Population structure of food-borne Staphylococcus aureus in China / 中华流行病学杂志

Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

Prediction of superantigen active sites and clonal expression of staphylococcal enterotoxin-like W / 中华流行病学杂志

Objective: The docking and superantigen activity sites of staphylococcal enterotoxin-like W (SElW) and T cell receptor (TCR) were predicted, and its SElW was cloned, expressed and purified. Methods: AlphaFold was used to predict the 3D structure of SElW protein monomers, and the protein models were evaluated with the help of the SAVES online server from ERRAT, Ramachandran plot, and Verify_3D. The ZDOCK server simulates the docking conformation of SElW and TCR, and the amino acid sequences of SElW and other serotype enterotoxins were aligned. The primers were designed to amplify selw, and the fragment was recombined into the pMD18-T vector and sequenced. Then recombinant plasmid pMD18-T was digested with BamHⅠand Hind Ⅲ. The target fragment was recombined into the expression plasmid pET-28a(+). After identification of the recombinant plasmid, the protein expression was induced by isopropyl-beta-D- thiogalactopyranoside. The SElW expressed in the supernatant was purified by affinity chromatography and quantified by the BCA method. Results: The predicted three-dimensional structure showed that the SElW protein was composed of two domains, the amino-terminal and the carboxy-terminal. The amino-terminal domain was composed of 3 α-helices and 6 β-sheets, and the carboxy-terminal domain included 2 α-helices and 7 antiparallel β-sheets composition. The overall quality factor score of the SElW protein model was 98.08, with 93.24% of the amino acids having a Verify_3D score ≥0.2 and no amino acids located in disallowed regions. The docking conformation with the highest score (1 521.328) was selected as the analysis object, and the 19 hydrogen bonds between the corresponding amino acid residues of SElW and TCR were analyzed by PyMOL. Combined with sequence alignment and the published data, this study predicted and found five important superantigen active sites, namely Y18, N19, W55, C88, and C98. The highly purified soluble recombinant protein SElW was obtained with cloning, expression, and protein purification. Conclusions: The study found five superantigen active sites in SElW protein that need special attention and successfully constructed and expressed the SElW protein, which laid the foundation for further exploration of the immune recognition mechanism of SElW.

Problems that should be emphasized in the diagnosis and treatment of tubal pregnancy / 中国实用妇科与产科杂志

Tubal pregnancy is common and is in lackof detailed clinical research.It seems to be simple todiagnose and easy to handle,but once it is ignored,itcan lead to serious consequences and even death.Withthe changes in today′s social environment and people′sconcept,and with the widespread use of IVF and othertechnologies,new cases have emerged in tubal preg-nancy.We should re-emphasize the diagnosis andtreatment of tubal pregnancy.

Effects of docosahexaenoic acid on cell apoptosis, invasion and migration of cervical cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of docosahexaenoic acid (DHA) on apoptosis, migration and invasion of cervical cancer cell lines.</p><p><b>METHODS</b>cervical cancer cell lines Hela and Siha in logarithmic phase were treated different concentrations of DHA. The morphological changes of the cells were observed microscopically and cell apoptosis was observed using Hoechst 33258 fluorescent staining. MTT assay was used to evaluate the effect of DHA in suppressing cell growth, and flow cytometry was employed to analyze the changes of cell apoptotic rate following DHA stimulations. Wound healing assay and Transwell migration assay were used to evaluate the migration of the cell lines. The expression levels of Bax, Bcl-2 cleaved caspase3, MMP-9 and VEGF proteins were detected by Western blotting.</p><p><b>RESULTS</b>DHA exposure of the cells caused obvious morphological changes and dose-dependently increased the number of apoptotic bodies in the cells. MTT assay showed that DHA inhibited the growth of the cancer cells in a time- and concentration-dependent manner. DHA also effectively suppressed migration and invasion of the cancer cells. The cells exposed to DHA showed significantly down-regulation of Bcl-2, MMP-9 and VEGF proteins and up-regulation of cleaved-caspase 3 and Bax.</p><p><b>CONCLUSION</b>DHA can promote cervical carcinoma cell apoptosis by down-regulating the anti-apoptotic proteins Bax, Bcl-2 and cleaved-caspase3 and suppress cell invasion by decreasing MMP-9 and VEGF expressions.</p>

Antimicrobial susceptibility of Streptococcus sp. to quinupristin-dalfopristin in China / 生物医学与环境科学（英文）

This study aimed to determine the in vitro activity of quinupristin-alfopristin against Streptococcus sp. isolated in China. This agent is not yet available for clinical use, but it has been tested against a high proportion of resistant Staphylococcus aureus strains. A total of 156 streptococcal isolates, which were recovered from various geographic areas and diseases, were tested using the Etest (AB Biodisk, Solna, Sweden). Quinupristin-alfopristin showed excellent activity against all of the tested streptococci isolates. These results provide useful data for the clinical use of quinupristin-alfopristin in China.

In vitro protein expression profile of Campylobacter jejuni strain NCTC11168 by two-dimensional gel electrophoresis and mass spectrometry / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the protein expression profiles of the major food-borne pathogen Campylobacter jejuni NCTC11168.</p><p><b>METHODS</b>Membrane and soluble cellular proteins were extracted from the genome-sequenced C. jejuni strain NCTC11168. Protein expression profiles were determined using two-dimensional gel electrophoresis (2-DE). All the detected spots on the 2-DE map were subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF) analysis.</p><p><b>RESULTS</b>A total of 537 and 333 spots were detected from the whole cell and membrane-associated proteins of C. jejuni NCTC11168 cultured on Columbia agar medium at 42 °C by 2-DE and Coomassie Brilliant Blue staining, respectively. Analyses of whole cell and membrane-associated proteins included 399 and 133 spots, respectively, which included 182 and 53 functional proteins identified by MALDI-TOF/TOF analysis.</p><p><b>CONCLUSION</b>The comprehensive expression protein profiles of C. jeuni NCTC11168 obtained in this study will be useful for elucidating the roles of these proteins in further pathogenesis investigation.</p>

Secreted protein HP1286 of Helicobacter pylori strain 26695 induces apoptosis of AGS cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Secreted proteins of Helicobacter pylori (H. pylori) interact with gastric epithelium cells and may contribute to cell damage. Considering the fact that HP0175 and hypothetical conserved protein HP1286 are included in the group and that HP0175 is a well-known apoptosis-induced factor, the present study aims to clarify whether HP1286 plays a role in bacterial pathogenicity or even functions as an apoptosis-induced factor in human stomach.</p><p><b>METHODS</b>Two genes encoding HP1286 and HP0175 were cloned into pET32a vector and expressed as recombinant proteins in Escherichia coli (E. coli) BL21. Signal peptide sequences were not included. The recombinant proteins were purified with His SpinTrap and desalted by using HiTrap Desalting. Immunoreactivity of the proteins was determined by Western blot. Human gastric epithelial cell AGS was challenged with these endotoxin-free proteins; and apoptosis of cells was assayed with the Cell Death ELISA kit.</p><p><b>RESULTS</b>Recombinant proteins and their respective products whose N-terminal his-tag were removed with thrombin were recognized by serum from the patient infected with H. pylori. Apoptotic AGS cells challenged by HP1286 of H. pylori 26695 were four times more than untreated cells. In addition, apoptosis-induced ability of HP1286 of SS1 was not as strong as that of H. pylori 26695 strain.</p><p><b>CONCLUSION</b>HP1286 of H. pylori 26695 induces apoptosis of AGS cells in a time-dependent manner, however the apoptosis-induced ability of HP1286 may differ due to variations between different strains.</p>

Evaluation of a new real-time PCR assay for detection of Mycoplasma pneumoniae in clinical specimens / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To establish and evaluate a real-time PCR assay to detect Mycoplasma pneumoniae (M.pneumoniae) in clinical specimens.</p><p><b>METHODS</b>By analysing the whole p1 gene sequence of 60 M.pneumoniae clinical isolates in Beijing of China, an optimized real-time PCR assay (MpP1) using p1 gene conserved region was designed. The specificity and sensitivity of this assay were evaluated and compared with other two reported assays (RepMp1 and Mp181) using 40 positive and 100 negative clinical specimens.</p><p><b>RESULTS</b>The detection limit of the new assay was 8.1 fg (about 1∼3CFU) M.pneumoniae DNA. The sensitivity of MpP1, RepMp1, and Mp181 assays appeared to be 100%, 100%, and 85%, respectively.</p><p><b>CONCLUSION</b>MpP1 assay is suitable for the detection of M.pneumoniae in Chinese clinical specimens.</p>

Acceptability of pre-exposure prophylaxis among female sex workers in Xinjiang / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To assess the acceptability of pre-exposure prophylaxis (Pr-EP) among the female sex workers in Xinjiang.</p><p><b>METHODS</b>A volunteer-based, anonymous and one-to-one questionnaire survey was conducted in 762 female sex workers (FSW) in Urumqi and Kelamayi of Xinjiang Uyghur Autonomous Region.</p><p><b>RESULT</b>Among 762 FSW surveyed, 673 (88.32%) was not aware of pre-exposure prophylaxis with an awareness rate of 11.55%. The awareness rate of FSWs working in high-end entertainment venues was higher than that of FSWs working in medium-low end entertainment venues(P<0.001). Five hundred and twenty eight FSWs (69.29%) were willing to take Pr-EP, 145 (19.03%) were unwilling to take the medicine and 89 (11.68%) were possible to use the Pr-EP. There was no significant difference in willingness of using Pr-EP among FSWs working in high and medium-low end entertainment venuew (P=0.285). The subjects who were willing to take Pr-EP mainly concerned of the drug security, effectiveness and cost. The main reasons for not willing to take Pr-EP were: not having risk of infecting HIV, suspecting effectiveness of Pr-EP and worrying about side effects.</p><p><b>CONCLUSION</b>The acceptability to use Pr-EP in female sex workers of Xinjiang is relatively high and the drug security, effectiveness and cost will influence the promotion and application of Pr-EP in the future.</p>

Proteome analysis of Neisseria meningitidis serogroup strains C associated with outbreaks in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>During 2003-2005, an outbreak of meningitis due to Neisseria meningitidis serogroup C occurred in China. With the aim to find strain clues result in the final epidemics, the ancestral strain 053442, a clinical isolate, and a carrier strain 053426 with different gene type were analyzed.</p><p><b>METHODS</b>Clinical strain 053442 and carrier strain 053426 were cultured on GC agar plates under the same condition. Two-dimensional electrophoresis was performed using the pH 3-10 nonlinear IPG strips of 24 cm length, and all the protein spots were identified by matrix-assisted laser desorption/ionization time of flight spectrometry.</p><p><b>RESULTS</b>502 and 380 protein spots were identified in 053426 and 053442 respectively, relating to 266 and 202 different genes covering a wide range of cellular functions. The express volume and number of proteins involved in energy metabolism, protein synthesis and amino acid biosynthesis in 053426 were higher than in 053442. Virulence factor Opa, Opc and a series of proteins involved in pilus assembly and retraction were identified in 053442, which appear to be of primary importance in colonization and invasion of human cells. Compared to 053442, virulence protein species were less in 053426, with lower express volumes too. No Opa and Opc were detected in 053426.</p><p><b>CONCLUSIONS</b>The different protein expression profiles of the clinical strain 053442 and carrier strain 053426 in the present study provide some clues of the different pathogenicity of the two strains, which may account for result in the final epidemics.</p>