Journal of Bacteriology最新文献

{"title":"Molecular characterization and resistance mechanisms of ertapenem-non-susceptible carbapenem-resistant <i>Klebsiella pneumoniae</i> co-harboring ESBLs or AmpC enzymes with porin loss or efflux pump overexpression.","authors":"Yingying Su, Guangmei Zou, Xin Huang, Jinli Bi, Liqin Meng, Wei Zhao, Taijie Li","doi":"10.1128/jb.00148-25","DOIUrl":"10.1128/jb.00148-25","url":null,"abstract":"<p><p>Carbapenem-resistant <i>Klebsiella pneumoniae</i> (CRKP) poses a significant challenge in clinical settings due to limited treatment options and high mortality rates. While carbapenemase-producing CRKP has been extensively studied, the mechanisms underlying resistance in non-carbapenemase-producing CRKP remain less understood. In this study, we investigated 30 ertapenem-resistant non-carbapenemase-producing CRKP clinical isolates. Antimicrobial susceptibility testing revealed multidrug resistance in all strains. Molecular analyses showed that all isolates carried extended-spectrum β-lactamase (ESBL) and/or AmpC β-lactamase genes. Sequencing of outer membrane porin (OMP) genes revealed mutations or deletions in <i>ompK35</i> and/or <i>ompK36</i> in the majority of isolates. SDS-PAGE analysis confirmed reduced or absent expression of the corresponding OMP proteins in these strains. Additionally, quantitative PCR showed that several isolates exhibited overexpression of efflux pump genes. These findings indicate that the combined effects of ESBL or AmpC production, porin loss at both the genetic and protein levels, and efflux pump overactivity contribute to ertapenem resistance in non-carbapenemase-producing CRKP. Our results underscore the complexity of resistance mechanisms and highlight the importance of integrated molecular and phenotypic assessments to inform appropriate antimicrobial therapy.</p><p><strong>Importance: </strong>This study highlights the complex, multifactorial nature of carbapenem resistance in carbapenem-resistant <i>Klebsiella pneumoniae</i> (CRKP), involving enzyme-mediated resistance, reduced membrane porin expression, and overactive efflux pumps. These findings provide valuable insights into CRKP resistance mechanisms and can aid in controlling CRKP in China.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0014825"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288452/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144284478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distinct cell division features in <i>Anabaena</i>, a multicellular cyanobacterium.","authors":"Antonia Herrero","doi":"10.1128/jb.00032-25","DOIUrl":"10.1128/jb.00032-25","url":null,"abstract":"<p><p>Filamentous cyanobacteria such as <i>Anabaena</i> display a distinct multicellular organization in the bacterial kingdom. In the filament, the cells share a common periplasm and continuous peptidoglycan sacculus and outer membrane. This structure is propagated by cell division proteins with specific features, including the Z-ring components FtsZ, ZipN, and SepF. Septal junction protein complexes, which provide cell-cell cohesion and communication functions key to the <i>Anabaena</i> multicellular behavior, are recruited to the intercellular septa by interaction with ZipN and SepF during cell division. <i>Anabaena</i> also shows specific features in relation to peptidoglycan growth. The activities of the elongasome and the divisome complexes are interdependent, and septal growth is maintained throughout the cell cycle, contributing to the determination of the proper filament geometry and building and maintaining intercellular communication structures. During the differentiation of heterocysts, cells specialized for the fixation of atmospheric nitrogen, cell division is lost, setting the point of commitment to differentiation. Genes encoding Z-ring components are repressed, and the incorporation of these components into functional divisional complexes is inhibited, involving specific regulatory proteins in connection to specificities of the <i>Anabaena</i> Z-ring. The essential dependence of FtsZ polymerization on SepF provides a mechanism for Z-ring inhibition by downregulating SepF during differentiation.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0003225"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288457/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144316995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Milestones in the development of <i>Myxococcus xanthus</i> as a model multicellular bacterium.","authors":"Lee Kroos, Daniel Wall, Salim T Islam, David E Whitworth, José Muñoz-Dorado, Penelope I Higgs, Mitchell Singer, Emilia M F Mauriello, Anke Treuner-Lange, Lotte Søgaard-Andersen, Christine Kaimer, Montserrat Elías-Arnanz, Emina A Stojković, Rolf Müller, Carsten Volz, Gregory J Velicer, Beiyan Nan","doi":"10.1128/jb.00071-25","DOIUrl":"10.1128/jb.00071-25","url":null,"abstract":"<p><p>From the humblest of beginnings (i.e. a pile of dry cow dung) over 80 years ago, the Gram-negative bacterium <i>Myxococcus xanthus</i> has emerged as a premier model system for studying diverse fields of bacteriology, including multicellular development, sporulation, motility, cell-envelope biogenesis, spatiotemporal regulation, signaling, photoreception, kin recognition, social evolution, and predation. As the flagship representative of myxobacteria found in varied terrestrial and aquatic environments, <i>M. xanthus</i> research has evolved into a collaborative global effort, as reflected by the contributions to this article. In celebration of the upcoming 50th anniversary of the International Conference on the Biology of Myxobacteria, this review highlights the historical and ongoing contributions of <i>M. xanthus</i> as a multifaceted model bacterium.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0007125"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288465/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144316996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reductive activation of the disulfide-containing antibiotic thiolutin is mediated by both bacillithiol and FAD-dependent disulfide reductases.","authors":"Ahmed Gaballa, Yesha Patel, John D Helmann","doi":"10.1128/jb.00181-25","DOIUrl":"10.1128/jb.00181-25","url":null,"abstract":"<p><p>Metal ions are universally essential for life and are required for critical enzymes throughout metabolism. Metalloenzymes rely on metal import and trafficking pathways for loading of the desired metal. Many microbes produce natural products that serve as metal chelators, both for their own nutrition and to serve as antimicrobials. In response to infection, our immune cells restrict bacterial growth by deploying proteins that chelate metal ions as part of nutritional immunity. Cells respond to metal depletion by the activation of pathways that prioritize metal delivery to the most essential enzymes. Dithiolopyrrolone (DTP) class natural products are prodrugs that are reduced in cells to generate a potent, dithiol-containing zinc chelator. Here, we identify the cellular reductants, bacillithiol and the FAD-dependent oxidoreductases TrxB and AhpF, that activate the DTP antibiotic thiolutin in <i>Bacillus subtilis</i>. Genetic studies reveal that loss of the Spx transcription factor also increases thiolutin resistance, consistent with the known role of Spx in transcriptional activation of thioredoxin reductase (<i>trxB</i>) and genes required for bacillithiol synthesis. Collectively, our results support a model in which several parallel pathways all contribute to the reductive activation of DTP class prodrugs <i>in vivo</i>.IMPORTANCEMetal ion chelators (metallophores) are deployed by microbes to obtain nutrient metals, sequester excess metals, and act as antimicrobials to inhibit the growth of other organisms. Dithiolopyrrolones (DTPs) are a class of natural products that inhibit bacterial growth by the intracellular chelation of zinc and iron, two metal ions essential for growth. Thiolutin, a model DTP antibiotic, is activated by reduction inside cells and selectively chelates intracellular metals. Here, we demonstrate that the activation of the thiolutin prodrug is mediated by several parallel pathways, which greatly reduces the ability of cells to evolve antibiotic resistance. Since DTP antibiotics appear to primarily target zinc enzymes, they provide a powerful tool for exploring how cells adapt to zinc deficiency.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0018125"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288471/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of electron transfer enzymes in <i>Thermoanaerobacterium saccharolyticum</i>.","authors":"João H T M Fabri, Layse C de Souza, Luana W Bergamo, Lee R Lynd, Daniel G Olson","doi":"10.1128/jb.00107-25","DOIUrl":"10.1128/jb.00107-25","url":null,"abstract":"<p><p><i>Thermoanaerobacterium saccharolyticum</i> is a promising candidate for the production of biofuels from lignocellulosic sugars; however, the genes associated with electron transfer from ferredoxin are poorly characterized. In this work, we deleted several key electron transfer genes. We showed that the <i>tsac_1705</i> gene is not necessary for high-yield ethanol production, but that a set of four other genes (<i>nfnA</i>, <i>nfnB</i>, <i>hfsD</i>, and <i>hydA</i>) are necessary. We showed that the <i>nfnB</i> gene can function as a monofunctional (i.e., non-bifurcating) FNOR enzyme in the absence of <i>nfnA</i>. The phenotypes of the <i>hfsD</i>, <i>hydA</i>, and <i>hfsD hydA</i> double-deletion strains are consistent with their function via hydrogen cycling.</p><p><strong>Importance: </strong>The improved understanding of electron transfer pathways in <i>T. saccharolyticum</i> will enable future efforts to transfer the robust ethanol production pathway from this microbe to other organisms, with potential implications for industrial biofuel production.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0010725"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288451/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144234200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond movement: the dynamic roles of Type IV pili in cyanobacterial life.","authors":"Jonas Hammerl, Nils Schuergers, Gen Enomoto, Conrad W Mullineaux, Annegret Wilde","doi":"10.1128/jb.00086-25","DOIUrl":"10.1128/jb.00086-25","url":null,"abstract":"<p><p>Type IV pili are versatile prokaryotic cell appendages that are extremely widespread in the bacterial and archaeal domains of life. The structure, dynamics, and functions of type IV pili have been most intensively studied in several species of heterotrophic bacteria, but these appendages also appear universal in cyanobacteria. Cyanobacterial type IV pili have much in common with those found in other bacteria, but they also show some unique features that may be crucial for facilitating the photoautotrophic lifestyles of cyanobacteria. Here, we discuss what is known of the structure and dynamic organization of cyanobacterial type IV pili. We discuss the multiple roles of cyanobacterial type IV pili in motility and phototaxis, sensory signal transduction, DNA uptake, and the formation of cell aggregates and biofilms. We conclude with some ideas on the likely importance of cyanobacterial type IV pilus functions in the natural environment and for biotechnological applications.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0008625"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288463/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144553659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lon-dependent proteolysis in oxidative stress responses.","authors":"Kubra Yigit, Peter Chien","doi":"10.1128/jb.00005-25","DOIUrl":"10.1128/jb.00005-25","url":null,"abstract":"<p><p>Accumulation of reactive oxygen species (ROS) induces oxidative stress, leading to substantial damage to cellular macromolecules, necessitating efficient protein quality control mechanisms. The Lon protease, a highly conserved ATP-dependent protease, is thought to play a central role in mitigating oxidative stress by targeting damaged and misfolded proteins for degradation. This review examines the role of Lon in oxidative stress responses, including its role in degrading oxidized proteins, regulating antioxidant pathways, and modulating heme and Fe-S cluster homeostasis. We highlight cases of substrate recognition through structural changes and describe situations where Lon activity is further regulated by redox conditions. By synthesizing studies across a range of organisms, we find that despite the clear importance of Lon for oxidative stress tolerance, universal rules for Lon degradation of damaged proteins during this response remain unclear.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0000525"},"PeriodicalIF":3.0,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288459/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144234201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Kolteria novifilia,</i> a novel planctomycetotal strain from the volcanic habitat of Panarea divides by unusual lateral budding.","authors":"Nicolai Kallscheuer, Christian Boedeker, Sandra Wiegand, Timo Kohn, Anja Heuer, Jörg Overmann, Stijn Peters, Mareike Jogler, Manfred Rohde, Christian Jogler","doi":"10.1128/jb.00337-24","DOIUrl":"10.1128/jb.00337-24","url":null,"abstract":"<p><p>Members of the phylum <i>Planctomycetota</i> are ubiquitous bacteria that play important roles in the global carbon and nitrogen cycle. In this study, we sampled the shallow-sea hydrothermal vent system close to Panarea Island, Italy, and analyzed the bacterial diversity in this habitat using a cultivation-independent amplicon sequencing approach. Motivated by the observed abundance of members of the phylum <i>Planctomycetota</i>, we employed cultivation conditions that facilitate the enrichment of planctomycetes and isolated strain Pan216^T. This strain shows a rarely observed type of cell division-lateral budding. Based on 16S rRNA gene- and multi-locus sequence analyses, its phylogenetic position in the phylum <i>Planctomycetota</i> appears vague. Strain Pan216^T clustered between the different described families in the class <i>Planctomycetia</i>. The novel isolate shares the highest sequence identity (85.4%) of the 16S rRNA gene with <i>Thermostilla marina</i> SVX8^T, indicating that this strain belongs to a novel family. In addition to its uncommon cell division mode, Pan216^T cells are pill-shaped and covered by a putative outer surface layer. Genomic analyses of strain Pan216^T revealed many giant genes, putative S-layer protein-encoding genes, and only a limited set of canonical cell division genes. Based on the results of the polyphasic analysis, we conclude that strain Pan216^T constitutes a novel family within the phylum <i>Planctomycetota</i>, for which we propose the name <i>Kolteriaceae</i> fam. nov. The novel species <i>Kolteria novifilia</i> gen. nov., sp. nov. is represented by the type strain Pan216^T (= DSM 100414^T = CECT 9536^T).</p><p><strong>Importance: </strong>We describe a novel family of the underrepresented bacterial phylum <i>Planctomycetota</i> that divides by unusual lateral budding. Our strain is the only validly described species that uses this mode of cell division. Furthermore, it represents the only planctomycete outside of the anammox bacteria that has an S-layer-like structure. Taken together, the novel family shows a novel mechanism of cell division that could only be studied in this species.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0033724"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288469/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel membrane stress response that blocks chromosomal replication by targeting the DnaA initiator via the ClpP protease.","authors":"Alabi Gbolahan, Tong Li, Rishit Saxena, Karen Wolcott, Aamna Sohail, Ishika Ahmed, Dhruba K Chattoraj, Elliott Crooke, Rahul Saxena","doi":"10.1128/jb.00151-25","DOIUrl":"10.1128/jb.00151-25","url":null,"abstract":"<p><p>In <i>Escherichia coli</i>, membrane stress due to interrupted lipoprotein (Lpp) maturation impairs DNA replication and arrests cell growth. How Lpp maturation and DNA replication are connected remains unclear. We demonstrate that upon membrane stress, the Rcs stress-response pathway is activated, and the replication initiator DnaA is lost, which explains the replication block. However, Lon protease, a key regulator of the Rcs pathway, is not required for the DnaA loss. We further ruled out the involvement of (p)ppGpp, one of the major mediators of stress responses in bacteria. On the other hand, upon deletion of the ClpP protease gene, DnaA was stable, replication was not inhibited, and there was no cell-growth arrest. In wild-type cells, overexpression of DnaA was lethal even without the membrane stress apparently from hyperinitiation. In ∆<i>crp</i> cells, hyperinitiation was restrained, and overexpression of DnaA was able to overcome the growth arrest. <i>∆fis</i> cells, which were earlier found resistant to the membrane stress, showed DnaA stability and normal replication upon stress-inducing treatments. We conclude that DnaA loss suffices to explain the growth arrest upon the membrane stress. The stress-response pathway described here appears novel because of its independence from Lon and (p)ppGpp, which have been implicated in other stress responses that block DNA replication.</p><p><strong>Importance: </strong>The observation that DNA replication stress can block cell division in <i>E. coli</i> (SOS response) introduced the concept of checkpoint control in the cell cycle. Here, we describe a novel checkpoint control that functions in the opposite direction: membrane stress causing replication block. We show how the accumulation of precursor lipoprotein (pLpp) could block replication. The pLpp accumulation causes a response culminating in activating the ClpP protease that blocks replication by targeting the initiator DnaA. DnaA being vital and highly conserved, a detailed understanding of the response pathway is likely to open new avenues to treat bacterial infection.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015125"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288453/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent advances in mycobacterial transcription: insights beyond the general pathway.","authors":"Nilanjana Hazra, Jayanta Mukhopadhyay","doi":"10.1128/jb.00154-25","DOIUrl":"10.1128/jb.00154-25","url":null,"abstract":"<p><p>The conventional idea of prokaryotic transcription represents a collection of pathways assembled from disparate studies across diverse bacterial species. This cumulative approach, though reveals core-conserved mechanisms, likely excludes the transcriptional pathways unique to an organism. The understanding of mycobacterial transcription suffers from such generalizations as its extreme GC bias, complex RNA polymerase (RNAP), abundance of short transcripts predominating its transcriptome, extensive σ factor utilization, and a constant battle against host stress implicates a distinct transcriptional landscape. This review highlights specific insights into mycobacterial RNAP architecture, promoter recognition, and elongation dynamics, against the general comprehensive narration of bacterial transcription.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0015425"},"PeriodicalIF":2.7,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12288462/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144475384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}