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Objective:To investigate the genetic diversity and molecular epidemiology of Bordetella pertussis in Shaanxi province, and analyze the possible reasons of resurgence in this region. Methods:We characterized clinical isolates collected during 2012-2017 using multilocus antigen sequence typing (MAST) and multilocus variable-number tandem repeat analysis (MLVA).Results:The circulating strains and vaccine strains were different in molecular characteristics. The majority (95%) of the isolates were typed as prn1/ ptxP1/ ptxA1/ fim3-1/ fim2-1. In addition, eight MLVA types (MTs) and eight PFGE profiles were identified, respectively. MT195, MT55 and MT104 were dominant and MT195 continually increased annually. Conclusions:The genetic characteristics of the current strains in Shaanxi province were different from those of the vaccine strain. The evolution through genetic variation might be one of the reasons for the recurrence of pertussis in this region.
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Objective:To analysis the macrolide resistance, molecular characteristics and plused-field gel electrophoresis(PFGE) type of Bordetella pertussis ( Bp), explore the possible resistance mechanism and the relationship between PFGE types and macrolide resistance profiles. Methods:Erythromycin, azithromycin and clarithromycin susceptibility of clinical isolates during 2016 to 2018 was determined by E-test. PCR was used to detect the drug-resistant genes and mutation sites. PFGE were employed to do molecular typing for the strains.Results:Thirty-five strains were isolated, of which 27 strains were resistant to all three antibiotics, two strains were resistant to erythromycin and azithromycin, and six strains were sensitive to all three antibiotics. Partial macrolide resistant strains carried the methylase gene ermA (27.6%, 8/29) and ermB (31.0%, 9/29); A2047G site mutation was detected in macrolide-resistant strains, while no drug-resistant genes or mutation sites were found in sensitive strains. Resistant strains were classified into BPSR23 and BPFINR9 types, while sensitive strains were other profiles. Conclusions:The clinical isolated Bp were seriously resistant to erythromy and showed signs of resistance to other macrolides. The acquisition of methylase gene and mutation of A2047G site might be the main mechanism of resistance. The macrolide resistance might have has a certain correlation with PFGE profile.
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Objective To understand the distribution of novel coronaviruses in the external environment of confirmed COVID-19 cases. Methods Environmental surface swab specimens such as bed rails, doorknob, closestool, hand washing sink, table, locker,ward pager, mobile phone, cup, clothes, were collected from the sentinel hospital of COVID-19, and samples were collected for the nucleic acid detection by RT-PCR. Results A total of 150 environmental samples were collected from 30 confirmed COVID-19 cases, 6 samples were determined to be novel coronaviruses postive (positive rate 4.00%). The total 14 mobile phone showed 3 novel coronaviruses positive.Among the 30 confirmed COVID-19 cases, 6 cases (positive rate 20.00%)were found novel coronaviruses in the external environment. Conclusions Novel coronaviruses exists in external environment of confirmed COVID-19 cases, which indicates the potential risk of COVID-19 infection.
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This paper reviews the computer vision and image analysis studies aiming at automated diagnosis or screening of malaria in microscope images of thin blood film smears. On the basis of introducing the background and significance of automatic detection technology,the existing detection technologies are summarized and divided into several steps,including image acqui-sition,pre-processing,morphological analysis,segmentation,count,and pattern classification components. Then,the princi-ples and implementation methods of each step are given in detail. In addition,the promotion and application in automatic detec-tion technology of thick blood film smears are put forwarded as questions worthy of study,and a perspective of the future work for realization of automated microscopy diagnosis of malaria is provided.
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Streptococcus dysgalactiae subspecies equisimilis (SDSE) belongs to group C or group G β-hemolytic Streptococcus, SDSE infection cases are mostly related with the consumption of contaminated dairy or meat products, the major symptom is upper respiratory tract infection, and is easily to be misdiagnosed.In June 2014, an outbreak of acute upper respiratory tract infection due to SDSE occurred in a kindergarten in Xi'an City.All cases were followed up, the initial case developed as latent nephritis, the main cause for the development of latent nephritis was not performing diagnosis and treatment timely.In order to enhance the understanding of the epidemiological and clinical features of SDSE infection, strengthen prevention and control ability, and reduce the occurrence of adverse sequelae, investigation of the case and epidemic situation should be reported.
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BACKGROUND:Whether transplanted bone marrow mesenchymal stem cells under hypoxic conditions can survive is crucial for the successful celltransplantation. Therefore, studies on the growth of bone marrow mesenchymal stem cells under hypoxic conditions in vitro can provide experimental evidence for in vivo celltransplantation. OBJECTIVE:To observe the expression of vascular endothelial growth factor in bone marrow mesenchymal stem cells under hypoxia. METHODS:Rat bone marrow mesenchymal stem cells were obtained and cultured, and observed under light microscopy. Passage 3 cells were cultured under normoxia (21%O2) and hypoxia (3%O2 hours. Then cellcounting kit-8 assay and flow cytometry were employed to detect cellproliferation in the two groups. Western blot assay was adopted to detect the expression of hypoxia-inducible factor-1αand vascular endothelial growth factor in the two groups. RESULTS AND CONCLUSION:(1)Rat bone marrow mesenchymal stem cells were obtained and cultured successful y, which were fusiform cells and had uniform shape under the light microscope. (2)The results of cellcounting kit-8 assay showed that the number of cells in the hypoxic group was higher than that in the normoxic group at each time point, and cellviability increased significantly at hours 36 and 48 (P<0.05). (3)The results of flow cytometry demonstrated that the proportion of cells in S phase and cellproliferation index in the hypoxic group were significantly increased, compared with the normoxic group (P<0.05). (4)Western blot results showed ), respectively, for 72 that there was a smal amount of the expression of hypoxia-inducible factor-1αand vascular endothelial growth factor in the normoxic group, but the expression of these two proteins in the hypoxic group was increased in a time-dependent manner (P<0.05). These findings suggest that hypoxia can induce proliferation of rat bone marrow mesenchymal stem cells cultured in vitro, and also raise hypoxia-inducible factor-1αand vascular endothelial growth factor expression in a time-dependent manner.