cases. Eight patients had only one seizure type and 8 patients had two or more seizure types. Nine patients had complete remission of seizures. All 16 patients with seizures had developmental delay before the seizure onset, of whom 13 patients had moderate to severe seizures. The brain magnetic resonance imaging (MRI) was abnormal in 13 patients, including cerebral atrophy (10 cases) and thinning of the corpus callosum (9 cases). The brain magnetic susceptibility weighted imaging (SWI) in preschool stage showed prominent T2 hypointense signals in bilateral globus pallidus and brainstem ventral in two cases. Five seizure types (spasm, focal, absence, myodonic and generalized tonic clonic seizures)were found on ictal electroencephalogram(EEG) recordings. Compared to female patients(17(6-24) months of ege), male cases had earlier seizure onset (3, 4, 5, 18 months of age) . All patients had de novo variations in WDR45(6 nonsense, 4 frameshift, 3 missense and 4 splicing variations), with hemizygous variants in 3 males, mosaic variants in a male and heterozygous variants in 13 females, within which 5 variations had not been reported (c.977-1C>T,c.976+1G>C,c.10C>T,c.806del and c.110T>C). Conclusions: The patients with BPAN have profound developmental delay and are vulnerable to seizures. The male patients with BPAN tend to have more severer clinical phenotype than females. Early brain SWI could facilitate the timely diagnosis of this disease.

Objective: To investigate the clinical characteristics of invasive Haemophilus influenzae (HI) infection in children. Methods: The clinical manifestations, laboratory examinations and treatment outcomes of 84 children with HI infection confirmed by bacterial culture in 7 tertiary children's hospitals from 2014 to 2018 were analyzed retrospectively. Results: Among the 84 cases, 50 were males. The age was 1.54 years (ranged from 5 days to 13 years).Twenty cases (24%) had underlying diseases and 48 cases (57%) had not received antibiotics before collecting specimens. Eighty-two cases (98%) had fever and 75 cases (89%) had clear infection foci, among which 31 cases (37%) had meningitis and 27 cases (32%) had pneumonia. Blood culture was positive in 62 cases (74%), cerebrospinal fluid culture was positive in 10 cases (12%), blood culture and cerebrospinal fluid culture were both positive in 11 cases (13%). Antibiotics susceptibility test showed that 27% (22/82) of all HI strains produced β-lactamases and 48% (37/77) strains were resistant to ampicillin. The drug resistance rates to cefuroxime, ampicillin-sulbactam, trimethoprim-sulfamethoxazole and azithromycin were 25% (20/80) , 20% (9/45) , 71% (44/62) and 19%(11/58), respectively. All strains were sensitive to meropenem, levofloxacin and ceftriaxone. After sensitive antibiotic therapy, 83% (70/84) of all patients were cured and improved, the mortality rate and loss of follow-up rate were 13% (11/84) and 4% (3/84) respectively. Conclusions: Meningitis and pneumonia are common presentation of invasive HI infections in children. Mortality in HI meningitis children is high and the third generation of cephalosporins, such as ceftriaxone can be used as the first choice for the treatment of invasive HI infection.

1例主诉为发热伴口腔疱疹5 d的患儿发现肝功能损害和Pelger-Huёt细胞，进一步完善基因检测发现NBAS基因复合杂合变异，变异位点为c.(7041_7043delTCT)和c.(3759delC)，分别来自于父亲和母亲杂合变异，此变异位点为新发现位点。检索国内外文献发现NBAS变异以c.(5741G>A)纯合变异为常见变异位点。结合患儿的临床表现及基因检测结果，诊断为NBAS基因缺陷性疾病(SOPH综合征和肝功能损伤)明确。.

新生儿疾病筛查属于三级预防的概念，通过新生儿筛查获得早期诊断、规范治疗的患儿预后获得极大改善。而正确解读新生儿筛查结果，是确保患儿获得及时诊治以及避免过度诊断造成社会、家庭资源浪费的重要保障。.

患儿女，6岁11月龄，1岁6月龄起病，以难治性局灶性癫痫为表现，皮肤见7个小色素脱失斑，既往2次头颅磁共振成像（MRI）未见异常，复查MRI 3.0T薄层扫描示右侧额叶孤立的局灶性皮层发育不良（FCD），父亲（有癫痫病史）及其伯父有皮肤色素脱失斑。TSC2基因发现来源于父亲的杂合错义变异c.2714G>A（p.Arg905Gln）。确诊结节性硬化症（TSC）。患儿在致痫灶切除术后6个月无发作。孤立的FCD可以作为TSC唯一的颅内病灶，此类患儿癫痫外科手术效果优于典型的TSC病例。.

Objective: To investigate the clinical and immunological laboratory features, mutations in SH2D1A gene and SAP protein expression in four children of two families with X-linked lymphoproliferative disease type 1(XLP-1). Method: Four patients (Family A including Patient 1 and Patient 2, Family B including Patient 3 and Patient 4) and their maternal relatives were enrolled in this study. The clinical manifestation, EBV infection status and chest CT scan were analyzed. The absolute and relative numbers of lymphocyte subsets, T lymphocyte proliferative response, SAP protein expression were assessed by flow cytometry. Quantification of signal joint TCR rearrangementexcision circle (sjTRECs), CDR3 spectratyping of TCRvβ and gene mutation of SH2D1A were detected by PCR based on genomic DNA or cDNA. Result: Four male patients from two families were diagnosed with XLP-1. The ages of disease onset were more than 1 year, more than 1 year, more than 1 month and 6 months. The ages at diagnosis were nine years and ten months, sixteen years and eight months, fourteen years and ten months, four years and nine months. All patients had recurrent infections and EBV infection. Patients 1, 2, and 3 had agammaglobulinemia and Patient 4 had hypogammaglobulinemia. Chest CT scan showed all patients had atelectasis and pneumonia, and Patient 3 had bronchiectasis. Patient 3 was diagnosised as Burkitt lymphoma. For immunological function, all patients exhibited reduced CD4/CD8 ratios, increased numbers of exhausted T lymphocyte, decreased number of NK cell. The numbers of total B lymphocyte and naïve B lymphocyte were normal, but the number of memory B lymphocyte declined in all cases. Four patients' copy numbers of sjTRECs were low and CDR3 spectratypings of TCRvβ showed mildly skewed. But their T lymphocyte proliferative response was normal. SAP protein expression in four cases were measured by flow cytometry. Two patients from Family A were absent and two patients from Family B showed decreased values. SH2D1A gene sequence analysis showed that the patients of Family A harbored a nonsense mutation (c.163 C>T; p.R55X) in exon 2. Their mother and two sisters were carriers. A missense mutation of SH2D1A gene (c.278 G>A; p.G93D) in exon 3 was found in the patients of Family B. The mother was carrier. Four patients remain survived, Patient 3 gave up treatment, other three patients received IVIG therapy. Conclusion: Four patients with XLP-1 from two families characterized by agammaglobulinemia have an extreme vulnerability to Epstein-Barr virus (EBV) infection. The functions of T cell, B cell and NK cell are impaired at different stages. The detection of SAP protein and SH2D1A gene are the key methods for diagnosis of XLP-1.

Objective: To explore the clinical features of atrial flutter (AFL) and evaluate the efficacy of radiofrequency catheter ablation (RFCA) for AFL in children. Method: Data were collected and analyzed on 50 consecutive pediatric AFL patients (male 37/female 13) who underwent electrophysiology study and RFCA from February 2009 to November 2016 in a case observational study. The average age was (6.2±3.5) years and body weight was (23.7±13.5) kg. Heart structure was normal in 26 patients. Twenty-four patients had congenital heart disease (CHD) and among them 22 patients underwent repaired surgery before. Patients were followed-up for 1 month to 7 years after RFCA. Clinical features and the outcomes of RFCA in AFL patients were analyzed. Result: The average onset age was (4.2±3.3) years. Of these patients, 84% had persistent AFL and 16% paroxysmal AFL. AFL with sick sinus syndrome (SSS) occurred in 36% patients without statistically significant difference between the groups with and without CHD (38.9%(7/18) vs. 61.1%(11/18), respectively, P=0.239 5); 49 patients underwent RFCA except one case with atrial standstill during the procedure. The total acute success rate was 96%. The follow-up recurrence rate was 8%.No complication of the procedures was observed. The cavotricuspid isthmus-dependent AFL occurred in all patients without CHD. However, in the children with CHD after the repair surgery 10 (45%) cases were with cavotricuspid isthmus-dependent AFL, 4 (8%) with atrial scars-dependent AFL, and 8(16%) with both cavotricuspid isthmus and atrial scars-dependent AFL. Conclusion: RFCA was effective and safe for pediatric AFL. There is no difference on the acute success rate, the follow-up AFL recurrence rate, as well as occurrence of SSS between the groups with and without CHD. AFL patients with CHD included the cavotricuspid isthmus-dependent AFL, atrial scars-dependent AFL or both.