Microbiology spectrum最新文献

{"title":"Distinct bacterial community structures with abundant carbon degradation and sulfur metabolisms found in different sea-ice types from the Central Arctic Ocean.","authors":"Siddarthan Venkatachalam, Mats A Granskog, Rafael Gonçalves-Araujo, Dmitry V Divine, Puthiya Veettil Vipindas, Thajudeen Jabir, Ahammed Shereef, Anand Jain","doi":"10.1128/spectrum.01291-25","DOIUrl":"https://doi.org/10.1128/spectrum.01291-25","url":null,"abstract":"<p><p>The rapid decline of sea ice in the relatively understudied Central Arctic Ocean has a significant impact on bacterial biodiversity and the ecological functions they support. We investigated the bacterial community composition and the associated metabolic functions from three geographically distinct sea-ice floes: first-year ice (FYI) at the North Pole and western Nansen Basin and second-year or multi-year ice (SYI/MYI) in the western Amundsen Basin. We resolved the sea-ice bacterial community diversity at species-level precision using a long-read amplicon (<i>n</i> = 18) and metagenomic (<i>n</i> = 3) sequencing approach. The amplicon sequencing highlighted marked differences in bacterial community structure driven by ice age, floe origin, and environmental factors, demonstrating pronounced vertical structuring among ice horizons. Bacterial taxa like <i>Paraglaciecola psychrophila, Hydrogenophaga crassostreae, Octadecabacter arcticus, and Polaribacter irgensii</i> mainly dominated the bottom layers of SYI/MYI, whereas species <i>Actimicrobium antarcticum, Polaromonas cryoconiti, O. antarcticus,</i> and <i>Rhodoferax sp</i>. dominated the FYI. Similarly, notable taxonomic differences were observed in bacterial taxa inhabiting the surface and interior layers of FYI and SYI/MYI (e.g., <i>F. frigoris and Hydrogenophaga</i> sp.). The metagenomic analysis showed the prevalence of sulfur cycling-associated (assimilatory and dissimilatory sulfur metabolism) and complex carbon degradation processes in sea ice. We also elucidated the potential ecological role of novel metagenome-assembled genomes belonging to the genus <i>Aquiluna</i> through phylogenomic and pangenomic analyses. Overall, our findings revealed novel insights on the distinct bacterial communities that inhabit ice horizons and their associated ecological functions correlating with sea-ice type, origin, and habitat characteristics in the Central Arctic Ocean.IMPORTANCEThe Arctic region is warming nearly four times faster than the global average, leading to the continuous replacement of its thick multi-year sea ice with thinner first-year ice. The reduction in Arctic sea-ice cover was previously shown to have cascading effects on sea-ice-associated microbial communities and their role in the functioning of the ecosystem. This study provides the first high-resolution, species-level insight into the bacterial community composition and metabolic potential across different sea-ice types in the Central Arctic Ocean-an understudied yet rapidly changing environment. By combining long-read amplicon and metagenomic sequencing, we uncover distinct bacterial assemblages and functional metabolic roles that were shaped by the ice age and other physicochemical properties. Our findings highlight the ecological importance of sea-ice associated bacterial communities and the prevalence of sulfur metabolism and carbon degradation processes in different sea-ice types found in the central Arctic Ocean throu","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0129125"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and biochemical characterization of a novel porcine circovirus associated with porcine respiratory and diarrheal diseases.","authors":"Xianhui Liu, Lin Wang, Xinming Zhang, Yilong Liu, Yixuan Li, Zan Li, Zhi Geng, Leyi Zhang, Yanling Liu, Pengshuai Liang, Yuhui Dong, Zheng Xu, Heng Zhang, Changxu Song","doi":"10.1128/spectrum.02299-25","DOIUrl":"https://doi.org/10.1128/spectrum.02299-25","url":null,"abstract":"<p><p>Eukaryotic circular Rep encoding single-stranded DNA (CRESS DNA) viruses exhibit high genomic diversity. Four species of circoviruses within the genus <i>Circovirus</i> have been identified in pigs, including the non-pathogenic porcine circovirus type 1 (PCV1), and the pathogenic PCV2, PCV3, and PCV4. In this study, a novel single circular DNA virus was identified in pigs suffering from respiratory, diarrheal, and reproductive failure diseases. The viral Rep and Cap showed low amino acid sequence identities to the four PCV species, with the highest identity of 26.2% to PCV2 Rep and 20.8% to PCV4 Cap. The classification of CRESS DNA viruses primarily relies on Rep, and biochemical analyses of the viral Rep confirm its classification as a CRESS DNA virus. Thus, it was tentatively named porcine circovirus type 5 (PCV5). This tentative designation reflects its host and genomic organization; however, phylogenetic analysis indicates that it clusters outside the family <i>Circoviridae</i> and is most closely related to the fur seal faces-associated circular DNA virus (FSfaCV). The positive detection rate for PCV5 in tested samples was 54.4% (294 out of 540), with 24.3% (17 out of 70) of pig farms in China testing positive for the virus. A close correlation between the copy number of PCV5 and the severity of infectious diseases was observed. Moreover, a PCV5 virus-like particles (VLPs)-based enzyme-linked immunosorbent assay, which was developed, also elucidated that PCV5 has been circulating. We subsequently established an <i>in vitro</i> culture system for PCV5, successfully purifying the virus. Morphological identification revealed that the purified PCV5 has a diameter of approximately 20 nm, and the recombinant PCV5 Cap could assemble into VLPs similar to purified PCV5. These results indicate that PCV5, associated with porcine circovirus-associated disease, commonly circulates within Chinese swine.IMPORTANCEThe single-stranded circular DNA virus, tentatively named porcine circovirus type 5 (PCV5), belongs to the circular Rep encoding single-stranded DNA (CRESS DNA) viruses. Notably, PCV5 is not classified within the same family as the previously reported PCV1-PCV4. PCV5, which was associated with porcine circovirus associated-disease, is widely prevalent in Southern China. PCV5 is characterized by a larger genome (2,904 nt), along with longer Cap (1,182 nt) and Rep (1,056 nt) regions, as well as an extended stem-loop structure (stem: 9 nt and loop: 17 nt). Importantly, we subsequently established an <i>in vitro</i> culture system for PCV5, successfully purifying the virus. Morphological identification revealed that the purified PCV5 has a diameter of approximately 20 nm. Additionally, a variant of the PCV5 Cap, lacking the N-terminal 63 residues, was expressed in <i>Escherichia coli</i>, and purified Cap could assemble into virus-like particles similar to purified PCV5. These results hold significant implications for the study of CRESS DNA viru","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0229925"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A minimal SufB₂C₂ complex functions as a [4Fe-4S] cluster scaffold in methanogenic archaea.","authors":"Cuiping Zhao, Nana Shao, Nicole Bryer, Haotian Chen, William B Whitman, David J Vinyard, Yuchen Liu","doi":"10.1128/spectrum.02134-25","DOIUrl":"https://doi.org/10.1128/spectrum.02134-25","url":null,"abstract":"<p><p>Iron-sulfur clusters are essential cofactors in all domains of life, yet their biogenesis in obligately anaerobic archaea remains poorly understood. Here, we characterized the minimal two-protein SUF system in methanogenic archaea, composed solely of SufB and SufC. Using <i>Methanococcus maripaludis</i> as a model, we demonstrate that the SUF proteins from its native host form a stable SufB₂C₂ heterotetramer that binds a [4Fe-4S] cluster via three conserved cysteines in SufC. Mutations of conserved cysteine and histidine residues of SufB do not impair cluster binding. The complex interacts with the SAM-containing methanogenesis marker protein 10 (MmpX), suggesting direct Fe-S cluster transfer from SufB₂C₂ to target proteins. Mutational analysis of <i>Methanothermococcus thermolithotrophicus</i> proteins confirmed that SufC is the primary cluster-binding component, while SufB enhances ATPase and cluster transfer activities. Evolutionary comparisons suggest that this two-protein SUF system represents an ancestral form of Fe-S cluster biogenesis.IMPORTANCEFe-S clusters are ancient and indispensable cofactors, yet their biosynthesis in obligately anaerobic archaea remains underexplored. This study provides mechanistic and evolutionary insights into the Fe-S cluster assembly machinery in methanogenic archaea. Unlike the bacterial six-component SUF systems, this minimal two-component SUF system (SufB₂C₂) operates without auxiliary proteins. Our findings expand the known diversity of Fe-S cluster biogenesis machineries and shed light on a potential evolutionary precursor adapted to the Earth's ancient anoxic environments. It also provides a foundation for engineering minimal Fe-S cluster biosynthesis pathways in synthetic biology applications.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0213425"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genomic diversity and global distribution of four new prasinoviruses from the tropical north Pacific.","authors":"Anamica Bedi de Silva, Shawn W Polson, Christopher R Schvarcz, Grieg F Steward, Kyle F Edwards","doi":"10.1128/spectrum.02583-24","DOIUrl":"https://doi.org/10.1128/spectrum.02583-24","url":null,"abstract":"<p><p>Viruses that infect phytoplankton are an integral part of marine ecosystems, but the vast majority of viral diversity remains uncultivated. Here, we introduce four near-complete genomic assemblies of viruses that infect the widespread marine picoeukaryote <i>Micromonas commoda</i>, doubling the number of reported genomes of <i>Micromonas</i> dsDNA viruses. All host and virus isolates were obtained from tropical waters of the North Pacific, a first for viruses infecting green algae in the order Mamiellales. Genome length of the new isolates ranges from 205 to 212 kb, and phylogenetic analysis shows that all four are members of the genus <i>Prasinovirus</i>. Three of the viruses form a clade that is adjacent to previously sequenced <i>Micromonas</i> viruses, while the fourth virus is relatively divergent from previously sequenced prasinoviruses. We identified 61 putative genes not previously found in prasinovirus isolates, including a phosphate transporter and a potential apoptosis inhibitor novel to marine viruses. Forty-eight genes in the new viruses are also found in host genome(s) and may have been acquired through horizontal gene transfer. By analyzing the coding sequences of all published prasinoviruses, we found that ~25% of prasinovirus gene content is significantly correlated with host genus identity (i.e., <i>Micromonas</i>, <i>Ostreococcus</i>, or <i>Bathycoccus</i>), and the functions of these genes suggest that much of the viral life cycle is differentially adapted to the three host genera. Mapping of metagenomic reads from global survey data indicates that one of the new isolates, McV-SA1, is relatively common in multiple ocean basins.IMPORTANCEThe genomes analyzed here represent the first viruses from the tropical North Pacific that infect the abundant phytoplankton order Mamiellales. Comparing isolates from the same location demonstrates high genomic diversity among viruses that co-occur and presumably compete for hosts. Comparing all published prasinovirus genomes highlights gene functions that are likely associated with adaptation to different host genera. Metagenomic data indicate these viruses are globally distributed, and one of the novel isolates may be among the most abundant marine viruses.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0258324"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of cervical microbiota in cervical intraepithelial neoplasia and cervical cancer using low-coverage whole genome sequencing.","authors":"Tingting Zhang, Fang Gu, Weihua Li, Ruxue Han, Xinyu Liu, Chan Dai, Di Zhang, Hua Li","doi":"10.1128/spectrum.03206-24","DOIUrl":"https://doi.org/10.1128/spectrum.03206-24","url":null,"abstract":"<p><p>This study characterized compositional shifts in cervical microbiota across disease stages from benign conditions through cervical intraepithelial neoplasia (CIN) to cervical cancer (CC) and investigated interactions with high-risk HPV (hr-HPV) infection using species-resolution profiling to identify severity-associated biomarkers. Cervical exfoliated epithelial cells from 50 patients (eight normal/CIN1, 15 CIN2, 19 CIN3, 5 CC) were analyzed using Low-Coverage Whole Genome Sequencing combined with the Ultrasensitive Chromosomal Aneuploidy Detector (UCAD), a technology featuring a two-step normalization framework that systematically converts raw microbial reads into statistically validated abundance deviations. This enables quantitative identification of pathologically relevant microbiota through cohort-wide Z-score benchmarking. Microbial diversity, differential biomarkers, and HPV-microbiota interactions were assessed using Kruskal-Wallis tests, LEfSe, and Random Forest modeling. Results revealed progressive <i>Lactobacillus</i> depletion (e.g., <i>Lactobacillus crispatus</i>: 32.9% in ≤CIN2 vs. 8.8% in CC) and enrichment of pathobionts like <i>Gardnerella</i> and <i>Bacteroides</i> with lesion severity. CC exhibited the highest microbial diversity (Shannon index: CC vs. CIN2, <i>P</i>=0.045), dominated by HPV16 (11.8%), <i>Bacteroides</i> (55.4%), and <i>Porphyromonas</i> (25.2%). LEfSe identified HPV16, HPV35, <i>Parvimonas micra</i>, and <i>Anaerococcus lactolyticus</i> as CC-specific markers, while Random Forest highlighted <i>Mobiluncus curtisii</i> (importance score=2.0) and HPV16 as key discriminators. CC microbiota showed significant Bacteroidetes enrichment (82% at class level) and reduced Firmicutes abundance. These findings suggest carcinogenesis-associated microbial restructuring, marked by <i>Lactobacillus</i> loss, anaerobic proliferation, and HPV16/35 dominance, potentially modulating disease progression. The identified signatures may inform diagnostic development and microbiome-targeted therapies.IMPORTANCEOur study pioneers an LC-WGS/UCAD approach to characterize microbial across the spectrum from benign lesions through precancerous cervical intraepithelial neoplasia to invasive cervical carcinoma. By identifying lesion-specific microbial biomarkers and HPV-associated cofactors, this work advances mechanistic understanding of microbiota-driven oncogenesis and informs future strategies for microbiota-targeted cervical cancer prevention.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0320624"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioluminescent reporter influenza A viruses to track viral infections.","authors":"Ramya S Barre, Ahmed Mostafa, Kevin Chiem, Rebecca L Pearl, Roy N Platt, Anastasija Cupic, Timothy J C Anderson, Ulla G Knaus, Randy A Albrecht, Adolfo García-Sastre, James J Kobie, Aitor Nogales, Luis Martinez-Sobrido","doi":"10.1128/spectrum.02150-25","DOIUrl":"10.1128/spectrum.02150-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Influenza A viruses (IAVs) infect a wide range of mammalian and bird species and are responsible for seasonal outbreaks and occasional pandemics of great consequences in humans. Studying IAVs requires methods to detect the presence of the virus in infected cells or animal models. Recombinant IAV-expressing fluorescent proteins has allowed monitoring of viral infection in cultured cells and &lt;i&gt;ex vivo&lt;/i&gt; in the organs of infected animals. However, fluorescent-expressing IAVs are often attenuated and are not suited for the imaging of infected animals using &lt;i&gt;in vivo&lt;/i&gt; imaging systems (IVISs). To overcome this limitation, we generated a recombinant pandemic influenza A/California/04/2009 H1N1 (pH1N1)-expressing nanoluciferase (Nluc) from the non-structural viral segment, hereafter referred to as pH1N1-Nluc. The pH1N1-Nluc replicates efficiently &lt;i&gt;in vitro&lt;/i&gt;, with growth kinetics and plaque morphology comparable to wild-type pH1N1 (pH1N1-WT). We used this pH1N1-Nluc to demonstrate its ability to effectively identify neutralizing monoclonal antibodies and antivirals, with neutralization and inhibition results comparable to pH1N1-WT. In mice, pH1N1-Nluc was able to induce similar body weight loss and mortality, and viral titers comparable to pH1N1-WT, results that were also recapitulated in a ferret model of IAV infection. Using IVIS, pH1N1-Nluc enabled non-invasive, real-time tracking of viral infection &lt;i&gt;in vivo&lt;/i&gt; and &lt;i&gt;ex vivo&lt;/i&gt; following infection of mice with viral titers in tissues comparable to pH1N1-WT. The flexibility of this approach was further demonstrated by the generation of a Nluc-expressing recombinant A/Puerto Rico/8/1934 H1N1 (PR8-Nluc). Altogether, our results demonstrate that Nluc-expressing recombinant IAVs represent a valuable tool for &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt; studies, including the identification of antivirals and/or neutralizing antibodies, and to assess the protective efficacy of vaccines.IMPORTANCEInfluenza A viruses (IAVs) pose a threat to human and animal health. Mechanisms that control IAV replication and pathogenesis are incompletely understood due to the lack of experimental approaches to visualize and quantify viral dynamics in real time. The use of replication-competent fluorescent-expressing IAV &lt;i&gt;in vivo&lt;/i&gt; has been challenging because such viruses typically have reduced replication fitness and are not suited for imaging of entire animals. Herein, we developed replication-competent recombinant IAV-expressing nanoluciferase (Nluc) that can be used to visualize viral infection in living animals. Infection with Nluc-expressing IAV could be monitored in real time using &lt;i&gt;in vivo&lt;/i&gt; imaging systems. Importantly, the Nluc reporter overcomes several shortcomings of fluorescent proteins and provides a new and sensitive tool to interrogate viral dynamics and immune responses &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo&lt;/i&gt;. This technology can be applied to advance studies and accelerate the development of n","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0215025"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lefamulin harbors promising anti-tuberculosis activity against multidrug-resistant <i>Mycobacterium tuberculosis</i> isolates.","authors":"Jing Wu, Yuanfei Ji, Weihe Zhang, Siyi Chen, Yao Dong, Xia Yu","doi":"10.1128/spectrum.02250-25","DOIUrl":"https://doi.org/10.1128/spectrum.02250-25","url":null,"abstract":"<p><p>Multidrug-resistant tuberculosis (MDR-TB) is often associated with poor clinical outcomes. This study evaluated the <i>in vitro</i> activity of lefamulin (LEF) and intracellular activities against <i>Mycobacterium tuberculosis</i>. In this study, we evaluated the potential of LEF as a new drug candidate for treating <i>M. tuberculosis</i> infections, including MDR-TB. The antimicrobial susceptibility testing was performed to determine the minimum inhibitory concentrations (MICs) of LEF against 132 clinical isolates of <i>M. tuberculosis</i>. The intracellular activity of LEF and its interaction with other anti-tuberculosis drugs were also evaluated using <i>M. tuberculosis</i> H37Rv. From the 132 <i>M</i>. <i>tuberculosis</i> clinical isolates<i>,</i> the MIC₅₀ and MIC₉₀ were 0.5 µg/mL and 1 µg/mL, respectively. The tentative epidemiological cut-off (ECOFF) against LEF was defined at 1 µg/mL. After 5 days of incubation, LEF at 2 µg/mL inhibited 89.88% ± 1.73% of intracellular bacterial growth, which was comparable with the inhibitory rate of 94.29% ± 1.32% achieved by INH at 2 µg/mL. In addition, a synergy between LEF and bedaquiline (BDQ) was observed with a fractional inhibitory concentration index = 0.5. Furthermore, LEF showed no correlation with resistance to 10 anti-tuberculosis drugs. The minimum bactericidal concentration/MIC of LEF values suggested that it is a bacteriostatic drug against <i>M. tuberculosis</i>, and the bactericidal activity is mainly characterized by a concentration-dependent pattern. LEF has potent inhibitory activities against <i>M. tuberculosis in vitro</i> as well as in macrophages. Furthermore, the synergistic effect with BDQ also favors LEF as a promising drug candidate for tuberculosis treatment, especially for MDR-TB.IMPORTANCELefamulin (LEF), the first systemic pleuromutilin antibiotic approved for human use, exhibits broad-spectrum activity against Gram-positive bacteria. However, its <i>in vitro</i> activity against <i>Mycobacterium tuberculosis</i> (<i>Mtb</i>) remains unexplored. This study evaluated the potential of LEF for treating <i>Mtb</i> infections, including multidrug-resistant tuberculosis. Our findings demonstrate that LEF possesses potent bacteriostatic activity against <i>Mtb in vitro</i> and exhibits synergistic effects when combined with bedaquiline. These results suggest LEF as a promising therapeutic candidate for tuberculosis treatment.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0225025"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence of ST11 <i>Klebsiella pneumoniae</i> co-carrying <i>bla</i>_KPC-2 and <i>bla</i>_IMP-8 on conjugative plasmids.","authors":"Lu Gong, Huishuang Yang, Xinrui Wang, Kun Wang, Bingyou Yin, Xiaolu Yang, Haowei Ye, Zhenghao Lou, Tongxi Hu, Weidong Zhu, Beiwen Zheng","doi":"10.1128/spectrum.03345-24","DOIUrl":"https://doi.org/10.1128/spectrum.03345-24","url":null,"abstract":"<p><p><i>Klebsiella pneumoniae</i> is a major pathogen with substantial antimicrobial resistance driven by β-lactamase production. The co-existence of carbapenemase genes <i>bla</i>_KPC-2 and <i>bla</i>_IMP-8 in the prevalent <i>K. pneumoniae</i> clone is rare and poses significant clinical challenges in China. In this study, we report the first identification of a clinical ST11 <i>K. pneumoniae</i> strain Kp4874, isolated from a hospitalized patient in China, co-carrying <i>bla</i>_KPC-2 on a ~134 kb IncFII/IncR hybrid plasmid and <i>bla</i>_IMP-8 on a ~75 kb untypable plasmid. Whole-genome sequencing revealed key insertion sequences, including Tn<i>As1</i> and IS<i>26</i>, facilitating horizontal transfer of these resistance genes. Conjugation experiments confirmed the high transferability of both plasmids, particularly the <i>bla</i>_KPC-2 plasmid. Despite harboring multiple virulence genes, the strain's clinical threat stems primarily from its multidrug-resistant profile. This study highlights the potential for rapid dissemination of such strains in healthcare settings and underscores the critical need for robust surveillance and infection control measures.</p><p><strong>Importance: </strong>This study is the first to report the co-existence of <i>bla</i>_KPC-2 and <i>bla</i>_IMP-8 in an ST11 <i>Klebsiella pneumoniae</i> strain, underscoring the clinical threat posed by these carbapenemase genes. The identification of <i>bla</i>_KPC-2 on an IncFII/IncR hybrid plasmid, coupled with the successful conjugation of both resistance genes, highlights the significant potential for horizontal gene transfer and multidrug-resistant dissemination. These findings advance our understanding of plasmid-mediated resistance and emphasize the urgent need for enhanced monitoring and infection control strategies to mitigate the spread of such high-risk strains.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0334524"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No evidence of multidrug-resistant <i>Enterobacterales</i> transmission between healthy companion animals and pet owners in the greater Atlanta area: a pilot study.","authors":"Wendy Cuevas-Espelid, Chiamaka U Uzuegbunam, Jessica H Carag, Michelle N Hargita, Alexander M Page, Taé C Stallworth, Nour Makkaoui, Sarah W Satola, Nadine G Rouphael, Susan Sanchez, Alexandra W Dretler","doi":"10.1128/spectrum.00503-25","DOIUrl":"https://doi.org/10.1128/spectrum.00503-25","url":null,"abstract":"<p><p>Antimicrobial resistance (AMR) is a global concern affecting both animals and humans. Pets share a close bond with humans and are exposed to human-related conditions that can, in many cases, facilitate the transmission of bacteria and mobile genetic elements. This prospective observational cohort pilot study aimed to determine the prevalence of multidrug-resistant Gram-negative bacteria (MDR-GNB) colonization in healthy individuals and their companion animals (dogs and cats) in the greater Atlanta area, as well as to understand the prevalence of enteric MDR-GNB. Serial fecal samples from paired humans and their pets were collected and analyzed over a 6-month period (at 0, 2, and 6 months). Thirty-four pet owners participated, with 26 providing stool samples at all three time points. A total of 226 fecal samples were collected from owners and their pets. Seven of 26 humans and 12 of 43 animals were found to carry MDR-GNB, specifically species such as <i>Escherichia coli, Enterobacter ludwigii, Enterobacter hormaechei,</i> and <i>Citrobacter pasteurii</i>. Whole-genome sequencing revealed nine different resistance genes in <i>E. coli</i> isolates from pets and eight from humans, six different plasmid replicons, and all were located in four different phylogroups. Phylogenetic analysis indicates species-specific clustering based on host. Our results demonstrate that while MDR Enterobacterales were present in both humans and their pets in this Atlanta population, there was no evidence of bacterial transmission between pets and their owners during the study period. This finding contradicts previous similar studies that have shown transfer of MDR bacteria. However, it aligns with research that suggests bacterial colonization depends on the strain and the host.IMPORTANCEAntimicrobial resistance in animals, particularly pets, may serve as a potential source of antimicrobial resistance. However, a definitive pathway for the transmission of clonal bacteria or horizontal gene transfer between humans and their pets has not yet been identified. This pilot study aimed to assess the risk of multidrug-resistant (MDR) Enterobacterales transmission between healthy humans and their companion animals (dogs and cats) in the greater Atlanta area. Additionally, it sought to explore any association between MDR bacterial colonization and transmission within participating households. Despite the lack of a fully defined method of transmission, our findings demonstrated that while MDR <i>Enterobacterales</i> were present in both humans and their pets in this Atlanta population, there was no evidence of bacterial transmission between pets and their owners during the study period.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0050325"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HCMV infection of terminally differentiated neurons disrupts microtubule organization, resulting in neurite retraction.","authors":"Jacob W Adelman, Andrew T Sukowaty, Kaitlyn J Partridge, Jessica E Gawrys, Allison Akins, Scott S Terhune, Allison D Ebert","doi":"10.1128/spectrum.01198-25","DOIUrl":"https://doi.org/10.1128/spectrum.01198-25","url":null,"abstract":"<p><p>Human cytomegalovirus (HCMV) is a prolific human herpesvirus that infects most individuals by adulthood. While typically asymptomatic in adults, congenital infection can induce serious neurological symptoms, including hearing loss, visual deficits, cognitive impairment, and microcephaly in 10%-15% of cases. HCMV has been shown to infect most neural cells, with our group recently demonstrating this capacity in stem cell-derived forebrain neurons. Infection of neurons induces deleterious effects on calcium dynamics and electrophysiological function paired with gross restructuring of neuronal morphology. Here, we utilize an induced pluripotent stem cell-derived model of the human forebrain to demonstrate how HCMV infection induces syncytia, drives neurite retraction, and remodels microtubule networks to promote viral production and release. We establish that HCMV downregulates microtubule-associated proteins while largely sparing other cytoskeletal elements. Furthermore, we pharmacologically modulate microtubule dynamics using paclitaxel (stabilize) and colchicine (destabilize) to examine the effects on neurite structure, syncytial morphology, and viral release. With paclitaxel, we found improvement of neurite outgrowth, but neither paclitaxel nor colchicine impacted viral titers. Together, these data suggest that HCMV infection-induced disruption of microtubules in human cortical neurons can be partially mitigated with microtubule stabilization, suggesting a potential avenue for future neuroprotective strategies.IMPORTANCEInfection by human cytomegalovirus (HCMV) continues to cause significant damage to human health. In the absence of a vaccine, vertical transmission from mother to fetus can result in profound neurological damage impacting quality of life. These studies focus on understanding the impact of HCMV infection on forebrain cortical neurons derived from induced pluripotent stem cells (iPSCs). We show that infection results in loss of neurite extension accompanied by cell-to-cell fusion. These pathogenic changes involve HCMV infection-mediated disruption of the microtubule network in iPSCs from different patient backgrounds. The microtubule stabilization agent paclitaxel partially protected neurite length and altered syncytia morphology without impacting viral replication. This work is part of our continued efforts to define putative strategies to limit HCMV-induced neurological damage.</p>","PeriodicalId":18670,"journal":{"name":"Microbiology spectrum","volume":" ","pages":"e0119825"},"PeriodicalIF":3.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}