Pub Date : 2024-12-01Epub Date: 2024-10-17DOI: 10.1080/21505594.2024.2411543
Tianhong Zheng, Lingyu Ji, Yi Chen, Chengjun Cao, Jian Bing, Tianren Hu, Qiushi Zheng, Dan Wu, Haiqing Chu, Guanghua Huang
Candida krusei, also known as Pichia kudriavzevii, is an emerging non-albicans Candida (NAC) species causing both superficial and deep-seated infections in humans. This fungal pathogen is inherently resistant to the first-line antifungal drug, fluconazole, and is widely distributed in natural environments such as soil, foods, vegetables, and fruits. In this study, we collected 86 C. krusei strains from clinical settings and traditional fermented vegetables from different areas of China. Compared to C. krusei strains from fermented vegetables, clinical isolates exhibited a higher ability to undergo filamentation and biofilm development, which could facilitate its host colonization and infections. Isolates from fermented vegetables showed higher resistance to several antifungal drugs including fluconazole, voriconazole, itraconazole, amphotericin B, and caspofungin, than clinical strains, while they were more susceptible to posaconazole than clinical strains. Although C. krusei has been thought to be a diploid organism, we found that one-fourth of clinical strains and the majority of isolates from fermented vegetables (87.5%) are triploid. Whole-genome sequencing and population genetic analyses demonstrated that isolates from clinical settings and fermented food are genetically associated, and distributed across a wide range of genetic clusters. Additionally, we found that six nucleotide substitutions at the promoter region of the ABC11 gene, encoding a multidrug efflux pump, could play a critical role in antifungal resistance in this species. Given the ubiquitous distribution of C. krusei strains in fermented vegetables and their genetic association with clinical strains, a One Health approach will be necessary to control the prevalence of this pathogen.
{"title":"Biology and genetic diversity of <i>Candida krusei</i> isolates from fermented vegetables and clinical samples in China.","authors":"Tianhong Zheng, Lingyu Ji, Yi Chen, Chengjun Cao, Jian Bing, Tianren Hu, Qiushi Zheng, Dan Wu, Haiqing Chu, Guanghua Huang","doi":"10.1080/21505594.2024.2411543","DOIUrl":"10.1080/21505594.2024.2411543","url":null,"abstract":"<p><p><i>Candida krusei</i>, also known as <i>Pichia kudriavzevii</i>, is an emerging non-<i>albicans Candida</i> (NAC) species causing both superficial and deep-seated infections in humans. This fungal pathogen is inherently resistant to the first-line antifungal drug, fluconazole, and is widely distributed in natural environments such as soil, foods, vegetables, and fruits. In this study, we collected 86 <i>C. krusei</i> strains from clinical settings and traditional fermented vegetables from different areas of China. Compared to <i>C. krusei</i> strains from fermented vegetables, clinical isolates exhibited a higher ability to undergo filamentation and biofilm development, which could facilitate its host colonization and infections. Isolates from fermented vegetables showed higher resistance to several antifungal drugs including fluconazole, voriconazole, itraconazole, amphotericin B, and caspofungin, than clinical strains, while they were more susceptible to posaconazole than clinical strains. Although <i>C. krusei</i> has been thought to be a diploid organism, we found that one-fourth of clinical strains and the majority of isolates from fermented vegetables (87.5%) are triploid. Whole-genome sequencing and population genetic analyses demonstrated that isolates from clinical settings and fermented food are genetically associated, and distributed across a wide range of genetic clusters. Additionally, we found that six nucleotide substitutions at the promoter region of the <i>ABC11</i> gene, encoding a multidrug efflux pump, could play a critical role in antifungal resistance in this species. Given the ubiquitous distribution of <i>C. krusei</i> strains in fermented vegetables and their genetic association with clinical strains, a One Health approach will be necessary to control the prevalence of this pathogen.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11487970/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142366735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-10-29DOI: 10.1080/21505594.2023.2284513
S M Hossein Khademi, Cecilia Sahl, Lotta Happonen, Åke Forsberg, Lisa I Påhlman
Achromobacter xylosoxidans is an emerging pathogen that causes airway infections in patients with cystic fibrosis. Knowledge of virulence factors and protein secretion systems in this bacterium is limited. Twin arginine translocation (Tat) is a protein secretion system that transports folded proteins across the inner cell membranes of gram-negative bacteria. Tat has been shown to be important for virulence and cellular processes in many different bacterial species. This study aimed to investigate the role of Tat in iron metabolism and host cell adhesion in A. xylosoxidans. Putative Tat substrates in A.xylosoxidans were identified using the TatFind, TatP, and PRED-Tat prediction tools. An isogenic tatC deletion mutant (ΔtatC) was generated and phenotypically characterized. The wild-type and ΔtatC A.xylosoxidans were fractionated into cytosolic, membrane, and periplasmic fractions, and the expressed proteome of the different fractions was analysed using liquid chromatography-mass spectrometry (LC-MS/MS). A total of 128 putative Tat substrates were identified in the A.xylosoxidans proteome. The ΔtatC mutant showed attenuated host cell adhesion, growth rate, and iron acquisition. Twenty predicted Tat substrates were identified as expressed proteins in the periplasmic compartment, nine of which were associated with the wild type. The data indicate that Tat secretion is important for iron acquisition and host cell adhesion in A.xylosoxidans.
{"title":"The twin-arginine translocation system is vital for cell adhesion and uptake of iron in the cystic fibrosis pathogen <i>Achromobacter xylosoxidans</i>.","authors":"S M Hossein Khademi, Cecilia Sahl, Lotta Happonen, Åke Forsberg, Lisa I Påhlman","doi":"10.1080/21505594.2023.2284513","DOIUrl":"10.1080/21505594.2023.2284513","url":null,"abstract":"<p><p><i>Achromobacter xylosoxidans</i> is an emerging pathogen that causes airway infections in patients with cystic fibrosis. Knowledge of virulence factors and protein secretion systems in this bacterium is limited. Twin arginine translocation (Tat) is a protein secretion system that transports folded proteins across the inner cell membranes of gram-negative bacteria. Tat has been shown to be important for virulence and cellular processes in many different bacterial species. This study aimed to investigate the role of Tat in iron metabolism and host cell adhesion in <i>A. xylosoxidans</i>. Putative Tat substrates in <i>A.</i> <i>xylosoxidans</i> were identified using the TatFind, TatP, and PRED-Tat prediction tools. An isogenic <i>tatC</i> deletion mutant (ΔtatC) was generated and phenotypically characterized. The wild-type and ΔtatC <i>A.</i> <i>xylosoxidans</i> were fractionated into cytosolic, membrane, and periplasmic fractions, and the expressed proteome of the different fractions was analysed using liquid chromatography-mass spectrometry (LC-MS/MS). A total of 128 putative Tat substrates were identified in the <i>A.</i> <i>xylosoxidans</i> proteome. The ΔtatC mutant showed attenuated host cell adhesion, growth rate, and iron acquisition. Twenty predicted Tat substrates were identified as expressed proteins in the periplasmic compartment, nine of which were associated with the wild type. The data indicate that Tat secretion is important for iron acquisition and host cell adhesion in <i>A.</i> <i>xylosoxidans</i>.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11533796/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136399456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recombinant Muscovy duck parvovirus (rMDPV) is a product of genetic recombination between classical Muscovy duck parvovirus (MDPV) and goose parvovirus (GPV). The recombination event took place within a 1.1-kb DNA segment located in the middle of the VP3 gene, and a 187-bp sequence extending from the P9 promoter to the 5' initiation region of the Rep1 ORF. This resulted in the alteration of five amino acids within VP3. Despite these genetic changes, the precise influence of recombination and amino acid mutations on the pathogenicity of rMDPV remains ambiguous. In this study, based on the rMDPV strain ZW and the classical MDPV strain YY, three chimeric viruses (rZW-mP9, rZW-mPR187, and rYY-rVP3) and the five amino acid mutations-introduced mutants (rZW-g5aa and rYY-5aa(ZW)) were generated using reverse genetic technology. When compared to the parental virus rZW, rZW-g5aa exhibited a prolonged mean death time (MDT) and a decreased median lethal dose (ELD50) in embryonated duck eggs. In contrast, rYY-5aa(ZW) did not display significant differences in MDT and ELD50 compared to rYY. In 2-day-old Muscovy ducklings, infection with rZW-g5aa and rYY-5aa(ZW) resulted in mortality rates of only 20% and 10%, respectively, while infections with the three chimeric viruses (rZW-mP9, rZW-mPR187, rYY-rVP3) and rZW still led to 100% mortality. Notably, rYY-rVP3, containing the VP3 region from strain ZW, exhibited 50% mortality in 6-day-old Muscovy ducklings and demonstrated significant horizontal transmission. Collectively, our findings indicate that recombination and consequent amino acid changes in VP3 have a synergistic impact on the heightened virulence of rMDPV in Muscovy ducklings.
{"title":"Recombination and amino acid point mutations in VP3 exhibit a synergistic effect on increased virulence of rMDPV.","authors":"Jianye Wang, Wanmei Li, Xiaoyan Gong, Zhixian Wang, Yu Wang, Jueyi Ling, Zhiwei Jiang, Guoqiang Zhu, Yufeng Li","doi":"10.1080/21505594.2024.2366874","DOIUrl":"10.1080/21505594.2024.2366874","url":null,"abstract":"<p><p>Recombinant Muscovy duck parvovirus (rMDPV) is a product of genetic recombination between classical Muscovy duck parvovirus (MDPV) and goose parvovirus (GPV). The recombination event took place within a 1.1-kb DNA segment located in the middle of the VP3 gene, and a 187-bp sequence extending from the P9 promoter to the 5' initiation region of the Rep1 ORF. This resulted in the alteration of five amino acids within VP3. Despite these genetic changes, the precise influence of recombination and amino acid mutations on the pathogenicity of rMDPV remains ambiguous. In this study, based on the rMDPV strain ZW and the classical MDPV strain YY, three chimeric viruses (rZW-mP9, rZW-mPR187, and rYY-rVP3) and the five amino acid mutations-introduced mutants (rZW-g5aa and rYY-5aa(ZW)) were generated using reverse genetic technology. When compared to the parental virus rZW, rZW-g5aa exhibited a prolonged mean death time (MDT) and a decreased median lethal dose (ELD<sub>50</sub>) in embryonated duck eggs. In contrast, rYY-5aa(ZW) did not display significant differences in MDT and ELD<sub>50</sub> compared to rYY. In 2-day-old Muscovy ducklings, infection with rZW-g5aa and rYY-5aa(ZW) resulted in mortality rates of only 20% and 10%, respectively, while infections with the three chimeric viruses (rZW-mP9, rZW-mPR187, rYY-rVP3) and rZW still led to 100% mortality. Notably, rYY-rVP3, containing the VP3 region from strain ZW, exhibited 50% mortality in 6-day-old Muscovy ducklings and demonstrated significant horizontal transmission. Collectively, our findings indicate that recombination and consequent amino acid changes in VP3 have a synergistic impact on the heightened virulence of rMDPV in Muscovy ducklings.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11178272/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141311938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-06-20DOI: 10.1080/21505594.2024.2367648
Nakjun Choi, Eunna Choi, Yong-Joon Cho, Min Jung Kim, Hae Woong Choi, Eun-Jin Lee
The emergence of multidrug-resistant bacteria poses a significant threat to human health, necessitating a comprehensive understanding of their underlying mechanisms. Uropathogenic Escherichia coli (UPEC), the primary causative agent of urinary tract infections, is frequently associated with multidrug resistance and recurrent infections. To elucidate the mechanism of resistance of UPEC to beta-lactam antibiotics, we generated ampicillin-resistant UPEC strains through continuous exposure to low and high levels of ampicillin in the laboratory, referred to as Low AmpR and High AmpR, respectively. Whole-genome sequencing revealed that both Low and High AmpR strains contained mutations in the marR, acrR, and envZ genes. The High AmpR strain exhibited a single additional mutation in the nlpD gene. Using protein modeling and qRT-PCR analyses, we validated the contributions of each mutation in the identified genes to antibiotic resistance in the AmpR strains, including a decrease in membrane permeability, increased expression of multidrug efflux pump, and inhibition of cell lysis. Furthermore, the AmpR strain does not decrease the bacterial burden in the mouse bladder even after continuous antibiotic treatment in vivo, implicating the increasing difficulty in treating host infections caused by the AmpR strain. Interestingly, ampicillin-induced mutations also result in multidrug resistance in UPEC, suggesting a common mechanism by which bacteria acquire cross-resistance to other classes of antibiotics.
{"title":"A shared mechanism of multidrug resistance in laboratory-evolved uropathogenic <i>Escherichia coli</i>.","authors":"Nakjun Choi, Eunna Choi, Yong-Joon Cho, Min Jung Kim, Hae Woong Choi, Eun-Jin Lee","doi":"10.1080/21505594.2024.2367648","DOIUrl":"10.1080/21505594.2024.2367648","url":null,"abstract":"<p><p>The emergence of multidrug-resistant bacteria poses a significant threat to human health, necessitating a comprehensive understanding of their underlying mechanisms. Uropathogenic <i>Escherichia coli</i> (UPEC), the primary causative agent of urinary tract infections, is frequently associated with multidrug resistance and recurrent infections. To elucidate the mechanism of resistance of UPEC to beta-lactam antibiotics, we generated ampicillin-resistant UPEC strains through continuous exposure to low and high levels of ampicillin in the laboratory, referred to as Low Amp<sup>R</sup> and High Amp<sup>R</sup>, respectively. Whole-genome sequencing revealed that both Low and High Amp<sup>R</sup> strains contained mutations in the <i>marR</i>, <i>acrR</i>, and <i>envZ</i> genes. The High Amp<sup>R</sup> strain exhibited a single additional mutation in the <i>nlpD</i> gene. Using protein modeling and qRT-PCR analyses, we validated the contributions of each mutation in the identified genes to antibiotic resistance in the Amp<sup>R</sup> strains, including a decrease in membrane permeability, increased expression of multidrug efflux pump, and inhibition of cell lysis. Furthermore, the Amp<sup>R</sup> strain does not decrease the bacterial burden in the mouse bladder even after continuous antibiotic treatment <i>in vivo</i>, implicating the increasing difficulty in treating host infections caused by the Amp<sup>R</sup> strain. Interestingly, ampicillin-induced mutations also result in multidrug resistance in UPEC, suggesting a common mechanism by which bacteria acquire cross-resistance to other classes of antibiotics.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11195483/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141427760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increasing antibiotic resistance poses a significant global health challenge, threatening our ability to combat infectious diseases. The phenomenon of collateral sensitivity, whereby resistance to one antibiotic is accompanied by increased sensitivity to another, offers potential avenues for novel therapeutic interventions against infections unresponsive to classical treatments. In this study, we elucidate the emergence of tobramycin (TOB)-resistant small colony variants (SCVs) due to mutations in the hemL gene, which render S. Typhimurium more susceptible to nitrofurantoin (NIT). Mechanistic studies demonstrate that the collateral sensitivity in TOB-resistant S. Typhimurium SCVs primarily stems from disruptions in haem biosynthesis. This leads to dysfunction in the electron transport chain (ETC) and redox imbalance, ultimately inducing lethal accumulation of reactive oxygen species (ROS). Additionally, the upregulation of nfsA/B expressions facilitates the conversion of NIT prodrug into its active form, promoting ROS-mediated bacterial killing and contributing to this collateral sensitivity pattern. Importantly, alternative NIT therapy demonstrates a significant reduction of bacterial load by more than 2.24-log10 cfu/g in the murine thigh infection and colitis models. Our findings corroborate the collateral sensitivity of S. Typhimurium to nitrofurans as a consequence of evolving resistance to aminoglycosides. This provides a promising approach for treating infections due to aminoglycoside-resistant strains.
抗生素耐药性的不断增加对全球健康构成了重大挑战,威胁着我们抗击传染病的能力。对一种抗生素产生耐药性的同时,对另一种抗生素的敏感性也随之增加,这种附带敏感性现象为治疗对传统疗法无反应的感染提供了新的潜在途径。在这项研究中,我们阐明了因 hemL 基因突变而出现的对妥布霉素(Tobramycin,TOB)耐药的小菌落变异体(SCVs),这种变异体使 S. Typhimurium 对硝基呋喃妥因(NIT)更敏感。机理研究表明,耐 TOB 的 S. Typhimurium SCVs 的附带敏感性主要源于血红素生物合成的中断。这导致电子传递链(ETC)功能失调和氧化还原失衡,最终诱发致命的活性氧(ROS)积累。此外,nfsA/B 表达的上调促进了 NIT 原药向其活性形式的转化,促进了 ROS 介导的细菌杀伤,并促成了这种附带敏感性模式。重要的是,在小鼠大腿感染和结肠炎模型中,NIT 替代疗法可显著减少细菌负荷,减少量超过 2.24-log10 cfu/g。我们的研究结果证实,由于对氨基糖苷类药物的耐药性不断发展,伤寒杆菌对硝基呋喃类药物具有附带敏感性。这为治疗耐氨基糖苷类药物菌株引起的感染提供了一种很有前景的方法。
{"title":"Tobramycin-resistant small colony variant mutant of <i>Salmonella enterica</i> serovar Typhimurium shows collateral sensitivity to nitrofurantoin.","authors":"Chang-Zhen Wang, Yue-Jun Zhang, Yue-Fei Chu, Long-Gen Zhong, Jin-Peng Xu, Liu-Yan Liang, Teng-Fei Long, Liang-Xing Fang, Jian Sun, Xiao-Ping Liao, Yu-Feng Zhou","doi":"10.1080/21505594.2024.2356692","DOIUrl":"10.1080/21505594.2024.2356692","url":null,"abstract":"<p><p>The increasing antibiotic resistance poses a significant global health challenge, threatening our ability to combat infectious diseases. The phenomenon of collateral sensitivity, whereby resistance to one antibiotic is accompanied by increased sensitivity to another, offers potential avenues for novel therapeutic interventions against infections unresponsive to classical treatments. In this study, we elucidate the emergence of tobramycin (TOB)-resistant small colony variants (SCVs) due to mutations in the <i>hemL</i> gene, which render <i>S</i>. Typhimurium more susceptible to nitrofurantoin (NIT). Mechanistic studies demonstrate that the collateral sensitivity in TOB-resistant <i>S</i>. Typhimurium SCVs primarily stems from disruptions in haem biosynthesis. This leads to dysfunction in the electron transport chain (ETC) and redox imbalance, ultimately inducing lethal accumulation of reactive oxygen species (ROS). Additionally, the upregulation of <i>nfsA/B</i> expressions facilitates the conversion of NIT prodrug into its active form, promoting ROS-mediated bacterial killing and contributing to this collateral sensitivity pattern. Importantly, alternative NIT therapy demonstrates a significant reduction of bacterial load by more than 2.24-log<sub>10</sub> cfu/g in the murine thigh infection and colitis models. Our findings corroborate the collateral sensitivity of <i>S</i>. Typhimurium to nitrofurans as a consequence of evolving resistance to aminoglycosides. This provides a promising approach for treating infections due to aminoglycoside-resistant strains.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11135859/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141155399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-05-14DOI: 10.1080/21505594.2024.2350892
Qiu-Yan Xu, Xin-Qi Zheng, Wei-Ming Ye, Dong-Yu Yi, Ze Li, Qing-Qi Meng, Man-Li Tong, Dan Liu, Tian-Ci Yang
The evasive tactics of Treponema pallidum pose a major challenge in combating and eradicating syphilis. Natural killer (NK) cells mediate important effector functions in the control of pathogenic infection, preferentially eliminating targets with low or no expression of major histocompatibility complex (MHC) class I. To clarify T. pallidum's mechanisms in evading NK-mediated immunosurveillance, experiments were performed to explore the cross-talk relations among T. pallidum, NK cells, and platelets. T. pallidum adhered to, activated, and promoted particle secretion of platelets. After preincubation with T. pallidum, platelets expressed and secreted high levels of MHC class I, subsequently transferring them to the surface of T. pallidum, potentially inducing an immune phenotype characterized by the "pseudo-expression" of MHC class I on the surface of T. pallidum (hereafter referred to a "pseudo-expression" of MHC class I). The polA mRNA assay showed that platelet-preincubated T. pallidum group exhibited a significantly higher copy number of polA transcript than the T. pallidum group. The survival rate of T. pallidum mirrored that of polA mRNA, indicating that preincubation of T. pallidum with platelets attenuated NK cell lethality. Platelets pseudo-expressed the MHC class I ligand on the T. pallidum surface, facilitating binding to killer cell immunoglobulin-like receptors with two immunoglobulin domains and long cytoplasmic tail 3 (KIR2DL3) on NK cells and initiating dephosphorylation of Vav1 and phosphorylation of Crk, ultimately attenuating NK cell lethality. Our findings elucidate the mechanism by which platelets transfer MHC class I to the T. pallidum surface to evade NK cell immune clearance.
苍白盘尾丝菌的躲避策略给抗击和根除梅毒带来了重大挑战。为了弄清苍白螺旋体逃避NK介导的免疫监视的机制,研究人员进行了实验来探索苍白螺旋体、NK细胞和血小板之间的交叉对话关系。苍白球粘附、激活并促进血小板分泌微粒。与苍白球预孵育后,血小板表达并分泌高水平的 MHC I 类,随后将其转移到苍白球表面,可能诱导出一种以苍白球表面 MHC I 类 "伪表达"(以下简称 MHC I 类 "伪表达")为特征的免疫表型。polA mRNA 检测显示,血小板预培养 T. pallidum 组的 polA 转录本拷贝数明显高于 T. pallidum 组。T. pallidum的存活率与polA mRNA的存活率一致,这表明T. pallidum与血小板预孵育可减轻NK细胞的致死率。血小板在苍白球表面伪表达了MHC I类配体,促进了与NK细胞上具有两个免疫球蛋白结构域和长胞质尾3(KIR2DL3)的杀伤细胞免疫球蛋白样受体的结合,并启动了Vav1的去磷酸化和Crk的磷酸化,最终降低了NK细胞的致死率。我们的发现阐明了血小板将 MHC I 类转移到苍白球表面以逃避 NK 细胞免疫清除的机制。
{"title":"Platelet-derived major histocompatibility complex class I coating on <i>Treponema pallidum</i> attenuates natural killer cell lethality.","authors":"Qiu-Yan Xu, Xin-Qi Zheng, Wei-Ming Ye, Dong-Yu Yi, Ze Li, Qing-Qi Meng, Man-Li Tong, Dan Liu, Tian-Ci Yang","doi":"10.1080/21505594.2024.2350892","DOIUrl":"10.1080/21505594.2024.2350892","url":null,"abstract":"<p><p>The evasive tactics of <i>Treponema pallidum</i> pose a major challenge in combating and eradicating syphilis. Natural killer (NK) cells mediate important effector functions in the control of pathogenic infection, preferentially eliminating targets with low or no expression of major histocompatibility complex (MHC) class I. To clarify <i>T. pallidum's</i> mechanisms in evading NK-mediated immunosurveillance, experiments were performed to explore the cross-talk relations among <i>T. pallidum</i>, NK cells, and platelets. <i>T. pallidum</i> adhered to, activated, and promoted particle secretion of platelets. After preincubation with <i>T. pallidum</i>, platelets expressed and secreted high levels of MHC class I, subsequently transferring them to the surface of <i>T. pallidum</i>, potentially inducing an immune phenotype characterized by the \"pseudo-expression\" of MHC class I on the surface of <i>T. pallidum</i> (hereafter referred to a \"pseudo-expression\" of MHC class I). The <i>polA</i> mRNA assay showed that platelet-preincubated <i>T. pallidum</i> group exhibited a significantly higher copy number of <i>polA</i> transcript than the <i>T. pallidum</i> group. The survival rate of <i>T. pallidum</i> mirrored that of <i>polA</i> mRNA, indicating that preincubation of <i>T. pallidum</i> with platelets attenuated NK cell lethality. Platelets pseudo-expressed the MHC class I ligand on the <i>T. pallidum</i> surface, facilitating binding to killer cell immunoglobulin-like receptors with two immunoglobulin domains and long cytoplasmic tail 3 (KIR2DL3) on NK cells and initiating dephosphorylation of Vav1 and phosphorylation of Crk, ultimately attenuating NK cell lethality. Our findings elucidate the mechanism by which platelets transfer MHC class I to the <i>T. pallidum</i> surface to evade NK cell immune clearance.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140923261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-05-02DOI: 10.1080/21505594.2024.2348251
Jiankang Zhao, Danni Pu, Ziyao Li, Yulin Zhang, Xinmeng Liu, Xianxia Zhuo, Binghuai Lu, Bin Cao
Objectives: This study aimed at revealing the underlying mechanisms of the loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing hypervirulent Klebsiella pneumoniae (hvKp).
Methods: Here we longitudinally recovered 3 non-carbapenemase-producing K1-ST23 hvKp strains at a one-month interval (KP29105, KP29499 and KP30086) from an elderly male. Antimicrobial susceptibility testing, whole genome sequencing, transcriptomic sequencing, gene cloning, plasmid conjugation, quantitative real-time PCR (qRT-PCR), and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were conducted.
Results: Among the 3 hvKp strains, KP29105 was resistant to the third- and fourth-generation cephalosporins, KP29499 acquired resistance to both ceftazidime-avibactam and carbapenems, while KP30086 restored its susceptibility to ceftazidime-avibactam, imipenem and meropenem but retained low-level resistance to ertapenem. KP29105 and KP29499 carried plasmid-encoded genes blaCTX-M-15 and blaCTX-M-71, respectively, but KP30086 lost both. Cloning of gene blaCTX-M-71 and conjugation experiment of blaCTX-M-71-carrying plasmid showed that the transformant and transconjugant were susceptible to ceftazidime-avibactam but had a more than 8-fold increase in MICs. Supplementation with an outer membrane permeabilizer could reduce the MIC of ceftazidime-avibactam by 32 folds, indicating that porins play a key role in ceftazidime-avibactam resistance. The OmpK35 of the 3 isolates was not expressed, and the OmpK36 of KP29499 and KP30086 had a novel amino acid substitution (L359R). SDS-PAGE and qRT-PCR showed that the expression of porin OmpK36 of KP29499 and KP30086 was significantly down-regulated compared with KP29105.
Conclusions: In summary, we reported the rare ceftazidime-avibactam resistance in a non-carbapenemase-producing hvKp strain. Resistance plasmid carrying blaCTX-M-71 and mutated OmpK36 had a synergetic effect on the resistance.
{"title":"Loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing K1-ST23 hypervirulent <i>Klebsiella pneumoniae</i>.","authors":"Jiankang Zhao, Danni Pu, Ziyao Li, Yulin Zhang, Xinmeng Liu, Xianxia Zhuo, Binghuai Lu, Bin Cao","doi":"10.1080/21505594.2024.2348251","DOIUrl":"10.1080/21505594.2024.2348251","url":null,"abstract":"<p><strong>Objectives: </strong>This study aimed at revealing the underlying mechanisms of the loss and gain of ceftazidime-avibactam susceptibility in a non-carbapenemase-producing hypervirulent <i>Klebsiella pneumoniae</i> (hvKp).</p><p><strong>Methods: </strong>Here we longitudinally recovered 3 non-carbapenemase-producing K1-ST23 hvKp strains at a one-month interval (KP29105, KP29499 and KP30086) from an elderly male. Antimicrobial susceptibility testing, whole genome sequencing, transcriptomic sequencing, gene cloning, plasmid conjugation, quantitative real-time PCR (qRT-PCR), and SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were conducted.</p><p><strong>Results: </strong>Among the 3 hvKp strains, KP29105 was resistant to the third- and fourth-generation cephalosporins, KP29499 acquired resistance to both ceftazidime-avibactam and carbapenems, while KP30086 restored its susceptibility to ceftazidime-avibactam, imipenem and meropenem but retained low-level resistance to ertapenem. KP29105 and KP29499 carried plasmid-encoded genes <i>bla</i><sub>CTX-M-15</sub> and <i>bla</i><sub>CTX-M-71</sub>, respectively, but KP30086 lost both. Cloning of gene <i>bla</i><sub>CTX-M-71</sub> and conjugation experiment of <i>bla</i><sub>CTX-M-71</sub>-carrying plasmid showed that the transformant and transconjugant were susceptible to ceftazidime-avibactam but had a more than 8-fold increase in MICs. Supplementation with an outer membrane permeabilizer could reduce the MIC of ceftazidime-avibactam by 32 folds, indicating that porins play a key role in ceftazidime-avibactam resistance. The OmpK35 of the 3 isolates was not expressed, and the OmpK36 of KP29499 and KP30086 had a novel amino acid substitution (L359R). SDS-PAGE and qRT-PCR showed that the expression of porin OmpK36 of KP29499 and KP30086 was significantly down-regulated compared with KP29105.</p><p><strong>Conclusions: </strong>In summary, we reported the rare ceftazidime-avibactam resistance in a non-carbapenemase-producing hvKp strain. Resistance plasmid carrying <i>bla</i><sub>CTX-M-71</sub> and mutated OmpK36 had a synergetic effect on the resistance.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11067985/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140870775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-09-01DOI: 10.1080/21505594.2024.2396484
Wesley Freppel, Laurie A Silva, Kenneth A Stapleford, Lara J Herrero
Chikungunya virus (CHIKV) is a mosquito-transmitted, RNA virus that causes an often-severe musculoskeletal illness characterized by fever, joint pain, and a range of debilitating symptoms. The virus has re-emerged as a global health threat in recent decades, spreading from its origin in Africa across Asia and the Americas, leading to widespread outbreaks impacting millions of people. Despite more than 50 years of research into the pathogenesis of CHIKV, there is still no curative treatment available. Current management of CHIKV infections primarily involves providing supportive care to alleviate symptoms and improve the patient's quality of life. Given the ongoing threat of CHIKV, there is an urgent need to better understand its pathogenesis. This understanding is crucial for deciphering the mechanisms underlying the disease and for developing effective strategies for both prevention and management. This review aims to provide a comprehensive overview of CHIKV and its pathogenesis, shedding light on the complex interactions of viral genetics, host factors, immune responses, and vector-related factors. By exploring these intricate connections, the review seeks to contribute to the knowledge base surrounding CHIKV, offering insights that may ultimately lead to more effective prevention and management strategies for this re-emerging global health threat.
{"title":"Pathogenicity and virulence of chikungunya virus.","authors":"Wesley Freppel, Laurie A Silva, Kenneth A Stapleford, Lara J Herrero","doi":"10.1080/21505594.2024.2396484","DOIUrl":"10.1080/21505594.2024.2396484","url":null,"abstract":"<p><p>Chikungunya virus (CHIKV) is a mosquito-transmitted, RNA virus that causes an often-severe musculoskeletal illness characterized by fever, joint pain, and a range of debilitating symptoms. The virus has re-emerged as a global health threat in recent decades, spreading from its origin in Africa across Asia and the Americas, leading to widespread outbreaks impacting millions of people. Despite more than 50 years of research into the pathogenesis of CHIKV, there is still no curative treatment available. Current management of CHIKV infections primarily involves providing supportive care to alleviate symptoms and improve the patient's quality of life. Given the ongoing threat of CHIKV, there is an urgent need to better understand its pathogenesis. This understanding is crucial for deciphering the mechanisms underlying the disease and for developing effective strategies for both prevention and management. This review aims to provide a comprehensive overview of CHIKV and its pathogenesis, shedding light on the complex interactions of viral genetics, host factors, immune responses, and vector-related factors. By exploring these intricate connections, the review seeks to contribute to the knowledge base surrounding CHIKV, offering insights that may ultimately lead to more effective prevention and management strategies for this re-emerging global health threat.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11370967/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142081764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-09-09DOI: 10.1080/21505594.2024.2399217
Donghao Li, Zongwei Li, Lei Wang, Yan Zhang, Shoubin Ning
Fusobacterium nucleatum (F. nucleatum), an anaerobic resident of the oral cavity, is increasingly recognized as a contributing factor to ulcerative colitis (UC). The adhesive properties of F. nucleatum are mediated by its key virulence protein, FadA adhesin. However, further investigations are needed to understand the pathogenic mechanisms of this oral pathogen in UC. The present study aimed to explore the role of the FadA adhesin in the colonization and invasion of oral F. nucleatum in dextran sulphate sodium (DSS)-induced colitis mice via molecular techniques. In this study, we found that oral inoculation of F. nucleatum strain carrying the FadA adhesin further exacerbated DSS-induced colitis, leading to elevated alveolar bone loss, disease severity, and mortality. Additionally, CDH1 gene knockout mice treated with DSS presented increases in body weight and alveolar bone density, as well as a reduction in disease severity. Furthermore, FadA adhesin adhered to its mucosal receptor E-cadherin, leading to the phosphorylation of β-catenin and the degradation of IκBα, the activation of the NF-κB signalling pathway and the upregulation of downstream cytokines. In conclusion, this research revealed that oral inoculation with F. nucleatum facilitates experimental colitis via the secretion of the virulence adhesin FadA. Targeting the oral pathogen F. nucleatum and its virulence factor FadA may represent a promising therapeutic approach for a portion of UC patients.
{"title":"Oral inoculation of <i>Fusobacterium nucleatum</i> exacerbates ulcerative colitis via the secretion of virulence adhesin FadA.","authors":"Donghao Li, Zongwei Li, Lei Wang, Yan Zhang, Shoubin Ning","doi":"10.1080/21505594.2024.2399217","DOIUrl":"10.1080/21505594.2024.2399217","url":null,"abstract":"<p><p><i>Fusobacterium nucleatum</i> (<i>F. nucleatum</i>), an anaerobic resident of the oral cavity, is increasingly recognized as a contributing factor to ulcerative colitis (UC). The adhesive properties of <i>F. nucleatum</i> are mediated by its key virulence protein, FadA adhesin. However, further investigations are needed to understand the pathogenic mechanisms of this oral pathogen in UC. The present study aimed to explore the role of the FadA adhesin in the colonization and invasion of oral <i>F. nucleatum</i> in dextran sulphate sodium (DSS)-induced colitis mice via molecular techniques. In this study, we found that oral inoculation of <i>F. nucleatum</i> strain carrying the FadA adhesin further exacerbated DSS-induced colitis, leading to elevated alveolar bone loss, disease severity, and mortality. Additionally, CDH1 gene knockout mice treated with DSS presented increases in body weight and alveolar bone density, as well as a reduction in disease severity. Furthermore, FadA adhesin adhered to its mucosal receptor E-cadherin, leading to the phosphorylation of β-catenin and the degradation of IκBα, the activation of the NF-κB signalling pathway and the upregulation of downstream cytokines. In conclusion, this research revealed that oral inoculation with <i>F. nucleatum</i> facilitates experimental colitis via the secretion of the virulence adhesin FadA. Targeting the oral pathogen <i>F. nucleatum</i> and its virulence factor FadA may represent a promising therapeutic approach for a portion of UC patients.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11385161/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142112635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01Epub Date: 2024-09-09DOI: 10.1080/21505594.2024.2397492
Yanan Wang, Aoying Sun, Yaru Guo, Lingxiang Xin, Yanping Jiang, Wen Cui, Jiaxuan Li, Yijing Li, Li Wang
Coronavirus nonstructural protein 2 (Nsp2) is regarded as a virulence determinant and plays a critical role in virus replication, and innate immunity. Screening and identifying host cell proteins that interact with viral proteins is an effective way to reveal the functions of viral proteins. In this study, the host proteins that interacted with transmissible gastroenteritis virus (TGEV) Nsp2 were identified using immunoprecipitation combined with LC-MS/MS. 77 host cell proteins were identified as putative Nsp2 interaction host cell proteins and a protein-protein interaction (PPI) was constructed. The identified proteins were found to be associated with various subcellular locations and functional categories through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. It is hypothesized that the host cell proteins interacting with TGEV Nsp2 are mainly involved in the formation of the cytoplasmic translation initiation complex, mRNA binding, ribosomes, and proteasomes. Among these, the ATP5B, a core subunit of the mitochondrial ATP synthase was further studied. The Coimmunoprecipitation (Co-IP) and indirect immunofluorescence (IFA) results confirmed that TGEV Nsp2 interacted with ATP5B. Furthermore, the downregulation of ATP5B expression was found to promote TGEV replication, suggesting that ATP5B might function as a negative regulator of TGEV replication. Collectively, our results offer additional insights into the functions of Nsp2 and provide a novel antiviral target against TGEV.
{"title":"ATP synthase subunit ATP5B interacts with TGEV Nsp2 and acts as a negative regulator of TGEV replication.","authors":"Yanan Wang, Aoying Sun, Yaru Guo, Lingxiang Xin, Yanping Jiang, Wen Cui, Jiaxuan Li, Yijing Li, Li Wang","doi":"10.1080/21505594.2024.2397492","DOIUrl":"10.1080/21505594.2024.2397492","url":null,"abstract":"<p><p>Coronavirus nonstructural protein 2 (Nsp2) is regarded as a virulence determinant and plays a critical role in virus replication, and innate immunity. Screening and identifying host cell proteins that interact with viral proteins is an effective way to reveal the functions of viral proteins. In this study, the host proteins that interacted with transmissible gastroenteritis virus (TGEV) Nsp2 were identified using immunoprecipitation combined with LC-MS/MS. 77 host cell proteins were identified as putative Nsp2 interaction host cell proteins and a protein-protein interaction (PPI) was constructed. The identified proteins were found to be associated with various subcellular locations and functional categories through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. It is hypothesized that the host cell proteins interacting with TGEV Nsp2 are mainly involved in the formation of the cytoplasmic translation initiation complex, mRNA binding, ribosomes, and proteasomes. Among these, the ATP5B, a core subunit of the mitochondrial ATP synthase was further studied. The Coimmunoprecipitation (Co-IP) and indirect immunofluorescence (IFA) results confirmed that TGEV Nsp2 interacted with ATP5B. Furthermore, the downregulation of ATP5B expression was found to promote TGEV replication, suggesting that ATP5B might function as a negative regulator of TGEV replication. Collectively, our results offer additional insights into the functions of Nsp2 and provide a novel antiviral target against TGEV.</p>","PeriodicalId":23747,"journal":{"name":"Virulence","volume":null,"pages":null},"PeriodicalIF":5.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11385163/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142141252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}