Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne pathogen of the Nairoviridae family, is classified as a high-risk biosafety level-4 (BSL-4) agent, which restricts its handling and limits mechanistic investiga...Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne pathogen of the Nairoviridae family, is classified as a high-risk biosafety level-4 (BSL-4) agent, which restricts its handling and limits mechanistic investigations. To overcome these challenges, we developed a CCHF pseudovirus as a safe and reliable surrogate for studying viral entry and evaluating antiviral candidates. Pseudovirus-based systems have proven valuable tools for elucidating viral infection mechanisms, conducting neutralization assays, and screening of small-molecule inhibitors. In the present study, a lentiviral packaging system incorporating CCHFV envelope glycoproteins (Gn and Gc) was established in HEK293T cells to generate infectious pseudovirions. Viral infectivity was quantified using a luciferase reporter assay. Cilnidipine, a clinically approved dual L-type and N-type calcium channel blocker with established antihypertensive activity, was investigated for its potential to inhibit CCHF pseudovirus entry in HEK293T and Huh-7 cells. Treatment with Cilnidipine resulted in a marked, dose-dependent reduction in luciferase signal, suggesting potent inhibition of pseudovirus entry at micromolar concentrations. Co-treatment assays further confirmed its inhibitory action at the early stages of infection. Overall, this study highlights Cilnidipine as a promising repurposed antiviral candidate targeting viral entry pathways. The findings provide a foundation for future mechanistic and pre-clinical evaluations aimed at developing effective therapeutics against CCHFV.
Porcine astrovirus (PAstV) is a small, non-enveloped virus of the genus Mamastrovirus within the family Astroviridae. Its genome consists of a positive-sense, single-stranded RNA of approximately 6.4-7.3 kb in length. PA...Porcine astrovirus (PAstV) is a small, non-enveloped virus of the genus Mamastrovirus within the family Astroviridae. Its genome consists of a positive-sense, single-stranded RNA of approximately 6.4-7.3 kb in length. PAstV displays considerable genetic diversity and is presently categorized into five distinct genotypes. While primarily recognized as an enteropathogen linked to varying degrees of gastroenteritis in pigs, its precise role in inducing diarrhea remains uncertain, as it has been detected in both diarrheic and healthy pigs with a similar prevalence. In addition to gastrointestinal disease, PAstV has recently been detected in pigs with respiratory and nervous disorders. The current review provides a comprehensive summary of the published literature on the PAstV genome, viral replication, epidemiology, geographical distribution, pathogenesis, clinical manifestations, diagnostic methods, co-infections, and probable cross-species transmission. Furthermore, it underscores the gaps in the current understanding, serving as a valuable reference for future investigations into the PAstV.
A novel ampelovirus, named as “plumeria ampelovirus 1” (PluAV1), was identified in plumeria (Plumeria spp.) through high-throughput sequencing. The PluAV1 genome was Sanger-sequenced independently, revealing a complete g...A novel ampelovirus, named as “plumeria ampelovirus 1” (PluAV1), was identified in plumeria (Plumeria spp.) through high-throughput sequencing. The PluAV1 genome was Sanger-sequenced independently, revealing a complete genome of 14,044 nucleotides and encoding 10 open reading frames. The amino acid sequences of the taxonomically informative gene products (RdRP, HSP70h, CP) of PluAV1 diverged from those of other ampeloviruses by over 25%, and maximum-likelihood phylogenetic analysis of these proteins revealed that PluAV1 belongs to the ampelovirus subgroup II. Two distinct PluAV1 phylogroups were identified underscoring the divergent nature of its natural populations. The species name Ampelovirus plumeria is proposed for PluAV1.
The increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) constitutes a substantial hazard to human health. Phage therapy represents a promising alternative for treating CRKP infections. This researc...The increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) constitutes a substantial hazard to human health. Phage therapy represents a promising alternative for treating CRKP infections. This research isolated a novel phage, vB_LSKP32, which targets the KL64 capsular type of CRKP from hospital sewage samples. The phage vB_LSKP32 adsorbs rapidly to host cells, features a 5–10 min latent period, and yields approximately 56 ± 3 new phage particles per infected cell. It remains stable and infectious under conditions ranging from 4 °C to 50 °C and pH 4 to 11. The phage vB_LSKP32 genome contains a 40,942 bp linear dsDNA with a GC content of 52.92%. Genome annotation predicted 50 ORFs, with no evidence of antibiotic resistance genes, virulence genes, lysogeny-related genes and tRNA. Through intergenomic similarity studies and phylogenetic analyses, vB_LSKP32 was classified as a novel species within the genus Przondovirus, family Autographiviridae. Phage vB_LSKP32 exhibited efficient suppression of host bacterial proliferation for approximately 7 h in vitro. Moreover, it significantly enhanced the survival rate of Galleria mellonella larvae post-infection, with the survival rate positively correlating with phage titer. Notably, larvae treated at an MOI of 100 elevated the survival rate to 90% (vs. 15% in controls). Our findings suggest that phage vB_LSKP32 shows significant potential as an antimicrobial agent against KL64-type CRKP.
In plant–pathogen interactions, infection typically leads to growth inhibition or even host mortality. However, under certain environmental conditions, some pathogens can paradoxically enhance host fitness in response to...In plant–pathogen interactions, infection typically leads to growth inhibition or even host mortality. However, under certain environmental conditions, some pathogens can paradoxically enhance host fitness in response to stress. Viroids, such as potato spindle tuber viroid (PSTVd), are circular single-stranded RNAs that cause plant diseases. In this study, PSTVd was used as a model to investigate adaptive host–pathogen interactions under polyethylene glycol (PEG)-simulated drought stress. Tomato (Solanum lycopersicum) plants were infected with PSTVd and then subjected to drought treatment using 15% PEG 6000. Compared with uninfected controls, PSTVd-infected plants exhibited increased drought tolerance. High-throughput transcriptome sequencing (RNA-seq) was employed to compare gene expression profiles between infected and uninfected plants under PEG-simulated drought stress. The results suggest that PSTVd may enhance drought tolerance by coordinately downregulating genes encoding light-harvesting complex proteins of photosystems I and II (LHC I/II). This suppression likely reduces photosynthetic electron flux, which may in turn limits stomatal conductance and improves water retention capacity under PEG-simulated drought stress. Our findings suggest that PSTVd infection can increase drought tolerance in tomato and may have potential applications in crop improvement under water-limited conditions.
Kiwifruit (Actinidia spp.) is a widely popular fruit crop worldwide with significant economic value. From kiwifruit leaves exhibiting symptoms of chlorosis and mosaic in Shaanxi Province of China, a novel tymovirus tenta...Kiwifruit (Actinidia spp.) is a widely popular fruit crop worldwide with significant economic value. From kiwifruit leaves exhibiting symptoms of chlorosis and mosaic in Shaanxi Province of China, a novel tymovirus tentatively named “Actinidia tymovirus 1” (AcTmV1) was identified by high-throughput sequencing, and its complete genome sequence was determined by RT-PCR and RACE technologies. The genome of AcTmV1 with a length of 6,155 nucleotides (nt) contains three open reading frames (ORFs) encoding movement protein (MP) of 610 amino acids (aa), replicase polyprotein (RP) of 1,782 aa and coat protein (CP) of 187 aa, exhibiting typical tymovirus-like organization. The AcTmV1 genome shares the highest nt sequence identity of 64.5% to that of Valeriana jatamansi tymovirus 1 (VaJV1) (GenBank No. OQ730267), and CP shares the highest aa sequence identity of 55.1% to that of Kennedya yellow mosaic virus (KYMV) (GenBank No. D00637). Phylogenetic analyses based on both genome nt and CP aa sequences confirmed that AcTmV1 is most closely related to VaJV1. Therefore, it is proposed that AcTmV1 represents a new member of the genus Tymovirus.
Bacillus subtilis is a key starter culture in food fermentation, but phage contamination threatens production stability. As fermentation processes scale up, the risk of phage contamination rises significantly, driving th...Bacillus subtilis is a key starter culture in food fermentation, but phage contamination threatens production stability. As fermentation processes scale up, the risk of phage contamination rises significantly, driving the need for fundamental research on phage-host interactions to develop targeted mitigation strategies. In this study, we isolated and characterized a novel lytic phage, vB_Bsu_W1188, which efficiently lyses B. subtilis WB800. Transmission electron microscopy revealed a short-tailed morphology, while stability tests demonstrated remarkable tolerance to pH 3-12, temperatures of 4-80℃, and even 90℃ for 30 minutes. Genomic and phylogenetic analysis classified it within the genus Beecentumtrevirus, with no virulence or antibiotic resistance genes detected. Through resistance mutant screening and functional validation, we identified that wall teichoic acid (WTA) glycosylation, mediated by the host tagE and galU genes, serves as the critical receptor for phage recognition. Although phage-resistant mutants exhibited fitness costs (e.g., delayed growth and impaired biofilm formation), their mCherry protein expression capacity remained unaffected. This study not only highlights the potential of vB_Bsu_W1188 as a biocontrol agent but, more importantly, elucidates the molecular basis of phage resistance, providing a theoretical foundation and technical support for engineering industrial phage-resistant strains.
Infectious diseases in birds represent a significant threat to poultry economies, wild bird biodiversity, and public health, underscoring the importance of surveillance within a One Health framework. Synanthropic birds,...Infectious diseases in birds represent a significant threat to poultry economies, wild bird biodiversity, and public health, underscoring the importance of surveillance within a One Health framework. Synanthropic birds, which live in close proximity to humans and domestic animals, can act as crucial bridge hosts for viral transmission between wild and domestic populations. This study aimed to assess the prevalence and diversity of four key viral families—Orthomyxoviridae, Paramyxoviridae, Coronaviridae, and Astroviridae—in synanthropic birds from the south of Western Siberia, an important convergence zone of major migratory flyways for many bird species. Using molecular detection methods, we identified avian coronaviruses (ACoV) and avastroviruses (AAstV), but found no evidence of avian influenza virus (AIV) or avian paramyxoviruses (APMV). Overall, 3.8% of birds tested positive for at least one of the studied viruses, with ACoV detected in 1.4% and AAstV in 2.4% of samples. Phylogenetic analysis revealed that the detected coronaviruses belong to the genus Deltacoronavirus and form a distinct clade with a previously identified virus from North Siberia, suggesting a stable, regional corvid-associated lineage. The detected astroviruses were highly diverse, falling within a broad group of unclassified passerine-associated avastroviruses with phylogenetic links to viruses from Kazakhstan and China, reflecting the region's role as a migratory crossroads. The absence of AIV and APMV may reflect low prevalence at the time of sampling or host-specific factors like low susceptibility or immunocompetence that suppress viral replication. These findings highlight that synanthropic birds in this key ecological region harbor novel and diverse viruses and represent important, though often overlooked, subjects for expanding our understanding of viral diversity in surveillance programs.
Mycoplasma ovipneumoniae (MO) and Ovine parainfluenza virus type 3 (OPIV3) are significant pathogens implicated in ovine respiratory diseases, which impose substantial threats to extensive sheep farming. However, no comm...Mycoplasma ovipneumoniae (MO) and Ovine parainfluenza virus type 3 (OPIV3) are significant pathogens implicated in ovine respiratory diseases, which impose substantial threats to extensive sheep farming. However, no commercial bivalent vaccines targeting both pathogens are currently available. In this study, we constructed a recombinant live-attenuated OPIV3 using Red/ET recombination, inserting MO adhesion protein genes (P60, P113) between the N and P genes of the OPIV3 genome. The recombinant candidate rOPIV3-MO was successfully generated and inhibited growth kinetics similar to those of the parental OPIV3 TJ2022 strain. Immunization trials in sheep indicated that rOPIV3-MO displayed a favorable safety profile. Both rOPIV3-MO and OPIV3 TJ2022 inoculation induced specific and neutralizing antibodies, as well as T-cell receptor (TCR) rearrangements.
Respiratory viruses, including influenza, SARS-CoV-2, and RSV, pose significant public health challenges in low-and-middle-income countries like Pakistan. This study, conducted from January-2023 to January-2024, investig...Respiratory viruses, including influenza, SARS-CoV-2, and RSV, pose significant public health challenges in low-and-middle-income countries like Pakistan. This study, conducted from January-2023 to January-2024, investigated SARS-CoV-2, Influenza virus and RSV infections in individuals with respiratory symptoms and explored the genomic diversity of these viruses in Pakistan. This study analyzed 320 oropharyngeal/nasopharyngeal swabs, of which 57.1% (n = 183) tested positive for respiratory viruses using RT-PCR, including Influenza virus (59%; n = 108), SARS-CoV-2 (30%; n = 54), and RSV (11%; n = 21). Whole-genome sequencing was performed on 100 samples with Ct-value < 30, yielding 85 complete genomes: 48.24% (n = 41) were Influenza A (H3N2: 87.80%, n = 36; H1N1pdm09: 12.20%, n = 5), 45.88% (n = 39) were SARS-CoV-2 Omicron variants, and 5.88% (n = 5) were RSV-B. H3N2 sequences clustered mainly in clade 3 C.2a1b.2a.2a.3a.1 (94.4%, n = 34/36) with 99.32%–99.56% nucleotide identity to 2023 strains from Russia, USA, UK, and Pakistan, and 1.05%–1.87% divergence from the vaccine strain A/Thailand/8/2022. Key NA gene mutations included E50K, T3A in the signal peptide, and R150H, that have implications on antiviral resistance. H1N1 sequences, confined to clade 6B.1 A.5a.2a, showed high similarity (99.41%–100%) with 2022–2023 USA and Pakistan strains but increased divergence (1.44%–1.66%) from vaccine strain A/Wisconsin/588/2019, with significant mutations (K54Q, D94N, E224A) at antigenic sites., that can potentially enhance viral fitness. The SARS-CoV-2 Omicron subvariants included GW.5, XBB.1.22, and FL, closely resembling sequences from England, Singapore, and Canada. All RSV-B sequences belonged to the GB5.0.5a G_clade, with 97.8% to 99.5% similarity to strains from England, Australia, Bangladesh, Senegal, and the USA. Notably, RSV-B exhibited a deletion (L250 to I268) in the G protein and key mutations in the F protein (S190N, S211N, and L173del), which could affect therapeutic and vaccine efficacy. These findings highlight the need for integrated surveillance of these viruses to inform public health responses.
As a persistent-propagative plant virus, Rice stripe virus (RSV) relies on specific interactions between viral proteins and components of its vector, the small brown planthopper (SBPH), for its efficient replication and...As a persistent-propagative plant virus, Rice stripe virus (RSV) relies on specific interactions between viral proteins and components of its vector, the small brown planthopper (SBPH), for its efficient replication and transmission. To identify vector factors involved in this process, we employed GST pull-down/MS to screen SBPH proteins that interact with RSV P3, a key nonstructural protein for virus transmission, and obtained 55 candidate proteins. Among these, Purα was selected for further investigation. A direct interaction between P3 and Purα was confirmed by co-immunoprecipitation (Co-IP). Confocal microscopy revealed extensive colocalization of Purα and P3 in the cytoplasm of Sf9 cells and critically, within key SBPH tissues for virus transmission, including the midgut, salivary glands, and ovaries. Functional studies showed that knocking down Purα via RNA interference (RNAi) inhibited viral accumulation in SBPHs, consequently reducing both horizontal and vertical transmission efficiency. Our results provide compelling evidence that RSV hijacks the vector protein Purα to promote viral accumulation within the insect body, thereby facilitating transmission. These findings deepen our understanding of plant virus-vector interactions and reveal a potential target for developing novel strategies to control virus spread.
Avian infectious bronchitis virus (IBV) remains a persistent threat to poultry health and production, particularly in Pakistan, where frequent outbreaks occur despite routine vaccination. To investigate suspected vaccine...Avian infectious bronchitis virus (IBV) remains a persistent threat to poultry health and production, particularly in Pakistan, where frequent outbreaks occur despite routine vaccination. To investigate suspected vaccine breakthrough events, one hundred clinical samples (oropharyngeal/tracheal swabs and kidney, lung, and liver tissues) were collected between January and May 2025 from ten commercial chicken farms experiencing IBV-like outbreaks. Postmortem findings revealed classic IBV-associated lesions, including hemorrhagic tracheitis, severe airsacculitis, nephritis with urate deposits, and fluid-filled abdominal cysts in layer birds. Nested RT-PCR confirmed IBV RNA in 26% of samples (26/100), representing 70% of the investigated farms (7/10). Phylogenetic characterization of three representative S1 gene sequences (GenBank PV818074–PV818076) demonstrated clustering within the GI-1 lineage, showing 99.7–100% nucleotide identity with Massachusetts-type vaccine strains (H120, H52, Ma5, M41). The detection of such highly conserved vaccine-like sequences in recently vaccinated flocks suggests that current outbreaks are more likely associated with re-isolation, persistence, or circulation of vaccine-derived strains rather than novel divergent field variants. These findings highlight the potential role of vaccine-related viruses in field outbreaks, emphasize the need for incorporating vaccination history into molecular surveillance, and call for periodic reassessment of vaccination programs to maintain protective efficacy. Overall, this study underscores the importance of continuous genomic monitoring to better understand IBV evolution under vaccine pressure and to support evidence-based strategies for improving disease control and ensuring poultry industry sustainability.
A convenient tool for identifying glycan receptors of new influenza virus strains is the PGA (printed glycan array), which contains up to a hundred sialoglycans. However, antigen diversity and drift complicate the detect...A convenient tool for identifying glycan receptors of new influenza virus strains is the PGA (printed glycan array), which contains up to a hundred sialoglycans. However, antigen diversity and drift complicate the detection of the virus bound to PGA by antibodies, since, generally speaking, new strain is needed for a new antibody. In this work, the bound virus was visualized on PGA using labeled sialopolymers, namely Neu5Acα2-3Galβ1-4GlcNAcβ-PAA-biotin (for avian viruses) or Neu5Acα2-6Galβ1-4GlcNAcβ-PAA-biotin (for human viruses), where PAA is soluble polyacrylamide. Detection of strains H6N1(Sarma/51c/2006), H7N1(FPV/Rostock/2007) and B19 (Moscow/19/2013) was routinely performed at a level of 16 hemagglutination units.
Colletotrichum gloeosporioides is a major phytopathogenic ascomycete that causes anthracnose disease in cardamom plants. Here, we report the discovery of a novel double-stranded (ds) RNA virus in C. gloeosporioides. The...Colletotrichum gloeosporioides is a major phytopathogenic ascomycete that causes anthracnose disease in cardamom plants. Here, we report the discovery of a novel double-stranded (ds) RNA virus in C. gloeosporioides. The virus genome consisted of four dsRNA segments, ranging in length from 2522 bp to 1236 bp. Each dsRNA has a single open reading frame flanked by 5' and 3' untranslated regions (UTRs). dsRNA1 codes for RNA-dependent RNA polymerase (RdRp) and dsRNA2 codes for a hypothetical protein with maximum similarity to Colletotrichum gloeosporioides polymycovirus 1 and Colletotrichum camelliae filamentous virus 1, respectively. The methyltransferase encoded by dsRNA3 and the proline-alanine-serine-rich protein (PASrp) encoded by dsRNA4 showed similarity to those of Fusarium redolens polymycovirus 1. Phylogenetic analysis based on RdRp sequences revealed that this virus clusters with known members of the family Polymycoviridae. Based on these observations, this virus isolate is tentatively named Colletotrichum gloeosporioides polymycovirus 2 (CgPmV2). To our knowledge, this is the first report of a polymycovirus from India.
Hantaan virus (HTNV), a negative-sense RNA virus, is the primary causative agent of Hemorrhagic Fever with Renal Syndrome (HFRS) and is predominantly endemic in Eurasia, with the highest incidence reported in China. In t...Hantaan virus (HTNV), a negative-sense RNA virus, is the primary causative agent of Hemorrhagic Fever with Renal Syndrome (HFRS) and is predominantly endemic in Eurasia, with the highest incidence reported in China. In this study, we applied a multiplex PCR amplification strategy combined with Oxford Nanopore GridION sequencing to analyze 33 HTNV-positive samples collected from Xi’an City, Shaanxi Province, China, between 2010 and 2022. The sample set included four cell culture isolates and 29 rodent lung tissue specimens. A total of 29 primer pairs targeting the S, M, and L genomic segments were used for whole-genome amplification. All samples were successfully sequenced, achieving > 98.2% genome coverage across all three segments (S, M, and L). Sensitivity evaluation demonstrated stable and uniform amplification at RNA concentrations ≥ 10⁴ copies/mL. Phylogenetic analysis revealed that all 33 HTNV genomes clustered within the H4 lineage and shared 98.1%–99.9% nucleotide identity with strains previously reported in Tianjin and Guizhou Provinces. The selection pressure analysis indicated that purifying selection is the dominant force across all four proteins. The Xi’an strains demonstrated sustained genetic stability over the surveillance period. This study establishes a rapid, sensitive, and reliable whole-genome sequencing approach for HTNV, offering a valuable tool for molecular surveillance, epidemiological tracking, and the evaluation of vaccine efficacy in HFRS-endemic regions.
Klebsiella pneumoniae (K. pneumoniae) is a leading cause of both nosocomial and community-acquired infections. In this study, we isolated a lytic bacteriophage (phage), designated Kpp-61, targeting K. pneumoniae with cap...Klebsiella pneumoniae (K. pneumoniae) is a leading cause of both nosocomial and community-acquired infections. In this study, we isolated a lytic bacteriophage (phage), designated Kpp-61, targeting K. pneumoniae with capsular serotype K1, which is prevalent in hypervirulent strains. Transmission electron microscopy showed that Kpp-61 had an icosahedral head and a non-contractile short tail. In vitro, Kpp-61 demonstrated significant antibiofilm activity, inhibiting biofilm formation and disrupting preformed biofilms. Furthermore, in a murine infection model, Kpp-61 improved the 7-day survival rate of mice to 60% and 90% at MOIs of 10 and 100, respectively, and mitigated pneumonia symptoms in K. pneumoniae strain Kp61-infected mice. Notably, Kpp-61 exhibited high specificity for K1-serotype strains, along with robust thermal and pH stability. Genomic analysis revealed a circular double-stranded DNA genome of 44,028 bp, with a G + C content of 50.28% and 54 predicted open reading frames. Crucially, no virulence or antibiotic-resistance genes were detected. These results indicate the therapeutic potential of phage Kpp-61 against K1-serotype K. pneumoniae infections.
In July 2023, 25 leaf samples of Gynura bicolor showing mosaic and chlorosis symptoms were collected in Hohhot, Inner Mongolia, China. Total RNA was extracted from pooled, homogenized tissues was subjected to high-throug...In July 2023, 25 leaf samples of Gynura bicolor showing mosaic and chlorosis symptoms were collected in Hohhot, Inner Mongolia, China. Total RNA was extracted from pooled, homogenized tissues was subjected to high-throughput sequencing (HTS), which revealed the presence of four known viruses and an unknown virus. The complete genome sequence of the unknown virus was obtained using RT-PCR and RACE, yielding an 8,750-nt positive-sense single-stranded RNA genome with six open reading frames. Sequence analysis revealed that its replicase gene shared 71.6% nucleotide and 78.4% amino acid sequence identity with pseudostellaria heterophylla carlavirus 1 (PhCV1). These values are below the species demarcation threshold. Phylogenetic analysis grouped the virus with members of the genus Carlavirus, supporting its classification as a novel member of this genus. We have tentatively designeatd it "gynura bicolor carlavirus" (GbCV). This is the first report of a carlavirus infecting G. bicolor.
Kuchijirosho virus (KJV) infects the brain of the tiger puffer, Takifugu rubripes, causing lethal disease in cultured populations. Next-generation sequencing identified eight RNA genome segments encoding proteins of 562,...Kuchijirosho virus (KJV) infects the brain of the tiger puffer, Takifugu rubripes, causing lethal disease in cultured populations. Next-generation sequencing identified eight RNA genome segments encoding proteins of 562, 498, 454, 369, 370, 164, 207, and 83 amino acids. BLAST analysis showed that segment 1 encodes a polymerase basic protein 1 (PB1)-like RNA-dependent RNA polymerase homologous to those of members of the family Amnoonviridae. Segment 5 encodes a protein that shows similarity to envelope proteins with two predicted transmembrane domains, suggesting a function as an envelope glycoprotein. The remaining segments could not be annotated due to the limited homology of their encoded proteins to known proteins. These findings indicate that KJV represents a novel lineage within the family Amnoonviridae.
Klebsiella pneumoniae is a significant pathogen responsible for a range of infections, including pneumonia, urinary tract infections, and sepsis, in both human and veterinary medicine. The extracellular polysaccharide pr...Klebsiella pneumoniae is a significant pathogen responsible for a range of infections, including pneumonia, urinary tract infections, and sepsis, in both human and veterinary medicine. The extracellular polysaccharide produced by this bacterium forms a capsule that protects the cell from immune responses and external influences, complicating treatment. The World Health Organization has placed this pathogen into the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) of pathogens that require special attention due to their resistance to multiple drugs, and hypermucoid K. pneumoniae strains with prevalent capsular types (e.g., K1 and K2) have been extensively studied. However, rare capsular types that are less well-characterised can still pose significant challenges. In the present study, we isolated a K. pneumoniae strain with capsular type K14, which is associated with antibiotic-resistant urogenital infections in felines, from a veterinary clinic. We successfully isolated and characterised three bacteriophages that exhibit rapid adsorption to and efficient lysis of the bacterium. All three phages demonstrated strictly lytic behavior and proved effective in degrading the extracellular polysaccharide capsule of the pathogen. We have modelled the receptor-binding proteins of these phages, which exhibit depolymerising activity. These proteins were produced in recombinant form, and experimental evidence has demonstrated their capacity to cleave the polysaccharide associated with the K14 capsular type. Furthermore, the chemical structure of the resulting cleavage products was determined. All three phages have been thoroughly characterised and show potential for application in combating multidrug-resistant K. pneumoniae.
Artemisia argyi is a significant medicinal plant in China. To date, no viruses have been reported to infect A. argyi. In this study, using the RNA-seq technique, we identified a novel marafivirus in A. argyi plants showi...Artemisia argyi is a significant medicinal plant in China. To date, no viruses have been reported to infect A. argyi. In this study, using the RNA-seq technique, we identified a novel marafivirus in A. argyi plants showing leaf mottle and albinism symptoms, which we have tentatively named “Artemisia argyi albinism-associated virus” (AAAaV). The AAAaV genome is a positive-sense single-stranded RNA with a length of 6749 nt, excluding the poly(A) tail, containing a single open reading frame (ORF) encoding a large polyprotein. Phylogenetic analysis based on the full-length genome and polyprotein amino acid sequences revealed that AAAaV is related to members of the genus Marafivirus of the family Tymoviridae. The polyprotein of AAAaV shares 33.68-38.14% amino acid sequence identity with those of 12 closely related marafiviruses and contains five conserved domains that are characteristic of members of this genus. This discovery expands our knowledge of marafivirus diversity, host range, and viruses capable of infecting A. argyi.