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 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 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 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.

This study aimed to explore the relationship between comorbidity factors and in-hospital mortality related to factors in patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) pneumonia. This study collected clinical data from 218 patients with CRKP pneumonia in Beijing hospital from November 2011 to December 2023, analyzed the number of comorbidities carried by CRKP pneumonia patients, comorbidity patterns, Charlson Comorbidity Index (CCI) scores, and comorbidity of underlying diseases, and explored the relationship between various indicators and comorbidity factors and in-hospital mortality in CRKP pneumonia patients. The Ward.D cluster analysis was performed on the comorbidities of patients and used to draw heatmaps. Using a multiple logistic regression model, a nomogram model was constructed to predict in-hospital mortality in patients with CRKP pneumonia. This study included 218 patients with CRKP pneumonia. The results showed that there were significant differences in the age ( P=0.003), comorbidities such as heart failure ( P<0.001), arrhythmia ( P=0.002), chronic liver disease ( P=0.003), chronic kidney disease ( P=0.002), CCI score ( P=0.007), total number of comorbidities ( P<0.001), and comorbidity patterns (respiratory/immune/psychiatric disease patterns and cardiovascular/tumor/metabolic disease patterns, P=0.003) between the survival and death groups of CRKP pneumonia patients. The multiple logistic regression showed that cardiovascular/tumor/metabolic disease patterns ( P=0.030), CCI score ( P=0.040), concomitant heart failure ( P=0.011), and concomitant arrhythmia ( P=0.025) were independent risk factors for in-hospital mortality in patients with CRKP pneumonia. The nomogram model for predicting the risk of in-hospital mortality in patients with CRKP pneumonia, constructed based on the identified risk factors, had an area under the ROC curve of 0.758. Both the ROC curve and validation curve indicated that the nomogram model had stable performance in predicting in-hospital mortality in patients with CRKP pneumonia. In summary, comorbidity factors are risk factors for predicting in-hospital mortality in patients with CRKP pneumonia, and the role of comorbidity factors in in-hospital mortality in patients with CRKP pneumonia should be taken seriously.

This study aimed to explore the relationship between comorbidity factors and in-hospital mortality related to factors in patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) pneumonia. This study collected clinical data from 218 patients with CRKP pneumonia in Beijing hospital from November 2011 to December 2023, analyzed the number of comorbidities carried by CRKP pneumonia patients, comorbidity patterns, Charlson Comorbidity Index (CCI) scores, and comorbidity of underlying diseases, and explored the relationship between various indicators and comorbidity factors and in-hospital mortality in CRKP pneumonia patients. The Ward.D cluster analysis was performed on the comorbidities of patients and used to draw heatmaps. Using a multiple logistic regression model, a nomogram model was constructed to predict in-hospital mortality in patients with CRKP pneumonia. This study included 218 patients with CRKP pneumonia. The results showed that there were significant differences in the age ( P=0.003), comorbidities such as heart failure ( P<0.001), arrhythmia ( P=0.002), chronic liver disease ( P=0.003), chronic kidney disease ( P=0.002), CCI score ( P=0.007), total number of comorbidities ( P<0.001), and comorbidity patterns (respiratory/immune/psychiatric disease patterns and cardiovascular/tumor/metabolic disease patterns, P=0.003) between the survival and death groups of CRKP pneumonia patients. The multiple logistic regression showed that cardiovascular/tumor/metabolic disease patterns ( P=0.030), CCI score ( P=0.040), concomitant heart failure ( P=0.011), and concomitant arrhythmia ( P=0.025) were independent risk factors for in-hospital mortality in patients with CRKP pneumonia. The nomogram model for predicting the risk of in-hospital mortality in patients with CRKP pneumonia, constructed based on the identified risk factors, had an area under the ROC curve of 0.758. Both the ROC curve and validation curve indicated that the nomogram model had stable performance in predicting in-hospital mortality in patients with CRKP pneumonia. In summary, comorbidity factors are risk factors for predicting in-hospital mortality in patients with CRKP pneumonia, and the role of comorbidity factors in in-hospital mortality in patients with CRKP pneumonia should be taken seriously.

Objective To investigate the distribution characteristics of nasal cavity and maxillary sinus microbiota in aged patients with chronic maxillary sinusitis.Methods A total of 15 aged patients with chronic unilateral maxillary sinusitis who received surgical treatment between January 2017 to June 2018 in Beijing Hospital were enrolled and analyzed retrospectively.Their lavage samples from nasal cavity(N)and maxillary sinus(M)were collected and the samples were labeled according to the location(N and M groups,n=15 each).The high-throughput sequencing was used for sequencing all bacterial 16S rRNA genes in the samples.The composition of nasal cavity and maxillary sinus microbial communities was obtained,and the distribution features of nasal cavity and maxillary sinus microbiota were analyzed.Results A total of 8 bacterial phyla and 34 bacterial genera were found in nasal cavity and maxillary sinus microbiota.The most widely distributed phyla in nasal and sinus groups were Bacteroidetes,Fusobacteria,Frimicutes,Spirochaetes and Proteobacteria.The abundance of Bacteroidetes was higher in group M(60.0 ％,51 762/86 301)than in group N(42.9 ％,37 999/88 576)with statistically significant difference(P ＜0.05).The most widely distributed bacteria genera were Prevotella,Fusobacterium,Alloprevotella,Treponema,Parvimonas,Streptococcus,Filifactor,Phocaeicola,Campylobacter,Prevotella-7 and Lentimicrobiaceae.The abundance of Prevotella was higher in group M(47.7％,41 252/86 414)than in group N(33.5％,29 680/88 598) with statistically significant difference(P ＜ 0.05).Conclusions In the aged patients with chronic maxillary sinusitis,the distribution of bacteria in the nasal cavity and maxillary sinus is partly consistent.The abundance of the anaerobes distribution is higher in maxillary sinus than in nasal cavity in aged patients with chronic maxillary sinusitis.