Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023.Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints.Results A total of 445199 clinical isolates were collected in 2023,of which 29.0％ were gram-positive and 71.0％ were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA,MRSE and MRCNS) was 29.6％,81.9％ and 78.5％,respectively.Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA,MSSE and MSCNS).Overall,92.9％ of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4％ of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1％ in the isolates from children and and 95.9％ in the isolates from adults.The resistance rate to carbapenems was lower than 15.0％ for most Enterobacterales species except for Klebsiella,22.5％ and 23.6％ of which were resistant to imipenem and meropenem,respectively .Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.6％ to 10.0％.The resistance rate to imipenem and meropenem was 21.9％ and 17.4％ for Pseudomonas aeruginosa,respectively,and 67.5％ and 68.1％ for Acinetobacter baumannii,respectively.Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates.However,the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a slightly decreasing trend.This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023.Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints.Results A total of 445199 clinical isolates were collected in 2023,of which 29.0％ were gram-positive and 71.0％ were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA,MRSE and MRCNS) was 29.6％,81.9％ and 78.5％,respectively.Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA,MSSE and MSCNS).Overall,92.9％ of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4％ of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1％ in the isolates from children and and 95.9％ in the isolates from adults.The resistance rate to carbapenems was lower than 15.0％ for most Enterobacterales species except for Klebsiella,22.5％ and 23.6％ of which were resistant to imipenem and meropenem,respectively .Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.6％ to 10.0％.The resistance rate to imipenem and meropenem was 21.9％ and 17.4％ for Pseudomonas aeruginosa,respectively,and 67.5％ and 68.1％ for Acinetobacter baumannii,respectively.Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates.However,the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a slightly decreasing trend.This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective To determine the pollution sources that influence the level of exposure to particulate matter 2.5 (PM2.5) in the elderly,and calculate the quantitative contributions of difference sources.Methods Personal exposure PM samples were collected in the summer and winter of 2011 from 101 elderly men in a Tianjin community.Chemical species (elements,water-soluble ions and carbonaceous species) were analyzed in PM samples to determine PM2.5 concentrations and chemical compositions.The Positive Matrix Factorization (PMF) model,which is recommended by the US Environmental Protection Agency,was employed to quantitatively analyze the contribution of each potential sources to personal levels of PM2.5 exposure.Results In both summer and winter,the model identified the same six sources of personal exposure to PM2.5 in the elderly:fugitive dust (marker species:Si,Al,Ca,Mg,Fe etc.),coal combustion emissions (marker species:organic carbon (OC) and SO42-),vehicle exhausts (marker species:inorganic carbon and NO3),secondary sulfates and nitrates (marker species:NO3-,SO42-and NH4 +),industrial emissions (marker species:Mn,Ni,Cu,Zn,Pb etc.),and indoor sources (marker species:OC,K,Si,Al etc.).Among these six potential sources,vehicle exhausts (summer:33.6％,winter:24.2％),secondary sulfates and nitrates (summer:27.4％,winter:29.1％),as well as coal combustion emissions (summer:19.9％,winter:24.1％) were the greatest contributors.Conclusions Coal combustion and vehicle exhaust emissions were the major sources of personal exposure to PM2.5 in the elderly,suggesting that these two sources were the key contributors to the precursor gases of secondary sulfate and nitrate.Key Project of Chinese National Programs for Fundamental Research and Development (2011CB503801)

Objective To determine the pollution sources that influence the level of exposure to particulate matter 2.5 (PM2.5) in the elderly,and calculate the quantitative contributions of difference sources.Methods Personal exposure PM samples were collected in the summer and winter of 2011 from 101 elderly men in a Tianjin community.Chemical species (elements,water-soluble ions and carbonaceous species) were analyzed in PM samples to determine PM2.5 concentrations and chemical compositions.The Positive Matrix Factorization (PMF) model,which is recommended by the US Environmental Protection Agency,was employed to quantitatively analyze the contribution of each potential sources to personal levels of PM2.5 exposure.Results In both summer and winter,the model identified the same six sources of personal exposure to PM2.5 in the elderly:fugitive dust (marker species:Si,Al,Ca,Mg,Fe etc.),coal combustion emissions (marker species:organic carbon (OC) and SO42-),vehicle exhausts (marker species:inorganic carbon and NO3),secondary sulfates and nitrates (marker species:NO3-,SO42-and NH4 +),industrial emissions (marker species:Mn,Ni,Cu,Zn,Pb etc.),and indoor sources (marker species:OC,K,Si,Al etc.).Among these six potential sources,vehicle exhausts (summer:33.6％,winter:24.2％),secondary sulfates and nitrates (summer:27.4％,winter:29.1％),as well as coal combustion emissions (summer:19.9％,winter:24.1％) were the greatest contributors.Conclusions Coal combustion and vehicle exhaust emissions were the major sources of personal exposure to PM2.5 in the elderly,suggesting that these two sources were the key contributors to the precursor gases of secondary sulfate and nitrate.Key Project of Chinese National Programs for Fundamental Research and Development (2011CB503801)

Objective To study the change of pancreatic microcirculation in the early phase of acute pancreatitis. Methods Literatures on acute pancreatitis and microcirculation were collected and reviewed.Results Pancreatic microcirculation has changed in the early phase of acute pancreatitis, including contraction of interlobular arteriole, slowing of blood fluid, increasing of pancreatic vascular permeability, leukocyte adherence in postcapillary venules, and decreasing of pancreatic perfusion.Conclusion Impairment of pancreatic microcirculation in the early phase of acute pancreatitis may play a key role in the progression of this disease.