Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:To carry out carrier screening among people of childbearing age, detect the pathogenic genes of monogenic genetic diseases and analyze the carrier status of pathogenic variants, so as to provide fertility guidance and intervention measures for high-risk families.Methods:From August 2022 to August 2023, 1 533 families of childbearing age who met the criteria were recruited in the Chinese PLA General Hospital, including a total of 3 044 subjects. According to the standard enrollment procedure, 223 genes (197 autosomal recessive genes and 26 X-linked genes) of the subjects were tested. According to the screening results, genetic counseling and fertility guidance were provided to the subjects. Invasive prenatal diagnosis was performed for high-risk couples (both couples being carriers of the same autosomal recessive disease gene or the woman was a carrier of X-linked disease gene), and their pregnancy pattern, outcome and offspring phenotype were followed up.Results:(1) A total of 3 044 cases from 1 511 couples and women of childbearing age from 22 families were included for carrier screening. Totally 1 503 families chose simultaneous screening and 30 families chose sequential screening out of the 1 533 families. Among the 3 044 subjects, 1 603 individuals carried at least one pathogenic or likely pathogenic variant, and the overall carrier rate was 52.66% (1 603/3 044). A total of 2 292 pathogenic or likely pathogenic variants were detected, and 0.75 variants (2 292/3 044) were detected per capita. (2) The three genes with the highest carrier rates were GJB2 (8.67%, 264/3 044), CYP21A2 (3.19%, 97/3 044) and PAH (3.09%, 94/3 044). There were 32 genes with a carrier rate ≥1/200, 17 genes with a carrier rate ≥1/100, and 7 genes with a carrier rate ≥1/50. (3) Thirty-eight high-risk families were identified. After excluding G6PD gene mutation, there were 33 high-risk families, of which 25 couples were carriers of the same autosomal recessive gene, 9 women were carriers of X-linked gene, and 1 family was double high-risk couple with both autosomal recessive and X-linked gene. After further excluding the GJB2 c.109G>A mutation, 21 high-risk families were identified. Preimplantation genetic testing for monogenic disease was performed in 12 families after genetic counseling. Prenatal diagnosis was completed in 4 out of 5 high-risk families who conceived naturally. Two fetuses carried the parental variants and terminated the pregnancy, one fetus did not carry the parental variants but was induced due to trisomy 21 syndrome, and one fetus was a carrier of congenital disorders of glycosylation type 1a.Conclusions:Carrier screening effectively identifies high-risk genetic disease families and provides reproductive guidance to prevent the birth of affected children. However, establishing multidisciplinary team is essential for managing complex cases. Implementation should prioritize prenatal institutions with genetic counseling or diagnostic expertise for monogenic disorders or established referral networks.

Objective To investigate the value of chest contrast-enhanced CT(C-CECT)combined with artificial intelligence iterative reconstruction(AIIR)for bronchial artery(BA)imaging.Methods Seventy patients who underwent C-CECT were prospectively enrolled.The images were reconstructed with AIIR(AIIR group)and hybrid iterative reconstruction(HIR,HIR group),respectively.The overall image quality,the traceability of BA,the sharpness of BA and the diagnostic confidence of abnormalities of BA were subjectively graded using a 5-point scale by two radiologists,respectively.The subjective scores and inter-observer agreement were compared between groups.The noise(SD)in reconstructed images of thoracic aorta,pulmonary trunk,BA and spinal erectors,the contrast-to-noise ratio(CNR)of the above 3 arteries relative to spinal erectors,and the diameters of BA at the origin,bifurcation and pulmonary hilum were compared between groups.Results The scores of the overall image quality,the traceability of BA,the sharpness of BA and the diagnostic confidence of abnormalities of BA were all significantly higher in AIIR group than those in HIR group(all P＜0.001),all with good inter-observer agreement(Kappa=0.46-0.73).SD of the aorta,pulmonary artery trunk,BA and erector spinal muscle in AIIR group were lower than those in HIR group,while CNR of above 3 arteries were higher than those in HIR group(all P＜0.05).No significant difference of the diameter of BA at each position was found between groups(all P＞0.05),while the consistency of measurement of AIIR group was higher than that of HIR group(intra-class correlation coefficient:0.89-0.94 vs.0.63-0.78).Conclusion C-CECT combined with AIIR could significantly improve imaging quality and diagnostic confidence of BA.

Objective:To explore the clinical features, histopathological morphology, and differential diagnosis of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers.Methods:From 2020 to 2021, 4 cases of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers diagnosed in Fujian Cancer Hospital (2 cases) and the Second Affiliated Hospital of Fujian Medical University (2 cases) were collected. Different ancillary procedures such as HE, special stains, immunohistochemistry, and in situ hybridization techniques were used to assess the histopathological features and immunophenotypes. The clinical data were collected and literature was reviewed.Results:All 4 cases of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers were male. They were 32, 45, 67 and 39 years old, respectively. The main clinical manifestations were bloody phlegm, abdominal pain, fatigue and anorexia. The clinical stages at diagnosis were stage Ⅳ (3 cases) and stage Ⅱ (1 case). Cases 2 and 3 had two pathological examinations at different sites, with a total of six pathological examinations. The histomorphology showed singly scattered or nests of tumor cells in a background of abundant small lymphocytes. The tumor cells were enlarged and pleomorphic, some appeared polygonal with inconspicuous cell borders, and they were arranged in a syncytial pattern. There were megakaryocytes, multinucleated tumor cells, and a few spindle-shaped cells seen. Atypical mitosis was commonly noted. By immunohistochemistry, the tumor cells were positive for CKpan(5/6), CK8/18(4/4), CAM5.2(2/5), CK-H(0/4), CK-L(3/4), EMA(4/5), CK5/6(3/6), p63(1/6), p40(1/6), E-cadherin (4/6), SSTR2(6/6), PD-L1(5/5), LCA(0/6), vimentin(5/6), CD2 (6/6), CD23(6/6), CD35(5/6), CXCL-13(4/5) and D2-40(1/5). The Ki-67 proliferative index was 60%-95%. In situ hybridization for EBER were all positive (6/6). Special stain for reticulin showed positive staining surrounding nests of tumor cells.Conclusions:The expression of follicular dendritic cell markers in lymphoepithelioma-like carcinoma is very rare, which may be related to EBV infection. Occasionally, it can overlap with follicular dendritic cell sarcoma by morphology and immunophenotype, which can lead to misdiagnosis. Only by combining clinical information, morphological characteristics and immunophenotype can an appropriate diagnosis be made.

Intravascular large B cell lymphoma (IVLBCL) is a rare, aggressive subtype of diffuse large B cell lymphoma, with nasal turbinate involvement being uncommon. We report a 51-year-old woman with a 1-month history of fever of unknown origin. Laboratory findings showed cytopenia, hypertriglyceridemia, elevated ferritin, increased soluble CD25, and bone marrow hemophagocytosis. No infectious cause was identified. PET-CT revealed abnormal 18F-fluorodeoxyglucose (FDG) uptake in the nasal turbinates. Turbinate biopsy revealed tumor cells localized predominantly within vascular lumens, positive for CD20, BCL6, PAX5, and MUM1, with a Ki-67 index >60%, confirming a diagnosis of IVLBCL with hemophagocytic lymphohistiocytosis (HLH). The patient received one cycle of the DEP regimen (liposomal doxorubicin, etoposide, and methylprednisolone) for HLH, followed by five cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) and consolidation with auto-HSCT, achieving sustained complete remission. IVLBCL outcomes are heterogeneous; early diagnosis and prompt treatment improve survival, and R-CHOP plus auto-HSCT may be an effective strategy.

Objective:To reassess the pathogenicity of copy number variants (CNVs) involving chromosomal microdeletions and microduplications classified as variants of uncertain significance (VUS).Methods:This retrospective study analyzed 1 882 pregnant women who underwent invasive prenatal diagnosis for chromosomal microarray analysis (CMA) at the First Medical Center, Chinese PLA General Hospital between January 1, 2018, and December 31, 2022. The results were classified according to the American College of Medical Genetics and Genomics guidelines, with 82 fetuses rated as VUS selected for the study. We analyzed invasive prenatal diagnostic indications, followed up on fetal ultrasound findings, parental origin identification results, and pregnancy outcomes, and reclassified VUS CNVs based on the latest evidence. Descriptive statistical analysis was applied to the data.Results:(1) Among the 82 fetuses with VUS CNVs, prenatal diagnostic indications included fetal structural abnormalities detected by ultrasound (21 cases, 25.6%), abnormal non-invasive prenatal testing (NIPT) results (12 cases, 14.6%), high-risk serum screening (seven cases, 8.5%), advanced maternal age (≥35 years at expected delivery, 28 cases, 34.1%), and other indications (14 cases, 17.1%). Sixteen cases (19.5%) exhibited abnormal phenotypes, with seven pregnancies terminated due to severe structural abnormalities detected by prenatal ultrasound. Seventy-five live births were followed up for 25 (13-66) months. (2) Among the 82 cases, five fetuses had two VUS CNVs detected by CMA, while the remaining 77 had only one, totaling 87 VUS CNVs. Of these, 63 (72.4%) were chromosomal microduplications and 24 (27.6%) were chromosomal microdeletions. The size of the CNV segments ranged from 0.85 (0.05-5.61) Mb, with 82 segments less than 2 Mb. Parental origin identification was refused by 44 cases (53.7%), while 38 (46.3%) underwent the test, revealing eight (21.0%) de novo variants and 30 (78.9%) inherited from either parent (12 maternal and 18 paternal). (3) Among the 87 VUS CNVs, the ratings of 11 CNVs (12.6%) changed after re-evaluation. This included one 4p16.2 microdeletion and two 15q11.2 microdeletions being upgraded to pathogenic, one 16p13.11 microduplication being upgraded to likely pathogenic, one Xp22.31 microduplication and two 2q13 microdeletions being downgraded to likely benign, and four Xp22.31 microduplications being downgraded to benign. (4) Among the 16 fetuses with abnormal phenotypes, seven with prenatal abnormalities terminated pregnancies, including six with structural abnormalities and one with severe fetal growth restriction. After re-evaluation, one case was upgraded to pathogenic, while six remained VUS. Nine live births with postnatal abnormal phenotypes showed no change in classification after re-evaluation. Among the 66 cases (80.5%) without abnormal phenotypes, 10 had their classifications changed after re-evaluation. Conclusions:Fetuses with VUS CNVs often exhibit no significant abnormal phenotypes and have a relatively favorable prognosis, however, further floow-up is still needed. Parental origin identification can provide valuable insights for genetic counseling.

This report detailed a case of granulomatous mastitis during pregnancy. At 25 +1 weeks of gestation, the patient presented with a 3 cm indurated mass in the upper outer quadrant of the right breast, exhibiting needle-like pain, tenderness, erythema, edema, and elevated skin temperature. Ultrasound at 26 +1 weeks of gestation revealed an 8.0 cm×2.4 cm×9.0 cm heterogeneous hypoechoic area (BI-RADS category 4B), suggestive of inflammation. Aspiration and biopsy at 27 +3 weeks of gestation confirmed granulomatous lobular mastitis. Surgical incision and drainage under general anesthesia were performed at 29 +1 weeks of gestation, and intraoperative cultures showed no bacterial growth. At 31 weeks of gestation, the wound on the right breast gradually healed with ulceration of the surrounding skin. Admitted at 38 weeks of gestation for delivery preparation, with erythematous and edematous skin on the right breast, multiple abscesses with rupture and crusting, and minimal purulent discharge; debridement was performed. At 38 +6 weeks of gestation, the patient delivered a baby girl vaginally. All ulcers healed within 4-5 months after delivery without abscess formation or purulent discharge. Postpartum breastfeeding guidance was provided in accordance with the patient's preferences. Despite inverted nipple on the affected side, successful breastfeeding was achieved through pump-assisted feeding from the affected breast and direct nursing from the unaffected breast. An eight-month follow-up confirmed sustained lactation and disease resolution.

Objective To summarize the changing prevalence of carbapenem resistance in Enterobacterales based on the data of CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021 for improving antimicrobial treatment in clinical practice.Methods Antimicrobial susceptibility testing was performed using a commercial automated susceptibility testing system according to the unified CHINET protocol.The results were interpreted according to the breakpoints of the Clinical & Laboratory Standards Institute(CLSI)M100 31st ed in 2021.Results Over the seven-year period(2015-2021),the overall prevalence of carbapenem-resistant Enterobacterales(CRE)was 9.43％(62 342/661 235).The prevalence of CRE strains in Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae was 22.38％,9.73％,and 8.47％,respectively.The prevalence of CRE strains in Escherichia coli was 1.99％.A few CRE strains were also identified in Salmonella and Shigella.The CRE strains were mainly isolated from respiratory specimens(44.23±2.80)％,followed by blood(20.88±3.40)％and urine(18.40±3.45)％.Intensive care units(ICUs)were the major source of the CRE strains(27.43±5.20)％.CRE strains were resistant to all the β-lactam antibiotics tested and most non-β-lactam antimicrobial agents.The CRE strains were relatively susceptible to tigecycline and polymyxins with low resistance rates.Conclusions The prevalence of CRE strains was increasing from 2015 to 2021.CRE strains were highly resistant to most of the antibacterial drugs used in clinical practice.Clinicians should prescribe antimicrobial agents rationally.Hospitals should strengthen antibiotic stewardship in key clinical settings such as ICUs,and take effective infection control measures to curb CRE outbreak and epidemic in hospitals.

Objective To characterize the changing species distribution and antibiotic resistance profiles of respiratory isolates in hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Commercial automated antimicrobial susceptibility testing systems and disk diffusion method were used to test the susceptibility of respiratory bacterial isolates to antimicrobial agents following the standardized technical protocol established by the CHINET program.Results A total of 589 746 respiratory isolates were collected from 2015 to 2021.Overall,82.6％of the isolates were Gram-negative bacteria and 17.4％were Gram-positive bacteria.The bacterial isolates from outpatients and inpatients accounted for(6.0±0.9)％and(94.0±0.1)％,respectively.The top microorganisms were Klebsiella spp.,Acinetobacter spp.,Pseudomonas aeruginosa,Staphylococcus aureus,Haemophilus spp.,Stenotrophomonas maltophilia,Escherichia coli,and Streptococcus pneumoniae.Each microorganism was isolated from significantly more males than from females(P＜0.05).The overall prevalence of methicillin-resistant S.aureus(MRSA)was 39.9％.The prevalence of penicillin-resistant S.pneumoniae was 1.4％.The prevalence of extended-spectrum β-lactamase(ESBL)-producing E.coli and K.pneumoniae was 67.8％and 41.3％,respectively.The overall prevalence of carbapenem-resistant E.coli,K.pneumoniae,Enterobacter cloacae,Pseudomonas aeruginosa,and Acinetobacter baumannii was 3.7％,20.8％,9.4％,29.8％,and 73.3％,respectively.The prevalence of β-lactamase was 96.1％in Moraxella catarrhalis and 60.0％in Haemophilus influenzae.The H.influenzae isolates from children(＜18 years)showed significantly higher resistance rates to β-lactam antibiotics than the isolates from adults(P＜0.05).Conclusions Gram-negative bacteria are still predominant in respiratory isolates associated with serious antibiotic resistance.Antimicrobial resistance surveillance should be strengthened in clinical practice to support accurate etiological diagnosis and appropriate antimicrobial therapy based on antimicrobial susceptibility testing results.