mSphere最新文献

{"title":"High prevalence of the recently identified clonal lineage ST1299/CT3109 <i>vanA</i> among vancomycin-resistant <i>Enterococcus faecium</i> strains isolated from municipal wastewater.","authors":"Giuseppe Valenza, David Eisenberger, Jan Esse, Jürgen Held, Verena Lehner-Reindl, Peter-Louis Plaumann, Tobias Ziegler, Max Knauer, Christian Bogdan, Patrick Dudler","doi":"10.1128/msphere.00396-24","DOIUrl":"10.1128/msphere.00396-24","url":null,"abstract":"<p><p>Previously, we demonstrated that the majority of vancomycin-resistant <i>Enterococcus faecium</i> (VREfm) strains from in-patients of the University Hospital Erlangen, Germany, belonged to only three clonal lineages, namely ST117/CT71 <i>vanB</i> and two novel ST1299 <i>vanA</i> lineages classified as CT3109 and CT1903. The goal of the current study was (i) to investigate whether VREfm is also detectable in wastewater of the city of Erlangen, (ii) to identify their molecular features, and (iii) to clarify whether VREfm could arise from the community of the city of Erlangen or can be (directly) connected to nosocomial infections in the hospital setting. From April to May 2023, a total of 244 VREfm strains from raw wastewater of the city of Erlangen were analyzed by core genome multilocus sequence typing (cgMLST). Moreover, 20 of them were further investigated for single nucleotide polymorphisms (SNPs). The molecular characterization of the wastewater VREfm strains revealed a high prevalence (27.9%) of the recently identified clonal lineage ST1299/CT3109 <i>vanA,</i> which is mainly characterized by the presence of the tetracycline-resistance determinant <i>tet(M</i>) and the virulence genes <i>pilA</i> and <i>prpA</i>. The SNPs analysis revealed the presence of two major clusters, namely cluster I (≤65 SNPs), which included well-known hospital-adapted <i>vanB</i> clonal lineages such as ST117/CT71 and ST80/CT1065 and cluster II (≤70 SNPs), which were mainly characterized by the lineage ST1299/CT3109 <i>vanA</i>. Based on the concomitant resistance to vancomycin and tetracycline, we propose that ST1299/CT3109 <i>vanA</i> primarily originated and spread outside of hospital settings.IMPORTANCEThis study provides a detailed genomic analysis of vancomycin-resistant <i>Enterococcus faecium</i> (VREfm) strains isolated from municipal wastewater with a particular focus on clonal lineages, antimicrobial resistance, and the presence of virulence genes. The high wastewater prevalence of the recently identified clonal lineage ST1299/CT3109 <i>vanA</i>, which has been previously detected in hospitals, suggests an enormous potential for future spread in Germany.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0039624"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423563/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional investigation of the two ClpPs and three ClpXs in <i>Myxococcus xanthus</i> DK1622.","authors":"Tianyu Wan, Ying Cao, Ya-Jun Lai, Zhuo Pan, Yue-Zhong Li, Li Zhuo","doi":"10.1128/msphere.00363-24","DOIUrl":"10.1128/msphere.00363-24","url":null,"abstract":"<p><p>ClpXP is a protease complex that plays important roles in protein quality control and cell cycle regulation, but the functions of multiple ClpXs and multiple ClpPs in <i>M. xanthus</i> remain unknown. The genome of <i>Myxococcus xanthus</i> DK1622 contains two <i>clpP</i>s and three <i>clpX</i>s. The <i>clpP1</i> and <i>clpX1</i> genes are cotranscribed and are both essential, while the other copies are isolated in the genome and are deletable. The deletion of <i>clpX2</i> caused the mutant to be deficient in fruiting body development, while the <i>clpX3</i> gene is involved in resistance to thermal stress. Both ClpPs possess catalytic active sites, but only ClpP1 shows <i>in vitro</i> peptidase activity on the typical substrate Suc-LY-AMC. All of these <i>clpP</i> and <i>clpX</i> genes exhibit strong transcriptional upregulation in the stationary phase, and the transcription of the three <i>clpX</i> genes appears to be coordinated. Our results demonstrated that multiple ClpPs and multiple ClpXs are functionally divergent and may assist in the environmental adaptation and functional diversification of <i>M. xanthus</i>.IMPORTANCEClpXP is an important protease complex of bacteria and is involved in various physiological processes. <i>Myxococcus xanthus</i> DK1622 possesses two ClpPs and three ClpXs with unclear functions. We investigated the functions of these genes and demonstrated the essential roles of <i>clpP1</i> and <i>clpX1</i>. Only ClpP1 has <i>in vitro</i> peptidase activity on Suc-LY-AMC, and the isolated <i>clpX</i> copies participate in distinct cellular processes. All of these genes exhibited significant transcriptional upregulation in the stationary phase. Divergent functions appear in multiple ClpPs and multiple ClpXs in <i>M. xanthus</i> DK1622.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0036324"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423568/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid and sensitive determination of residual prion infectivity from prion-decontaminated surfaces.","authors":"Sara M Simmons, Vivianne L Payne, Jay G Hrdlicka, Jack Taylor, Peter A Larsen, Tiffany M Wolf, Marc D Schwabenlander, Qi Yuan, Jason C Bartz","doi":"10.1128/msphere.00504-24","DOIUrl":"10.1128/msphere.00504-24","url":null,"abstract":"<p><p>Prion diseases are untreatable fatal transmissible neurodegenerative diseases that affect a wide range of mammals, including humans, and are caused by PrP^Sc, the infectious self-templating conformation of the host-encoded protein, PrP^C. Prion diseases can be transmitted via surfaces (e.g., forceps, EEG electrodes) in laboratory and clinical settings. Here, we use a combination of surface swabbing and real-time quaking-induced conversion (RT-QuIC) to test for residual surface-associated prions following prion disinfection. We found that treatment of several prion-contaminated laboratory and clinically relevant surfaces with either water or 70% EtOH resulted in robust detection of surface-associated prions. In contrast, treatment of surfaces with sodium hypochlorite resulted in a failure to detect surface-associated prions. RT-QuIC analysis of prion-contaminated stainless steel wires paralleled the findings of the surface swab studies. Importantly, animal bioassay and RT-QuIC analysis of the same swab extracts are in agreement. We report on conditions that may interfere with the assay that need to be taken into consideration before using this technique. Overall, this method can be used to survey laboratory and clinical surfaces for prion infectivity following prion decontamination protocols.IMPORTANCEPrion diseases can be accidentally transmitted in clinical and occupational settings. While effective means of prion decontamination exist, methods for determining the effectiveness are only beginning to be described. Here, we analyze surface swab extracts using real-time quaking-induced conversion (RT-QuIC) to test for residual prions following prion disinfection of relevant clinical and laboratory surfaces. We found that this method can rapidly determine the efficacy of surface prion decontamination. Importantly, examination of surface extracts with RT-QuIC and animal bioassay produced similar findings, suggesting that this method can accurately assess the reduction in prion titer. We identified surface contaminants that interfere with the assay, which may be found in clinical and laboratory settings. Overall, this method can enhance clinical and laboratory prion safety measures.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0050424"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423590/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the transcriptomic profile of human monkeypox virus via CAGE and native RNA sequencing approaches.","authors":"Gergely Ármin Nagy, Dóra Tombácz, István Prazsák, Zsolt Csabai, Ákos Dörmő, Gábor Gulyás, Gábor Kemenesi, Gábor E Tóth, Jiří Holoubek, Daniel Růžek, Balázs Kakuk, Zsolt Boldogkői","doi":"10.1128/msphere.00356-24","DOIUrl":"10.1128/msphere.00356-24","url":null,"abstract":"<p><p>In this study, we employed short- and long-read sequencing technologies to delineate the transcriptional architecture of the human monkeypox virus and to identify key regulatory elements that govern its gene expression. Specifically, we conducted a transcriptomic analysis to annotate the transcription start sites (TSSs) and transcription end sites (TESs) of the virus by utilizing Cap Analysis of gene expression sequencing on the Illumina platform and direct RNA sequencing on the Oxford Nanopore technology device. Our investigations uncovered significant complexity in the use of alternative TSSs and TESs in viral genes. In this research, we also detected the promoter elements and poly(A) signals associated with the viral genes. Additionally, we identified novel genes in both the left and right variable regions of the viral genome.IMPORTANCEGenerally, gaining insight into how the transcription of a virus is regulated offers insights into the key mechanisms that control its life cycle. The recent outbreak of the human monkeypox virus has underscored the necessity of understanding the basic biology of its causative agent. Our results are pivotal for constructing a comprehensive transcriptomic atlas of the human monkeypox virus, providing valuable resources for future studies.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0035624"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423596/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142081025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellulose binding and the timing of expression influence protein targeting to the double-layered cyst wall of <i>Acanthamoeba</i>.","authors":"Bharath Kanakapura Sundararaj, Manish Goyal, John Samuelson","doi":"10.1128/msphere.00466-24","DOIUrl":"10.1128/msphere.00466-24","url":null,"abstract":"<p><p>The cyst wall of the eye pathogen <i>Acanthamoeba castellanii</i> contains cellulose and has ectocyst and endocyst layers connected by conical ostioles. Cyst walls contain families of lectins that localize to the ectocyst layer (Jonah) or the endocyst layer and ostioles (Luke and Leo). How lectins and an abundant laccase bind cellulose and why proteins go to locations in the wall are not known and are the focus of the studies here. Structural predictions identified β-jelly-roll folds (BJRFs) of Luke and sets of four disulfide knots (4DKs) of Leo, each of which contains linear arrays of aromatic amino acids, also present in carbohydrate-binding modules of bacterial and plant endocellulases. Ala mutations showed that these aromatics are necessary for cellulose binding and proper localization of Luke and Leo in the <i>Acanthamoeba</i> cyst wall. BJRFs of Luke, 4DKs of Leo, a single β-helical fold (BHF) of Jonah, and a copper oxidase domain of the laccase each bind to glycopolymers in both layers of deproteinated cyst walls. Promoter swaps showed that ectocyst localization does not just correlate with but is caused by early encystation-specific expression, while localization in the endocyst layer and ostioles is caused by later expression. Evolutionary studies showed distinct modes of assembly of duplicated domains in Luke, Leo, and Jonah lectins and suggested Jonah BHFs originated from bacteria, Luke BJRFs share common ancestry with slime molds, while 4DKs of Leo are unique to <i>Acanthamoeba</i>.IMPORTANCE<i>Acanthamoebae</i> is the only human parasite with cellulose in its cyst wall and conical ostioles that connect its inner and outer layers. Cyst walls are important virulence factors because they make <i>Acanthamoebae</i> resistant to surface disinfectants, hand sanitizers, contact lens sterilizers, and antibiotics applied to the eye. The goal here was to understand better how proteins are targeted to specific locations in the cyst wall. To this end, we identified three new proteins in the outer layer of the cyst wall, which may be targets for diagnostic antibodies in corneal scrapings. We used structural predictions and mutated proteins to show linear arrays of aromatic amino acids of two unrelated wall proteins are necessary for binding cellulose and proper wall localization. We showed early expression during encystation causes proteins to localize to the outer layer, while later expression causes proteins to localize to the inner layer and the ostioles.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0046624"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423589/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enzymatically enhanced ultrastructure expansion microscopy unlocks expansion of <i>in vitro Toxoplasma gondii</i> cysts.","authors":"Kseniia Bondarenko, Floriane Limoge, Kayvon Pedram, Mathieu Gissot, Joanna C Young","doi":"10.1128/msphere.00322-24","DOIUrl":"10.1128/msphere.00322-24","url":null,"abstract":"<p><p>Expansion microscopy (ExM) is an innovative approach to achieve super-resolution images without using super-resolution microscopes, based on the physical expansion of the sample. The advent of ExM has unlocked the detail of super-resolution images for a broader scientific circle, lowering the cost and entry skill requirements for the field. One of its branches, ultrastructure expansion microscopy (U-ExM), has become popular among research groups studying apicomplexan parasites, including the acute stage of <i>Toxoplasma gondii</i> infection. Here, we show that the chronic cyst-forming stage of <i>Toxoplasma</i>, however, resists U-ExM expansion, impeding precise protein localization. We then solve the <i>in vitro</i> cyst's resistance to denaturation required for successful U-ExM. As the cyst's main structural protein CST1 contains a mucin domain, we added an enzymatic digestion step using the pan-mucinase StcE prior to the expansion protocol. This allowed full expansion of the cysts in fibroblasts and primary neuronal cell culture without disrupting immunofluorescence analysis of parasite proteins. Using StcE-enhanced U-ExM, we clarified the localization of the GRA2 protein, which is important for establishing a normal cyst, observing GRA2 granules spanning across the CST1 cyst wall. The StcE-U-ExM protocol allows accurate pinpointing of proteins in the bradyzoite cyst, which will greatly facilitate investigation of the underlying biology of cyst formation and its vulnerabilities.</p><p><strong>Importance: </strong><i>Toxoplasma gondii</i> is an intracellular parasite capable of establishing long-term chronic infection in nearly all warm-blooded animals. During the chronic stage, parasites encapsulate to form cysts predominantly in neurons and skeletal muscle. Current anti-<i>Toxoplasma</i> drugs do not eradicate chronic parasites, leaving a reservoir of infection. The cyst is critical for disease transmission and pathology, yet it is harder to study, with the function of many chronic-stage proteins still unknown. Ultrastructure expansion microscopy, a new method to overcome the light microscopy's diffraction limit by physically expanding the sample, allowed in-depth studies of acute <i>Toxoplasma</i> infection. We show that <i>Toxoplasma</i> cysts resist expansion using standard protocol, but an additional enzymatic digestion with the mucinase StcE allows full expansion. This protocol offers new avenues for examining the chronic stage, including precise spatial organization of cyst-specific proteins, linking these locations to morphological structures, and detailed investigations of components of the durable cyst wall.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0032224"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423595/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142073341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two cyanobacterial species exhibit stress responses when grown together in visible light or far-red light.","authors":"Ting-Shuo Nien, Ting-Hsuan Chan, Ying-Yang Li, Ting-So Liu, Yo-Jin Shiau, Ming-Yang Ho","doi":"10.1128/msphere.00251-24","DOIUrl":"10.1128/msphere.00251-24","url":null,"abstract":"<p><p>Although most cyanobacteria grow in visible light (VL; <i>λ</i> = 400-700 nm), some cyanobacteria can also use far-red light (FRL; <i>λ</i> = 700-800 nm) for oxygenic photosynthesis by performing far-red light photoacclimation. These two types of cyanobacteria can be found in the same environment. However, how they respond to each other remains unknown. Here, we reveal that coculture stresses FRL-using <i>Chlorogloeopsis fritschii</i> PCC 9212 and VL-using <i>Synechocystis</i> sp. PCC 6803. No significant growth difference was found in <i>Synechocystis</i> sp. PCC 6803 between the coculture and the monoculture. Conversely, the growth of <i>Chlorogloeopsis fritschii</i> PCC 9212 was suppressed in VL under coculture. According to transcriptomic analysis, <i>Chlorogloeopsis fritschii</i> PCC 9212 in coculture shows low transcript levels of metabolic activities and high transcript levels of ion transporters, with the differences being more noticeable in VL than in FRL. The transcript levels of stress responses in coculture were likewise higher than in monoculture in <i>Synechocystis</i> sp. PCC 6803 under FRL. The low transcript level of metabolic activities in coculture or the inhibition of cyanobacterial growth indicates a possible negative interaction between these two cyanobacterial strains.IMPORTANCEThe interaction between two cyanobacterial species is the primary focus of this study. One species harvests visible light, while the other can harvest far-red and visible light. Prior research on cyanobacteria interaction concentrated on its interactions with algal, coral, and fungal species. Interactions between cyanobacterial species were, nevertheless, rarely discussed. Thus, we characterized the interaction between two cyanobacterial species, one capable of photosynthesis using far-red light and the other not. Through experimental and bioinformatic approaches, we demonstrate that when one cyanobacterium thrives under optimal light conditions, it stresses the remaining cyanobacterial species. We contribute to an ecological understanding of these two kinds of cyanobacteria distribution patterns. Cyanobacteria that utilize far-red light probably disperse in environments with limited visible light to avoid competition with other cyanobacteria. From a biotechnological standpoint, this study suggests that the simultaneous cultivation of two cyanobacterial species in large-scale cultivation facilities may reduce the overall biomass yield.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0025124"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423583/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141907155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Community organization and network complexity and stability: contrasting strategies of prokaryotic versus eukaryotic microbiomes in the Bohai Sea and Yellow Sea.","authors":"Xiaoxiao Wang, Hualong Wang, Yantao Liang, Andrew McMinn, Min Wang","doi":"10.1128/msphere.00395-24","DOIUrl":"10.1128/msphere.00395-24","url":null,"abstract":"<p><p>Unraveling the effects of spatial gradients on microbiome assembly and association is a challenging topic that remains understudied in the coastal ecosystem. Here, we aimed to investigate the effects of spatial variation on the network complexity and stability of plankton microbiomes in the Bohai Sea and Yellow Sea. These seas serve as spawning and nursery grounds for economically important fisheries valued at billions of dollars annually. Environmental heterogeneity structures microbial communities into distinct spatial patterns, leading to complex direct/indirect relationships and broader ecological niches of bacterioplankton compared to microeukaryotic communities. Interestingly, salinity gradients positively influenced the richness of rare subgroups of bacterioplankton, while the rare microeukaryotic subgroups showed an opposite trend. Abundant subgroups of prokaryotic/eukaryotic microbiomes exhibited greater environmental niche breadth and lower phylogenetic distance compared to the rare subgroups. Stochastic processes contributed greatly to microbiome dynamics, and deterministic processes governed the bacterioplankton organization with a lower phylogenetic turnover rate. Compared to microeukaryotes, bacterioplankton exhibit higher network modularity, complexity, and robustness and lower fragmentation, and vulnerability. These observations offer vital insights into the anti-interference ability and resistance of plankton microbiomes in response to environmental gradients in terms of organization and survival strategy as well as their adaptability to environmental disturbances.IMPORTANCEAn in-depth understanding of community organization and stability of coastal microbiomes is crucial to determining the sustainability of marine ecosystems, such as the Bohai Sea and Yellow Sea. Distinct responses between prokaryotic and eukaryotic microbiomes to spatial heterogeneity were observed in terms of geographical distribution, phylogenetic distance, niche breadth, and community assembly process. Environmental variations are significantly correlated with the dynamics of rare eukaryotic plankton subcommunities compared to prokaryotic plankton subcommunities. Deterministic processes shaped prokaryotic plankton community organization with a lower phylogenic turnover rate. Rare subgroups had noticeably higher phylogenetic distance and lower niche breadth than the corresponding abundant subgroups. Prokaryotic microbiomes had higher molecular network complexity and stability compared to microeukaryotes. Results presented here show how environmental gradients alter both the geographical characteristics of the microbial organization in coastal seas and also their co-occurrence network complexity and stability and thus have critical implications for nutrient and energy cycling.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0039524"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423591/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141971504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction for Sharma et al., \"Specific and Randomly Derived Immunoactive Peptide Mimotopes of Mycobacterial Antigens\".","authors":"Archna Sharma, Abhik Saha, Surajit Bhattacharjee, Subrata Majumdar, Sujoy K Das Gupta","doi":"10.1128/msphere.00609-24","DOIUrl":"10.1128/msphere.00609-24","url":null,"abstract":"","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0060924"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423581/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142133291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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>In vivo</i> evolution to hypermucoviscosity and ceftazidime/avibactam resistance in a liver abscess caused by <i>Klebsiella pneumoniae</i> sequence type 512.","authors":"Valerio Capitani, Gabriele Arcari, Cecilia Ambrosi, Daniela Scribano, Mariateresa Ceparano, Riccardo Polani, Alice De Francesco, Giammarco Raponi, Giancarlo Ceccarelli, Paolo Villari, Anna Teresa Palamara, Carolina Marzuillo, Alessandra Carattoli","doi":"10.1128/msphere.00423-24","DOIUrl":"10.1128/msphere.00423-24","url":null,"abstract":"<p><p>Carbapenemase-producing <i>Klebsiella pneumoniae</i> represents a major public health issue globally. Isolates with resistance to the newest drugs, like ceftazidime/avibactam (CZA), are increasingly reported. In this study, we analyzed the evolution of KPC-3-producing sequence type (ST) 512 <i>K</i>. <i>pneumoniae</i> strains isolated at three different times (hospitalization days 45, 56, and 78) from the same patient, two of which were observed in a pericholecystic liver abscess. The three <i>K. pneumoniae</i> isolates (295Kp, 304Kp, and hmv-318Kp) from the same patient were subjected to antimicrobial susceptibility testing, whole-genome sequencing, sedimentation assay, biofilm measurement, serum resistance assay, macrophage phagocytosis, and adhesion assays. KPC-producing isolate hmv-318Kp exhibited carbapenem susceptibility, hypermucoviscous (hmv) colony phenotype and CZA resistance. Virulence markers of hypervirulent <i>Klebsiella</i> were absent. Two non-synonymous mutations were identified in the hmv-318Kp genome comparing with isogenic strains: a single-nucleotide polymorphism (SNP) occurred in the pKpQIL plasmid, changing <i>bla</i>_KPC-3 in the <i>bla</i>_KPC-31 gene variant, conferring CZA resistance; and a second SNP occurred in the <i>wzc</i> gene of the capsular biosynthesis cluster, encoding a tyrosine kinase, resulting in the F557S Wzc protein mutation. The <i>Klebsiella pneumoniae</i> strain exhibiting an hmv phenotype (hmv-Kp) phenotype has been previously associated with amino acid substitutions occurring in the Wzc tyrosin kinase protein. We observed <i>in vivo</i> evolution of the ST512 strain to CZA resistance and acquisition of hypermucoviscosity. The pathogenetic role of the detected Wzc substitution is not fully elucidated, but other Wzc mutations were previously reported in hmv <i>K. pneumoniae</i>. Wzc mutants may be more frequent than expected and an underreported cause of hypermucoviscosity in <i>K. pneumoniae</i> clinical isolates.</p><p><strong>Importance: </strong>Here we describe the evolution of KPC-3-producing ST512 <i>K. pneumoniae</i> isolated at three different times from the same patient of which the last one, from a biliary abscess, showed CZA resistance by KPC-31 production and manifested hmv colony phenotype. Hypervirulent <i>Klebsiella pneumoniae</i> (hv-Kp) isolates are increasingly reported worldwide. Their hypervirulent traits are associated with the presence of rmpA/A2 genes and an hmv. In this study, we identified an hmv-Kp that lacked the rmpA-D cluster but showed an amino acid substitution in the Wzc tyrosin kinase protein, involved in the capsular biosynthesis. This hmv-Kp strain emerged <i>in vivo</i> and evolved resistance to ceftazidime/avibactam resistance in a liver abscess of a patient. Our findings suggest that wzc mutations may be underreported, making it challenging to distinguish hv-Kp from \"classic\" <i>K. pneumoniae</i> with an hmv phenotype.</p>","PeriodicalId":19052,"journal":{"name":"mSphere","volume":" ","pages":"e0042324"},"PeriodicalIF":3.7,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11423586/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142018100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}