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Objective:To investigate the resistance and transmission mechanism of carbapenem-resistant Enterobacterales (CRE), so as to provide the scientific evidence for the treatment and prevention of CRE infection.Methods:Seventy-six isolates of CRE isolated from Shaoxing Second Hospital between May 2016 and August 2018 were included. The isolates were re-identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The minimum inhibitory concentrations (MICs) of colistin, tigecycline, ceftazidime-avibactam, fosfomycin and other antibacterial drugs were determined using broth microdilution or agar dilution methods. PCR and sequencing analysis were performed to detect carbapenemase encoding genes ( blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48). Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analyze homology of strains. S1-PFGE combined with Southern blot hybridization were used to locate the carbapenamase genes. Filter mating test were performed to determine the horizontal transfer ability of plasmids harboring carbapenamase genes. Results:Among the 76 isolates of CRE, 51 isolates were Klebsiella pneumoniae; 10 isolates were Escherichia coli; 15 isolates were other Enterobacterales. The 76 CREs were mainly isolated from urine, sputum and blood samples. The distribution rate of ICU was the highest (55.26%). The 76 CREs showed low resistance rates (0%, 1.33%, 18.42%) to colistin, tigecycline and ceftazidime-avibactam. The resistance rates to amikacin and fosfomycin were <45%, and the resistance rates to other drugs were >97%. The detection rate of KPC-2 carbapenemase was the highest (85.33%). The ST11 CRKP producing KPC-2 carbapenemase accounted for the highest proportion (62.75%), mainly distributed in the ICU (62.50%). Southern blot hybridization showed that blaKPC-2 was mainly located on a plasmid about 90 kb (39/63). Filter mating test showed that blaKPC, blaNDM and blaIMP could be transferred horizontally to recipient bacteria through plasmids. Conclusions:The 76 CRE isolates were only susceptible to a few antibacterial drugs, such as colistin, tigecycline and ceftazidime-avibactam. The production of KPC-2 carbapenemase was the main reason for the resistance of Enterobacterales to carbapenems. KPC-2 carbapenemase-producing ST11 Klebsiella pneumoniae was the main epidemic clone of carbapenem-resistant Klebsiella pneumoniae (CRKP). The 90 kb size plasmid was the main plasmid encoding blaKPC-2 gene. Carbapenemase genes can be transferred horizontally through plasmids. The hospital should strengthen prevention of nosocomial infections to control the clonal prevalence of CRE.
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OBJECTIVE： To study the improvement effects and its mechanism of erythropoietin derivative helix B surface peptide （HBSP） on epirubicin-induced myocardial injury in rats. METHODS： SD rats were randomly divided into control group， model group， erythropoietin （EPO） group and HBSP group， with 10 rats in each group. Except for control group， other groups were given epirubicin 2.5 mg/kg intraperitoneally， once a week， for consecutive 6 weeks to induce myocardial injury model. EPO group and HBSP groups were given rhEPO 5 000 u/kg or HBSP 60 μg/kg intraperitoneally， 3 times a week （one day before medication， first day and third day after medication of epirubicin）， for consecutive 6 weeks. At the beginning of the first administration， the rats were weighed at the 11th week. The cardiac function was measured by echocardiography [left ventricular end-diastolic diameter （LVIDd）， ejection fraction （EF）， fractional shortening （FS） and cardiac output（CO）]. The serum levels of troponin I （cTnI） and amino-terminal B-type natriuretic peptide （NT-proBNP） were determined by ELISA. mRNA expression of PI3K and Akt in myocardial tissue was detected by RT-PCR. The protein expression of p-PI3K and p-Akt in rat myocardium were detected by Western blot. RESULTS： During research period， two rats died in model group， one in EPO group and none in HBSP group. Compared with control group， body weight， the levels of EF， FS and CO were decreased significantly in model group， while the contents of LVIDd and cTnI， NT-proBNP were increased significantly； mRNA expression of PI3K and Akt as well as protein expression of p-PI3K and p-Akt were decreased significantly， above differences were statistical significant （P＜0.05）. Compared with model group， body weight， the levels of EF， FS and CO were increased significantly in EPO group and HBSP group， while the contents of LVIDd and cTnI， NT-proBNP were decreased significantly； mRNA expression of PI3K and Akt as well as protein expression of p-PI3K and p-Akt were increased significantly， above differences were statistical significant （P＜0.05）. Compared with EPO group， the contents of cTnI and NT-proBNP were decreased significantly in HBSP group， with statistical significance （P＜0.05）. CONCLUSIONS： HBSP can improve myocardial injury in rats as much as EPO， and has less toxity. Their mechanism may be related to the activation of PI3K/Akt signaling pathway.
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Infectious disease is still one of the leading causes of death nowadays .More than half of pathogens causing infections are still unclear through conventional microbiological diagnostics in clinical laboratory.Recently, the metagenomic sequencing is being applied in the pathogenic diagnosis with full coverage, high efficiency and few bias.Though metagenomic sequencing has shown good performance in pathogenic diagnosis for respiratory tract infection , central nervous system infection and bloodstream infection, it still cannot replace the conventional microbiological tests ; however, this state-of-the-art tool should be considered as an effective supplement to pathogen diagnosis .This article reviews the current application of metagenomic sequencing in clinical scenarios and related pitfalls , with the aim of promoting better utilization of the tool.
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Objective To investigate the effect on electrical restitution of β1-adrenergic receptor antagonist esmolol administered during cardiopulmonary resuscitation in the porcine ventricular fibrillation model. Method Ventricular fibrillation untreated for four minutes was induced by dynamic steady state pacing protocol in 40 healthy male pigs, in which local unipolar electrograms were recorded using one 10-electrode catheter that was sutured to the left ventrieular epicarditan. During CPR, animals were randomized into two groups to receive saline as placebo or esmolol after two standards doses of epinephrine. At postresuscitation 2-hour, six pigs were randomly selected from each group and the second VF induction was performed. Local activation-recovery intervals (ARI) restitutions and the VF inducibility between control group and esmolol group were compared. Western blotting was performed to determine cardiac ryanodine receptor (RyR2) protein expression, and their phosphorylation status. Results No sig-nificant differences were observed at the restoration of spontaneous circulation between two groups. Higher postre-suseitation 2-hour survival rate was observed in the esmolol group. Esmolol significantly flattened ARI restitution slope, lessened regional difference of ARI restitution, decreased the VF inducibility, and alleviated RyR2 hyper-phosphorylation. Conclusions Esmolol given during CPR significantly improved postresuscitation 2-hour survival rate. Its effects on modulating electrical restitution property and intracellular calcium handling make up the most important reasons why β1-blockade significantly reduced the onset and maintenance of VF.
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Objective To evaluate the efficacy and safety of a novel mutated recombinant tissue-type plas-minogen activator (rt-Pam) in a rat model of acute cerebral thrombosis. Method Eighty-seven adult Wister rats were randomly divided into control group, recombinant tissue-type plasminogen activator (rt-PA) group, low dose of rt-Pam group and routine dose of rt-Pam group. The rats of different groups were treated for 3 hours after thrombosis of middle cerebral artery. The size of infarction, neurological scores and severity of hemorrhage were observed 24 hours after treatment. The protective role of rt-Pam in the brain tissue was evaluated as per the infiltration of neutrophils and the concentration of plasminogen activator receptor-1 (PAR-1). Results Compared with control group, the sizes of infarction in the low dose of rt-Pam group and routine dose of rt-Pam group were significantly smaller [(108.5 ±27.3) mm3 and (68.3 ±17.2) mm3 vs. (323.4 ±42.3) mm3]. The neurological scores were evidently correlated with the size of infarction (r = 0.613, P<0.001), while the liability of cerebral hemorrhage in low dose of rt-Pam group was not significantly increased. The rt-Pam also reduced the production of myeloperox-idase, as well as the production of PAR-1 in comparison with rt-PA group [(13.8 ± 3.1) vs. (28.3±4.5), P <0.00l]. Conclusions The novel rt-Pam could be a better thrombolytic agent than rt-PA in treating acute stroke.
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Objective To investigate the age-associated changes of electrophysiological properties of atrial muscle and the relationship between these changes and atrial fibrillation (AF). Methods According to their ages forty Wistar rats were divided into 4 age groups: young group, adult group, middle-aged group and old group (n=10 each group ). Hearts were isolated and perfused by Langendorff. MAP (monophasic action potential) of atrial muscle was recorded. MAPD (duration of MAP) and ERP (effective refractory period) at 400 ms of the stimulation cycle length, and MAPD at other different stimulation cycle lengths were measured in each group. Results At the stimulation cycle length of 400 ms, MAPD_(90) of right atrial muscle prolonged gradually from young group to old group (P