Viral metagenomic sequencing was used to characterize viral sequences in six pools comprising 90 ticks collected in Tibet in 2026. Viruses belonging to 35 families were identified based on read-level taxonomic assignments. Chuviridae, Phenuiviridae, and Rhabdoviridae were prominent RNA viral families in the pooled profiles. Five representative RNA viral sequences were examined by annotation and phylogenetic analysis: one Phenuiviridae-associated partial L-region sequence, two Chuviridae-associated sequences, and two Rhabdoviridae-associated partial L-region sequences. Their recovered L-protein regions were closely related to previously reported tick-associated viruses, with amino acid identities of 98.67–99.95% over the compared regions. The Phenuiviridae-associated sequence grouped with Uukuvirus-related sequences, the Chuviridae-associated sequences with Mivirus-related references, and the Rhabdoviridae-associated sequences near Deltarhabdovirinae references. Chu4909 has read coverage across the assembled sequence, but its circular configuration remains putative, and its topology and genome completeness remain unconfirmed. No novel viruses were identified in this study. These observations provide additional sequence data from Tibetan tick pools. The sequence detections were not independently confirmed by PCR/RT-PCR and do not establish individual-tick infection prevalence, active infection, or viral replication.
The relationship between active Helicobacter pylori infection and clinical oral findings remains uncertain. This study compared oral mucosal lesions, oral symptoms and gingival bleeding between adults with and without active infection.This retrospective cross-sectional study included 61 adults examined between March and September 2025 and selected nonconsecutively according to their willingness to participate (83 eligible patients approached; 22 declined). Participants referred for non-invasive H. pylori testing were classified as infected (n = 29) or test-negative (n = 32) by urea breath or monoclonal stool antigen testing. Recorded oral examinations included gingival screening of 318 index teeth and 1272 sites. Firth penalized logistic regression evaluated mucosal lesions; mixed models and generalized estimating equations addressed clustered gingival outcomes. At least one mucosal lesion was present in 55.2% of infected and 21.9% of test-negative participants (difference 33.3 percentage points, 95% confidence interval [CI] 8.9–53.0; p = 0.007). The adjusted odds ratio was 5.68 (95% CI 1.67–22.84; p = 0.005; 4.61 after shrinkage for optimism). Oral burning was reported by 31.0% versus 3.1% (9 versus 1 participant; p = 0.004), whereas halitosis, dysgeusia and xerostomia did not differ significantly. The adjusted site-level odds ratio for bleeding on probing was 1.93 (95% CI 1.15–3.25) and was attenuated after exclusion of current smokers (1.55; 95% CI 0.91–2.67). Active H. pylori infection was associated with the presence of oral mucosal lesions in this small sample with a test-negative comparator group; the associations with oral burning and gingival bleeding rested on few events or were sensitive to smoking status and should be regarded as hypothesis-generating. The cross-sectional design cannot establish causation, and larger longitudinal studies with confirmed infection status are needed.
Extracellular metabolites mediate microbial interactions in plant-associated environments, among which bacterial volatile organic compounds (VOCs) play important roles in regulating competition, colonization, and pathogen establishment. However, the physiological and transcriptional responses of Pectobacterium aroidearum to extracellular compounds produced by other bacteria remain poorly understood. This study aimed to characterize changes in VOC profiles during interactions between P. aroidearum SM2 and Kosakonia cowanii Cp1 and to investigate the electrochemical and transcriptional responses of P. aroidearum SM2 following exposure to the cell-free filtrate of K. cowanii Cp1. Volatile profiling by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) after 2 h of bacterial growth revealed changes in VOC composition during co-culture in tryptic soy broth (TSB), particularly a marked reduction in the relative abundance of 2,5-dimethylpyrazine compared with monocultures. Electrochemical impedance spectroscopy (EIS) revealed numerical variations in impedance magnitude and phase following exposure to the cell-free filtrate obtained from a 2 h culture of K. cowanii Cp1, with the largest numerical difference in impedance magnitude (27.9% relative to the control) observed after 1 h of exposure at 200 kHz. This exposure time was subsequently selected for transcriptomic analysis. RNA-Seq analysis identified significant transcriptional changes, including the downregulation of genes involved in sulfur assimilation and cysteine biosynthesis, together with increased expression of genes associated with galactose utilization and glycerol metabolism. Although these responses cannot be attributed exclusively to VOCs, the results provide a basis for further investigating the contribution of volatile and non-volatile extracellular compounds to bacterial interactions and their potential relevance to the management of soft rot disease.
The nasopharyngeal microbiome contributes to respiratory health and may influence host responses to respiratory viral infections, including SARS-CoV-2, yet its association with viral detection remains incompletely understood, particularly in outpatients from Latin America. In this cross-sectional study, adult outpatients undergoing SARS-CoV-2 RT-PCR testing in Guayaquil, Ecuador, were consecutively recruited between 2 and 7 June 2021, and their nasopharyngeal microbiome was characterized using 16S rRNA gene (V3–V4) sequencing. Microbiome diversity, taxonomic composition, differential abundance, and predicted functional profiles were compared between RT-PCR positive (n = 41) and RT-PCR negative (n = 17) individuals. Compositional analyses used 57 samples after taxon filtering (41 RT-PCR positive and 16 RT-PCR negative). No differences by RT-PCR status were detected in alpha or beta diversity, and no taxa or predicted pathways were differentially abundant; alpha- and beta-diversity results were unchanged after accounting for collection date. Both groups displayed similar microbial communities dominated by Corynebacterium sp. and Staphylococcus sp., which together with Cutibacterium sp. formed the core microbiome. These findings indicate that SARS-CoV-2 detection was not associated with major alterations in the taxonomic composition or predicted functional profiles of the nasopharyngeal microbiome in this outpatient Ecuadorian cohort, although smaller effects cannot be excluded given the size of the RT-PCR negative group.
Antibiotic therapy is important in clinical practice, yet its collateral disruption of the gut microbiota often causes dysbiosis with lasting health consequences. However, the factors underlying interindividual differences in gut microbiota resilience remain poorly understood. Through the reanalysis of a previously published longitudinal human metagenomic cohort, we found clear heterogeneity across individuals in gut microbiota resilience after ciprofloxacin exposure and identified baseline microbial structure as a baseline feature associated with subsequent microbiota recovery. Using a mouse model, we further found that tryptophan supplementation promoted early gut microbiota recovery following antibiotic exposure. Overall, this study defines the ecological assembly dynamics of the gut microbiota under antibiotic stress, identifies baseline community structure as a factor associated with resilience, and highlights tryptophan supplementation as a potential strategy to promote microbiota recovery following antibiotic exposure.
