ABSTRACT
Objective:To investigate the prevalence and characteristics of mcr genes in clinical isolates of Aeromonas spp. in our hospital, and provide reference for clinical analysis of the prevalence and expression of colistin resistance genes. Methods:Polymerase chain reaction (PCR) was used to detect mcr genes in 183 Aeromonas spp. strains. The minimum inhibitory concentrations (MICs) of colistin and polymyxin against mcr-positive Aeromonas spp. were detected by micro broth dilution method. Broth conjugation and filter mating conjugation were performed. Whole genome sequencing was used to analyze the genetic environment of mcr-3 gene in Aeromonas spp.. A recombinant Escherichia coli ( E. coli) DH5α-pGEM-T: : p mcr-3 strain was constructed to verify the expression of mcr-3 gene. Results:The positive rate of mcr-3 gene in 183 strains of Aeromonas spp. was 2.19% (4/183). No mcr-1 or mcr-2 gene was detected among these isolates. Antimicrobial susceptibility test showed that four mcr-3-carrying Aeromonas hydrophilia ( A. hydrophilia) strains were sensitive to colistin and polymyxin (MIC<2 μg/ml). Conjugation experiments indicated that mcr-3 gene could not be transferred between strains. Whole-genome sequencing analysis suggested that the mcr-3 genes carried by the A. hydrophilia isolates belonged to mcr-3.2 and mcr-3-like variants, and no adjacent transfer element was detected upstream and downstream. The recombinant E. coli DH5α-pGEM-T: : p mcr-3 strain was sensitive to colistin (MIC=2 μg/ml). Conclusions:The clinical isolates of A. hydrophilia in our hospital carried mcr-3 gene, but does not exhibit colistin resistance, and no evidence supported the transfer of mcr-3 gene for the time being.
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As a part of our ongoing research program to isolate novel phragmalin limonoids from the stem bark of Chukrasia tabularis var. velutina, two new phragmalin limonoids orthesters, tabularin Q (1) and tabulalide O (4), along with two known compounds tabularin C (2) and tabularin H (3) were isolated. Their structures were elucidated by means of extensive 1D and 2D spectroscopic analyses which included HSQC, HMBC, and ROESY experiments and HR-ESI-MS.
ABSTRACT
Background Patients often suffer from a few complications of neurological and psychiatric problems after traumatic brain injury including damage of cognition, mental disorders and behavior problems. Damage of cognition is a common sequela in traumatic brain injury. Numerous researchers were focus on the cognition changes of patients with mild brain injury. But their conclusions are debatable. Executive function is one of the important components of cognition. In this study,we tried to find out the executive functional alterations of the patients with mild brain injury.Methods 159 patients with brain injury caused by transportation events and 68 normal controls were assessed executive function. The executive function tests included the block design in WAIS, the Stroop test, the verbal fluency and the modified version of Wisconsin card sorting test (M-WCST). These tests were applied to compare the scores of traumatic brain injury patients with various severities including mild, moderate, and severe and with different CT/MRI results.Results Patients with mild head injury got significantly lower scores on all tests than normal controls ( P＜0.01 ). But there was no significant difference between mild and moderate brain injury group. Except Stroop test and WCST categories, patients with mild brain injury got significantly lower scores on all other tests than those with severe brain injury ( P ＜0.05). In the brain injury cases with damage signs on CT/MRI, there was no significant difference on scores of all tests except block design tests among brain injury patients with various severities. Among the brain injury cases without any damage signs on CT/MRI, there was no significant difference on scores of all tests among brain injury patients with various severities. The correlation analysis showed that scores of block design and verbal fluency test were negatively related to the severity of brain injury( P＜0.05). The age and the education level of the patients had negative and positive correlation, respectively, to executive function.Conclusions The executive function of patients with mild brain injury was impaired when the medication was terminated. We should pay more attention to patients with mild brain injury by performing various tests for assessment of disability.