Objective To understand the change in distribution and antimicrobial resistance of bacteria isolated from blood specimens of Hunan Province,and provide for the initial diagnosis and treatment of clinical bloodstream infection(BSI).Methods Data reported from member units of Hunan Province Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacterial antimicrobial resistance surveillance method was imple-mented according to the technical scheme of China Antimicrobial Resistance Surveillance System(CARSS).Bacteria from blood specimens and bacterial antimicrobial susceptibility testing results were analyzed by WHONET 5.6 soft-ware and SPSS 27.0 software.Results A total of 207 054 bacterial strains were isolated from blood specimens from member units in Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021,including 107 135(51.7％)Gram-positive bacteria and 99 919(48.3％)Gram-negative bacteria.There was no change in the top 6 pathogenic bacteria from 2012 to 2021,with Escherichia coli(n=51 537,24.9％)ranking first,followed by Staphylococcus epidermidis(n=29 115,14.1％),Staphylococcus aureus(n=17 402,8.4％),Klebsiella pneu-moniae(17 325,8.4％),Pseudomonas aeruginosa(n=4 010,1.9％)and Acinetobacter baumannii(n=3 598,1.7％).The detection rate of methicillin-resistant Staphylococcus aureus(MRSA)decreased from 30.3％in 2015 to 20.7％in 2021,while the detection rate of methicillin-resistant coagulase-negative Staphylococcus(MRCNS)showed an upward trend year by year(57.9％-66.8％).No Staphylococcus was found to be resistant to vancomy-cin,linezolid,and teicoplanin.Among Gram-negative bacteria,constituent ratios of Escherichia coli and Klebsiella pneumoniae were 43.9％-53.9％and 14.2％-19.5％,respectively,both showing an upward trend(both P＜0.001).Constituent ratios of Pseudomonas aeruginosa and Acinetobacter baumannii were 3.6％-5.1％and 3.0％-4.5％,respectively,both showing a downward trend year by year(both P＜0.001).From 2012 to 2021,resistance rates of Escherichia coli to imipenem and ertapenem were 1.0％-2.0％and 0.6％-1.1％,respectively;presenting a downward trend(P＜0.001).The resistant rates of Klebsiella pneumoniae to meropenem and ertapenem were 7.4％-13.7％and 4.8％-6.4％,respectively,presenting a downward trend(both P＜0.001).The resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannii to carbapenem antibiotics were 7.1％-15.6％and 34.7％-45.7％,respectively.The trend of resistance to carbapenem antibiotics was relatively stable,but has de-creased compared with 2012-2016.The resistance rates of Escherichia coli to the third-generation cephalosporins from 2012 to 2021 were 41.0％-65.4％,showing a downward trend year by year.Conclusion The constituent ra-tio of Gram-negative bacillus from blood specimens in Hunan Province has been increasing year by year,while the detection rate of carbapenem-resistant Gram-negative bacillus remained relatively stable in the past 5 years,and the detection rate of coagulase-negative Staphylococcus has shown a downward trend.

Objective To investigate changes in the distribution and antimicrobial resistance of bacteria isolated from cerebrospinal fluid(CSF)specimens in Hunan Province,and provide reference for correct clinical diagnosis and rational antimicrobial use.Methods Data reported by member units of Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021 were collected according to China Antimicrobial Resistance Surveillance Sys-tem(CARSS)technical scheme.Data of bacteria isolated from CSF specimens and antimicrobial susceptibility tes-ting results were analyzed with WHONET 5.6 and SPSS 20.0 software.Results A total of 11 837 bacterial strains were isolated from CSF specimens from member units of Hunan Province Antimicrobial Resistance Surveillance Sys-tem from 2012 to 2021.The top 5 strains were coagulase-negative Staphylococcus(n=6 397,54.0％),Acineto-bacter baumannii(n=764,6.5％),Staphylococcus aureus(n=606,5.1％),Enterococcus faecium(n=465,3.9％),and Escherichia coli(n=447,3.8％).The detection rates of methicillin-resistant coagulase-negative Staphyloco-ccus(MRCNS)and methicillin-resistant Staphylococcus aureus(MRSA)were 58.9％-66.3％and 34.4％-62.1％,respectively.No Staphylococcus spp.were found to be resistant to vancomycin,linezolid,and teicoplanin.The de-tection rate of Enterococcus faecium was higher than that of Enterococcus faecalis,and the resistance rates of En-terococcus f aecium to penicillin,ampicillin,high concentration streptomycin and levofloxacin were all higher than those of Enterococcus faecalis(all P=0.001).Resistance rate of Streptococcus pneumoniae to penicillin was 85.0％,at a high level.Resistance rate of Escherichia coli to ceftriaxone was＞60％,while resistance rates to enzyme inhibitors and carbapenem antibiotics were low.Resistance rate of Klebsiella pneumoniae to ceftriaxone was＞60％,to en-zyme inhibitors piperacillin/tazobactam and cefoperazone/sulbactam was＞30％,to carbapenem imipenem and me-ropenem was about 30％.Resistance rates of Acinetobacter baumannii to most tested antimicrobial agents were＞60％,to imipenem and meropenem were 59.0％-79.4％,to polymyxin B was low.Conclusion Among the bac-teria isolated from CSF specimens,coagulase-negative Staphylococcus accounts for the largest proportion,and the overall resistance of pathogenic bacteria is relatively serious.Bacterial antimicrobial resistance surveillance is very important for the effective treatment of central nerve system infection.

Objective To investigate the distribution and antimicrobial susceptibility of clinically isolated bacteria from intensive care units(ICUs)in hospitals of Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021.Methods According to China Antimicrobial Resistance Surveillance System,data of clinically isolated bacterial strains and antimicrobial susceptibility testing results of bacteria from ICUs reported by all member units of Hunan Province Antimicrobial Resistance Surveillance System were analyzed with WHONET 2022 software.Results From 2012 to 2021,the total number of bacteria isolated from ICUs of member units of the Hunan Province Antimi-crobial Resistance Surveillance System was 5 777-22 369,with Gram-negative bacteria accounting for 76.1％-78.0％annually.Staphylococcus aureus ranked first among isolated Gram-positive bacteria each year.The top 5 bacteria among Gram-negative bacteria were Acinetobacter baumannii,Klebsiella pneumoniae,Escherichia coli,Pseudo-monas aeruginosa,and Stenotrophomonas maltophilia.Detection rate of methicillin-resistant Staphylococcus aureus showed a downward trend year by year.No Staphylococcus spp.were found to be resistant to vancomycin,teico-planin and linezolid.Detection rates of vancomycin-resistant Enterococcus faecalis and vancomycin-resistant Entero-coccus faecium were 0.6-1.1％and 0.6％-2.2％,respectively.Resistance rates of Escherichia coli and Kleb-siella pneumoniae to imipenem were 3.1％-5.7％and 7.7％-20.9％,respectively.Resistance rates of Pseudo-monasaeruginosa and Acinetobacter baumannii to imipenem were 24.6％-40.1％and 76.1％-80.9％,respective-ly.Detection rates of carbapenem-resistant Pseudomonas aeruginosa declined year by year.Acinetobacter baumannii maintained high susceptibility to polymyxin B,with resistance rate＜10％.Conclusion Antimicrobial resistance of bacteria from ICUs is serious.Carbapenem-resistant Enterobacteriales has an upward trend after 2019.It is nece-ssary to strengthen the surveillance of bacterial resistance and carry out multidisciplinary collaboration.

Objective To understand the antimicrobial resistance of clinically isolated Enterococcus spp.in Hunan Province.Methods Surveillance data of Enterococcus spp.resistance from member units of Hunan Provincial Anti-microbial Resistance Surveillance System from 2012 to 2021 were collected.Data were cleaned according to a unified method,and WHONET 5.6 software was adopted for statistical analysis.Results From 2012 to 2021,a total of 110 652 non-repetitive Enterococcus spp.strains were included in the analysis,mainly Enterococcus faecalis and Enterococcus faecium,accounting for 46.9％(n=37 774)and 45.9％(n=36 968),respectively,followed by En-terococcus avium(2.5％,n=1 982),Enterococcus gallinarum(1.8％,n=1 428),and Enterococcus casseliflavus(1.5％,n=1 185).The main specimen sources of Enterococcus spp.was urine(51.8％,n=57 350),followed by secretions(9.6％,n=10 660)and bile(8.5％,n=9 377).From 2012 to 2021,the resistance rates of Enteroco-ccus faecalis to ampicillin,teicoplanin,and vancomycin were 5.5％-12.0％,1.3％-2.0％,and 0.6％-1.4％,respectively.The resistance rates of Enterococcus faecium to ampicillin,teicoplanin,and vancomycin were 69.2％-85.0％,1.5％-2.8％,and 0.7％-2.5％,respectively.Except for linezolid and minocycline,the resistance rates of Enterococcus faecium to tested antimicrobial agents were all higher than those of Enterococcus faecalis.The re-sistance rates of Enterococcus faecalis and Enterococcus faecium to vancomycin decreased from 1.4％and 2.1％in 2012 to 0.6％and 0.7％in 2021,respectively,presenting a decreased trend.Conclusion Clinically isolated En-terococcus spp.maintain high antimicrobial susceptibility to vancomycin and teicoplanin.Resistance rates of Entero-coccus faecalis and Enterococcus faecium to vancomycin present decreased trends.

Objective To analyze the distribution and changing trend of antimicrobial resistance of bacteria isolated from bile from Hunan Province Antimicrobial Resistance Surveillance System.Methods Data of pathogens isolated from bile from Hunan Province Antimicrobial Resistance Surveillance System from 2012 to 2021 were collected.The constituent of bacteria and antimicrobial susceptibility testing results were analyzed by WHONET 5.6 software.Changes in antimicrobial resistance was analyze by trend chi-square test.Results The major pathogenic bacteria isolated from bile were Gram-negative bacteria,accounting for 70.84％.The top three isolated Gram-negative pathogens were Escherichia coli(30.14％),Klebsiella pneumoniae(12.15％),and Pseudomonas aeruginosa(5.18％),and the top two Gram-positive bacteria were Enterococcus faecium(10.34％)and Enterococcus faecalis(9.52％).The resistance rates of Klebsiella pneumoniae and Escherichia coli to imipenem were highest in 2012-2013,being 15.7％and 14.9％,respectively,presenting an downward trend(P＜0.05);resistance rates to piperacillin/tazobactam and cefoperazone/sulbactam were＜24％,presenting an upward trend year by year(P＜0.05);the sus-ceptibility rate to amikacin was＞94％,to levofloxacin and ciprofloxacin was 15.5％-65.2％.The highest resis-tance rate of Pseudomonas aeruginosa to imipenem(32.0％)was higher than that of meropenem(22.9％),resis-tance rates to piperacillin/tazobactam and cefoperazone/sulbactam were＜19％.The highest resistance rates of Acinetobacter baumannii to imipenem and meropenem were 59.4％and 62.6％,respectively,resistance rate to cefo-perazone/sulbactam was＜48％,presenting an upward trend(P＜0.05);the highest resistance rate to ciprofloxa-cin(60.8％)was higher than levofloxacin(48.7％);resistance rate to tigecycline was＜8％.The resistance rates of Enterococcus faecium to penicillin and ampicillin were both higher than those of Enterococcus faecalis,presenting an upward trend(P＜0.05).Resistance rate of Enterococcus faecium to vancomycin was lower than that of Entero-coccus faecalis.The resistance rates of Enterococcus faecium to vancomycin and linezolid were 0.5％-4.5％and 0.5％-3.4％,respectively;resistance rates of Enterococcus faecalis to vancomycin and linezolid were 0.2％-1.7％and 0.5％-3.5％,respectively(both P＜0.05),all presenting a downward trend(all P＜0.05).Conclusion Pathogenic bacteria isolated from bile are mainly related to the intestinal flora.The resistance rates of Enterococcus faecalis and Enterococcus faecium to vancomycin and linezolid as well as resistance rate of Enterobacterales to car-bapenem antibiotics all present a downward trend.

Objective To understand the antimicrobial resistance of Escherichia spp.from member units of Hu-nan Province Antimicrobial Resistance Surveillance System from 2012 to 2021.Methods According to the technical scheme of China Antimicrobial Resistance Surveillance System(CARSS),data about Escherichia spp.and the anti-microbial susceptibility testing results reported from member units of Hunan Province Antimicrobial Resistance Sur-veillance System were analyzed by WHONET 5.6 software.Results From 2012 to 2021,a total of 476 351 clini-cally isolated Escherichia spp.were collected,475 520 of which were Escherichia coli,accounting for 99.8％;92.6％were isolated from inpatients;39.3％were isolated from urine specimens.Over the past 10 years,the proportion of Escherichia spp.in total detected pathogens remained relatively stable,ranging 20％-23％,the lowest rate was 18.7％in 2012,and the highest rate was 22.9％in 2015.In the past 10 years,the resistance rates of Escherichia spp.to ampicillin,ceftriaxone,cefotaxime and ampicillin/sulbactam were＞80％,＞47％,＞45％,and＞39％,respectively;resistance rates to piperacillin/tazobactam,cefoperazone/sulbactam,and nitrofurantoin were all＜8％,to tigecycline,amikacin,imipenem,and meropenem(except in 2012)were all＜5％.Resistance of Escherichia spp.to 22 commonly clinically used antimicrobial agents fluctuated,but overall trend decreased year by year.The resistance rates of Escherichia spp.from patients in the intensive care unit(ICU),non-ICU patients,outpatients,and emergency patients to 22 clinically commonly used antimicrobial agents were compared among different depart-ments,and the differences were statistically significant(all P＜0.05).The resistance rates of Escherichia spp.iso-lated from ICU and non-ICU patients were compared,and except for tigecycline,the resistance rates to the other 21 antimicrobial agents were statistically different(all P＜0.05).The resistance rates of Escherichia spp.isolated from patients to commonly clinically used antimicrobial agents were statistically different among patients of different age groups(all P＜0.05).Conclusion Escherichia spp.isolated from patients in different years,departments,specimens,and ages have different resistance to commonly used antimicrobial agents.It is necessary to continue to strengthen the surveillance on bacterial resistance,so as to guide the rational choice of antimicrobial agents.

Objective To understand the distribution of frequently isolated pathogenic bacteria from clinical speci-mens and their antimicrobial resistance changes in Hunan Province from 2012 to 2021,and to provide scientific evi-dence for the formulation and evaluation of antimicrobial clinical administration policies.Methods Species identifi-cation,selection of quality control strains and antimicrobial susceptibility testing agents were conducted according to the technical scheme of the China Antimicrobial Resistance Surveillance System(CARSS).Duplicate strains were excluded based on the principle of counting the first strain in each case.Statistical analysis was performed by WHO-NET 5.6 software.The the variations in constituent ratio and resistance rate of strains were analyzed with linear trend test,and the magnitude of change was described with Pearson correlation coefficient.Results From 2012 to 2021,the number of clinically isolated bacteria in the analysis increased from 82 759 to 312 914,with Gram-negative bacteria accounting for 69.5％-72.4％.The major Gram-positive bacteria were Staphylococcus aureus,Staphylo-coccus epidermidis,Streptococcus pneumoniae,Enterococcus faecalis and Enterococcus faecium,and the major Gram-negative bacteria were Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa,Acinetobacter baumannii and Enterobacter cloacae.Isolation rate of Gram-positive bacteria increased yearly(r=0.022,P=0.001).Isolation rate of methicillin-resistant Staphylococcus aureus(MRSA)decreased from 34.3％to 24.8％.Isolation rates of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis were less than 3％and 2％,respectively,presenting a downward trend.The detection rate of penicillin-resistant Streptococcus pneumoniae(PRSP)decreased from 5.6％to 1.0％.Except cefoperazone sulbactam,resistance rates of Escherichia coli to other tested antimicrobial agents showed decreasing trends(r＜0,P=0.001).Isolation rates of third-generation cephalo-sporin-resistant Escherichia coli(CTX/CRO-R-EC)and carbapenem-resistant Escherichia coli(CREC)decreased year by year(from 70.5％to 45.3％,and 12.2％to 2.0％,respectively).Resistance rates of Klebsiella pneumo-niae to imipenem and meropenem have increased year by year,reaching 9.1％and 11.0％respectively in 2021,while isolation rate of carbapenem-resistant Pseudomonas aeruginosa(CRPA)decreased from 28.5％to 15.0％.Resistance rates of Acinetobacter baumannii to most antimicrobial agents were 40％-60％,and remained relatively stable.Isolation rate of carbapenem-resistant Acinetobacter baumannii(CRAB)ranged from 39.5％ to 59.6％.Conclusion The clinical isolation rates of most important special antimicrobial-resistant bacteria have been decrea-sing year by year,while the resistance rate of Klebsiella pneumoniae to carbapenem agents gradually increased.Antimicrobial stewardship as well as the prevention and control of healthcare-associated infection on specific antimi-crobial-resistant bacteria should continue to be implemented in the future.The coverage and quality of antimicrobial resistance surveillance in H unan Province should continue to be improved.

Objective To understand the distribution and antimicrobial resistance changes of bacteria isolated from pleural and peritoneal effusion in Hunan Province,and provide reference for correct clinical diagnosis and rational antimicrobial use.Methods Data reported by member units of Hunan Provincial Antimicrobial Resistance Survei-llance System from 2012 to 2021 were collected.Bacteria antimicrobial resistance surveillance method was imple-mented according to technical scheme of China Antimicrobial Resistance Surveillance System(CARSS),and WHO-NET 5.6 software was used to analyze the data of bacteria isolated from pleural and peritoneal effusion as well as antimicrobial susceptibility testing results.Results From 2012 to 2021,a total of 28 934 bacterial strains were iso-lated from specimens of pleural and peritoneal effusions from member units of Hunan Provincial Antimicrobial Re-sistance Surveillance System,with 5 752 strains from pleural effusion and 23 182 from peritoneal effusion.The top five bacteria isolated from pleural effusion were Escherichia coli(n=907,15.8％),Staphylococcus aureus(n=535,9.3％),Klebsiella pneumoniae(n=369,6.4％),Staphylococcus epidermidis(n=452,7.9％),and Staphy-lococcus haemolyticus(n=285,5.0％).The detection rate of methicillin-resistant Staphylococcus aureus(MR-SA)from pleural effusion was 24.3％-39.2％,and that of methicillin-resistant coagulase negative Staphylococcus(MRCNS)was 58.8％-77.1％.The top five bacteria isolated from peritoneal effusion were Escherichia coli(n=8 264,35.6％),Klebsiella pneumoniae(n=2 074,9.0％),Enterococcus faecium(n=1 458,6.3％),Staphylo-coccus epidermidis(n=1 383,6.0％),and Pseudomonas aeruginosa(n=1 152,5.0％).The detection rate of MRSA from peritoneal effusion was 22.1％-52.4％,which presented a decreasing trend(P=0.004).The detec-tion rate of MRCNS was 60.4％-79.4％.The resistance rates of Enterobacterales from peritoneal effusion to ce-fazolin,cefuroxime,ceftriaxone and cefepime all showed decreasing trends(all P＜0.05).Vancomycin-,linezo-lid-,and teicoplanin-resistant Staphylococcus strains were not found in pleural and peritoneal effusions.The resis-tance rates of Enterococcus faecium to most tested antimicrobial agents were higher than those of Enterococcus fae-calis.The resistance rates of Enterobacterales to imipenem and meropenem were ≤8.5％.The resistance rates of non-fermentative Gram-negative bacilli to imipenem and meropenem were ≤43.3％.Conclusion The data structure of Hunan Antimicrobial Resistance Surveillance System for pleural and peritoneal effusions from 2012 to 2021 is relatively complete.The constituent and antimicrobial susceptibility of isolated pathogenic bacteria vary in different years.

Objective To understand the distribution and changes in antimicrobial resistance of clinically isolated Pseudomonas aeruginosa(P.aeruginosa)in the member hospitals of Hunan Provincial Antimicrobial Resistance Surveillance System from 2012 to 2021.Methods Antimicrobial susceptibility testing by disk diffusion or automa-ted instrument was performed on clinical isolates.Testing results were determined according to the standards of 2022 edition from American Clinical Laboratory Standards Institute(CLSI).Statistical analysis was performed by WHONET 5.6 software.Data were analyzed by trend test(Cochran-armitage)and Chi-square test with SPSS.Results A total of 176 441 strains of P.aeruginosa were surveilled by Hunan Provincial Antimicrobial Resistance Surveillance System from 2012 to 2021.99.4％of the strains were isolated from hospitalized patients,and about 70％of the strains were isolated from respiratory specimens.8.4％of P.aeruginosa were from children(0-17 years old),91.6％were from adults.Antimicrobial susceptibility testing results showed that P.aeruginosa was most sensitive to polymyxin B over 10 years,with a resis-tance rate of less than 6％.Resistance rates to piperacil-lin,piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,imipenem,amikacin,gentamicin,tobramycin,cip-rofloxacin,levofloxacin,and polymyxin B all showed downward trends.A total of 29 920 carbapenem-resistant P.aeruginosa(CRPA)strains were detected.The average isolation rate of CRPA in this province was 18.0％over 10 years.CRPA detection rate from adult was 18.5％,higher than that from children(12.3％),and both showing downward trends.Conclusion The resistance rate of clinically isolated P.aeruginosa in Hunan Province to most commonly used antimicrobial agents is decreasing.

Objective To understand the epidemiology of clinically isolated Acinetobacter baumannii(A.bauma-nnii)in Hunan Province.Methods Bacterial antimicrobial resistance surveillance was carried out according to the requirements of the technical program of National Antimicrobial Resistance Surveillance System.Clinical data of Acinetobacter spp.reported to Hunan Provincial Antimicrobial Resistance Surveillance System by multiple centers in Hunan Province from 2012 to 2021 were summarized and analyzed with reference to the standards of the American Clinical and Laboratory Standards Institute.Results A total of 169 438 strains of Acinetobacter spp.were detected during the 10-year period,with the detection rate of A.baumannii being the highest(82.74％).70 923 strains(53.63％)of carbapenem-resistant A.baumannii(CRAB)and 58 149 strains(43.97％)of carbapenem-sensitive A.baumannii(CSAB)were detected respectively.Both CRAB and CSAB were detected most frequently in the age group＞70 years,which were 34.44％and 32.02％,respectively.The percentage of CRAB and CSAB detected in the intensive care unit were 34.80％and 11.31％,respectively.CRAB and CSAB were mainly isolated from spu-tum/bronchoalveolar lavage fluid,followed by pus/secretion,urine,and blood.The resistance rates of CRAB to commonly used antimicrobial agents didn't change much during the 10-year period.Resistance rates of CRAB to ceftazidime and cefepime were both＞84％,to ampicillin/sulbactam and piperacillin/tazobactam were both＞82％,to aminoglycosides and quinolones were both＞59％,to minocycline and polymyxin B were 15.9％-25.0％and 1.3％-6.9％,respectively.CSAB were sensitive to commonly used antimicrobial agents.Conclusion The isolation rate of CRAB is high and there is no significant change in resistance to commonly used antimicrobial agents.