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 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.

Oocyte maturation defect is an extremely rare primary infertility, which is characterized by ovum development arrest, oocyte complete fertilization failure, oocyte apoptosis before and after fertilization, and early embryonic development arrest. This case explored the genetic etiology of a primary infertility patient, who had no mature oocyte after two cycles of controlled ovarian hyperstimulation. Peripheral blood samples of the patient were collected for whole exome sequencing, the suspected pathogenic variants were screened by bioinformatics and verified by sanger sequencing on the patient and her parents. Results showed that the patient was found to harbor homozygous variant of the PATL2 gene, namely c.1363C>T (p.Gln455*). Sanger sequencing has verified that the parents are both heterozygous. The mutation of c.1363C>T is a rare pathogenic mutation that had not yet been recorded in HGMD database. In this case, PATL2 gene mutation can cause oocyte maturation arrest, it is recommended to use whole exome sequencing and genetic counseling as soon as possible for these patients, so as to select appropriate treatment.

Objective To investigate the distribution and antimicrobial resistance profiles of the clinical isolates from wound pus in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods All the bacterial strains were isolated from wound pus samples from 2015 to 2021.The isolates were identified according to conventional methods.Antimicrobial susceptibility test was conducted by disk diffusion method or commercial automated susceptibility testing systems according to CHINET-specified uniform protocol.The results are interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition).Results A total of 90856 bacterial strains were isolated from wound pus samples from 2015 to 2021,of which gram positive bacteria accounted for 36.0％ (32729/90856) and gram negative bacteria accounted for 64.0％ (58127/90856).The most common bacterial species were Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Enterococcus.About 88.9％ of these strains were isolated from inpatients and 11.1％ from outpatients.The strains collected from surgery department and internal medicine accounted for (53.4±3.6)％ (49191/90856) and (9.6±1.0)％ (8960/90856) on average over the 7-year period.E.coli showed low level resistance to carbapenems (1.1％).The prevalence of ESBLs-producing E.coli was 51.1％.More than 35％ of the E.coli isolates were resistant to cefotaxime,ciprofloxacin,and trimethoprim-sulfamethoxazole.The prevalence of ESBLs-producing K.pneumoniae was 29.7％.The prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae varied from 2015 to 2021,but reached the peak level (12.5％ and 12.7％) in 2020.However,other Enterobacterales species showed low resistance rates to carbapenems.The prevalence of ESBLs-producing Klebsiella oxytoca and Proteus was 18.3％ and 32.5％,respectively.About 13.1％ and 10.6％ of P.aeruginosa isolates were resistant to imipenem and meropenem,respectively.However,71.1％ and 72.4％ of A.baumannii isolates were resistant to imipenem and meropenem,respectively.The overall prevalence of MRSA was 22.7％ in wound pus samples over the 7-year period.Three vancomycin-resistant strains and 122 linezolid-resistant isolates were identified in Enterococcus faecalis.Thirty-one vancomycin-resistant strains and 11 linezolid-resistant strains were detected in Enterococcus faecium.Conclusions The overall prevalence of MRSA,vancomycin-resistant Enterococcus (VRE),linezolid-resistant Enterococcus (LRE),ESBLs-producing Enterobacterales,and carbapenem-resistant organisms (CRO) in the isolates from wound pus samples was relatively lower than the corresponding prevalence in the total clinical isolates collected in the CHINET program.This finding suggests that the antimicrobial resistance profile of bacterial isolates may vary with the source of clinical samples.Therefore,we should strengthen the antimicrobial resistance surveillance for the isolates from different sites of infection.

Objective To investigate the distribution and antimicrobial resistance profiles of the clinical isolates from wound pus in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods All the bacterial strains were isolated from wound pus samples from 2015 to 2021.The isolates were identified according to conventional methods.Antimicrobial susceptibility test was conducted by disk diffusion method or commercial automated susceptibility testing systems according to CHINET-specified uniform protocol.The results are interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition).Results A total of 90856 bacterial strains were isolated from wound pus samples from 2015 to 2021,of which gram positive bacteria accounted for 36.0％ (32729/90856) and gram negative bacteria accounted for 64.0％ (58127/90856).The most common bacterial species were Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Enterococcus.About 88.9％ of these strains were isolated from inpatients and 11.1％ from outpatients.The strains collected from surgery department and internal medicine accounted for (53.4±3.6)％ (49191/90856) and (9.6±1.0)％ (8960/90856) on average over the 7-year period.E.coli showed low level resistance to carbapenems (1.1％).The prevalence of ESBLs-producing E.coli was 51.1％.More than 35％ of the E.coli isolates were resistant to cefotaxime,ciprofloxacin,and trimethoprim-sulfamethoxazole.The prevalence of ESBLs-producing K.pneumoniae was 29.7％.The prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae varied from 2015 to 2021,but reached the peak level (12.5％ and 12.7％) in 2020.However,other Enterobacterales species showed low resistance rates to carbapenems.The prevalence of ESBLs-producing Klebsiella oxytoca and Proteus was 18.3％ and 32.5％,respectively.About 13.1％ and 10.6％ of P.aeruginosa isolates were resistant to imipenem and meropenem,respectively.However,71.1％ and 72.4％ of A.baumannii isolates were resistant to imipenem and meropenem,respectively.The overall prevalence of MRSA was 22.7％ in wound pus samples over the 7-year period.Three vancomycin-resistant strains and 122 linezolid-resistant isolates were identified in Enterococcus faecalis.Thirty-one vancomycin-resistant strains and 11 linezolid-resistant strains were detected in Enterococcus faecium.Conclusions The overall prevalence of MRSA,vancomycin-resistant Enterococcus (VRE),linezolid-resistant Enterococcus (LRE),ESBLs-producing Enterobacterales,and carbapenem-resistant organisms (CRO) in the isolates from wound pus samples was relatively lower than the corresponding prevalence in the total clinical isolates collected in the CHINET program.This finding suggests that the antimicrobial resistance profile of bacterial isolates may vary with the source of clinical samples.Therefore,we should strengthen the antimicrobial resistance surveillance for the isolates from different sites of infection.

Oocyte maturation defect is an extremely rare primary infertility, which is characterized by ovum development arrest, oocyte complete fertilization failure, oocyte apoptosis before and after fertilization, and early embryonic development arrest. This case explored the genetic etiology of a primary infertility patient, who had no mature oocyte after two cycles of controlled ovarian hyperstimulation. Peripheral blood samples of the patient were collected for whole exome sequencing, the suspected pathogenic variants were screened by bioinformatics and verified by sanger sequencing on the patient and her parents. Results showed that the patient was found to harbor homozygous variant of the PATL2 gene, namely c.1363C>T (p.Gln455*). Sanger sequencing has verified that the parents are both heterozygous. The mutation of c.1363C>T is a rare pathogenic mutation that had not yet been recorded in HGMD database. In this case, PATL2 gene mutation can cause oocyte maturation arrest, it is recommended to use whole exome sequencing and genetic counseling as soon as possible for these patients, so as to select appropriate treatment.

Objective:To investigate and analyze the epidemiological and clinical characteristics of 46 patients with corona virus disease 2019 (COVID-19) in Beijing City.Methods:A retrospective study was conducted to analyze the data of 46 patients with COVID-19 in Beijing from 20th January 2020 to 8th February 2020 at the Fifth Medical Center of the PLA General Hospital in Beijing City. Twelve, 23 and 11 patients were assigned to the mild group, common group and severe group, respectively. The epidemiological history, clinical characteristics, laboratory tests and imaging inspections were analyzed. Statistical analysis used Fisher exact test. If P<0.05, post- hoc test was used for pairwise comparison, and the statistics were corrected by Bonferroni test. Results:Among the 46 patients included in this study, 27 were male and 19 were female. The age range was between 3-79 years old, and the age was (41.8±16.3) years old. The average incubation period was (4.85±3.00) days. A total of 26 cases (56.5%) were clustered patients, and 26 cases had a history of staying in Wuhan, 10 cases had contact with Wuhan personnel. Fever (39 cases, 84.8%), cough (27 cases, 58.7%), and fatigue (25 cases, 54.3%) were the main clinical symptoms for these patients. The decrease in white blood cell counts occurred in 12 patients, four had the decrease in T lymphocyte percentage, 17 had the decrease in CD4 + T lymphocyte counts, seven had the decrease in CD8 + T lymphocyte counts, 21 had the increase level of C reactive protein (45.7%), and interleukin-6 (IL-6) level increased in 32 cases (69.6%), erythrocyte sedimentation rate (ESR) increased in 23 cases (50.0%), serum ferritin level increased in 26 cases (56.5%), and blood lactic acid level increased in nine cases. There were statistically significant differences in the proportion of cases with decreased absolute value of CD8 + T lymphocytes and T lymphocytes counts among the mild, common and severe groups (all P<0.05). Comparing the proportion of cases in the three groups with elevated C reactive protein, IL-6, ESR, serum ferritin and blood lactic acid levels, the differences were statistically significant (all P<0.05). The proportion of cases with elevated C reactive protein levels in severe group was higher than those in mild and common groups. The proportion of cases with elevated IL-6, ESR, and serum ferritin levels in severe and common group were higher than those in mild group. The proportion of cases with elevated blood lactic acid levels in severe group was higher than those in mild group. The differences between the above groups were statistically significant (all adjusted P<0.017). Analysis of chest X-rays results showed that 34 patients (73.9%) had inflammation in the lungs. Conclusions:The epidemiological characteristics of patients with COVID-19 in Beijing City are mainly imported cases and clustered cases. The clinical manifestations are mainly fever, fatigue and cough. C reactive protein, IL-6, ESR, serum ferritin and blood lactic acid levels are higher in severe patients.

Objective To study the hematopoietic stem cell injury(HSC)induced by busulfan. Methods C57BL/6 mice were treated with i.p. injection of 20 mg/kg or 40 mg/kg busulfan. All mice were euthanized at 15 days and 30 days after busulfan treatment for analysis of the peripheral blood cell counts, bone marrow cellularity and HPC (LKS-, lineage-sca1 -c-kit+), HSC(LSK, lineage-sca1 +c-kit+)and long-term HSC(CD34 - LSK, CD34 - lineage-sca1 +c-kit+)frequency. The colony-forming unit-granulocyte and macrophage(CFU-GM)ability of HPC was measured by colony-forming cell(CFC)assay,and the HSC self-renewal capacity was analyzed by single-cell colony-forming assay. Results The busulfan administration decreased the WBC,RBC and PLT compared with control mice. The HPC function (CFU-GM)was impaired(P < 0.05), and the HSC colony forming ability was decreased at 15 days after busulfan treatment(P < 0.05), whereas the body weight of the mice didn't change significantly after busulfan treatment. Conclusions Our findings suggest that busulfan can induce hematopoietic stem cell injury,and provide a support for the study of hematopoietic stem cell injury mechanism.