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Objective To investigate the spectrum and antimicrobial resistance of major pathogens causing nosocomial infections in China, 2016. Methods Non-duplicated nosocomial cases as well as pathogens causing bloodstream infections ( BSI) , hospital-acquired pneumonia ( HAP) and intra-abdominal infections ( IAI ) from 12 teaching hospitals across China were collected. The minimum inhibitory concentrations (MICs) of important clinical common strains were determined by agar dilution method or broth microdilution method. The CLSI M100-S27 criteria was used for interpretation. Data were analyzed by using WHONET-5. 6 software. Results A total of 2060 cases were collected, including 894 cases from BSI, 630 cases from HAP and 536 cases from IAI. The MICs of 1896 important clinical common strains were determined. Escherichia coli and Klebsiella pneumoniae were the most prevalent pathogens causing BSI and IAI, while Acinetobacter baumanii and Pseudomonas aeruginosa were dominated in HAP. All Staphylococcus aureus were susceptible to tigecycline, linezolid, daptomycin and glycopeptides. Methicillin-resistant S. aureus accounted for 44. 4％ ( 75/169 ) of all the S. aureus. The rate of methicillin-resistant coagulase-negative staphylococci was 80. 9％ ( 72/89 ) . No Enterococcus strains were found resistant to tigecycline, linezolid or daptomycin. Vacomycin resistant enterococcus was found in Enterococcus faecium, accounting for 1. 8％ ( 2/111 ) of all E. faecium strains. Tigecycline, meropenem, amikacin, imipenem, and polymyxin B exhibited high potency against Enterobacteriaceae and the susceptibility rates were 96. 6％(865/895), 94. 3％ (859/911), 94. 2％ (858/911), 94. 1％ (857/911), and 91. 6％ (820/895), respectively. The prevalence of extended-spectrum β-lactamase was 58. 4％ ( 263/450 ) in E. coli and 28. 6％ ( 84/294 ) in K. pneumonia. The rate of carbapenem resistant K. pneumonia and E. coli was 15. 3％ ( 45/294 ) and 1. 8％ ( 8/450 ) , respectively. The percentage of polymyxin B resistant K. pneumonia and E. coli was 4. 1％ ( 12/294 ) and 4. 4％ ( 20/450 ) , respectively. The rate of tigecycline resistant K. pneumonia and E. coli was 2. 4％ ( 7/294 ) and 0. 2％ ( 1/450 ) , respectively. A. baumanii showed low susceptibility to the antimicrobial agents except tigecycline ( 91. 4％, 235/257 ) and polymyxin B (100％, 257/257). The rate of carbapenem resistant A. baumanii was 80. 5％ (207/257). The rate of carbapenem resistant P. aeruginosa was 31. 7％ ( 59/186 ) . Polymyxin B and amikacin demonstrated high antibacterial activity against P. aeruginosa with susceptility rate of 100％ ( 186/186 ) and 90. 9％ ( 169/186), respectively. Conclusions Nosocomial pathogens showed high susceptibilities against tigecycline and polymyxin B. Antimicrobial resistance in A. baumannii is a serious problem. The prevalence of carbapenem-resistant Enterobacteriaceae and polymyxin B resistant Enterobacteriaceae has increased, which should be monitored continuously in China.
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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.
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Objective To investigate the molecular epidemiological characteristics of the Acinetobacter baumannii strains isolated from blood and sputum samples of patients with ventilator-associated pneumonia (VAP) in ICU.Methods The patients were analyzed in two groups:Group A,A.baumannii was isolated from both blood and sputum,and Group B,A.baumannii was isolated only from sputum.Clinical data of the patients were collected,including the results of antimicrobial susceptibility test.Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed for the strains.Results During the study period from June 2015 to December 2105,28 nonduplicate A.baumannii strains were collected from 14 patients in group A and 28 nonduplicate strains from 28 patients in group B.The 56 A.baumannii strains were multidrug-resistant (MDR).More than 80％ of the strains were resistant to carbapenem,third-generation cephalosporins or aminoglycoside,but highly sensitive to tigecycline.No significant difference was found for the resistance rates between group A and group B.The nonduplicate A.baumannii isolates from blood and sputum samples of the same patient in group A were all homologous strains confirmed by PFGE.Six pulsotypes were identified from the 28 strains in Group A and 9 pulsotypes in Group B.Five pulsotypes were shared between the two groups.MLST analysis showed that there were 9 ST types (ST195,ST208,ST229,ST369,ST373,ST457,ST836 and two new phenotypes ST N2,ST N5) in Group A and 8 ST types (ST195,ST208,ST381 and 5 new phenotypes ST N1,ST N2,ST N3,ST N4,ST N5) strains in group B.There was no significant difference in the proportion of the main ST types between the two groups.eBURST analysis indicated that ST195,ST208,ST457,ST369,ST N1,ST N2,ST N51 belonged to CC92 prevalent strain.Conclusions The antimicrobial susceptibility profile and genotype of A.baumannii isolates from blood and sputum samples are similar.There was CC92 prevalent strain in the ward.There is no direct relation between the risk factors for bloodstream infection in VAP patients and the genotype of A.baumannii strain.It is particularly important to reinforce infection control for prevention and treatment ofA.baumannii bloodstream infections.
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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.
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Objective To investigate the distribution and antibiotic resistance proifle of clinicalEnterobacter isolates using the data from CHINET during the period from 2005 through 2014.Methods A total of 20 558 clinical strains ofEnterobacter spp. were collected from 2005 to 2014 in CHINET Antimicrobial Resistance Surveillance Program. Antimicrobial susceptibility testing was performed with Kirby-Bauer or minimum inhibitory concentration method. The results were analyzed according to CLSI 2014 breakpoints.ResultsEnterobacter cloacae andEnterobacter aerogenes accounted for 71.1% (14 617/20558) and 20.1% (4 129/20 558) of all theEnterobacterisolates, respectively. The proportion ofEnterobacter spp. increased with time from 3.5% in 2005 to 4.3% in 2014. The main source of the isolates was respiratory tract, accounting for 55.2% (11 358/20 558). More than 90% of theEnterobacterisolates were resistant to cefazolin and cefoxitin, but less than 30% of the strains were resistant to cefepime, piperacillin-tazobactam, cefoperazone-sulbactam, amikacin, gentamicin, ciprolfoxacin, meropenem, imipenem and ertapenem. TheEnterobacterisolates showed a trend of declining resistance to most antibiotics except ertapenem and meropenem. The resistance proifle ofEnterobacterisolates varied with departments where they were isolated. The strains from ICU and Department of Surgery were relatively more resistant to antibiotics. The prevalence of multi-drug resistant (MDR) strains was decreasing, but the prevalence of carbapenem-resistantEnterobacter (CRE, resistant to any of imipenem, meropenem or ertapenem) was increasing. The MDR and CRE strains were primarily isolated from ICU and Department of Surgery. At least 30% of the MDREnterobacter strains were resistant to any of the antimicrobial agents tested except meropenem, imipenem and ertapenem and at least 35% of the CRE strains were resistant to any of the antimicrobial agents tested except amikacin and ciprolfoxacin.Conclusions TheEnterobacter isolates in CHINET Antimicrobial Resistance Surveillance Program showed decreasing resistance to most of the antimicrobial agents tested since 2011, but the prevalence of CRE strains increased progressively. Effective measures should be carried out to prevent the spread of CRE strains in hospitals.
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Objective To understand the changing resistance proifle ofProteus,Serratia,Citrobacter,Morganella andProvidencia in hospitals across China according to the data from CHINET Antimicrobial Resistance Surveillance Program 2005-2014.Methods Antimicrobial susceptibility was tested by using Kirby-Bauer method or automatic minimum inhibitory concentration determination according to a uniifed protocol.Results A total of 21 663 clinical isolates were collected from January 2005 to December 2014. The proportion ofProteus andSerratia isolates increased with time from 1.41% in 2005 to 2.09% in 2014, and from 0.99% in 2005 to 1.28% in 2014 among all the isolates. No change was found for the proportion ofCitrobacter,Morganella, orProvidencia. Less than 10% of theProteus isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, ceftazidime, cefoxitin, amikacin and tigecycline. Less than 10% of theSerratia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, amikacin and tigecycline. Less than 20% of theCitrobacter isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 10% of theMorganella isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, amikacin and tigecycline. Less than 20% of theProvidencia isolates were resistant to cefoperazone-sulbactam, piperacillin-tazobactam, cefepime, cefoxitin and tigecycline.Conclusions The antibiotic resistance ofProteus,Serratia, Citrobacter,Morganella andProvidencia isolates in hospitals across China is growing during the period from 2005 to 2014. Strengthening infection control and rational antibiotic use are effective to slow the growth of drug resistance.
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Objective To investigate the distribution and changing resistance proifle ofSalmonella isolates in hospitals across China during the period from January 2005 to December 2014.Methods Seventeen general hospitals and two children’s hospitals were involved in this program. Antimicrobial susceptibility testing was carried out by means of a unified protocol using Kirby-Bauer method or MIC determination. The results were analyzed according to CLSI 2014 breakpoints.Results The proportion ofSalmonella isolates increased with time from 0.2% in 2005 to 0.7% in 2014. A total of 3 478Salmonella strains were collected from 19 hospitals. The proportion ofSalmonella typhimurium andSalmonella enteritidis was 27.4% and 24.4%, respectively. During the 10-year period, theSalmonella strains showed highest resistance rate to ampicillin (33.3%-64.8%), but low resistance to cefoperazone-sulbactam (0-5.3%) and ciprofloxacin (2.4%-14.3%).S. typhimurium showed higher resistance rate thanS. typhi,S. paratyphi andS. enteritidis. About 76.8% and 50.5% ofS. typhimurium were resistant to ampicillin and trimethoprim-sulfamethoxazole. The average prevalence of multi-drug resistantSalmonellawas 3.9% in the ten-year period, the highest (7.5%) was in 2005, the lowest (1.5%) in 2013.Conclusions During the period from 2004 to 2015, majority of theSalmonella isolates in hospitals across China wasS. typhimurium andS. enteritidis. Ampicillin and trimethoprim-sulfamethoxazole are no longer appropriate for empirical treatment ofS. typhimurium infection due to high resistance rate.Salmonella isolates are relatively more susceptible to third-generation cephalosporins and quinolones. Ongoing monitoring is necessary to identify multi-drug resistant strains ofSalmonella.
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Objective To analyze the resistance proifle of bacterial strains isolated from geriatric patients in 17 hospitals across China from 2005 to 2014.Methods A total of 17 representative general hospitals were involved in this program. Bacterial susceptibility testing was carried out by means of a uniifed protocol using Kirby-Bauer method and MIC determination. The results were analyzed according to CLSI 2014 breakpoints.Results The proportion of the strains isolated from geriatric patients among all the clinical isolates increased with time from 30.0% in 2005 to 32.7% in 2014. A total of 159 888 clinical isolates were collected from geriatric patient during the period from 2005 to 2014, about 33.1% of the whole patient population. Gram negative organisms and gram positive cocci accounted for 77.1% (123 229/159 888) and 22.9% (36 659/159 888), respectively. Majority (92.8%, 148 376/159 888) of the isolates were from inpatients and more than half (55.2%, 88 201/159 888) of the isolates were from sputum or other respiratory tract specimens. Methicillin-resistant strains inS. aureus (MRSA) and coagulase negativeStaphylococcus (MRCNS) accounted for an average of 67.1% and 75.9%, respectively. The resistance rates of methicillin-resistant strains to β-lactams and other antimicrobial agents were much higher than those of methicillin-susceptible strains. No staphylococcal strains were found resistant to vancomycin, teicoplanin or linezolid. Some strains ofE. faecalis (0.4%) andE. faecium (4.6%) were resistant to vancomycin, which was higher than average national level (0.3%, 3.2%). Vancomycin-resistant strains ofE. faecalisandE. faecium were mainly VanA type and VanB type based on their phenotype. The prevalence of penicillin-susceptibleS. pneumoniae strains was 78.2%, slightly lower than the 95.0% in Chinese adults in year 2014. The prevalence of ESBLs-producing strains was 67.5% inE. coli, 40.4% inKlebsiella (K. pneumoniae andK. oxytoca) and 34.3% inProteus mirabilis isolates on average. The strains ofEnterobacteriaceae were still highly susceptible to carbapenems (<10% resistant), followed by amikacin and the beta-lactam and beta-lactamase inhibitor combinations. Overall, 35.9% and 33.0% of theP. aeruginosa strains were resistant to imipenem and meropenem. More than 50% of theA. baumannii strains were resistant to imipenem and meropenem. The prevalence of extensively drug-resistant (XDR)P. aeruginosa (4.0%-1.8%) was higher than the average national level (2.1%-1.6%). The prevalence of XDR A. baumannii (19.2%-15.5%) and XDREnterobacteriaceae (0.1%-1.0%) was lower than the average national level (21.4%-19.7% and 0.3%-3.2%).Conclusions The proportion of clinical isolates from geriatric patients is different from average national level at the same period. The isolates from geriatric patients are more likely from inpatients, respiratory tract specimens and more likely non-fermentative gram-negative bacilli compared to average national level. The proportion of fastidious bacteria andEnterobacteriaceae species is generally lower than average national level. MRSA, VRE, ESBLs-producing strains and XDRP. aeruginosa are more prevalent in geriatric patients than in general Chinese patient population. This study suggests that surveillance of antimicrobial resistance for the clinical isolates from geriatric patients is very important for rational antimicrobial therapy.
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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 .
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Objective To build a supervision mechanism for independent clinical labs (ICL),surveyed the current situation of such novel institutions in China.Methods By way of the nationwide network of clinical labs,ICL in China were surveyed by written questionnaires and spot inspection.Results In the surveyed 38 ICLs,the maximum registered capital was 44 900 thousands,the minimum was 2 000 thousands.The maximum number of employee was 1 105,the minimum was 19.6 labs passed ISO15189 ratification,4 labs passed CAP ratification.17 labs participated in local external quality control,29 labs par-ticipated in national external quality control.Conclusion Although ICL in our country have developed well in the past dec-ade,such vulnerabilities as unbalanced staff ratio,full-range quality control bugs,cutthroat competition,asymmetrical infor-mation disclosure and bio-safety have loomed in the meantime.It is time to formulate a stricter industry access system and appropriate regulatory modes.
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Objeetive To explore the mechanism of drug resistance of New Delhi metallo-β-lactamase-1 (NDM-1) producing Enterobacteriaceae,and to investigate the characteristics of blaNDM-1 carrying plasmid and its gene environment.Methods A total of 48 strains of carbapenem-resistant Enterobacteriaceae were successively collected from six general hospitals in south China during August 2011 and January 2013.Escherichia coli J53 was used for plasmid conjugation.Modified Hodge test was performed,and PCR method was used for the detection of carbarpenase-related genes.The relative molecular mass of the blaNDM-1 carrying plasmid was determined using pulsed field gel electrophoresis (PFGE)assay,and enzyme digestion was performed to investigate the homology and incompatibility group of the plasmid.Clinical feature of blaNDM-1 producing Enterobacteriaceae infection was also investigated.Results Among 48 strains of carbapenem-resistant Enterobacteriaceae,43 were positive in modified Hodge tests.blaVIM,blaGIM and blaSPM genes were negative in all strains,while blaNDM-1 was positive in 19 strains including 3 strains of Escherichia coli,5 strains of Klebsiella pneumoniae,6 strains of Enterobacter cloacae,3 strains of Citrobacterfreundii,1 strain of Klebsiella oxytoca and 1 strain of Providencia rettgeri.All the 19 strains were resistant to imipenem,cefotaxime,ceftazidime,cefepime,aztreonam and piperacillin/tazobactam,47.3％ strains were resistant to ciprofloxacin and levofloxacin,but 68.4％ strains were sensitive to amikacin.Conjugation experiment showed that,blaNDM-1 carrying plasmids in 13 strains were transmitted to the Escherichia coli J53.The conjugants were resistant to imipenem,ceftazidime,cefotaxime and piperacillin/tazobactam,but were sensitive to amikacin,ciprofloxacin and levofloxacin.All genes in conjugant J-FR90 (Providencia rettgeri) were negative,while the remaining 12 conjugants carried blaNDM-1,blaSHV and aac-(6')-Ib genes.PFGE showed that,the sizes of all blaNDM-1 carrying plasmids were about 50 kb,and more than 80％ of their macrorestriction maps were similar.The plasmid belonged to incompatibility group IncX3,and exhibited 100％ passage stability after 500 generations of propagation.Among 19 patients infected with NDM-1 producing Enterobacteriaceae,6 died and 13 survived.Conclusions NDM-1 producing Enterobacteriaceae is emerging in south China,and blaNDM-1 is transmitted to Enterobacteriaceae through IncX3.Patients infected with NDM-1 producing Enterobacteriaceae usually have good prognosis.
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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 .
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Objective To investigate the distribution and susceptibility of carbapenem-resistant Enterobacteriaceae (CRE) isolates in 2012 from CHINET surveillance .Methods Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated Systems .Results were analyzed according to the breakpoints of CLSI 2012 M100-S22 .Results A total of 1 499 CRE isolates were collected from January to December 2012 ,of which K lebsiella spp .,Enterobacter spp .and E .coli accounted for 63 .5% ,15 .1% and 13 .7% ,respectively .Of the 1 499 isolates , 48 .2% and 29 .3% were from respiratory tract and ICU , respectively . The results of antimicrobial susceptibility testing showed that the resistance rate of CRE isolates to most antimicrobial agents was 70 .0%-100% except amikacin (46 .9% ) and trimethoprim-sulfamethoxazole (49 .8% ) .CRE isolates from adults were more resistant to ciprofloxacin ,aminoglycosides and trimethoprim-sulfamethoxazole than those from children .Conclusions The antibiotic resistance of CRE isolates is very high . The spread of CRE strains in a specific region such as ICU and neurosurgery ward poses a serious threat to clinical practice and implies the importance of strengthening infection control .
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Objective To investigate the distribution and antibiotic resistance of clinical Enterobacter isolates .Methods A total of 3 031 clinical strains of Enterobacter were collected from 15 hospitals from January 1 through December 31 , 2012 . Antimicrobial susceptibility testing was performed with Kirby-Bauer or minimum inhibitory concentration method .The results were analyzed according to CLSI 2012 breakpoints .Results Enterobacter cloacae and Enterobacter aerogenes accounted for 73 .0% (2 212/3 031) and 23 .9% (725/3 031) of all the Enterobacter strains .The isolates of other Enterobacter species accounted for 3 .1% (94/3 031 ) . The main source of the isolates was respiratory tract specimen , accounting for 53 .2% (1 612/3 031) .Most (> 89% ) of the Enterobacter strains were resistant to cefazolin and cefoxitin . Generally ,54 .4% ,47 .5% and 34 .3% of the strains were resistant to cefuroxime ,cefotaxime and cefazidime ,respectively . About 6 .6% to 26 .3% of the strains were resistant to amikacin ,gentamicin ,piperacillin-tazobactam ,cefepime ,cefoperazone-sulbactam ,ciprofloxacin and trimethoprim-sulfamethoxazole .Imipenem ,meropenem and ertapenem showed the highest activity , to which only 3 .5% ,3 .7% and 10 .3% of the strains were resistant ,respectively .About 8 .9% (269/3 031) of the strains were resistant to at least imipenem ,meropenem or ertapenem .Four Enterobacter strains were extensive-drug resistant (XDR) .Conclusions The prevalence of antibiotic resistance in Enterobacter isolates decreased slightly in 2012 compared to the data in 2011 ,but the situation is still very serious .We should continue to take effective measures to control the resistant strains .
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Objective To investigate the antimicrobial resistance in the A cinetobacter baumannii strains in different parts of China during 2012 .Methods A total of 8 739 clinical isolates of Acinetobacter were collected from 13 general hospitals and two children’s hospitals ,of which most were A . baumannii (89 .6% , 7 827/8 739 ) . Antimicrobial susceptibility testing was carried out by means of Kirby-Bauer method according to the unified protocol . The susceptibility testing data were analyzed by WHONET 5 .6 software according to CLSI 2013 breakpoints .Results Majority (85 .4% ) of the Acinetobacter strains were isolated from inpatients .The remaining 14 .6% were from outpatients and emergency room patients .Of the 7 827 strains of A .baumannii , 10 .9% ,35 .2% ,35 .7% and 43 .4% were resistant to tigecycline ,minocycline ,cefoperazone-sulbactam and amikacin , respectively .The percentage of A .baumannii resistant to imipenem and meropenem was 63 .5% and 68 .2% ,respectively . The antimicrobial resistant pattern varied in different hospitals . The resistance of A . baumannii varied between different clinical departments .A number of pandrug resistant (PDR) (20 .0% ,1 567/7 827) and multidrug-resistant (MDR) (45 .0% , 3 521/7 827 ) A . baumannii were identified . Conclusions A . baumannii is the most popular pathogenic bacteria among Acinetobacter .The antibiotic resistance of A .baumannii is still increasing .Cefoperazone-sulbactam and minocycline has good in vitro antibacterial activity against A .baumannii .The antibiotic resistance of A .baumannii varies greatly with hospital and department .
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Objective To investigate the antimicrobial resistance of clinical strains of K lebsiella spp .isolated from 15 hospitals in China CHINET during 2012 .Methods Kirby-Bauer method and automatic microbiology analysis system were employed to study the antimicrobial resistance . WHONET 5 .6 software was applied for data analysis according to Clinical and Laboratory Standards Institute (CLSI) 2012 breakpoints .Results A total of 9 621 clinical K lebsiella isolates were analyzed ,including 8 772 strains of K . pneumoniae and 804 strains of K . oxytoca . About 54 .9% (5 285/9 621) of the K lebsiella strains were isolated from sputum ,and 16 .3% (1 564/9 621) were isolated from pediatric patients .Antimicrobial susceptibility testing showed that about 8 .9% ,10 .8% and 12 .9% of the strains were resistant to imipenem ,meropenem and ertapenem ,respectively .About 14 .1% and 17 .0% of the strains were resistant to piperacillin-tazobactam and cefoperazone-sulbactam , respectively . Carbapenem-resistant K lebsiella strains were identified from all the 15 hospitals ,including 945 strains of K .pneumoniae and 45 strains of K .oxytoca ,which were resistant to either imipenem ,meropenem or ertapenem .Conclusions The Klebsiella isolates collected from 15 hospitals in China during 2012 are relatively sensitive to carbapenems ,cefoperazone-sulbactam and piperacillin-tazobactam .The prevalence of carbapenem-resistant strains is still increasing in China ,about 10 .3% in 2012 ,and relatively higher in Eastern China .More efforts should be made to control the superbug .
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Objective To investigate the resistance of clinical Stenotrophomonas maltophilia isolates from 15 hospitals in several regions of China during 2011.Methods Fifteen repre-sentative general hospitals were involved in this program. Bacterial susceptibility testing was carried out by means of a unified protocol using Kirby-Bauer method and MIC determi-nation.Results were analyzed according to CLSI 2011 break-points.Results Majority (93.3%) of the 1 889 clinical strains of S.maltophilia were isolated from inpatients.On-ly 6.7% of the isolates were from outpatients.About 62.9% of these S .maltophilia strains were isolated from old patients whose age was 60 years or older.Only 8.2% of the strains were from the patients younger than 18 years old.Sputum and re-spiratory tract secretion were the most common specimen source,accounting for 82.6%.Another 4.2% isolates were from blood,abdominal fluid and other sterile body fluids.The percentage of the S .maltophilia strain resistant to trimethoprim-sul-famethoxazole,levofloxacin and minocycline was 16.6%,10.0% and 1.8%,respectively.The strains resistant to cefopera-zone-sulbactam accounted for 19.0%.About 37.1% of the strains isolated from blood or sterile body fluids were resistant to trimethoprim-sulfamethoxazole,significantly higher than the strains from urine or wound specimens (P < 0.01).Conclusions S.maltophilia strains are mainly isolated from inpatients.The most common source is sputum and other respiratory speci-mens.Most of the patients with S.maltophilia isolate are 60 years of age or older.The S.maltophilia strains are constitu-tively resistant to several antibacterial agents,but showed relatively lower resistance to trimethoprim-sulfamethoxazole,levo-floxacin and minocycline.Cefoperazone-sulbactam is still active against these strains.The antimicrobial therapy targeting S. maltophilia infections should be selected cautiously according to the results of antimicrobial resistance surveillance.
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<p><b>OBJECTIVE</b>To investigate serum IL-18 levels in mice with collagen-induced arthritis treated by recombinant adenoviral vector containing mIL-18BP and mIL-4 fusion gene (AdmIL-18BP/mIL-4).</p><p><b>METHODS</b>Arthritis was induced by injection of collagen in male DBA-1/BOM mice. Mice with collagen-induced arthritis (CIA) were intra-articularly injected with 10(7)pfu/6μL of AdmIL-18BP/mIL-4; and in mice of control groups AdLacZ or PBS were used. The animals were sacrificed at week 1, 2 and 4 after treatment. Serum IL-18 levels were determined by ELISA at the different time points.</p><p><b>RESULT</b>The mean serum levels of IL-18 at weeks 1, 2, and 4 after injection of AdmIL-18BP/mIL-4 were (36.5±5.4)ng/L, (32.5 ± 3.2) ng/L and (28.7 ±2.9)ng/L, respectively, which were significantly lower than those at the same time point of AdLacZ group [(66.2 ±5.1)ng/L, (69.2 ±4.2)ng/L and (77.7 ±3.9)ng/L] and PBS group [(67.3 ±7.1)ng/L, (71.9 ±1.8)ng/L and (78.7±4.1)ng/L] (P<0.01 at all time points). In the therapy group, there were no significant differences in the mean serum concentrations of IL-18 at all time points.</p><p><b>CONCLUSION</b>The serum IL-18 levels in CIA mice are down-regulated by treatment of recombinant adenovirus containing mIL-18BP and mIL-4 fuse gene, which might be a promising therapeutic strategy for rheumatoid arthritis.</p>
Subject(s)
Animals , Male , Mice , Adenoviridae , Genetics , Arthritis, Experimental , Blood , Therapeutics , Gene Fusion , Genetic Therapy , Genetic Vectors , Interleukin-18 , Blood , Genetics , Interleukin-4 , Genetics , Mice, Inbred DBAABSTRACT
Objective To investigate distribution and antimicrobial resistance among nosocomial pathogens from 13 teaching hospitals in China in 2009. Methods Non-repetitive pathogens from nosocomial BSI, HAP and IAI were collected and sent to the central lab for MIC determination by agar dilution method.WHONET5.6 software was used to analyze the data. Results A total of 2 502 clinical isolates were collected. The top three pathogens of BSI were Escherichia coli [27. 1% (285/1 052 )] , coagulase-negutive staphylococcus [12. 6% ( 133/1 052)] and Klebsiella pneumoniae [10. 8% ( 114/1 052)]. The top three pathogens of HAP were Acinetobacter baumannii [28. 8% (226/785)], Pseudomonas aeruginosa [16. 1% (126/785)] and Klebsiella pneumoniae [14.6% (115/785 )] . The top three pathogens of IAI were Escherichia coli[31.0% ( 206/665 )], Klebsiella pneumonia [11.3% ( 75/665 )] and Enterococcus faecium [10. 8% (72/665)]. Against Escherichia coil and Klebsiella spp. , the antimicrobial agents with higher than 80% susceptibility rate included imipenem and meropenem (98. 1%-100% ), tigecycline (95.3%-100% ), piperacillin-tazobactam ( 88.6% -97. 1% ) and amikacin ( 88. 3% -92. 5% ). Against Enterobacter spp. , Citrobacter spp. and Serratia spp. , the susceptibility rates of tigecycline were 93.5% -100% whereas the value of imipenem and meropenem were 92.9% -100%. Other antimicrobial agents with high activity included amikacin ( 85.2% -96. 7% ), pipcracillin-tazobactam ( 82.4% -96.4% ), cefepime ( 79. 6% -96. 7% ) and cefoperazonc-sulbactam (78. 7%-90. 0% ). Polymyxin B showed the highest susceptibility rateagainst Pseudomonas aeruginosa ( 100% ), followed by amikacin ( 81.9% ) and piperacillin-tazobactam (80.1% ). Polymyxin B also showed the highest susceptibility rate against Acinetobacter baumannii (98. 8% ), followed by tigecycline (90. 1% ) and minocycline (72. 0% ). The incidence of carbapenemresistant Acinetobacter baumannii was 60. 1%. The MRSA rate was 60. 2% and the MRSCoN rate was 84. 2%. All Staphylococcus strains were susceptible to tigecycline, vancomycin, teicoplanin and linezolid except for one isolate of Staphylococcus haemolysis with intermediate to teicoplanin. Two Enterococcus faecalis isolates which were intermediate to linezolid and one Enterococcus faecium isolate which was resistant to vancomycin and teicoplanin was found in this surveillance, while the MICs of tigecycline against these three isolates were 0. 032-0. 064 μg/ml. Conclusions Tigecycline, carbapenems, piperacillin-tazobactam,amikacin and cefepime remain relatively high activity against nosocomial Enterobacteriaceae. Pseudomonas aeruginosa exhibite high susceptibility to polymyxin B, while Acinetobacter baumanni shows high susceptibility to polymyxin B and tigecycline. Tigecycline, vancomycin, teicoplanin and linezolid remain high activity against nosocomial gram-positive cocci.
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Objective To study the molecular characteristic of the epidemic plasmids carrying blaCTX-M-15 in Guangzhou. Methods A total of 38 strains of E. coli and 47 strains of K. pneumoniae both producing CTX-M-15 ESBLs were collected from nine hospitals in Guangzhou from 2007 to 2008. The clonal relationship of isolates carrying blaCTX-M-15 was determined by PFGE and MLST. Antimicrobial susceptibility was determined by microdilution test for all isolates. Conjugative plasmids carrying blaCTX-M-15 were obtained by mating and were subject to restriction analysis. PCR was used to determine phylogenetic groups of E. coli,and to study replicon type and the genetic contexts of the plasmids harboring blaCTX-M-15. Serum agglutination test was used to detect the serotype of E. coli. Results The 37 strains of E. coli were classified into 28 genotypes, while the 47 strains of K. pneumoniae were divided into 30 genotypes. ST131 was found in E. coli but not O25 serotype. Two novel-alleles of tonB and new ST were determined in K. pneumoniae. Forty out of 58 isolates represented independent genotypes have been succeeded to transfer the plasmid carrying blaCTX-M-15 to the E. coli C600(Rif) by conjugation. The sizes of plasmids carrying blaCTX-M-15 are 65 kb in 57.9% isolates of E. coli and 92 kb in 87.5% isolates of K. pneumoniae. Two epidemic plasmids were detected in E.coli and K. pneumoniae by restriction enzyme, designated p15-e and p15-k respectively. The blaCTX-M-15 and ISEcpI were identified on p15-e, and the blaCTX-M-15 ,ISEcpI,aac(6')- Ⅰ b,aac(3')-Ⅲ ,blaOXA-1 ,qnrB,qnrS,blaDHA-1 , blaTEM-1 were determined on p15-k. The p15-k also was identified to belong to the incompatible group FⅡ. Conclusion The local dissemination of blaCTX-M-15 appears to be due to the spread of epidemic plasmids harboring blaCTX-M-15. No evidence supports the dissemination of clone strains which carried blaCTX-M-15.