Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective To investigate the correlation between baseline plasma soluble triggering receptor expressed on myeloid cell-1(sTREM-1),steroid hormone cortisol and dehydroepiandrosterone(DHEA),immunoendocrine markers,and disease severity in patients with pulmonary tuberculosis(PTB).Methods From March 2020 to May 2022,76 PTB patients and 78 healthy controls were recruited.The plasma sTREM-1 levels were compared between controls and PTB patients.Plasma sTREM-1 and C-reactive protein(CRP),interleukin(IL)-6 and interferon(IFN)-y,erythrocyte sedimentation rate(ESR),steroid hormone cortisol and dehydroepiandrosterone(DHEA)were analyzed to correlate with inflammatory transcripts(IL-6,IFN-γ)in peripheral blood mononuclear cells.Results The sTREM,CRP,ESR,IL-6,IFN-γ,cortisol and cortisol/DHEA were significantly increased(P＜0.05)while DHEA was significantly decreased(P＜0.05)in PTB patients compared with the control group.Futhermore,severe PTB patients had higher sTREM-1 and ESR levels than mild and moderate PTB patients.Spearman correlation analysis showed that sTREM-1 was significantly positively correlated with CRP in all patients(P＜0.05).Only in patients with severe PTB,sTREM-1 was significantly positively correlated with cortisol/DHEA(P＜0.05),and significantly negatively correlated with DHEA(P＜0.05).Conclusions High plasma sTREM-1 levels may be an important factor contributing to the persistence of immunoendocrine imbalance specific to advanced disease in patients with PTB.

Objective To compare the safety and efficacy of vancomycin in obese patients guided by trough concentration and AUC24h/MIC,and to provide data for individualized administration of vancomycin in obese patients.Methods We retrospectively collected the data of obese adult patients(BMI 30 kg/m2)who had severe infection caused by gram-positive cocci and treated with vancomycin intravenously in two Grade A tertiary hospitals in Shanghai from 2012 to 2024.The patients were assigned to trough concentration monitoring group or AUC24h/MIC monitoring group according to the therapeutic drug monitoring(TDM)method at the time of admission.Nephrotoxicity and efficacy were compared between the two groups of patients.Results A total of 22 obese patients were included in this study,including 12 in the trough concentration monitoring group and 10 in the AUC24h/MIC monitoring group.No significant difference was found between the two groups in gender,age,BMI,creatinine clearance before treatment,underlying disease,site of infection,pathogen type,or concomitant medications.The proportion of ICU admission was higher in AUC24h/MIC monitoring group.The length of ICU stay,vancomycin treatment duration,bacterial clearance rate and comprehensive efficacy rate did not show significant difference between the two groups.The average daily dose of vancomycin in trough concentration monitoring group was significantly lower than that in A UC24h/MIC monitoring group[(1.63±0.59)g vs(2.29±0.72)g,P=0.026].The average treatment duration was not significantly different between the two groups[(15.33±10.28)d vs(14.90±6.92)d,P=0.911].Compared with the trough concentration monitoring group,the initial peak concentration[(30.99±16.22)mg/L vs(19.41±5.42)mg/L,P=0.025]and overall peak concentration[(33.67±16.53)mg/L vs(22.08±3.96)mg/L,P=0.045]of vancomycin were lower in theAUC24h/MIC monitoring group,but the initial trough concentration[(11.03±8.66)mg/L vs(6.33±4.45)mg/L,P=0.139]and overall trough concentration[(13.75±9.74)mg/L vs(9.74±4.24)mg/L,P=0.218]were similar in the two groups.Vancomycin-associated nephrotoxicity did not occur in any group,but 41.7％of the patients in the trough concentration monitoring group reached the threshold of renal toxicity,i.e.trough concentration ≥15 mg/L.Conclusions Vancomycin treatment with conventional dosing regimen still have good clinical efficacy in obese adult patients.Vancomycin therapy guided by A UC24h/MIC can achieve the target value at lower concentration or exposure,which is promising for reducing vancomycin-associated nephrotoxicity.

Objective To examine the diagnosis and treatment of disseminated infection caused by Enterocytozoon bieneusi in a child with leukemia and improve the awareness of the pathogen in clinical and laboratory practice.Methods A case of disseminated infection caused by Enterocytozoon bieneusi in a child with leukemia in Shanghai Children's Hospital was retrospectively analyzed,including diagnosis and treatment details.Similar cases were identified from PubMed,Wanfang Data,VIP,and CNKI databases since database establishment until June 30,2024,using search terms"Enterocytozoon bieneusi".The relevant literature was reviewed.Results This child had acute lymphoblastic leukemia as the underlying disease and was admitted to hospital for antimicrobial treatment due to fever and abdominal discomfort.The case was considered bacterial infection complicated with Enterocytozoon bieneusi infection,confirmed by detection of Klebsiella pneumoniae in blood and detection of Enterocytozoon bieneusi in blood and ascites by metagenomic next-generation sequencing(mNGS).The treatment was switched to tigecycline plus trimethoprim-sulfamethoxazole at a sufficient dose,which resulted in resolution of symptoms.Six months later,the patient suffered from acute lymphoblastic leukemia and bone marrow depression,Enterocytozoon bieneusi disseminated infection,septic shock.Her family gave up treatment and the child died.Literature review indicated that most patients infected with Enterocytozoon bieneusi had underlying conditions such as organ transplantation,AIDS,and leukemia associated with poor immunity.The onset symptoms are diarrhea,abdominal discomfort,and fever.Enterocytozoon bieneusi was detected by using methods such as modified Masson's trichrome stain,fluorescent calcofluor white staining,molecular detection techniques,and immunofluorescence.The patients were treated with drugs such as albendazole,nitazoxanide,fumagillin,and trimethoprim-sulfamethoxazole.Conclusions Enterocytozoon bieneusi is an opportunistic pathogenic fungus that infects immunocompromised patients and can cause abdominal discomfort,diarrhea,fever,and even disseminated infection and death.Conventional laboratory methods cannot culture Enterocytozoon bieneusi.Molecular detection techniques can be used to identify the pathogen early.

Objective To investigate the susceptibility of Cryptococcus neoformans strains to antifungal drugs and examine the relevant clinical manifestations and laboratory test results in a tertiary hospital in Shanghai during the period from 2019 to 2023.Methods The isolates were identified by MALDI-TOF and biochemical identification cards.The minimum inhibitory concentration(MIC)values of 5-fluorocytosine,amphotericin B,fluconazole,voriconazole,and itraconazole against C.neoformans strains were measured using broth microdilution method.The corresponding clinical data were reviewed and compared.Results Majority(78.7％)of the 75 strains of C.neoformans were isolated from cerebrospinal fluid(CSF).The prevalence of wild type(WT)strains was the lowest(36.0％)for itraconazole and the highest(94.7％)for voriconazole.Cryptococcus capsular antigen test was positive in 62 strains.The results of Cryptococcus capsular antigen test was consistent with fungal culture in 96.9％of the cases.Conclusions Most of the C.neoformans strains were isolated from CSF.The prevalence of non-WT C.neoformans strains was the highest for itraconazole.The prevalence of WT C.neoformans strains was the highest for voriconazole.

Objective To investigate the changing antimicrobial resistance profiles of Streptococcus pneumoniae isolates from children in Chongqing area from 2011 to 2022,and to provide evidence for rational use of antibiotics and prevention of nosocomial infections.Methods The clinical data of S.pneumoniae strains isolated from pediatric patients during 2011-2022 were retrospectively analyzed.Antimicrobial susceptibility testing was performed with commercial automated systems and E-test.The results were interpreted according to the breakpoints in CLSI document(2022 edition).Results A total of 26 668 strains of S.pneumoniae were isolated during the 12-year period.The proportion of S.pneumoniae was 16.0％in the total pathogenic bacterial isolates and 46.4％in all the gram-positive bacterial pathogens.S.pneumoniae strains were mainly isolated from respiratory specimens(97.1％),followed by blood samples(1.5％).The highest proportion of S.pneumoniae isolates was in infants(38.2％),followed by toddlers(32.4％),preschool age(22.9％),school age(5.6％),adolescents(0.6％)and neonates(0.4％).All of the 38 strains of nonmeningitis SS.pneumoniae(0.1％)isolated from cerebrospinal fluid were resistant to penicillin.Overall,35.7％and 32.4％of these strains were resistant to cefotaxime and meropenem,respectively.The majority of S.pneumoniae(99.9％,26 630/26 668)were nonmeningitis isolates.The prevalence of penicillin-susceptible(PSSP),-intermediate(PISP),and-resistant(PRSP)strains was 71.9％(16 083),25.1％(5 610),and 3.0％(674),respectively.The prevalence of PRSP in infants and preschool children was higher than that in other age groups.The nonmeningitis S.pneumoniae isolates showed higher than 95％resistance rate to erythromycin,clindamycin and tetracycline,but 0.2％,0.2％and 0.1％resistance rate to levofloxacin,moxifloxacin and rifampicin,respectively.No S.pneumoniae strains were found resistant to vancomycin or linezolid.Conclusions The proportion and antimicrobial resistance profiles of S.pneumoniae strains isolated from pediatric patients varied with age group and specimen type.The decreasing prevalence of PRSP may inform empirical treatment of S.pneumoniae infections in children in Chongqing area.

Objective To investigate the distribution and antibiotic resistance profiles of clinical isolates in Beijing Children's Hospital,Capital Medical University from 2016 to 2022.Methods All the strains isolated from inpatients in Beijing Children's Hospital during the period from 2016 to 2022 were analyzed.Antimicrobial susceptibility test was conducted by Kirby-Bauer method or automated system.Results were interpreted according to the breakpoints recommended in the CLSI Ml00 2022 edition.Results A total of 24 904 isolates were analyzed,including Gram-positive bacteria(49.4％)and Gram-negative bacteria(50.6％).The top three Gram-positive bacteria were Staphylococcus aureus(15.6％),coagulase-negative Staphylococcus(14.0％),and Streptococcus pneumoniae(8.9％).The top three Gram-negative bacteria were Klebsiella spp.(8.6％),Pseudomonas aeruginosa(8.6％),and Haemophilus influenzae(8.1％).The prevalence of methicillin-resistant strains was 30.9％in SS.aureus(MRSA)and 82.7％in coagulase-negative Staphylococcus(MRCNS).The prevalence of PRSP was 75.0％(24/32)in meningitis isolates and 2.6％(57/2 195)in non-meningitis isolates.Five strains of E.faecium and 10 strains of E.faecalis were found resistant to linezolid.Two strains of E.faecium were resistant to vancomycin.The prevalence of extended-spectrum beta-lactamases(ESBLs)and carbapenem-resistant strains(CREco)in E.coli isolates was 69.0％and 9.7％,respectively.The prevalence of ESBLs and carbapenem-resistant strains(CRKpn)in K.pneumoniae isolates was 73.7％,and 37.2％,respectively.The prevalence of carbapenem-resistant strains was 21.9％in P.aeruginosa isolates and 59.3％in A.baumannii isolates.β-lactamase was detected in 68.3％of the H.influenzae isolates.Conclusions Antimicrobial resistance is still serious in children.It is necessary to strength the surveillance of bacterial resistance and use antibiotics rationally in order to curb the spread of drug-resistant strains.

Objective To understand the distribution and antimicrobial resistance profiles of bacterial strains isolated from blood cultures at Yunyang County People's Hospital from 2019 to 2023.Methods The data of bacterial isolates from blood samples and the results of antimicrobial susceptibility testing were analyzed retrospectively from 2019 to 2023 at Yunyang County People's Hospital.Results A total of 3 789 bacterial strains were isolated from blood culture,including 1 931(51.0％)strains of Gram negative bacteria and 1 858(49.0％)strains of Gram positive bacteria.Coagulase negative Staphylococcus(33.3％),Escherichia coli(25.4％),Klebsiella pneumoniae(13.7％),Staphylococcus aureus(9.9％),and Enterobacter cloacae(1.8％)were the top five bacterial pathogens.Antimicrobial susceptibility testing showed that the prevalence of methicillin-resistant strains was 27.1％in S.aureus,34.5％in S.epidermidis,and 49.9％in other coagulase-negative Staphylococcus.Methicillin resistant strains(MRSA,MRSE,and other MRCNS)showed significantly higher resistance rates to most antibiotics than corresponding methicillin-susceptible strains(MSSA,MSSE,and other MSCNS).No staphylococcal isolates were resistant to vancomycin,teicoplanin,linezolid,or tigecycline.Enterococcus faecium showed significantly higher resistance rate to antibiotics than Enterococcus faecalis.No enterococcal strains were resistant to vancomycin,teicoplanin,linezolid,or tigecycline.No streptococcal isolates were found resistant to vancomycin or linezolid.Serratia marcescens strains had a resistance rate of 25.0％to carbapenems.All other Enterobacterales species showed a resistance rate of less than 10.0％to carbapenems.No Enterobacterales isolates were found resistant to tigecycline.The resistance rates of P.aeruginosa to imipenem and meropenem were 5.7％and 3.8％,respectively.No P.aeruginosa isolates were found resistant to colistin.The resistance rates of Acinetobacter baumannii to imipenem and meropenem were 41.4％and 38.0％,respectively.Conclusions The proportion of Gram negative bacteria is slightly higher than that of Gram positive bacteria in the bacterial isolates from blood samples at Yunyang County People's Hospital.The prevalence of MRSA and MRCNS is relatively high,while A.baumannii and S.marcescens showed high resistance rates to carbapenems.Antimicrobial resistance surveillance should be strengthened for the bacterial isolates from blood samples in order to learn the changing resistance profiles,use antibiotics reasonably,and prevent the spread of drug-resistant bacteria.

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.