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Objective To compare the antibacterial activity in vitro of Haizhengmeite and Mepem. Methods Four hundreds and eighteen bacteria isolated were collected from clinical settings in different area,including 104 strains of Escherichia coli(52 strains of ESBLs +and 52 strains of ESBLs -), 104 strains of Klebsiella pneumonia(52 strains of ESBLs +and 52 strains of ESBLs -),56 strains of Proteus spp. (28 strains of ESBLs +and 28 strains of ESBLs -), 52 strains of other Enterobacteriaceae, 51 strains of Acinetobacter baumanii and 51 strains of Pseudomonas aeruginosa.Two pharmaceutical products of meropenem injection were Mepem from Japan Sumitomo Pharmaceuticals Co., Ltd and Haizhengmeite from Zhejiang Haizheng Pfizer pharmaceuticals Co.Ltd in China, respectively.Minimum inhibitory concentrations(MIC)of two products of meropenem were determined by broth microdilution method and agar dilution method according to the Clinical and Laboratory Standards Institute(CLSI,2016).Results The sensitive rates of Escherichia coli, Klebsiella pneumoniae, and Proteus spp.to Haizhengmeite and Mepem were >85%,while the rates of the sensitivity to Acinetobacter baumanii and Pseudomonas aeruginosa were lower,with the rates of 33.3%,31.4% and 58.8%,52.9%,respectively.Conclusions Haizhengmeite and Mepem both show good antibacterial activity against Enterobacteriaceae, but lower activity against Acinetobacter baumanii and Pseudomonas aeruginosa.Both products are stable to ESBLs,and no significant difference is observed between the two products in antibacterial activity in vitro.
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Objective To investigate the mechanism and epidemiological characteristics of carbap-enem-resistant Proteus mirabilis ( PM) strains deficient in swarming motility. Methods PM strains were isolated from Hangzhou General Hospital of CAPF ( Chinese People′s Armed Police Forces) during January 2013 to December 2014. Bacterial motility and flagella of the PM strains were observed through semi-solid agar culture and flagella staining. Pulsed-field gel electrophoresis ( PFGE) was performed for homology anal-ysis. Antimicrobial susceptibility test and phenotypic confirmatory test were also carried out. PCR analysis and DNA sequencing were performed to confirm the genotype of resistant genes. Plasmid electroporation and S1-PFGE in combination with Southern blot hybridization were used to determine the location of the carbap-enem-resistant genes. Genetic structure of the blaKPC-2 gene was obtained by PCR mapping. Results A total of 42 PM isolates deficient in swarming motility were screened out and the resistance rates to imipenem and meropenem were 57. 1% and 52. 4%, respectively. PCR analysis and DNA sequencing confirmed that 24 carbapenem-resistant PM isolates deficient in swarming motility carried blaKPC-2 gene and belonged to three clones as indicated by the results of PFGE. Southern blot hybridization indicated that the blaKPC-2 gene was located on plasmids varying in size (26 kb, 55 kb and 139 kb). In addition, some of the strains harbored several resistant genes, such as blaTEM-1 , blaCTX-M-65 and rmtB. The genetic structures of strains carrying blaKPC-2 gene were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream. Conclusion Compared with the PM strains with swarming motility, the carbapenem-resistance rate was significantly higher in these PM strains deficient in swarming motility. Carbapenemases KPC-2 played an important role in the carbapen-em-resistant PM strains deficient in swarming motility. There was a cloning spread trend for carbapenem-re-sistant PM strains in our hospital. Clinicians should pay more attention to the risk of spreading.
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Objective To analyze the colistin heteroresistance in Pseudomonas aeruginosa strains and their in vitro susceptibility to antibiotics used in combination.Methods Two hundred and ninety-seven carbapenem-resistant Pseudomonas aeruginosa strains were selected for this study.Broth microdilution method was used to determine the minimum inhibitory concentrations of colistin and other antimicrobials against the Pseudomonas aeruginosa strains.The colistin heterogeneity of 20 colistin sensitive strains was analyzed by using population analysis profiles.The time-kill curves of 3 randomly selected colistin heteroresistant strains were used to determine the bacteriostatic activity of colistin.Chequer-board method was used to measure the combination efficacy of colistin with other antimicrobials including imipenem,meropenem,biapenem,ceftazidime,levofloxcin,piperacillin/tazobactam and cefoperazone/sulbactam.Results The colistin sensitive Pseudomonas aeruginosa strains accounted for 99.66％ of the 297 isolates.Population analysis profiles displayed that 35％ of the 20 isolates were colistin heteroresistant and 20％ of the 20 isolates were heterogeneous.It showed that when colistin was used in combination with other drugs,they mainly had synergistic and additive effects on heteroresistant isolates,but additive and indifferent effects on non-heterogeneous isolates.Conclusion Multidrug resistant Pseudomonas aeruginosa strains were highly susceptible to colistin,but heteroresistant and heterogeneous strains were common.The efficacy of colistin against heteroresistant isolates could be enhanced by using in combination with other drugs.
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Objective To investigate the mechanism of carbapenem-resistant in Enterobacteriaceae strains isolated from Fuyang First People′s Hospital and to analyze their epidemiological features. Methods The Enterobacteriaceae strains with reduced ertapenem susceptibility were isolated from the Fuy-ang First People′s Hospital during January 2013 to August 2014.K-B disk diffusion and E-test were per-formed to detect the antimicrobial susceptibilities of those strains.The modified Hodge test, ethylenediami-netetraacetic acid ( EDTA) disk synergy test and extended-spectrumβ-lactamases ( ESBLs) confirmation test were used to screen out the carbapenem-resistant phenotypes.PCR analysis and gene sequencing were used to analyze drug resistance genes, genetic structures surrounding the blaKPC-2 gene and seven house-keeping genes of Klebsiella pneumonia ( K.pneumoniae) strains.The sequences of the seven house-keeping genes were analyzed with multilocus sequence typing ( MLST) .Pulsed field gel electrophoresis ( PFGE) was per-formed for homology analysis within the same species.S1-PFGE in combination with Southern blot analysis was used to determine the location of carbapenem resistance genes.Results A total of 19 Enterobacteriace-ae isolates with reduced susceptibility to ertapenem were screened out.Each of them was resistant to multiple antibiotics and harbored several resistance genes.Seven genes including the blaKPC-2 , blaIMP-4 , blaSHV-1 , blaCTX-M-65 , blaCTX-M-15 , blaTEM-1 and rmtB genes were the prevalent drug resistance genes.Fourteen out of the nineteen strains were identified as K.pneumoniae strains, mainly belonged to the ST11 type according to the results of MLST.Among the nineteen strains, eleven K.pneumoniae isolates and one Escherichia coli isolate carried the blaKPC-2 gene, located on plasmids varying in size (95 kb, 140 kb, 200 kb and 240 kb) .The ge-netic structures of all isolates were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream.The blaIMP-4 gene was detected in one Klebsiella oxytoca isolate and one K.pneumoniae isolate, located on a plas-mid about 300 kb in size.Conclusion Carbapenemases KPC-2 and IMP-4 were closely related to the car-bapenem resistance in carbapenem-resistant Enterobacteriaceae strains isolated form the Fuyang First People′s Hospital.No predominant clone was found in those carbapenem-resistant K.pneumoniae isolates.
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Objective To evaluate antimicrobial activity of fosfomycin combined with tigecycline against Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae and study the mechanism of drug resistance to fosfomycin. Methods Broth microdilution method was used to independently determine the minimum inhibitory concentrations (MIC)of fosfomycin and tigecycline against 42 Klebsiella pneumoniae isolates (including 20 KPC-producing and 22 KPC non-producing isolates).Checkerboard design method was applied to evaluate combined effect of different concentrations on antimicrobial susceptibility and calculate the fractional inhibitory concentration index (FICI).FICI=MICfosfomycin joint/MICfosfomycin monotherapy +MICtigecycline joint/MICtigecycline monotherapy .Related interpretation criteria were as following:FICI≤0.5 means synergy;0.5 2 means antagonism.The fosfomycin resistant genes in KPC-producing Klebsiella pneumoniae isolates were screened.The data were analyzed by t test.Results Antimicrobial susceptibility testing results indicated the fosfomycin and tigecycline susceptibility rates in KPC-producing isolates were 35 .0%(7/20)and 70.0% (14/20 ),respectively.The susceptibility rates of drug combination increased to 50.0% (10/20 )and 95 .0% (19/20 ),respectively,with both MIC decreased.MIC of tigecycline decreased significantly after combination therapy and showed a statistical significance compared with the MIC of monotherapy (t = - 2.596,P = 0.013 ),whereas there was no significant difference between single and combined therapy of fosfomycin (t=-1 .274,P =0.211).FICI indicated that a total of 60.0%isolates showed synergy and additive effects between two antimicrobial agents,followed by indifference (40.0%),but there was no antagonism effect.Among 22 KPC non-producing isolates,there were 54.5 %showing indifference effects,followed by additive (31 .8%)and synergy (13.6%)effects.No antagonism effect was found.The study also identified two isolates with fosA resistant gene which located on the same plasmid as well as the bla KPC gene.The plasmid sizes in the two isolates were 138.9 kb and 104.5 kb, respectively.Conclusions KPC-producing Klebsiella pneumoniae are more susceptible to tigecycline. Combined use of two antimicrobial agents mainly exerts synergy and additive effect rather than antagonism,which may suggest the combination therapy strategy could inhibit the activity of KPC-producing Klebsiella pneumoniae .
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Objective:To report and analyze a rare family of sponduloepiphyseal dysplasia congenital(SEDC) in order to supply more resources for genetic bone disease. Methods:Investigation and analysis was performed on a four generation's family of SEDC.Clinic characteristics including X-ray image and chromosome analysis were evaluated.Results:Nine persons suffered from SEDC in this four(generation's) family.The patients presented with same clinical characteristics.The main bone damages affected vertebrae,articulatio coxae,caput femoris and neck. Conclusion:The mode of inheritance of SEDC may be autosomal dominant inheritance.Gene defect during embryonic period may interfere the growth of osteoepiphysis.Further molecular pathologic studies were needed to find the evidence of genetic prognostication of SEDC.