ABSTRACT Staphylococcus aureus is a pathogen responsible for diverse severe infections. The global spread of methicillin-resistant S. aureus (MRSA) necessitates innovative therapeutic approaches beyond traditional antibiotics. S. aureus virulence mechanisms remain a critical concern. Targeting histidinol dehydrogenase (HisD), a key enzyme in histidine biosynthesis, presents a novel anti-virulence strategy. We used the derivative strains of Newman strains (ΔhisD, ΔhisD::pRAB-hisD, and WT::pRAB-hisD) and clinical strains to study the role of HisD in the pathogenicity of S. aureus. HisD inhibition by pixantrone was further evaluated. The absence of hisD significantly reduced hemolytic activity and biofilm formation, accompanied by the downregulation of virulence genes (hla, coa, hlgA-C, lukE/S/F, and NWMN_1873) and the saeR/S two-component system (P < 0.05). The expression of biofilm-inhibiting proteases was elevated, notably Aur and ScpA. Murine challenge revealed that ΔhisD exhibited 5.6-fold higher LD50 (4.17 × 109 CFU/mL vs. WT 7.42 × 108 CFU/mL) and reduced organ colonization (P < 0.05). Through structure-based virtual screening and SPR affinity verification, we discovered pixantrone—a nitrogenated anthraquinone—as a potent HisD inhibitor binding via four hydrogen bonds and two salt bridges. Pixantrone dose-dependently (25–200 μM) suppressed virulence phenotypes in vitro, achieving hemolysis inhibition, virulence gene inhibition, and biofilm reduction. In vivo, pixantrone (30 mg/kg) decreased serum CRP, IL-6, and TNF-α levels while diminishing abscess sizes and splenic bacterial loads (P < 0.05 vs. untreated). These findings establish HisD as a pivotal virulence regulator in S. aureus through saeR/S-mediated pathways. Pixantrone demonstrates potent anti-virulence efficacy, positioning HisD inhibition as a promising therapeutic strategy against S. aureus infections. This study provides foundational insights for developing HisD-targeted agents to combat antibiotic-resistant staphylococcal pathogens.IMPORTANCEThe increase in drug-resistant Staphylococcus aureus (MRSA) demands therapies that block virulence without promoting resistance. We identify histidinol dehydrogenase (HisD), a histidine-synthesis enzyme, as a key controller of S. aureus pathogenicity. Disrupting HisD genetically or with pixantrone—a newly identified inhibitor—reduces bacterial toxicity, biofilm formation, and virulence gene activity while improving survival and reducing organ damage in infected mice. Pixantrone's dose-dependent suppression of infection severity and inflammation positions it as a therapeutic candidate. Unlike traditional antibiotics, this strategy disarms bacteria rather than killing them, reducing resistance risks. By uncovering HisD’s role in connecting metabolism to virulence through the saeR/S system, we reveal a druggable target for fighting multidrug-resistant infections. This work addresses the urgent need for innovative solutions to the global antibiotic resistance crisis, paving the way for therapies that outsmart evolving superbugs.

ABSTRACT Glutamate metabolism plays a pivotal role in linking the tricarboxylic acid cycle, arginine biosynthesis, and purine metabolism, and these pathways have been shown to be involved in persister formation. However, the relationship among glutamate metabolism, bacterial antibiotic tolerance, and virulence remains unclear. In this study, gltB, which encodes the large subunit of glutamate synthase in Staphylococcus aureus, was knocked out. The ∆ gltB mutant in the stationary phase showed less tolerance to antibiotics and was killed completely after exposure to lethal doses of ampicillin and norfloxacin after 11 and 6 days, respectively, while the parent strain still had abundant viable bacteria. The gltB complemented strain restored antibiotic tolerance. Interestingly, exogenous glutamate supplementation of ∆ gltB restored the tolerance to antibiotics. Moreover, ∆ gltB is more susceptible to heat, carbon starvation, and oxidative stress. Furthermore, the ability of ∆ gltB to coagulate plasma, produce staphyloxanthin, and form biofilms was significantly weakened. In addition, ∆ gltB attenuated virulence in BALB/c mice, and its 50% lethal dose (LD50) (1.14 × 10 10 CFU/mL, 95% CI: 7.29 × 10 9 –2.75 × 10 10 ) was higher than that of the parent strain (2.39 × 10 9 CFU/mL, 95% CI: 9.99 × 10 8 –4.42 × 10 9 ). The expression levels of major virulence genes, including eta, hla, hlgA, hlgC, lukD, lukE, lukS, lukF, and sea, as well as staphyloxanthin synthesis-related genes, including crtM and c rtQ, were significantly downregulated in ∆ gltB . This study revealed that gltB is involved in both antibiotic tolerance and virulence in S. aureus and provides new insights into the mechanism of persister formation and virulence, with implications for the development of novel drugs. IMPORTANCE Staphylococcus aureus is a leading bacterial cause of death, and persister formation renders it tolerant to antibiotics and is associated with its persistent infections. Glutamate metabolism plays a critical role in linking the tricarboxylic acid cycle, arginine biosynthesis, and purine metabolism, and these pathways have been shown to be involved in persister formation. This work first discovered that gltB , the large subunit of glutamate synthase gene in S. aureus , is involved in tolerance to antibiotics and heat, carbon starvation, and oxidative stress. Furthermore, the gltB mutant attenuated virulence in mice, owing to the inhibition of glutamate synthesis, which significantly weakened the ability of S. aureus to coagulate plasma, produce staphyloxanthin, form biofilms, and express virulence factors. These findings confirm the important role of glutamate metabolism in the formation of persister and virulence in S. aureus and provide new targets for developing novel anti-persister and anti-virulence drugs.

Previous studies revealed that both Helicobacter pylori infection and some cytokine gene polymorphisms are risk factors for gastric diseases. The association between H. pylori and gene polymorphisms is worth exploring. Here we conducted a case-control study and systematically evaluate on association between H. pylori infection and IL4, TNFA, and IL10 polymorphisms in a Chinese Han population in northwestern China, where gastric cancer is the major burden on the health and the leading cause of death in local community. The Sequenom MassArray platform was used to screen the genotypes and C-14-urea breath test was employed to determine H. pylori infection status of 705 participants of the local rural residents. Significant association between H. pylori infection and the IL4 rs34142320 polymorphism was observed in the dominant model (OR = 0.57, 95% CI = 0.40-0.80, P = 0.030). No significant association was found between IL4 rs2243250, TNFA rs1800630, TNFA rs1800629, TNFA rs1799964, IL10 rs1800871, IL10 rs1800896 and H. pylori infection. Haplotype analysis showed that T-DEL and G-C haplotypes of the observed IL4 SNPs were significantly associated with H. pylori infection. Our analysis demonstrated that the IL4 rs34142320 polymorphism has a protective effect on H. pylori infection in Chinese Han population.

Staphylococcus aureus can cause chronic infections which are closely related to persister formation. Purine metabolism is involved in S. aureus persister formation, and purN, encoding phosphoribosylglycinamide formyltransferase, is an important gene in the purine metabolism process. In this study, we generated a ΔpurN mutant of the S. aureus Newman strain and assessed its roles in antibiotic tolerance and virulence. The ΔpurN in the late exponential phase had a significant defect in persistence to antibiotics. Complementation of the ΔpurN restored its tolerance to different antibiotics. PurN significantly affected virulence gene expression, hemolytic ability, and biofilm formation in S. aureus. Moreover, the LD50 (3.28 × 1010 CFU/mL) of the ΔpurN for BALB/c mice was significantly higher than that of the parental strain (2.81 × 109 CFU/mL). Transcriptome analysis revealed that 58 genes that were involved in purine metabolism, alanine, aspartate, glutamate metabolism, and 2-oxocarboxylic acid metabolism, etc., were downregulated, while 24 genes involved in ABC transporter and transferase activity were upregulated in ΔpurN vs. parental strain. Protein-protein interaction network showed that there was a close relationship between PurN and GltB, and SaeRS. The study demonstrated that PurN participates in the formation of the late exponential phase S. aureus persisters via GltB and regulates its virulence by activating the SaeRS two-component system.

新型冠状病毒疫情的流行给全球人民健康带来了巨大威胁,生物安全防控问题再一次引起国家的高度重视,对于医护人员感染的防护提出了更高要求,由此对于医学生的生物安全教育和生物安全实验室的管理有必要进行重新审视并进一步完善.以兰州大学医学部为例,在总结了高校开展工作的现状与已取得成绩的基础上,针对尚存的问题和新冠疫情下的新要求,从教育体系、管理体系和保障体系三方面对医学生物安全教育与实验室管理进行再思考,提出建议与实施方案,期望在不断的改进下,使我国医学院校在培养医务人才的初期,在生物安全防控的教育与管理方面更上一层楼.

利用专业知识教学进行课程思政教育是高校开展立德树人教育的重要举措.建设基础医学课程思政教育案例库,发挥在课程思政教学中的指南作用,将对提升相关课程的思政教育水平、提高医学人才培养质量产生重要影响.该研究探讨了通过组建团队、挖掘和梳理思政元素、专家审核、科学归纳和整合等,并通过应用信息化管理技术和撰写教学辅导用书,建设基础医学课程思政教育案例库、并在实践中不断完善和升级的方式和方法.

基于岗位胜任力的要求,为适应现代医学特点,阐明了课程整合的必要性.以器官系统为框架梳理了"病原生物学"与"免疫学"两门课程内容,同时结合CBL教学,围绕培养目标,以问题为导向,探讨建立全新的课程模式.通过学科的整合减少了教学内容的重复,弥合了基础与临床医学分离的缺点,落实了以学生为中心、以任务为导向的现代医学教育理念,推动了基础医学拔尖人才和卓越医师培养,提升了人才培养质量.最后指出了课程整合中存在的教师教学能力有待提高、缺乏权威整合教材等问题.

挖掘临床微生物学检验课程中蕴含的思政元素,以课程为载体,以思政教育为灵魂,在教学中贯穿思政元素,增强检验医学生职业认同感、社会责任感,培养德才兼备的高素质检验医学人才.

Staphylococcus aureus can be converted to cell wall-deficient L-form bacteria in specific environment which is associated with recurrent and persistent infections. The biophysical properties and molecular basis involved in S. aureus L-form formation are poorly understood. Here, S. aureus unstable L-form model was established not only in Newman strain, but also in ATCC 25923 and five different antibiotic-resistant clinical strains, and the morphology and mechanical properties of Newman strain L-forms were characterized by using atomic force microscopy. Meanwhile, zeta potential, growth and proliferation properties, and hemolysis of L-forms were determined. Gene expression changes involved in transition from S. aureus wild type into L-forms were identified. Our studies showed that L-form S. aureus presented pleomorphism, rough surface, and higher elasticity modulus. L-forms were characterized by less surface charge and had higher hemolysis than the walled form. The S. aureus L-form "fried egg" colony was derived from a single bacterium rather than from aggregation of different bacterial cells. Transcriptomics analysis revealed that several pathways involved in energy metabolism, stress response, protein synthesis, RNA metabolism, and virulence were involved in L-form formation in S. aureus. Our results shed new light on the biological properties and mechanisms underlying L-form formation in S. aureus. These findings will not only be useful for understanding the unique properties and mechanisms of L-form bacteria, but also provide therapeutic targets for developing more effective treatments for S. aureus L-forms.

Staphylococcus aureus is the leading cause of wound and nosocomial infections. Persister formation and virulence factors play crucial roles during S. aureus infection. However, the mechanisms of persister formation and its relationship to virulence in S. aureus are poorly understood. In this study, we screened a transposon mutant library and identified a LysR-type global transcriptional regulator NWMN_0037, which we called RpvA, for regulator of persistence and virulence, whose mutation leads to higher susceptibility to antibiotics ampicillin and norfloxacin and various stresses including oxidative stress, heat, and starvation in late exponential and early stationary phase. Interestingly, the rpvA mutant was highly attenuated for virulence compared with the parent S. aureus Newman strain as shown by a much higher lethal dose, reduced ability to survive in macrophages and to form abscess in the mouse model. Transcriptional profiling and metabolomic analysis revealed that RpvA could repress multiple genes including gapR , gapA , tpi , pgm , eno , glpD , and acs expression and enhance production of numerous intermediate metabolites including dihydroxyacetone phosphate, 2-phosphoglycerate, acetyl-CoA, glycerol 3-phosphate, L-glutamate in the cells. The differentially expressed genes and altered production of metabolites are distributed in global metabolism including carbohydrate metabolism, amino acid metabolism, energy metabolism and metabolism of cofactors and vitamins. These metabolic adjustments could cause the cell to go into dormancy, thus promoting S. aureus to convert to persisters. In addition, RpvA could upregulate the expression of virulence genes including hla , hlgA , hlgB , hlgC , lukF , lukS , lukD , sea and coa , and carotenoid biosynthesis genes ( crtI , crtM , crtN ). Gel shift assay confirmed that RpvA could bind to the promoters of candidate target genes hla , hlgB and crtM , thus promoting S. aureus virulence. Because of the important functions of the RpvA, it may serve as an attractive target for developing new drugs and vaccines to more effectively control S. aureus infections.

病原微生物实验室存在可感染操作者的危险生物因子,重视医学生培养中的实验室生物安全问题是人才培养中师生安全的需要,同时,将在源头上提升今后医务工作者的生物安全防范能力,是长远之计.本科在校阶段是进行实验室生物安全教育的最佳时期.影响提升医学生病原微生物实验室生物安全防范能力的因素很多,主要包括以下几个关键环节:提升管理层的重视;加强师资队伍的实验室生物安全意识和技能培训;强化理论和实验教学,提升医学生生物安全防范意识;结合现代数字化技术,建设相关资料库,提升教学质量;加强实验室生物安全硬件和管理体系建设;重视培养医学生对意外生物安全事故的应急处理能力;关注其他医学学科领域的生物安全问题等.

生物安全涉及医学、生物学、农学、军事科学等多学科的教学和科研领域.医学生物安全涉及医学人才培养、科学研究和临床实践的多个环节,本文通过总结这些环节中的危险生物因子防范问题,分析和探讨了医学生物安全的范畴、特征、内容和提升防范的方法,为进一步提升我国医学生物安全防范教育水平提供思路.

目的 探讨胃癌高发区河西走廊地区患者幽门螺杆菌(Hp)iceA和babA基因型的分布及其与消化道疾病相关因素的关系.方法 收集甘肃省第二人民医院、张掖市人民医院、武威市肿瘤医院及金川公司职工医院82例胃镜检查患者的胃黏膜标本、从胃黏膜中分离并培养H p菌株,设计引物进行PC R扩增及基因型判定,通过病例资料整理,分析Hp菌株中iceA和babA2基因不同基因型与患者临床病理类型、性别和年龄的关系.结果 分离Hp菌株并成功扩增73份目的基因,其中Hp iceA1型和2型的构成比分别为76.71％(56/73)和23.29％(17/73),babA2基因型为38.36％(28/73).Hp iceA1型在浅表性胃炎、萎缩性胃炎、消化性溃疡组的患者中的感染率均明显高于iceA2型(P<0.05),而胃癌组患者Hp iceA1型感染率均明显低于iceA2型(P<0.05);Hp iceA1型在20～<41岁、41～<61岁年龄组的患者中的感染率均显著高于iceA2型(P<0.05),不同性别患者间iceA基因型H p感染率比较差异无统计学意义(P>0.05).消化性溃疡、胃癌患者中babA2型感染率明显高于其他病理组(P<0.05);不同年龄及性别患者间babA2基因型Hp感染率比较,差异无统计学意义(P>0.05).结论 河西走廊地区H p菌株iceA基因均为阳性并且以1型为主,其分布与患者的疾病类型、年龄相关;babA2基因型感染多与消化性溃疡和胃癌有关.

病原生物学是由医学微生物学和人体寄生虫学整合而成的学科.根据学科发展和教学需求,需要编写《病原生物学》教材.项目组在该教材编写中进行了如下探索,包括:遵循“三基五性”原则,努力做好传承和创新;深度融合病原生物的共性特征,形成特色鲜明的总论;遵循学科特点、教学对象及传统习惯,调整各论内容;统一教材中的概念和内容;做好纠错、去旧和补新工作;融入数字资源新模块;密切联系临床.

[目的]系统评价黄连素联合硫糖铝治疗慢性胃炎的临床疗效与安全性.[方法]检索数据库关于黄连素联合硫糖铝治疗慢性胃炎的文献,时间截止至2017年9月.建立比例优势比模型,以对数优势比lnOR作为临床疗效分析的效应量;采用Stata11.0软件进行有序数据的Meta分析.[结果]联合用药的疗效优于黄连素单独用药[lnOR=1.11,95％CI(0.95,1.27),P＜0.0001],其不良反应率与黄连素单独用药比较差异无统计学意义[OR=1.03,95％CI(0.65,1.63),P=0.906].[结论]现有证据表明,黄连素与硫糖铝治疗慢性胃炎可提高临床疗效且使用安全.

The case-based teaching was inserted in the lecture-based teaching in clinical microbiol-ogy. The teachers conducted the case-based teaching through proper selection of cases, leading students to discuss and analyze cases. The students explored and reported from the cases independently. Finally, the teachers summarized and evaluated from the case-based teaching. The combination of case-based teaching and lecture-based study stimulated the students' interest in learning and motivation, consolidated their theoretical knowledge, cultivated their abilities of self-learning and clinical idea, and made the correlation between the theory and the clinical practice closely. These methods improved the teaching quality of clinical microbiology.

幽门螺杆菌(Hp)感染与胃炎、消化性溃疡、胃癌的发生相关[1].全球50％以上的人群存在Hp感染,但大多数感染者并不出现或仅出现较轻的临床症状,仅20％左右的感染者会发展为消化性溃疡,极少数感染者最终发展为胃癌等严重疾病[2].Hp感染后的多样性临床结局提示其具有复杂的致病机制,Hp菌株的定植黏附及毒力因子、宿主的易感性与反应性以及社会环境因素均与其相关[3].

目的:探讨陇马陆分别与红芪、黄连、红景天、马齿苋、蒲公英配伍后的抗幽门螺杆菌(Helicobacter pylori,Hp)作用以及药物间是否有协同效应.方法:采用水提法和醇提法提取上述药物配方及陇马陆、红景天和黄连单药的有效成分,应用纸片琼脂扩散法筛选上述配方对Hp的抑制作用;建立Hp液体培养模型,采用稀释法测定陇马陆、黄连、红景天单药及复方提取物的抗Hp最小抑菌浓度(minimal inhibitory concentration,MIC),并比较药物间配伍后的协同效应.结果:陇马陆与红芪、红景天、黄连、马齿苋、蒲公英药配伍后对Hp均有抑制作用,以与黄连配伍后抑制作用最强;陇马陆、黄连、红景天、陇马陆-黄连、陇马陆-红景天对Hp的MIC分别为20~40、0.63~1.25、1.25~2.50、1.25~2.50、10~20 mg/mL;与陇马陆配伍后,黄连和红景天的抗Hp MIC仅为单药的1/2倍.结论:陇马陆分别与红芪、红景天、黄连、马齿苋、蒲公英配伍对Hp均有一定的抑菌作用;陇马陆与黄连、红景天配伍后可产生抗Hp的协同效应;Hp液体培养稀释法可以有效判断中药的抗Hp效能.

Objective To investigate the characteristics of persistence formation of four important pathogens,including Staphylococcus aureus,Enterococcus faecalis,Shigella flexneri and Pseudomonas aeruginosa,against antimicrobial agents under cultural conditions.Methods The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the four pathogens against the antimicrobial agents were determined by the microdilution method.The antimicrobial agents at 10 to 100 folds MIC concentrations were used to carry out exposure experiments with cultured bacteria.S.aureus,E.faecalis,S.flexneri,and P.aeruginosa were exposed against norfloxacin (100 μg/mL),ampicillin (390.63 μg/mL),norfloxacin (50 μg/mL) and norfloxacin (100 μg/mL) respectively.The characteristic changes in the persistence formation of the four pathogens were analyzed by counting the number of viable cells in the liquid cultures with time extension.Results Under exposure to high concentrations of antimicrobial agents,the four pathogens generally showed similar characteristics.The bacteria in the logarithmic phase could be killed by a high concentrations of antimicrobial agents in several hours to three days,while in stationary phase there were still a large number of bacterial survival after they were exposed to the drugs for one week.Conclusion The persistence formation against antimicrobial agents under cultural conditions of S.aureus,E.faecalis,S.flexneri and P.aeruginosa showed the same characteristics,indicating few persisters forming in the logarithmic phase while numerous persisters forming in the stationary phase.

Background: Staphylococcus aureus is a prominent pathogen responsible for human pyogenic and nosocomial infections. Although numerous studies on S. aureus L-forms and virulence are available in the literatures, there are still various impediments in the research methods employed. Objectives: This study aimed to perform fluorescence reporter in studying S. aureus L-form and its virulence, and wild strain virulence. Methods: Newman-pCM29 strain which can express green fluorescent protein (GFP) was constructed and used to detect S. aureus L-form formation and virulence in vitro and in vivo. Results: “Fried egg” like L-form colonies of GFP reporter S. aureus and the dense core of the colonies embedded into soft agar can be observed obviously. GFP reporter can contribute to preparing L-form suspension for injection and track the protoplasts and reverted cells in lesions of mice. GFP reporter, also, can help to detect S. aureus wild strain distribution and inflammation scope in lesions, and the fluorescence intensity can be used as an effective surrogate to represent the bacterial quantity in lesions. Fluorescence can improve to distinguish the colonies of varying sizes derived from the injected bacteria or from contaminants. Conclusions: Fluorescence reporter in S. aureus is a powerful tool which can provide new insight into S. aureus L-form formation in vitro and its fate in vivo, and wild strain virulence in vivo in a non-traditional manner.