Frontiers in Microbiology最新文献

{"title":"Clinical emergence of a novel sequence type (ST3672) NDM-1-producing <i>Vibrio parahaemolyticus</i> in foodborne disease.","authors":"Chengpei Ni, Jiancheng Wang, Chao Yang, Song Gao, Ze Xu, Yajing Wang, Honghong Peng, Wengting Cao, Yi Han","doi":"10.3389/fmicb.2026.1767946","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1767946","url":null,"abstract":"<p><strong>Background: </strong>This study characterized a newly identified ST3672-type <i>Vibrio parahaemolyticus</i> (<i>V. parahaemolyticus</i>) strain (VP1434), isolated directly from a patient involved in a food poisoning outbreak, highlighting its rare multidrug resistance (MDR) phenotype. The objectives were to investigate its resistance mechanisms, elucidate its evolutionary relationships, and assess its pathogenicity.</p><p><strong>Methods: </strong>The VP1434 isolate was analyzed as follows: (1) Antimicrobial susceptibility was tested against 29 antibiotics, and plasmid conjugation experiments verified drug resistance in recipient strains post-transfer. (2) Whole-genome sequencing was used to characterize its genomic features, including plasmid sequences and inter-plasmid relationships. (3) Evolutionary tracing of VP1434 and the plasmid pVP1434-NDM was performed by constructing phylogenetic trees. (4) Virulence factors (VFs) were identified via the Virulence Factor Database, and pathogenicity was assessed through mouse infection.</p><p><strong>Results: </strong>The strain demonstrated a concerning MDR profile, exhibiting resistance to all tested <i>β</i>-lactam antibiotics. Additionally, it displayed resistance to sulfonamides and aminoglycosides, with intermediate susceptibility to tetracyclines. Plasmid conjugation experiments showed the <i>bla</i> _NDM-1-harboring plasmid was transferable to VP0577, and transconjugants also showed MDR. Whole-genome sequencing identified a <i>bla</i> _NDM-1-carrying plasmid harboring multiple resistance genes, which fully explaining its phenotypic resistance to at least four classes of antibiotics. Phylogenetic analysis placed VP1434 on a distinct branch within the maximum-likelihood tree constructed from global <i>V. parahaemolyticus</i> isolates, while the closest relative of the <i>bla_NDM-1</i> -harboring plasmid was identified in a shrimp-derived <i>V. parahaemolyticus</i> strain. VP1434 was found to harbor 185 VFs, including <i>tlh</i> and <i>trh</i>, but lacked the key pathogenicity determinant <i>tdh</i>. In mouse infection experiments, strain VP1434 (<i>tdh^-/trh⁺</i> ) exhibited significantly higher lethality than environmental isolates (<i>tdh^-/trh^-</i> ), suggesting TRH plays a significant role in pathogenicity even in the absence of TDH.</p><p><strong>Conclusion: </strong>This first report of <i>bla</i> _NDM-1-positive clinical <i>V. parahaemolyticus</i> reveals plasmid-mediated MDR emergence in human infections. Its unexpected virulence without classical toxins indicates evolutionary adaptation, necessitating diagnostic updates and strengthened surveillance.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1767946"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144090/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836059","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":"Yeast infections in sterile body fluids: species distribution, antifungal susceptibility, and cross-cutting risk factors for fungemia, sepsis, and mortality (2019-2023).","authors":"Jiaxing Liu, Mei Han, Fan Yang, Shuo Gao, Wanqing Zhou, Han Shen, Xiaoli Cao, Yan Zhang","doi":"10.3389/fmicb.2026.1773098","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1773098","url":null,"abstract":"<p><strong>Background: </strong>Yeast infections from sterile body fluids are increasingly encountered in tertiary care, yet contemporary links between species ecology, antifungal susceptibility, and patient outcomes remain underdefined.</p><p><strong>Methods: </strong>We conducted a retrospective cohort study of 231 consecutive sterile-site yeast isolates at Nanjing Drum Tower Hospital (2019-2023). Species were identified by CHROMagar and MALDI-TOF MS; antifungal MICs were determined using YeastOne and interpreted by CLSI M27-Ed3. Clinical data were abstracted from electronic records. Variables with <i>p</i> < 0.10 in univariate testing entered multivariable logistic regression to identify independent predictors of fungemia, sepsis, and in-hospital mortality.</p><p><strong>Results: </strong>The four major Candida species showed distinct susceptibility profiles, with <i>C. albicans</i> broadly susceptible, <i>C. tropicalis</i> exhibiting notable azole resistance, <i>Nakaseomyces glabratus</i> (<i>C. glabrata</i>) displaying high azole MICs but good echinocandin activity, and <i>C. parapsilosis</i> maintaining low azole MICs but intrinsically higher echinocandin MICs. Clinically, bloodstream involvement was frequent. Fungemia was independently associated with blood transfusion and hemodialysis catheterization, whereas surgery was protective (OR 0.320, 95% CI 0.171-0.599). Sepsis occurred in 23.8% and was independently associated with ICU admission (OR 7.119, 95% CI 2.811-18.026); surgical treatment again showed a protective association (OR 0.426, 95% CI 0.190-0.954). Overall mortality was 26.8%; acute kidney injury (AKI) independently predicted death (OR 3.354, 95% CI 1.563-7.198).</p><p><strong>Conclusions: </strong>In this five-year cohort, <i>Candida</i>-led by <i>C. albicans</i> with a rising <i>non-albicans</i> share-dominated sterile-site infections. Echinocandins and amphotericin B retained broad activity, whereas azole activity was reduced in <i>C. tropicalis/N. glabratus</i>. Across outcomes, transfusion and hemodialysis catheters increased fungemia risk, ICU admission increased sepsis risk, AKI drove mortality, and early surgical source control was consistently protective. These findings support prompt device removal, restrictive transfusion, proactive renal management, and echinocandin-first strategies in high-risk patients.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1773098"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144016/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836113","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":"Longitudinal dynamics and characterization of discriminative taxa in fecal microbiota of suckling and weaned piglets.","authors":"Bo Song, Shuo Yang, Boxuan Yang, Zhijian Xu, Feilong Deng, Ying Li","doi":"10.3389/fmicb.2026.1783640","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1783640","url":null,"abstract":"<p><strong>Introduction: </strong>Early-life microbial colonization is fundamental to porcine health and production efficiency. However, the distinction between age-related development and weaning-induced shifts in the gut microbiota remains insufficiently characterized.</p><p><strong>Methods: </strong>This study investigated the longitudinal development of fecal microbiota in Duroc × Landrace × Yorkshire piglets from birth to day 28.</p><p><strong>Results and discussion: </strong>Using 16S rRNA gene sequencing, we first mapped the microbial development of suckling piglets, identifying a non-linear progression characterized by three distinct stages: initial colonization (days 1-7), rapid transition (days 14-21), and a stabilization stage (days 24-28). We then compared suckling piglets with those weaned at day 21. While no differences were observed on the day of weaning, weaned piglets exhibited significantly higher microbial richness and diversity by days 24 and 28 compared to suckling counterparts. β-diversity analysis confirmed a significant structural difference post-weaning, suggesting that weaning disrupt the developmental progress. Based on the LEfSe analysis and Random Forest models, <i>Lactobacillus</i> and <i>Collinsella</i> were identified as discriminative taxa in suckling and weaned piglets. These findings provide a map of microbial assembly and offer theoretical targets for mitigating weaning stress through microbial modulation.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1783640"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144040/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836018","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":"Coexistence of <i>bla</i> _NDM-1 and <i>bla</i> _IMP-4 in an IncHI5 plasmid harbored by carbapenem- resistant <i>Raoultella ornithinolytica</i>.","authors":"Yuanye Qu, Weiqiang Xiao, Yanmin Chang, Mingyue Sun, Wenjiao Li, Qingxia Xu","doi":"10.3389/fmicb.2026.1744139","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1744139","url":null,"abstract":"<p><strong>Background: </strong><i>Raoultella ornithinolytica</i> is an emerging pathogen. This study aimed to characterize the genomic and molecular features of a carbapenem-resistant <i>R.ornithinolytica</i> strain co-harboring <i>bla</i> _NDM-1 and <i>bla</i> _IMP-4.</p><p><strong>Methods: </strong>Strain he2023 was identified and subjected to antimicrobial susceptibility testing using the BD Phoenix-M50 fully automated system. The strain was verified using MALDI-TOF. Carbapenemase genes were confirmed by PCR. Whole-genome sequencing (WGS) was performed to identify resistance genes and plasmid types. Conjugation experiments were conducted to assess transferability, and plasmid stability was evaluated through serial subculturing.</p><p><strong>Results: </strong>The BD Phoenix-M50 system misidentified strain he2023 as <i>Klebsiella pneumoniae</i>, whereas MALDI-TOF and WGS correctly identified it as <i>R. ornithinolytica</i>. The strain was resistant to most antimicrobial agents, remaining susceptible only to amikacin,Tigecycline and polymyxin B. The <i>bla</i> _NDM-1 and <i>bla</i> _IMP-4 genes were both located on the plasmid pNDM-IMP, which belongs to the replicon type IncHI5. The <i>bla</i> _NDM-1 was located in the structure of <i>ISAba125</i>-<i>bla</i> _NDM-1-<i>ble</i> _MBL-<i>trpF</i>-<i>dsbC</i>, residing in a region within the remnant of transposon <i>Tn125</i>, flanked by two copies of <i>ISCR1</i>. The <i>bla</i> _IMP-4 was located downstream of <i>bla</i> _NDM-1 within a novel class 1 integron (<i>In1965</i>) carrying the structure <i>sul1</i>-<i>qacE</i>-<i>arr-3-ltrA</i>-<i>bla</i> _IMP-4-<i>IntI1</i>. Conjugation and transformation assays showed that the plasmid pNDM-IMP was non-transferable but exhibited high structural stability.</p><p><strong>Conclusion: </strong>This study is the first to report an IncHI5 plasmid co-harboring <i>bla</i> _NDM-1 and <i>bla</i> _IMP-4 in <i>R. ornithinolytica</i>. Non-transferable plasmids may serve as reservoirs or initial carriers for antibiotic resistance genes. Our findings highlights the importance of mobile genetic elements in the formation of multidrug resistance.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1744139"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144124/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836073","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":"Raman signatures of <i>Cnm</i>-positive <i>Streptococcus mutans</i>: II, screening the virulence of clinical isolates.","authors":"Giuseppe Pezzotti, Tetsuya Adachi, Kazunori Kitagawa, Saki Ikegami, Hayata Imamura, Toshiro Yamamoto, Kazu Okuma, Yoshiyuki Matsuo, Wenliang Zhu, Yoshiki Yasukochi, Koichiro Higasa, Saki Nishihama, Katsuhiro Takeda, Hideki Shiba, Miki Kawada-Matsuo, Hitoshi Komatsuzawa","doi":"10.3389/fmicb.2026.1784126","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1784126","url":null,"abstract":"<p><p>This study dealt with developing a Raman spectroscopic method for estimating the degree of virulence of <i>Streptococcus mutans</i> bacteria isolated from clinical swab samples. Raman experiments aimed at establishing suitable spectroscopic parameters to quantify bacterial virulence and were conducted on a limited series of six clinical isolates three of which were genomically classified as Cnm-positive and three as Cnm-negative. Samples were characterized after biofilm purification and compared with cultures of the same bacteria in physiological state of equilibrium, namely, after long-term stabilization <i>in vitro</i>. Statistically significant series of ten Raman spectra were collected at different locations on each clinical sample, and their averages interpreted as multiomic snapshots of bacterial structure. Building upon the spectroscopic analyses described in the companion paper Part I, Raman characterizations of clinical isolates revealed a significant degree of variability in the bacterial structure, but also suggested clear classification criteria for clinical samples. These spectroscopic criteria reflected specific biochemical circumstances affecting the structure of bacteria in their pathophysiological state. Raman algorithms based on the fractional balance between proteins and peptidoglycans, and the degree of protein structural disorder vs. presence of oxysulfur compounds enabled insightful classifications of bacterial virulence, which matched genomic analyses. These structural characteristics, which allowed distinguishing between Cnm-positive and Cnm-negative bacteria, could provide fast and unbiased diagnostic criteria for risk assessments of endocarditis and hemorrhagic strokes as induced by Cnm-positive bacteria. In summary, the present study proposes a new spectroscopic approach to oral flora-related diagnostics and confirms the potential utility of Raman spectroscopy in chairside analyses of clinical isolates.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1784126"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13148223/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836142","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":"Composition and diversity of gut microbiota in non-erosive reflux disease.","authors":"Xiuxiu Wei, Gaoxiang Wang, Yuchen Wei, Tai Zhang, Mengxiong Lu, Luzhou Xu, Beihua Zhang, Xudong Tang","doi":"10.3389/fmicb.2026.1795756","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1795756","url":null,"abstract":"<p><strong>Objective: </strong>Non-erosive reflux disease (NERD) is a prevalent gastrointestinal disorder with complex pathophysiology. Recent evidence suggests a potential role of gut microbiota in its development. This study aimed to characterize the gut microbiota in patients with NERD, and to explore microbial biomarkers for disease differentiation.</p><p><strong>Methods: </strong>We enrolled 40 patients with NERD, along with 18 healthy controls (HCs). Fecal samples were collected and analyzed using 16S ribosomal RNA (rRNA) gene sequencing. Gut microbial diversity and composition, linear discriminant analysis effect size (LEfSe), and receiver operating characteristic (ROC) curves were evaluated.</p><p><strong>Results: </strong>The microbial structure and composition of NERD patients were distinct from those of HCs. Alpha diversity was significantly lower in NERD patients than in controls (<i>p</i> < 0.01). At the phylum level, Actinobacteriota was increased, while Bacteroidota and Proteobacteria were decreased in NERD patients. At the genus level, <i>Faecalibacterium</i> and <i>Bacteroides</i> were decreased, whereas <i>Streptococcus</i>, <i>Blautia</i>, <i>Bifidobacterium</i>, and <i>Enterococcus</i> were enriched in NERD patients. Additionally, LEfSe was developed to identify several bacterial genera that can differentiate patients with NERD from those HCs. Furthermore, the area under the curve (AUC) value of <i>Streptococcus</i> for distinguishing NERD from HCs was 0.9333, indicating exceptionally high diagnostic power.</p><p><strong>Conclusion: </strong>This study identified microbiota dysbiosis of gut microbiota in NERD patients. <i>Streptococcus</i> showed extremely high diagnostic efficacy, which can be used as a microbial biomarker, and may serve as potential therapeutic target for NERD.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1795756"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143873/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147835397","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":"Integrated transcriptome-microbiome analysis reveals a host-microbe interplay associated with insecticide resistance in <i>Aedes albopictus</i>.","authors":"Lifang Liu, Guorui Liang, Heting Gao, Siyu Xing, Kai Wang, Xinyu Zhou, Xinan Huang, Chunxiao Li","doi":"10.3389/fmicb.2026.1788609","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1788609","url":null,"abstract":"<p><strong>Introduction: </strong><i>Aedes albopictus</i> is the primary vector of major arboviral diseases such as dengue fever, chikungunya fever, and Zika virus disease, and its control is highly dependent on chemical insecticides. However, the long-term use of pyrethroid insecticides has led to the development of insecticide resistance in <i>Ae. albopictus</i>, which severely undermines the efficacy of vector control programs.</p><p><strong>Methods: </strong><i>Ae. albopictus</i> populations were collected from five sites in Guangdong and Hainan provinces, China. Beta-cypermethrin resistance levels were determined via bioassays, with resistance ratios at the median lethal concentration (RR₅₀) calculated. Target-site resistance was evaluated via <i>kdr</i> mutation detection in the voltage-gated sodium channel (VGSC) gene. Transcriptome sequencing identified differentially expressed genes (DEGs), and 16S rRNA sequencing characterized gut microbiome alterations. Correlation analysis and <i>Cedecea neteri</i> dietary supplementation assays verified the role of gut microbiota in resistance.</p><p><strong>Results: </strong>The results showed that all four populations (except the CP population) exhibited varying degrees of resistance to beta-cypermethrin, with resistance ratios at the median lethal concentration (RR₅₀) ranging from 2.84 to 29.18. Detection of <i>kdr</i> mutations revealed three mutations (F1534C, F1534L, F1534S) at codon 1534 of the voltage-gated sodium channel (VGSC) gene in all field populations, with mutation frequencies ranging from 49.4% to 100.0%, and a low-frequency V1016G mutation at codon 1016. Transcriptome analysis identified a total of 2,566 commonly upregulated genes and 994 commonly downregulated genes across the resistant populations. Gut microbiome analysis revealed a significant alteration in the intestinal microbial community structure of resistant populations; specifically, the relative abundance of the genus <i>Cedecea</i> differed significantly between resistant and susceptible populations and correlated strongly with the expression of most differentially expressed genes. Furthermore, dietary supplementation with Cedecea neteri significantly increased the survival rate of <i>Ae. albopictus</i> exposed to β-cypermethrin (73.86% vs 40.00%; <i>P</i> < 0.0001).</p><p><strong>Discussion: </strong>From the perspectives of target-site mutations, gene expression regulation, and gut microbe interactions, this study providing a foundation for further studies on resistance mechanisms in <i>Ae. albopictus</i>, thereby providing a theoretical foundation for further dissection of resistance mechanisms and optimization of vector control strategies.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1788609"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143895/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836009","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":"Characterization and phage-antibiotic synergy of bacteriophages PES-1 and PES-2 against porcine enterotoxigenic <i>Escherichia coli</i>.","authors":"Tingfang Li, Lina Fu, Jiansong You, Fazal Mehmood Khan, Jianguang Li, Yanfen Liu, Xiaoyu Li, Yongping Xu, Lili Wang","doi":"10.3389/fmicb.2026.1713167","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1713167","url":null,"abstract":"<p><p>The emergence of drug-resistant porcine enterotoxigenic <i>Escherichia coli</i> (ETEC) necessitates the exploration of alternative antibacterial approaches. Two lytic bacteriophages, PES-1 and PES-2, have been isolated and characterized to control ETEC. PES-1 exhibited a wide host range, lysing five ETEC strains, whereas PES-2 displayed restricted specificity, impacting only one of the seven strains. Both phages demonstrated optimal stability at a pH of 4.0-7.0 and a temperature of 4 °C-37 °C. Comparative genomic characterization revealed that the bacteriophages PES-1 have a 40.3 kb size and 48.29% GC contents, while the PES-2 have 67.8 kb size and 46.12% GC Contents, both of which possess a double-stranded linear DNA genomes, lacking tRNA genes, lysogeny-related elements, virulence factors, and antibiotic-resistant factors, emphasizing their obligately lytic lifestyle and genomic biosafety. Genomic analysis revealed that PES-1 exhibited sensitivity to EcoR-I and Hind-III. PES-2 demonstrated resistance to all tested restriction enzymes. Combining bacteriophages with antibiotics such as amoxicillin and neomycin significantly enhanced antibacterial efficacy (<i>p</i> < 0.05). A notable synergy was observed with amoxicillin, resulting in a decrease in bacterial loads by 2.02-3.47 log units compared to amoxicillin alone. This synergy likely arises from dual selective pressure and improved antibiotic penetration after phage-mediated lysis. However, no significant difference was observed in the gentamycin-phage combination group compared to the phage cocktail group. The results indicate that PES-1 and PES-2 show environmental stability and effectiveness as biocontrol agents for ETEC. This research introduces an innovative method for developing bacteriophage-based solutions applicable to veterinary and food safety contexts.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1713167"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144091/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836056","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":"An Orc1 initiator-specific motif (ISM)-related region limits ORC-ssDNA binding and promotes replication origin specificity in budding yeast.","authors":"Hironori Kawakami, Takeaki Chichibu, Ryuya Muraoka, Shota Kanamoto, Kanako Asada, Eiji Ohashi, Takuya Kurihara, Tsutomu Katayama","doi":"10.3389/fmicb.2026.1778270","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1778270","url":null,"abstract":"<p><p>Single-stranded DNA (ssDNA) is an essential intermediate of genome duplication but can also arise in the genome, including at highly transcribed loci. Although the origin recognition complex (ORC), a eukaryotic replication initiator, has been reported to bind ssDNA, how interactions with ssDNA-exposing regions are regulated without compromising origin specificity and genome stability remains poorly understood. Here, we characterize the ssDNA-binding properties of budding yeast ORC and the role of an initiator-specific motif (ISM)-related region within the AAA+ domain of Orc1. <i>In vitro</i>, ORC binds ssDNA (except for poly dA) at affinities comparable to those of replication protein A (RPA) under identical binding conditions, suggesting base composition-dependent modulation of ORC-ssDNA binding. Genome-wide analyses show partial overlap between ORC- and RPA-enriched peaks, consistent with ORC binding at a subset of ssDNA-forming loci <i>in vivo</i>. Mutations of the Orc1 ISM-related region increase ORC binding to ssDNA and promote higher-order ORC-ssDNA complex formation <i>in vitro</i>, indicating that this region normally limits ORC-ssDNA binding. In contrast, these mutations impair origin-specific ORC binding through mechanisms involving the essential A-element-proximal region. Genetic and chromatin-based analyses further reveal that enhanced ssDNA binding correlates with reduced origin binding <i>in vivo</i>, indicating a redistribution of ORC from replication origins to ssDNA-forming loci. Despite conservation of the ISM across domains of life, these results suggest that eukaryotic ORC has functionally diverged such that origin binding is coupled to the repression of ssDNA binding through the Orc1 ISM-related region, thereby safeguarding faithful origin selection.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1778270"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13144144/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836089","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":"Non-invasive molecular surveillance of drug-resistant bacterial and fungal pathogens in severe ICU pneumonia: a comparative study of nasopharyngeal swabs and BALF.","authors":"Hua Li, Yicheng Yang, Chun Lin, Daoyong Huang, Mingyue Lin, Ziting Wu, Haidan Lin, Xiao Zhan, Zufu Cheng, Youshe Lu, Ling Ouyang","doi":"10.3389/fmicb.2026.1794266","DOIUrl":"https://doi.org/10.3389/fmicb.2026.1794266","url":null,"abstract":"<p><strong>Background: </strong>Drug-resistant bacterial and fungal infections represent a major cause of morbidity and mortality among critically ill and immunocompromised patients with severe pneumonia. Molecular diagnostics using bronchoalveolar lavage fluid (BALF) are considered the reference standard for pathogen identification but are invasive and often contraindicated in unstable intensive care unit (ICU) patients. Safer non-invasive sampling strategies that maintain diagnostic reliabilityfor clinically relevant and potentially drug-resistant pathogens are therefore urgently needed.</p><p><strong>Methods: </strong>In this prospective cohort study conducted between January 1 and July 30, 2024, paired nasopharyngeal swabs (NPS) and BALF samples were collected from 105 ICU patients with severe pneumonia. Pathogen detection was performed using targeted next-generation sequencing (tNGS) with a focus on clinically significant bacterial, viral, and fungal pathogens commonly associated with antimicrobial resistance. Concordance between NPS and BALF was evaluated using positive percent agreement (PPA) and negative percent agreement (NPA), with BALF serving as the reference standard. Longitudinal two-phase sampling was performed in 74 patients to assess the capacity of NPS to monitor temporal changes in pathogen profiles.</p><p><strong>Results: </strong>Compared with BALF, NPS demonstrated high concordance for major bacterial pathogens frequently associated with drug resistance, including <i>Acinetobacter baumannii</i>, <i>Staphylococcus aureus</i>, and <i>Escherichia coli</i>, with PPA ≥ 80.0% and overall detection rates ≥90.0%. NPA exceeded 95.0% for most pathogens, indicating a low false-positive rate. Viral detection showed moderate sensitivity (PPA ≤ 80.0%), while fungal concordance was variable, ranging from 0.0% for <i>Aspergillus flavus</i> to 50.0% for <i>Pneumocystis jirovecii</i>. Longitudinal analyses revealed limited utility of NPS for monitoring dynamic pathogen changes over time, with higher agreement observed only for <i>Staphylococcus aureus</i> (72.7%), <i>Acinetobacter baumannii</i> (62.5%), and fungal pathogens (75.0%).</p><p><strong>Conclusion: </strong>Nasopharyngeal swab-based tNGS represents a feasible and less invasive approach for the early molecular identification of common bacterial pathogens, including those frequently implicated in drug-resistant infections, in patients with severe ICU pneumonia. While NPS may support early antimicrobial decision-making when BALF is not immediately available, its reduced sensitivity for fungal and viral pathogens and limited performance in longitudinal surveillance underscore the continued necessity of BALF for comprehensive infection assessment, particularly in immunocompromised and high-risk ICU populations.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1794266"},"PeriodicalIF":4.0,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13143981/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147836128","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}