简介：AbstractObjective:The aim of this work was to measure the antibacterial activity (against Escherichia coli and Staphylococcus aureus [S. aureus]) of the ethyl acetate part of Abrus cantoniensis and assess their potential as medicines.Methods:The experiment was divided into four groups: negative control group [with Mueller-Hinton broth (MHB)], positive control group (with 75% ethanol), blank group (with MHB) and test group (with the ethyl acetate part of Abrus cantoniensis). The antibacterial activities of the extracts were evaluated by the Oxford cup assay and minimum inhibitory concentration (MIC). Time-kill curve experiments, scanning electron microscopy, the content of DNA, RNA and protein were used to study the antibacterial mechanism of the ethyl acetate extract part on the growth and viability of S. aureus. The study procedures were approved by the Animal Care and Use Committee of Xi’an Jiaotong University (approval No. XJTULAC2016-412) on January 22, 2016.Results:The ethyl acetate part of Abrus cantoniensis extract exhibited the highest inhibitory activity against the growth of S. aureus with an inhibition zone diameter of 16.4 mm and MIC value of 0.5 μg/mL. The general activity range of the ethyl acetate part, determined using a time-killing curve, was found to be 0.5 μg/mL to 40 μg/mL (MIC to 80 × MIC). Changes in the scanning electron microscopy images and of DNA, RNA and proteins of S. aureus indicated possible mechanisms of the inhibitory activity of the ethyl acetate part.Conclusion:The ethyl acetate part of Abrus cantoniensis damaged bacterial cell structures, which results in protoplasm leakage, and eventually bacterial cell death.

简介：AmicrocalorimetricmethodwasusedtoevaluatetheactionofYb^3+ionsonthegrowthmetabolismofStaphylococcusaureus.Thepower-timecurvesofthegrowthmetabolismofStaphylo.coccusaureusandtheactionofYb^3+ionswereobtainedbyus-ingstopped-flowmethodat37℃.Forevaluationoftheaction,thegrowthrateconstants(k1andk2)forthelogphase1,logphase2,andthetotalheateffect(Qtotal)forStaphylococcusaureusweredetermined.TheresultsshowthatYb^3+ionsatlowconcentrationshavethestimnlatoryeffectonStaphylococcusau-reusandthatYb^3+ionsathigherconcentrationcouldinhibititsgrowth.

简介：Aone-year-oldbabygirlwithone-monthhistoryofrecurrentpusfluidexudingfromherleftpreauricularsinusorifice,whofailedmultiplecoursesofsurgicaldrainageoftheabscessandpersistentdebridementforthewound,presentedwithMRSAinfection.Thepatientwastreatedwithlinezolidforthreedays.Herpainandparesthesiaresolved,andC-reactiveproteindecreasedtonormal.

简介：AbstractSingle-nucleotide polymorphisms (SNPs) are the third generation of genetic markers, having been refined from the first generation of restriction fragment length polymorphisms and the second generation of microsatellite polymorphisms. SNPs represent a focal point of current studies of Staphylococcus aureus. On one hand, this review aims to summarize common methodologies for detecting SNPs. These methods have typically included DNA genome sequencing methods and PCR-based detection methods. Alternative methods, such as mass spectrometry, denaturing high-performance liquid chromatography, SNaPshot, and SNP array have also been employed for SNP analysis. On the other hand, we enumerate a series of applications of SNP analysis in investigations of Staphylococcus aureus. SNP analysis can be applied to investigate epidemiological outbreaks and transmission of Staphylococcus aureus infections, the transmission and evolution of antimicrobial resistance genes in Staphylococcus aureus isolates, interactions of Staphylococcus aureus with other bacteria, and the links between Staphylococcus aureus in humans and livestock.

简介：Thepurposeofthissubjectwastoinvestigatemolecularepidemiologyofoxacillin-resistantStaphylococcusaureus(MRSA)isolatedfromhospitalizedpatients,andtosurveytheinvitroactivityofteicoplanin,vancomycinandother9antibioticsagainstStaphylococcusspecies.MRSAweredetectedbyoxacillin-NaCl-containingscreenagar.ThehomologyofnosocomialMRSAfromICUandRCUwasdeterminedbypulse-fieldgelelectrophoresis.Agardiffusion,EtestandagardilutionwereusedtocomparetheinvitroactivityofteicoplaninandvancomycinagainstStaphylococcussppfrom2001to2003atPekingUnionMedicalCollegeHospital.WHONET-5.3softwarewasusedtoanalyzetheantimicrobialsusceptibilitydata.From2001to2003,theprevalencesofMRSAwere56.5%,65.3%,64.7%,respectively.PFGEfoundmostofMRSAfromICUandRCUwerecloselyrelated.AllofS.aureusandS.epidimidisisolatesweresusceptibletoteicoplaninandvancomycinfrom2001to2003.However,1isolateofS.haemolyticuswasresistantand9isolatesintermediatetoteicoplanin.Theminimalinhibitoryconcentrationofteicoplanindidnotcorrelatewellwithzonediameter,wheninoculumincreasedby100folds,thezonediametersofteicoplanindecreasedmoregreatlythanthoseofvancomycin.In2002,severeoutbreakscausedbyMRSAstrainshadbeenfoundinICUandRCUwards.TeicoplaninandvancomycinhadgoodactivityagainstclinicalisolatesofStaphylococcispp.TeicoplaninwaslessactivethanvancomycinagainstS.haemolyticus.MostofS.haemolyticusisolateswereintermediatetoteicoplanin.Antimicrobialsusceptibilitytestingofteicoplaninwasinfluencedbythediffusionspeedintheagarandinoculumsize.

简介：Thepurposeofthisinvestigationistostudytheclinicalcharacteristicsofinfectionsbycommunity-acquiredmethicillin-resistantStaphylococcusaureus(MRSA)andtheconditionofantibioticsresistanceoftheclinicalisolatesinordertoguidefortherationaluseofantibiotics.Withtheclinicalisolatesfromcasesofhospital-acquiredMRSAatthesameperiodascontro|s,theclinicalcharacteristicsofinfectionsbycommunity-acquiredMRSAinHangzhouareaandthepatternofnon-β-lactamaseantibioticsresistanceweredeterminedinthisstudy.Itwasfoundthattheaverageageofpatientswithcommunity-acquiredMRSAinfectionswas30.89+13.3,incomparisonwiththoseofthehospital-acquiredpatientsof56.0+11.8,appearingtobeyoungerthanthoseofthelatter,andtheformershowingnoanybasicillness.Bothoftheformerandthelatterweresensitivetovancomycin(100%vs100%),andtheyhadthesamedegreesofsensitivitytorifampicin,fosfomycin,andSTM/TMP(86.8%vs88.1%,P>0.05;81.6%vs82.9%,P>0.05;and52.6%vs61.9%,P>0.05,respectively).Theformerwasmoresensitivetonetimycin,chndamycin,erythromycinandminocyclinethanthoseofthelatter(73.7%vs50.5%,P<0.01;60.5%vs45.7%,P<0.05;28.9%vs11.4%,P<0.01;and81.6%vs58.6%,P<0.01respectively).Meanwhile,theincidenceofmulti-resistantstrainofisolatesintheformerwassignificantlylowerthanthatofthelatter(31.6%vs81.0%,P<0.01).Inconclusion,itappearsthatthestrainsofclinicalisolatesisolatedfrompatientswiththecommunity-acquiredMRSAinfectionsshowdifferentclinicalcharacteristicsandantimicrobialsusceptibilityincomparisonwiththoseofthehospital-acquiredcasesofinfection,andthisnecessitatesanalterationinthechemotherapyofinfectionssuspectedtobecausedbycommunity-acquiredMRSA.

简介：无

简介：AbstractObjective:In order to study the important role and molecular mechanism of Brevinin-2 family antimicrobial peptide Brevinin-2ISb in methicillin-resistant Staphylococcus aureus (MRSA) infection of Caenorhabditis (C.) elegans, and to find the optimal therapeutic concentration of Brevinin-2ISb.Methods:By using a C. elegans model and MRSA infection modelto study the therapeutic effect of different concentrations of Brevinin-2ISb on C. elegans. Real-time PCR was used for investigating the effect of Brevinin-2ISb on the downstream gene expression of DAF-2/DAF-16 innate immune pathway and the major virulence factor gene expression of MRSA. With protein activity tests to study the inhibitory effect of Brevinin-2ISb on MRSA virulence factor protein activity. Finally, laser confocal imaging was carried out to observe real-time expression and distribution of downstream antimicrobial proteins to further prove the effect of Brevinin-2ISb on the activation of DAF-2/DAF-16 pathway by in vivo imaging. All animal study procedures were approved by the Academic Committee at Xidian University and Xi’an Jiaotong University Animal Care and Use Committee, China (approval No. JGC201207) on July 15, 2017.Results:Host immunity was largely enhanced by Brevinin-2ISb, and the expression of staphylococcal enterotoxin genes, as well as virulence factors, was suppressed by Brevinin-2ISb. Indeed, the expression of many C. elegans innate immune genes, including lys-7, spp-1, K05D8.5 and C29F3.7, was induced by Brevinin-2ISb. In particular, robust, sustained expression of the antibacterial gene lys-7 was observed after Brevinin-2ISb treatment, resulting in increased protein levels. These effects correlated with a reduction in the MRSA-mediated death of the C. elegans host. Low concentrations of Brevinin-2ISb exhibited very low hemolytic activity, and may play a positive role in host innate immunity. Specifically, activation of the DAF-2/DAF-16 pathway appears to be essential for immune activation in C. elegans treated with Brevinin-2ISb. Based on the evolutionary conservation of innate immune pathways, our results suggest that Brevinin-2ISb not only has strong antibacterial activity, but may also enhance the innate immune response in humans. This study demonstrates that Brevinin-2ISb-related peptides are potential candidates for the development of novel anti-inflammatory or anti-microbial drugs.Conclusion:Antimicrobial peptide Brevinin-2ISb effectively inhibits MRSA at low concentration. This antimicrobial peptide can prolong the life of MRSA-infected C. elegans, has very low hemolytic activity and inhibits the activity and expression of various MRSA virulence factors. More importantly, Brevinin-2ISb activated the expression of antimicrobial genes downstream of DAF-2/DAF-16, which enhanced the MRSA resistance of C. elegans. This peptide could be used as the basis for developing new drugs to replace antibiotics.

简介：随着抗生素抗性污染日益严重,快速评估环境中典型病原菌与条件性致病菌的抗生素抗性水平,对掌握区域环境抗生素抗性污染状况、揭示抗性污染传播规律至关重要。通过以最低抑菌浓度浸入抗生素改进MI、VJ培养基,并结合滤膜法,建立了针对近岸海洋环境中指示性病原微生物大肠杆菌（Escherichiacoli,E.coli）与金黄色葡萄球菌（Staphylococcusaureus,S.aureus）的抗生素抗性监测方法。水体和沉积物样品抗生素抗性水平评估实验结果显示,该方法具有较好重现性（水体和沉积物中E.coli和S.aureus抗生素抗性水平的相对标准偏差分别为11%、8%）与准确度（水体和沉积物中E.coli和S.aureus的平均回收率分别为83.5%、68.4%;相对于CLSI药敏试验的偏离度为±0.1）。且与CLSI药敏实验相比,该方法过程简便、耗时短（36h/84h）,能最大限度节约经济和人员成本提高抗性评价效率。应用该方法评估辽河口与莱州湾环境中2种病原微生物磺胺类抗生素抗性水平,结果显示辽河口水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为27.0%、28.4%,沉积物中分别为35.5%、34.6%;莱州湾水体中E.coli和S.aureus磺胺二甲嘧啶的平均抗性率分别为26.0%、14.5%,沉积物中分别为12.0%、32.9%。该方法适用于河口、近岸海洋及入海排污口水体与沉积物样品中E.coli与S.aureus的快速分析及抗生素抗性水平评估。