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.

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.

In order to establish a simple,sensitive and specific diagnostic method for the simultane-ous detection of Mycoplasma hyorhinis(Mhr)and Mycoplasma hyopneumoniae(Mhp)in swine,specific primers and probes were designed using the Mhr p37 and Mhp p36 gene sequences as the target genes,and the dual LFD-RPA rapid test was established by screening the primers and probes,optimizing primer ratios and evaluating its effectiveness through the sensitivity,reproduc-ibility and clinical sample testing.The sensitivity,specificity,reproducibility and clinical samples were evaluated.The results showed that the established dual LFD-RPA assay could complete the amplification in 15 min at 39 ℃,and its optimal primer ratio was 1.6∶0.8,and the lowest detection limits were up to 3.63 and 3.60 copies/μL,respectively;the reproducibility was stable;and there was no cross-reactivity with Pasteurella multocida,Bordetella bronchiseptica,Haemophilus pa-rasuis,Actinobacillus pleuropneumoniae,Escherichia coli.The test successfully established a dual LFD-RPA assay,which can detect Mhr and Mhp simultaneously,and is simple,sensitive and spe-cific without relying on specialized equipment,and is suitable for carrying out on-site rapid diagno-sis of Mhr and Mhp.

Objective:To explore the value of using computed tomography(CT)values to distinguish fresh and old fractures vertebral bodies in osteoporotic vertebral compression fractures(OVCF).Methods:Retrospective analysis of clinical data of 101 OVCF patients in our hospital from September 2022 to September 2023.Kappa test for consistency between magnetic resonance imaging(MRI)and vertebral CT values in distinguished fresh or old OVCF.The difference of CT values between fresh,old fractures and adjacent normal vertebral bodies were compared.The diagnostic efficiency was analyed by receiver operating characteristic(ROC)curve.Results:There was a high consistency between vertebral CT values and MRI in the diagnosis of OVCF in fresh and old fractures(Kappa value=0.934).There was a difference in difference of CT values between adjacent normal vertebral bodies and fresh fractures vertebral bodies(P＜0.05).There was a difference in difference of CT values of fresh fractures vertebral bodies and old fractures vertebral bodies(P＜0.05).The ROC curve analysis results showed that,the combined measurement of CT values of fresh and old fractured vertebral bodies has an area under the curve(AUC)of 0.723,which was higher than alone measurement of the CT values of fresh fractured vertebral bodies and old fractured vertebral bodies of 0.536 and 0.610(Z=2.548,2.605,2.841,P＜0.05).Conclusion:CT values of vertebral bodies show high consistency in distinguish fresh and old fractures of OVCF compared to MRI findings,and the diagnostic efficiency of combine detection is relatively high.

Objective:To explore the diagnostic value of conventional computed tomography(CT)combined with enhanced CT scan in bone metastases.Methods:This study was a retrospective observational study,84 suspected bone metastases patients admitted to our hospital from January 2022 to August 2024 were selected,All patients underwent conventional CT and enhanced CT scan and pathological examination,Using pathological examination results as the"gold standard"for diagnosis.The imaging manifestations of bone metastases using conventional CT combined with enhanced CT scan examination were observed;The detection rate and bone metastases types of conventional CT and enhanced CT scan were analyzed;The bone metastases location in different types of malignant tumors were analyzed;The detection results of bone metastases between conventional CT and enhanced CT scan were compared;the diagnostic efficacy of conventional CT and enhanced CT scan alone and in combination for bone metastases were analyzed by Receiver operating characteristic(ROC)curve.Results:The detection rate of osteogenic,osteolytic,cystic and mixed bone metastases by conventional CT combined with enhanced CT scan was supered to that of conventional CT and enhanced CT scan alone(P＜0.05).Bone metastases from lung cancer,breast cancer and other tumors mainly occur in the spine,limbs and ribs,while esophageal cancer,gastric cancer,liver cancer,prostate cancer,thyroid cancer,renal cancer,and nasopharyngeal cancer had relatively fewer bone metastases.The positive detection cases of bone metastases used conventional CT combined with enhanced CT scan were supered to those used conventional CT and enhanced CT scan alone.The sensitivity,specificity and accuracy of conventional CT combined with enhanced CT scan for the diagnosis of bone metastases were 94.00％,94.11％and 94.04％,respectively,and the positive/negative predictive values were 95.91％and 91.42％,respectively.The sensitivity,specificity and accuracy of conventional CT scan were 84.00％,78.78％and 80.95％,respectively,and the positive/negative predictive values were 85.71％and 74.28％,respectively.The sensitivity,specificity and accuracy of enhanced CT were 89.79％,85.71％and 88.09％,respectively.and the positive and negative predictive values were 89.79％and 85.71％,respectively.The diagnostic efficacy of conventional CT combined with enhanced CT scan for bone metastases was significantly better than that of conventional CT and enhanced CT scan alone.Conclusions:Conventional CT combined with enhanced CT scan can significantly improve the diagnostic efficiency of bone metastases,and provide an important basis for clinical treatment.

In order to establish a simple,sensitive and specific diagnostic method for the simultane-ous detection of Mycoplasma hyorhinis(Mhr)and Mycoplasma hyopneumoniae(Mhp)in swine,specific primers and probes were designed using the Mhr p37 and Mhp p36 gene sequences as the target genes,and the dual LFD-RPA rapid test was established by screening the primers and probes,optimizing primer ratios and evaluating its effectiveness through the sensitivity,reproduc-ibility and clinical sample testing.The sensitivity,specificity,reproducibility and clinical samples were evaluated.The results showed that the established dual LFD-RPA assay could complete the amplification in 15 min at 39 ℃,and its optimal primer ratio was 1.6∶0.8,and the lowest detection limits were up to 3.63 and 3.60 copies/μL,respectively;the reproducibility was stable;and there was no cross-reactivity with Pasteurella multocida,Bordetella bronchiseptica,Haemophilus pa-rasuis,Actinobacillus pleuropneumoniae,Escherichia coli.The test successfully established a dual LFD-RPA assay,which can detect Mhr and Mhp simultaneously,and is simple,sensitive and spe-cific without relying on specialized equipment,and is suitable for carrying out on-site rapid diagno-sis of Mhr and Mhp.

Objective:To explore the value of using computed tomography(CT)values to distinguish fresh and old fractures vertebral bodies in osteoporotic vertebral compression fractures(OVCF).Methods:Retrospective analysis of clinical data of 101 OVCF patients in our hospital from September 2022 to September 2023.Kappa test for consistency between magnetic resonance imaging(MRI)and vertebral CT values in distinguished fresh or old OVCF.The difference of CT values between fresh,old fractures and adjacent normal vertebral bodies were compared.The diagnostic efficiency was analyed by receiver operating characteristic(ROC)curve.Results:There was a high consistency between vertebral CT values and MRI in the diagnosis of OVCF in fresh and old fractures(Kappa value=0.934).There was a difference in difference of CT values between adjacent normal vertebral bodies and fresh fractures vertebral bodies(P＜0.05).There was a difference in difference of CT values of fresh fractures vertebral bodies and old fractures vertebral bodies(P＜0.05).The ROC curve analysis results showed that,the combined measurement of CT values of fresh and old fractured vertebral bodies has an area under the curve(AUC)of 0.723,which was higher than alone measurement of the CT values of fresh fractured vertebral bodies and old fractured vertebral bodies of 0.536 and 0.610(Z=2.548,2.605,2.841,P＜0.05).Conclusion:CT values of vertebral bodies show high consistency in distinguish fresh and old fractures of OVCF compared to MRI findings,and the diagnostic efficiency of combine detection is relatively high.

Objective:To explore the diagnostic value of conventional computed tomography(CT)combined with enhanced CT scan in bone metastases.Methods:This study was a retrospective observational study,84 suspected bone metastases patients admitted to our hospital from January 2022 to August 2024 were selected,All patients underwent conventional CT and enhanced CT scan and pathological examination,Using pathological examination results as the"gold standard"for diagnosis.The imaging manifestations of bone metastases using conventional CT combined with enhanced CT scan examination were observed;The detection rate and bone metastases types of conventional CT and enhanced CT scan were analyzed;The bone metastases location in different types of malignant tumors were analyzed;The detection results of bone metastases between conventional CT and enhanced CT scan were compared;the diagnostic efficacy of conventional CT and enhanced CT scan alone and in combination for bone metastases were analyzed by Receiver operating characteristic(ROC)curve.Results:The detection rate of osteogenic,osteolytic,cystic and mixed bone metastases by conventional CT combined with enhanced CT scan was supered to that of conventional CT and enhanced CT scan alone(P＜0.05).Bone metastases from lung cancer,breast cancer and other tumors mainly occur in the spine,limbs and ribs,while esophageal cancer,gastric cancer,liver cancer,prostate cancer,thyroid cancer,renal cancer,and nasopharyngeal cancer had relatively fewer bone metastases.The positive detection cases of bone metastases used conventional CT combined with enhanced CT scan were supered to those used conventional CT and enhanced CT scan alone.The sensitivity,specificity and accuracy of conventional CT combined with enhanced CT scan for the diagnosis of bone metastases were 94.00％,94.11％and 94.04％,respectively,and the positive/negative predictive values were 95.91％and 91.42％,respectively.The sensitivity,specificity and accuracy of conventional CT scan were 84.00％,78.78％and 80.95％,respectively,and the positive/negative predictive values were 85.71％and 74.28％,respectively.The sensitivity,specificity and accuracy of enhanced CT were 89.79％,85.71％and 88.09％,respectively.and the positive and negative predictive values were 89.79％and 85.71％,respectively.The diagnostic efficacy of conventional CT combined with enhanced CT scan for bone metastases was significantly better than that of conventional CT and enhanced CT scan alone.Conclusions:Conventional CT combined with enhanced CT scan can significantly improve the diagnostic efficiency of bone metastases,and provide an important basis for clinical treatment.

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.

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.