OBJECTIVE To establish a method for simultaneous determination of venetoclax， busulfan and voriconazole in plasma of patients with acute myeloid leukemia （AML）， and apply it clinically. METHODS Plasma samples were subjected to protein precipitation using acetonitrile and subsequently analyzed by liquid chromatography-tandem mass spectrometry （LC-MS/MS） using venetoclax-D 8 ， busulfan-D 8 and posaconazole as internal standards. The separation was performed on a Phenomenex Kinetex ® C 18 column with a mobile phase composed of 0.1% formic acid solution （2 mmol/L ammonium acetate）-0.1% formic acid in acetonitrile （gradient elution） at a flow rate of 0.8 mL/min. The column temperature was set at 40 ℃， the sample size was 5 μL， and the total run time was 3.10 min. An electrospray ionization source was employed， and positive ion scanning was conducted using multiple reaction monitoring mode. The ion pairs used for quantitative analysis included m/z 868.4→636.3 （venetoclax）， m/z 264.1→151.1 （busulfan）， and m/z 350.1→224.0 （voriconazole）. The above LC-MS/MS method was adopted to determine plasma concentrations of venetoclax and voriconazole in 10 AML patients， as well as plasma concentration of busulfan in 5 patients undergoing conditioning treatment for allogeneic hematopoietic stem cell transplantation. RESULTS The linear ranges of venetoclax， busulfan and voriconazole were 50-10 000， 15-3 000 and 50-10 000 ng/mL， respectively （ R 2 ≥0.999 0）， with lower limits of quantification of 50， 15 and 50 ng/mL， respectively. The RSDs of intra-day and inter-day precision tests for all three analytes were all less than 10%， with accuracy （relative errors） ranging from －10.00% to 12.96%. The average extraction recovery ranged from 92.54% to 100.95%， and the average matrix effect was 89.98%-101.49%. Dilution reliability covered all dilution factors used in the test samples， and the absolute values of relative errors in stability tests were all≤16.25%. The plasma concentrations of venetoclax， busulfan and voriconazole in enrolled patients were 496.20-4 250.45， 233.48-2 002.28 and 475.51-5 710.18 ng/mL， respectively. CONCLUSIONS The LC-MS/MS method established in this study is rapid， sensitive and easy to operate， and can be used for the therapeutic drug monitoring of venetoclax， busulfan and voriconazole.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Creutzfeldt-Jakob disease(CJD)is a rapidly progressive and fatal neurodegenerative disorder caused by prions,with certain infectivity and iatrogenic transmission risks.With the rapid progress and application of new dia-gnostic biomarkers and detection methods,as well as the construction and improvement of surveillance and reporting systems,the detection of CJD in patients domestically and internationally has shown an increasing trend year by year.Due to its long incubation period and heterogeneity of early symptoms,early identification and diagnosis of the disease is difficult,increasing the risk of transmission within medical institutions.Currently,there is a lack of con-sensus on the infection prevention and control of CJD.In order to timely identify and diagnose CJD as well as effec-tively block its transmission in medical institutions,this consensus summarizes 15 clinical concerns and formulates 24 specific recommendations based on the latest domestic and international research findings and clinical evidence,as well as combines with clinical practice,aiming to standardize healthcare-associated infection prevention and control measures for CJD and reduce its transmission risk in medical institutions.

Creutzfeldt-Jakob disease(CJD)is a rapidly progressive and fatal neurodegenerative disorder caused by prions,with certain infectivity and iatrogenic transmission risks.With the rapid progress and application of new dia-gnostic biomarkers and detection methods,as well as the construction and improvement of surveillance and reporting systems,the detection of CJD in patients domestically and internationally has shown an increasing trend year by year.Due to its long incubation period and heterogeneity of early symptoms,early identification and diagnosis of the disease is difficult,increasing the risk of transmission within medical institutions.Currently,there is a lack of con-sensus on the infection prevention and control of CJD.In order to timely identify and diagnose CJD as well as effec-tively block its transmission in medical institutions,this consensus summarizes 15 clinical concerns and formulates 24 specific recommendations based on the latest domestic and international research findings and clinical evidence,as well as combines with clinical practice,aiming to standardize healthcare-associated infection prevention and control measures for CJD and reduce its transmission risk in medical institutions.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objectives:We evaluated the clinical significance of unipolar electrogram and bipolar electrogram in guiding radiofrequency ablation for outflow tract ventricular premature contractions(PVC).Methods:Data were collected from 78 patients who underwent successful radiofrequency ablation of PVC.Pre-procedure electrocardiogram showed a LBBB morphology on inferior leads.In the included patients,the right-side ablation was performed at first,and if the ablation failed,the left-side ablation was then performed.According to the location of the successful ablation target,they were divided into unilateral ablation successful group and bilateral ablation successful group.The differences in the earliest bipolar local activation to QRS(LATBi),unipolar-dV/dTmax to QRS(LATUni),and local activation time were compared between the two groups.Furthermore,the electrogram characteristics predicting bilateral ablation were explored.Results:Patients were divided into unilateral ablation group(n=57)and bilateral ablation group(n=21)according to the ablation site.There were statistically significant differences in LATBi(25[21,30]ms vs.14[10,24]ms),LATUni(7[0,17]ms vs.-23[-41,-11]ms),and ΔLATBi-Uni(15[11,25]ms vs.44[25,56]ms)between the unilateral ablation group and the bilateral ablation group(all P<0.05).Multivariate regression analysis suggested that LATBi,LATUni,and ΔLATBi-Uni were independent predictors of the need for bilateral ablation.There was no significant difference between left and right LATBi,LATUni and ΔLATBi-Uni in the bilateral ablation group.LATUni≤-1 was the most accurate parameter for predicting the need for bilateral ablation(AUC=0.941;specificity 80.7%;sensitivity 100%).Conclusions:LATUni≤-1ms is a useful indicator for predicting the need for bilateral PVC ablation in this patient cohort.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

The objective of this study was to develop a rapid and precise detection technique for por-cine Senecavirus A(SVA)employing reverse transcription recombinase polymerase amplification(RT-RAA)in conjunction with CRISPR Cas13a technology.Additionally,the study aimed to opti-mize the assay's reaction conditions to enhance amplification efficiency.Eight RT-RAA primer sets were designed based on the conserved gene sequence of porcine SVA,and a series of reaction condi-tions were evaluated to refine the RT-RAA reaction system.Subsequently,CRISPR-derived RNA(crRNA)sequences were developed and selected to construct the RT-RAA-CRISPR reaction sys-tem.The method's specificity was determined by examining six prevalent porcine pathogenic nucleic acids,while its sensitivity was assessed using SVA cRNA standards quantified by digital PCR.The method's stability and the consistency of clinical sample analysis were also evaluated.The findings revealed that the optimized RT-RAA and CRISPR reaction systems exhibited the highest amplifi-cation efficiency at a reaction temperature of 37 ℃.Among the eight crRNAs,five were identified as exhibiting the strongest detection signals.The formulated RT-RAA-CRISPR Cas13a method demonstrated exceptional specificity,showing no cross-reactivity with other common porcine disea-ses,including ASFV,PRRSV,PEDV,PCV2,CSFV,and PRV.The method achieved high sensitivi-ty,detecting as low as 0.86 copies/μL of SVA,and exhibited stable fluorescence output,robust re-producibility,and the ability to complete clinical sample analysis within 50 minutes.Consistency e-valuation with six positive and 58 negative samples indicated 100％agreement in outcomes.These results substantiate that the study successfully established a rapid and specific RT-RAA-CRISPR Cas13a detection method for the on-site identification of porcine Senecavirus A,demonstrating high specificity and sensitivity,and holds promise for application in SVA monitoring and control initia-tives.

This research investigated the contamination level,distribution of drug-resistant strains,and molecular epidemiologi-cal characteristics of Campylobacter,and further explored transmission pathways and prevention strategies.Cecum,chicken carcass,chicken product,and environmental samples,as well as swabs from workers'hands,were collected from a slaughterhouse in a large broiler group in the Jiaodong area between August 2023 and July 2024.Quantitative contamination assessment of Campylobacter in chicken carcasses and chicken products was performed.After microbial mass spectrometry identification,the representative strains of different links were selected for drug resistance testing and whole genome sequencing(WGS).On the basis of the sequencing results,the resistance genes,virulence genes,multilocus sequence typing(MLST),and phylogenetic characteristics of representative strains were analyzed.Homology comparisons were performed between isolates and strains from patients with diarrhea in the NCBI database.A total of 297 Campylobacter strains were isolated from 806 samples,and the overall detection rate was 36.85%.The detection rate of Campylobacter was highest in the evisceration process(47.33%),followed by the cutting process(35.64%).Overall,the Campylo-bacter detection rate first increased,then decreased,and subsequently increased.Drug sensitivity testing revealed that 90 isolates were resistant to nalidixic acid and ciprofloxacin,and 94.97%of isolates were resistant to tetracycline.WGS showed that both Campylo-bacter jejuni(C.jejuni)and Campylobacter coli(C.coli)carried many drug resistance and virulence genes.ST-14176 of C.jejuni was isolated for the first time herein.The predominant ST-8261 strain of C.jejuni and ST-860,ST-829,and ST-1586 strains of C.coli are known to cause human diarrhea.LOS expression genes associated with Guillain-Barré syndrome(GBS)were detected in both C.jejuni isolates from the slaughter chain and patients with GBS.Some strains exhibited close genetic relatedness to human-derived Campylo-bacter strains from the NCBI database.The detection rate of Campylobacter in the slaughterhouse first increased,then decreased,and subsequently increased,and the quantitative contamination level of each link was similar to the detection rate.Quantitative analysis of chicken carcasses/products revealed that the average bacterial load was highest in eviscerated carcasses(102.80 cfu/g),and the high-est amount of Campylobacter in chicken products reached 451.80 cfu/g.Abundant drug resistance genes and virulence genes were iden-tified,and the drug resistance genes were highly correlated with the drug resistance rate.Therefore,surveillance intensity and control measures for Campylobacter in slaughter processes should be strengthened.

This research investigated the contamination level,distribution of drug-resistant strains,and molecular epidemiologi-cal characteristics of Campylobacter,and further explored transmission pathways and prevention strategies.Cecum,chicken carcass,chicken product,and environmental samples,as well as swabs from workers'hands,were collected from a slaughterhouse in a large broiler group in the Jiaodong area between August 2023 and July 2024.Quantitative contamination assessment of Campylobacter in chicken carcasses and chicken products was performed.After microbial mass spectrometry identification,the representative strains of different links were selected for drug resistance testing and whole genome sequencing(WGS).On the basis of the sequencing results,the resistance genes,virulence genes,multilocus sequence typing(MLST),and phylogenetic characteristics of representative strains were analyzed.Homology comparisons were performed between isolates and strains from patients with diarrhea in the NCBI database.A total of 297 Campylobacter strains were isolated from 806 samples,and the overall detection rate was 36.85%.The detection rate of Campylobacter was highest in the evisceration process(47.33%),followed by the cutting process(35.64%).Overall,the Campylo-bacter detection rate first increased,then decreased,and subsequently increased.Drug sensitivity testing revealed that 90 isolates were resistant to nalidixic acid and ciprofloxacin,and 94.97%of isolates were resistant to tetracycline.WGS showed that both Campylo-bacter jejuni(C.jejuni)and Campylobacter coli(C.coli)carried many drug resistance and virulence genes.ST-14176 of C.jejuni was isolated for the first time herein.The predominant ST-8261 strain of C.jejuni and ST-860,ST-829,and ST-1586 strains of C.coli are known to cause human diarrhea.LOS expression genes associated with Guillain-Barré syndrome(GBS)were detected in both C.jejuni isolates from the slaughter chain and patients with GBS.Some strains exhibited close genetic relatedness to human-derived Campylo-bacter strains from the NCBI database.The detection rate of Campylobacter in the slaughterhouse first increased,then decreased,and subsequently increased,and the quantitative contamination level of each link was similar to the detection rate.Quantitative analysis of chicken carcasses/products revealed that the average bacterial load was highest in eviscerated carcasses(102.80 cfu/g),and the high-est amount of Campylobacter in chicken products reached 451.80 cfu/g.Abundant drug resistance genes and virulence genes were iden-tified,and the drug resistance genes were highly correlated with the drug resistance rate.Therefore,surveillance intensity and control measures for Campylobacter in slaughter processes should be strengthened.