Objective To determine the genetic background and evolutional route of macrolideresistance Streptococcus pneumoniae(MRSP)strains in Shanghai.Methods Forty-seven MRSP clinical isolates were genotyped by pulse field gel electrophoresis(PFGE)to detect the donal relationship of therm.Serotyping and muhilocus sequence typing(MIST)on 6 multi-resistant strains wag used to investigate the evolutional relationship between serum types and international epidemic strain among MRSP strains in Shanghai.Results There were 2 epidemical clones(type A 45%,type B 17%)in MRSP clinical isolates containing both the ermB and the mefE genes in Shanghai.MIST analysis showed that all 6 multi-resistant strains whose PFGE pattern was A type belonging to Asia clonal complex-CC236(Taiwan19F-14 clone).There was a novel ST-ST2116,which might derived from CC236 due to the recombination with alldic change.Conclusion,The high prevalence of erythromycin-resistant Streptococcus pneumoniae containing both the ermB and the mere genes in Shanghai is partly due to the clonal spread of a few mtdtidrng-resistant clones.

Objective To investigate the effects of intensive antihypertensive treatment and guidelinerecommended standard blood pressure control on early reperfusion and outcomes after intravenous recombinant tissue plasminogen activator (rtPA) thrombolysis in patients with acute ischemic stroke.Methods A total of 50 patients with acute ischemic stroke (systolic blood pressure,150-185 mmHg;1 mmHg=0.133 kPa) and received intravenous rtPA therapy were enrolled prospectively.They were randomly divided into either a intensive antihypertensive treatment group or a guideline antihypertensive treatment group.In the the intensive antihypertensive treatment group,systolic blood pressure was decreased to 140-150 mmHg in 60 min for at least 72 h.In the guideline antihypertensive treatment group,systolic blood pressure was decreased to the target value ＜ 180 mmHg according to the guideline recommendation.Multi-mode MRI was completed at 24 h before and after thrombolysis.The primary endpoints were the modified Rankin Scale (mRS) score at day 90 and the mortality at day 90;the secondary endpoints were the early reperfusion rate in ischemic brain tissue,recanalization rate,and incidence of symptomatic intracranial hemorrhage.Results There was no significant difference in demographics and baseline data between the 2 groups.Within 24,48,and 72 h after thrombolysis the mean systolic blood pressure in the intensive antihypertensive treatment group was significantly lower than those in the guideline antihypertensive treatment group,while there was no significant difference in diastolic blood pressure.There were no significant differences in favorable outcome rate at day 90 (mRS score 0-2:68％ vs.64％;x2 =0-089,P=0.765),mortality (4％ vs.12％;x2 =1.087,P=0.297),incidence of symptomatic intracranial hemorrhage (4％ vs.8％;x2 =0.355,P =0.552),reperfusion rate after thrombolysis (76％ vs.68％;x2 =0.397,P =0.529),and recanalization rate (56％ vs.52％;x2 =0.081,P =0.777) between the intensive antihypertensive treatment group and the guideline antihypertensive treatment group.Conclusions Early intensive antihypertensive treatment in patients with acute ischemic stroke received intravenous rtPA thrombolysis does not have adverse effect on reperfusion rate,and does not increase the risk of death or disability either.

Objective To investigate the susceptibility profile of clinical isolates collected from hospitals across China.Methods Twenty-six general hospitals and four children's hospitals were involved in this program.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were analyzed according to CLSI 2016 breakpoints.Results A total of 153 059 clinical isolates were collected from Junuary to December 2016,of which gram-negative organisms and gram-positive cocci accounted for 71.6％ and 28.4％,respectively.The overall prevalence of methicillin-resistant strains was 38.4％ in S.aureus (MRSA) and 77.6％ in coagulase negative staphylococcus (MRCNS),respectively.The resistance rates of methicillin-resistant strains to most of other antimicrobial agents were much higher than those of methicillin-susceptible strains.However,92.3％ of the MRSA strains were still sensitive to trimethoprim-sulfamethoxazole,while 86.5％ of the MRCNS strains were susceptible to rifampin.No staphylococcal strains were found resistant to vancomycin or teicoplanin.The resistance rates of E.faecalis strains to most drugs tested (except chloramphenicol) were much lower than those of E.faecium.A few strains of both species were resistant to vancomycin.Vancomycin resistant E.faecalis and E.faecium strains were mainly VanA,VanB or VanM type based on their phenotype or genotype.Regarding the non-meningitis S.pneumoniae strains,the prevalence of PSSP or PISP strains isolated from children was higher than that isolated in 2015,but the prevalence of PRSP strains decreased.However,the prevalence of PISP and PRSP strains isolated from adults was lower than that isolated in 2015.The prevalence of ESBLs-producing strains was 45.2％ in E.coli,25.2％ in Klebsiella spp.(K.pneumoniae and K.oxytoca) and 16.5％ in Proteus mirabilis isolates on average.ESBLs-producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rate.The strains of Enterobacteriaceae were still highly susceptible to carbapenems.Overall,less than 10％ of these strains were resistant to carbapenems.About 68.6％ and 71.4％ ofAcinetobacter spp.(A.baumannii accounts for 90.6％) strains were resistant to imipenem and meropenem,respectively.The prevalence of extensively-drug resistant strains in P.aeruginosa was higher than that in 2015.Conclusions Bacterial resistance to commonly used antibiotics is still on the rise.It is necessary to strengthen hospital infection control and management of clinical use of antimicrobial agents,and maintain good practice in surveillance of bacterial resistance.

Objective To investigate the resistance profile of clinical bacterial isolates to antibiotics in Shanghai during 2016.Methods Antimicobial susceptibility testing was carried out for the clinical isolates collected from 47 hospitals according to a unified protocol using Kirby-Bauer method or automated systems.The participating hospitals included 28 tertiary hospitals and 19 secondary hospitals across Shanghai.Results were analyzed according to CLSI 2016 breakpoints.Results A total of 122 548 clinical isolates were collected,including 35 522 (29.0％) strains of gram positive cocci and 87 026 (71.0％) strains of gram negative bacilli.Overall,28.9％ of the isolates were from secondary hospitals and 71.1％ from tertiary hospitals.Gram positive and gram negative isolates accounted for 25.8％ and 74.2％ in secondary hospitals,30.3％ and 69.7％ in tertiary hospitals,respectively.The overall prevalence of MRSA in Staphylococcus aureus was 48.7％ and 77.2％ of MRCNS in coagulase-negative Staphylococcus.The average prevalence of MRSA and MRCNS was 55.9％ and 73.3％ in secondary hospitals,45.9％ and 78.6％ in tertiary hospitals.No strains were found resistant to vancomycin in Staphylococcus.About 77.4％ of the 1 111 strains of non-meningitis S.pneumoniae isolated from children were penicillin-susceptible (PSSP),13.2％ were penicillin-intermediate (PISP) and 9.4％ were penicillinresistant (PRSP).The prevalence of PSSP,PISE and PRSP was 97.8％,2.2％,and 0 in secondary hospitals,76.5％,13.7％,and 9.8％ in tertiary hospitals.Of the 285 strains isolated from adults,94.0％,4.2％ and 1.8％ were PSSP,P1SP and PRSP,respectively.The prevalence of PSSP,PISP and PRSP among the isolates from adults was 93.7％,5.3％,and 1.0％ in secondary hospitals,94.2％,3.7％,and 2.1％ in tertiary hospitals.Overall,37 strains of vacomycin-resistant E.feacium (14 from secondary hospitals and 23 from tertiary hospitals) and 25 strains of vacomycin-resistant E.feacalis (all from tertiary hospitals) were identified.PCR and sequencing analysis indicated that most of these resistant strains were vanA type.The overall prevalence of ESBLs-producing srains was 52.2％ in E.coli,30.9％ in Klebsiella pneumoniae and 29.8％ in Proteus mirabilis.Specifically,the corresponding prevalence of such strains was 55.1％,33.6％ and 34.0％ in secondary hospitals,51.0％,29.7％ and 28.0％ in tertiary hospitals,respectively.Enterobacteriaceae strains were still highly susceptible to carbapenem antibiotics.Overall,8.9％ and 9.1％ of the Enterobacteriaceae strains were resistant to imipenem and meropenem,respectively.The figure was 6.6％ and 7.1％ in secondary hospitals,9.9％ and 10.0％ in tertiary hospitals.Extensively drug-resistant strains were identified in A.baumannii,K.pneumoniae,P.aeruginosa,and E.coli,specifically,223,63,10,and 4 strains in secondary hospitals;224,201,22,and 9 strains in tertiary hospitals.Conclusions Antibicotic resistance is still very serious in the common clinical strains,which poses a critical threat to healthcare facilities.This issue should be taken seriously and effective infection control measures must be put in place.

Objective To investigate the susceptibility and resistance of clinical isolates from hospitals in several regions of China .Methods Fifteen general hospitals and two children′s hospitals were involved in this program . Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby‐Bauer method or automated systems .Results were analyzed according to CLSI 2014 breakpoints .Results A total of 78 955 clinical isolates were collected from January to December 2014 ,of which gram negative organisms and gram positive cocci accounted for 72 .6% and 27 .4% ,respectively . Methicillin‐resistant strains in S .aureus(MRSA)and coagulase negative Staphylococcus(MRCNS)accounted for an average of 44 .6% and 83 .0 % ,respectively .The resistance rates of methicillin‐resistant strains to β‐lactams and other antimicrobial agents were much higher than those of methicillin‐susceptible strains .However ,92 .0% of MRSA strains were still susceptible to trimethoprim‐sulfamethoxazole ,while 85 .6% of MRCNS strains were susceptible to rifampin .No staphylococcal strains were found resistant to vancomycin ,teicoplanin or linezolid .In Enterococcus spp .,the resistance rates of E .f aecalis strains to most tested drugs (except chloramphenicol) were much lower than those of E . f aecium .Some strains of both species were resistant to vancomycin .Vancomycin resistant strains of E . f aecalis and E . f aecium were mainly V anA ,V anB or V anM type based on their phenotype or genotype .Regarding non‐meningitis S .pneumoniae strains ,the prevalence of penicillin‐susceptible S .pneumoniae strains isolated from both adults and children were higher than those isolated in 2013 ,but the prevalence of penicillin‐intermediate S . pneumoniae or penicillin‐resistant S . pneumoniae strains decreased . The prevalence of ESBLs producingstrainswas55.8% in E.coliand29.9% in Klebsiellaspp.(K.pneumoniaeand K.oxytoca)and24.0% in Proteus mirabilis isolates on average . ESBLs‐producing Enterobacteriaceae strains were more resistant than non‐ESBLs‐producing strains in terms of antibiotic resistance rates . The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 10 % of these strains were resistant to carbapenems . About 62 .4% and 66 .7% of Acinetobacter spp .(A .baumannii accounts for 93 .0 % ) strains were resistant to imipenem and meropenem ,respectively . Compared with the data of year 2013 ,extensively‐drug resistant strains in K . pneumoniae and A .baumannii increased . Conclusions The antibiotic resistance of clinical bacterial isolates is growing .The disseminated multi‐drug or pan‐drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .

Objective To investigate the susceptibility and resistance of clinical isolates collected from hospitals in several regions of China . Methods Fourteen general hospitals and two children ’ s hospitals were involved in this program . Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated Systems .Results were analyzed according to CLSI 2013 breakpoints .Results A total of 84 572 clinical isolates were collected from January to December 2013 ,of which gram negative organisms and gram positive cocci accounted for 73 .0% and 27 .0%respectively .Methicillin-resistant strains in S .aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) accounted for an average of 45 .2% and 73 .5% respectively .The resistance rates of methicillin-resistant strains to β-lactams and other antimicrobial agents were much higher than those of methicillin-susceptible strains .However ,92 .2% of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole while 87 .4% of MRCNS strains were susceptible to rifampin . No staphylococcal strains were found resistant to vancomycin ,teicoplanin or linezolid .In Enterococcus spp .,the resistance rates of E . f aecalis strains to most tested drugs (except chloramphenicol) were much lower than those of E . f aecium .Some strains of both species were resistant to vancomycin .Vancomycin-resistant strains of E . f aecalis and E . f aecium were mainly VanA type based on their phenotype .Regarding non-meningitis S . pneumoniae strains ,the prevalence of penicillin-susceptible S . pneumoniae and penicillin-intermediate S . pneumoniae strains isolated from both adults and children were lower than those isolated in 2012 ,but the prevalence of penicillin-resistant S .pneumoniae strains increased .The prevalence of ESBLs producing strains was 54 .0% in E .coli ,31 .8% in Klebsiella spp .(K .pneumoniae and K .oxytoca) and 16 .5% in Proteus mirabilis isolates on average . ESBLs-producing Enterobacteriaceae strains were more resistant than non-ESBLs-producing strains in terms of antibiotic resistance rates .The strains of Enterobacteriaceae were still highly susceptible to carbapenems .Overall less than 7 .0% of these strains were resistant to carbapenems .About 62 .8% and 59 .4% of Acinetobacter spp .(A .baumannii accounts for 89 .2% ) strains were resistant to imipenem and meropenem ,respectively .Compared with the data of year 2012 , extensively-drug resistant strains in K . pneumoniae and A . baumannii decreased .Conclusions The antibiotic resistance of clinical bacterial isolates is growing in 2013 .The disseminated multi-drug or pan-drug resistant strains in a special region poses a serious threat to clinical practice and implies the importance of strengthening infection control .

Objective To evaluate the changing pattern of antibiotic resistance inKlebsiella strains isolated from the patients in 19 hospitals across China based on the data from CHINET Antimicrobial Resistance Surveillance Program during the period from 2005 through 2014.Methods Kirby-Bauer disk diffusion and automated susceptibility testing methods were used to test the susceptibility ofKlebsiella isolates to the commonly used antibiotics. The results were interpreted according to the criteria of the Clinical and Laboratory Standards Institute (CLSI) Performance Standards for Antimicrobial Susceptibility Testing (CLSI-2014).Results A total of 61 406Klebsiella strains were identified between 2005 and 2014, includingK. pneumoniae (56 281 strains), K. oxytoca(4 779),Klebsiella pneumoniae subsp.Ozaenae (300) and otherKlebsiella species (46). Most (89.0%, 54 664/61 406) of theKlebsiella strains were isolated from inpatients, and 60.0% (36 835/61 406) were from respiratory tract speciems. About 16.7% (10 248/61 406) of the strains were isolated from pediatric patients aged 0-17 years and 83.3% (51 158/61 406) from adult patients. The prevalence ofKlebsiella spp. increased with time from 10.1% in 2005 to 14.3% in 2014. Based on the surveillance data during the 10-year period, we found a marked increase of resistance to imipenem (2.9% to 10.5%) and meropenem (2.8% to 13.4%) inKlebsiella spp. The prevalence of ESBLs-producing isolates inK. pneumoniae andK. oxytoca decreased from 39.0% in 2005 to 30.1% in 2014. The resistance to amikacin, ceftazidime, ciprolfoxacin, pipracillin-tazobactam and cefoperazone-sulbactam was on decline. The resistance rate to cefotaxime remained high about 49.5%. Carbapenem resistantance was identiifed in 5 796 (9.4%) of the isolates, including 5 492 strains ofK. pneumoniae and 280 strains ofK. oxytoca. Overall, 4 740 (7.8%) strains were identiifed as extensively-drug resistant (XDR), including 4 520 strains ofK. pneumoniae and 202 strains ofK. oxytoca. The carbapenem-resistant strains showed high (>60%) resistance rate to majority of the antimicrobial agents tested, but relatively low resistance to tigecycline (16.8%), amikacin (54.4%), and trimethoprim-sulfamethoxazole (55.5%).Conclusions During the 10-year period from 2005 through 2014, carbapenem resistance amongKlebsiella isolates has increased dramatically in the hospitals across China. The level of resistance to other antibiotics remains stable.

Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.