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BackgroundHepatitis B virus infection remains a major public health challenge, particularly among people living with human immunodeficiency virus, due to shared transmission routes and the potential for accelerated liver disease progression. Molecular characterization of circulating HBV strains is essential for understanding viral epidemiology, mutation patterns, and implications for diagnostics and vaccination. MethodsThis study investigated the prevalence of hepatitis B infection and molecular characteristics of the hepatitis B virus surface gene among HIV-infected individuals receiving antiretroviral therapy in Nairobi County, Kenya. Plasma samples were screened for hepatitis B surface antigen using enzyme-linked immunosorbent assay. Hepatitis B viral DNA was extracted from HBsAg-positive samples and the surface gene region amplified by polymerase chain reaction. Amplified products were subjected to Sanger sequencing. Sequence assembly, genotype determination, and mutation analysis. ResultsThe prevalence of HIV/HBV co-infection among HIV-positive individuals was determined to be 8.97%. Genotype analysis revealed the circulation of HBV genotype A (sub-genotypes A1 and A4) and genotype D (sub-genotypes D4 and D10) among the studied population. Amino acid sequence analysis of the major hydrophilic region of the surface gene identified several mutations, with R122K and Y134F being the most frequently observed substitutions. ConclusionHepatitis B infection remains prevalent among HIV-infected individuals receiving antiretroviral therapy in Nairobi County. The circulation of multiple hepatitis B virus genotypes and the presence of mutations within the surface gene highlight the importance of continuous molecular surveillance to monitor viral evolution and its potential implications for hepatitis B virus diagnosis, vaccination strategies, and clinical management in HIV-infected populations

IntroductionAcinetobacter is a highly diverse genus which includes a range of common pathogenic species such as A. baumannii, A. lwoffii etc. Acinetobacter species causes bacteremia, pneumonia, wound infections, Urinary tract infections in community as well as hospital settings. A. baumannii is one of the ESKAPE pathogen which makes it even more lethal as antibiotics cannot action on this. AimTo isolate Acinetobacter species from various clinical samples and to check their antimicrobial susceptibility pattern by VITEK {square} Compact in SGT Hospital, Gururam, Haryana. ResultsOut of total 6673 samples 595 were the positive isolates from which 35 were Acinetobacter isolates which were received from various wards of the hospital. Occurrence of Acinetobacter was seen more in males(57.14%) as compare to females (46.8%). A total of 31 strains were A. baumannii, 3 were A. lwoffi and 1 strain was of A. haemolyticus. Prominent presence of Acinetobacter was seen in Blood (48.57%) specimen along with pus(22.85%), endotracheal (22.85%), tracheal (2.85%) and eye swabs (2.85%). All the isolates were resistant to piperacillin/tazobactam (100%), ceftriazone (100%), amikacin (100%), gentamicin (100%) ciprofloxacin (91.42%), ceftazidime (91.42%), cefepime (88.57%), levofloxacin (88.57%) and trimethoprim/sulfamethoxazole (80%). Colistin susceptibility was observed in 88.57% of the isolates. ConclusionAcinetobacter is a common pathogen in hospital acquired as well as in community acquired infections as it is a opportunistic pathogen hence to identify the Acinetobacter species and to understand their antimicrobial resistance pattern this study was conducted.

It has been known for decades that bacteriophages encode tRNA genes, but their function and the factors contributing to their acquisition and retention are unclear. Although tRNAs are found in a variety of phages infecting a variety of bacteria, many large-scale computational studies investigating tRNA acquisition and retention in phages are specific to Mycobacterium phages; however, these findings may not be representative of other phages or bacteria. This work uses a broader sampling of phages and hosts to investigate the relationships between codon usage bias, infection cycle, and tRNA gene numbers in phage genomes. We analyzed 154 phages infecting 7 host genera, including Gram-negative (Escherichia, Shigella, Salmonella) and Gram-positive (Bacillus, Lactobacillus, Staphylococcus, Mycobacterium) bacteria. Phages included temperate and virulent representatives, plus a range of tRNA numbers and morphologies. All phages and hosts were analyzed using four metrics: GC content, Effective Number of Codons, Relative Synonymous Codon Usage, and tRNA Adaptation Index. On a global scale, virulent phages with many tRNA genes show greater differences in codon usage and codon adaptation compared to their respective hosts. Gram-negative bacteria and their phages generally exhibit greater differences in codon usage compared to Gram-positive bacteria and their phages. Phages infecting Gram-negative hosts also tend to encode more tRNA genes. In nearly all genus-level comparisons, Mycobacterium phages were different from any other host and from global patterns. This suggests previous computational studies performed in Mycobacterium phages are likely not applicable on a global scale or to phages infecting other host genera. AUTHOR SUMMARYBacteriophages, or phages, are viruses infecting bacteria. They are abundant in all environments, yet how they interact with their bacterial hosts is still not well-understood. Like other viruses, phages must rely on the host translational components to replicate and form new phage particles; and similarly to other parasites, phages have genomes that differ significantly from their hosts in terms of composition. In this work, we explore the relationship between phage lifestyle, number of tRNA genes encoded, and genome differences from the host using a variety of phages and their associated hosts. Phages can be either virulent (do not integrate into the host genome) or temperate (capable of integrating into the host genome), with differences from the host genome more pronounced in virulent phages. There are many phages that also carry tRNA genes, and having higher numbers of tRNAs is associated with larger differences from the host genome. The findings here indicate that virulent phages carrying large numbers of tRNAs diverge the most from host genome composition.

The strain LEGE 10371, isolated from the surface of a marine sponge at Praia da Memoria, Portugal, was characterized as a new Thalassoporum species (Pseudanabaenales) using a polyphasic approach that included 16S rRNA gene phylogenetic analysis (Maximum Likelihood and Bayesian Inference), 16S-23S ITS secondary structures, p-distance calculations, MALDI-TOF MS profiling, and morphological analysis by optical and scanning electron microscopy, as well as ecological and biochemical characterization. Phylogenetically, LEGE 10371 clustered within the Thalassoporum clade, however distant from the other existent species of the genus. The p-distance analysis revealed low sequence identity with other Thalassoporum species, with a maximum value of 97.2% to Th. komareki. The MALDI-TOF profile displayed high-intensity peaks at approximately 3,000, 4,000, 6,000 and 8,000 m/z, representing strong candidates for diagnostic markers of the new species. Morphologically, the new species differ from the other species of the genus by presenting trichomes with more than 10 cells and lack of aerotopes. Biocompatibility of the fractions was evaluated in HaCaT keratinocytes, showing no cytotoxic effects at most tested concentrations. PCR screening targeting mcyE, sxtG, anaC, and cyrA confirmed the absence of the genetic potential for the production of major cyanotoxins. Chemical characterization revealed a pigment-rich profile dominated by chlorophyll-a and carotenoids, including {beta}-carotene, zeaxanthin, lutein, and mixoxanthophyll. Bioactivity assays showed superoxide anion radical scavenging by the aqueous fraction (IC2 {approx} 0.042-0.045 mg mL-{superscript 1}), strong nitric oxide radical scavenging by the acetonic fraction (IC = 0.045 mg mL-{superscript 1}), and lipoxygenase inhibition ([~]41%, for a fraction concentration of 0.25 mg mL-), suggesting a potential contribution of these fractions to modulate inflammation-related pathways. Additionally to this results, the polyphasic analysis permitted to confirm previous data that Pseudanabaena and Limnothrix represent the same generic entity. Both genera clustered together, presented high 16S rRNA gene identity (up to 99.9%) and share the same morphological and ecological features. Consequently, we formally proposed the synonimization of Limnothrix into Pseudanabaena.

The prediction of phage-host interactions is key for several applications in biotechnology, medicine, and microbial ecology. Wide studies in machine learning tools have allowed the exploration of these interactions across multiple taxonomic levels. A systematic review and meta-analysis were conducted on 570 records retrieved from PubMed, Scopus, and Web of Science. Eleven studies were selected for the meta-analysis, encompassing 61 datasets. Precision across taxonomic levels (Domain, Phylum, Class, Order, Family, Genus, Species) was evaluated for several prediction tools. Statistical tests, including the Shapiro-Wilk and ANOVA tests, were used. A mixed-effects meta-regression model was used to examine the impact of taxonomic subgroups on the prediction of the proportion of Correctly Predicted PHIs. The results indicated significant variability in the performance of prediction tools across taxonomic levels. Domain-level predictions exhibited near-perfect Proportion of Correctly Predicted PHIs (0.99), whereas finer resolutions (Family and Order) showed considerable variability, with average precision values of 0.682 and 0.775, respectively. The mixed-effects meta-regression analysis revealed that Family and Species taxonomic subgroups were associated with significant reductions in the prediction Proportion of Correctly Predicted PHIs with effect sizes of -0.1464 and -0.1944, respectively. Residual heterogeneity was negligible, indicating that the moderators adequately explained the variability in prediction precision. This study highlights the importance of selecting the appropriate prediction tool based on the desired taxonomic resolution. The findings emphasize the need for further refinement of prediction algorithms, particularly at the Family and Species levels, where tools exhibit the most variability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/721508v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@4105bforg.highwire.dtl.DTLVardef@e07c46org.highwire.dtl.DTLVardef@1ff139corg.highwire.dtl.DTLVardef@1608690_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract.C_FLOATNO Overview of the systematic review and meta-analysis framework evaluating ML-based phage-host interaction prediction tools across taxonomic levels. C_FIG

AbstractEmergomyces africanus is a thermally dimorphic fungal pathogen endemic to Southern Africa which can cause fatal systemic infections in persons with advanced HIV disease. Its mechanisms of pathogenesis are not well understood. Characterisation of virulence traits in this pathogen requires appropriate molecular tools for genetic manipulation. Molecular technologies developed for the transformation of H. capsulatum were adapted for use in E. africanus. Agrobacterium-mediated transformation was used to generate a reporter strain expressing green fluorescent protein (GFP). The E. africanus GFP reporter strain facilitated the study of yeast interaction with macrophages in vitro and allowed the identification of infected phagocyte cell types in the mouse lung by flow cytometry. E. africanus could also maintain episomal plasmids with telomere-like sequences, to introduce expression constructs without genome modification. Using this plasmid system, RNA interference constructs were used to knock down the expression of cell wall (1,3)-glucan by targeting the transcripts of the -glucan synthase (AGS1). An episomal CRISPR/Cas9 system was evaluated for E. africanus, which effectively disrupted GFP in a reporter strain and enabled the generation of a URA5 uracil auxotroph. These tools and strains will facilitate future studies to elucidate the mechanisms of pathogenesis of E. africanus. ImportanceEmergomyces africanus is an opportunistic fungal pathogen affecting persons with advanced HIV disease in South Africa. The biology and pathogenesis of E. africanus are not well understood, as the importance of the disease caused by this fungus (emergomycosis) has only been recognised in recent years and molecular studies have been impaired by the lack of genetic technologies. In this work, we describe tools and methods for the genetic modification of this pathogen, which will accelerate future studies investigating how the fungus causes disease in the human host. These essential tools include (1) the ability to create fluorescent reporter strains, such as the green fluorescent protein E. africanus strain described here, which facilitates tracking the spread of the fungus during infection and enhances microscopy studies, (2) methods for knocking down gene expression in E. africanus, and (3) the permanent disruption of genes through CRISPR/Cas9 gene editing.

Ralstonia solanacearum species complex (RSSC) is a genetically diverse group of plant pathogens, yet genomic data from South America remain limited. Here, we characterize 13 RSSC strains isolated from tomato, pepper, and eggplant in northeastern Argentina. Phylogenetic analysis of the egl marker gene assigned these strains to phylotype IIA and suggested two closely related lineages. Complete genomes (5.63-5.76 Mb) were generated for four representative strains, yielding high-quality (99.94% completeness with f_Burkholderiaceae CheckM markers), closed assemblies with canonical bipartite architecture. Phylogenetic analysis of the egl marker, 49 conserved bacterial genes, and average nucleotide identity (ANI) analyses, consistently assigned one lineage to sequevar IIA-50, forming a coherent and monophyletic group. In contrast, although egl analysis suggested the second lineage was related to one sequevar IIA-38 reference strain, genomic analysis did not support this assignment. Further, the genomic analysis revealed significant genomic distance between the genomes for two sequevar 38 representative strains, supporting a conclusion that sequevar 38 itself was not monophyletic and instead appears paraphyletic. These findings highlight limitations of single-locus classification and support genome-informed refinement of RSSC sub-phylotype taxonomy. Outcome statementReports of bacterial wilt disease in Argentina had not yet been published in the international literature although the disease has been long-standing. This study provides complete genome sequences for four Ralstonia solanacearum strains from Northern Argentina and places them within a global phylogenomic framework. The Argentine strains cluster into two closely related phylotype IIA lineages, indicating that bacterial wilt in this regional dataset is associated with genetically similar populations. For clear communication of which strains are present in Northern Argentina, we attempted to classify the lineages to the long-standing sequence variant (sequevar) system for naming R. solanacearum species complex (RSSC) strains. One lineage was confidently assigned to IIA-50 with genomic support that confirmed phylogenetic analysis of the classical genetic marker egl. However, newly available genomes for sequevar reference strains revealed an issue where two distantly related strains are currently recognized as references for sequevars. Overall, these results provide evidence supporting the need for genome-informed refinement of sub-phylotype classification and expand genomic representation of South American RSSC populations. Data summaryComplete genome assemblies and raw reads for INTABV18, INTABV29, INTABV624 and INTABV2657 are deposited to NCBI under the project number PRJNA1407867. The curated dataset of public RSSC genomes is available to users who register a free account on KBase via a KBase narrative (https://narrative.kbase.us/narrative/189849). The narrative described in a living BioRxiv pre-print [1]. Supplemental files such as Figure S1, rectangular versions of all trees (Figure 2 and 3 and S1) and supplementary table S1, S2, S3 and S4 are available on Zenodo at doi.org/10.5281/zenodo.19502890 O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/721750v1_figS1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1ac3168org.highwire.dtl.DTLVardef@1dfd0d6org.highwire.dtl.DTLVardef@107ae42org.highwire.dtl.DTLVardef@141937c_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure S1.C_FLOATNO Maximum-likelihood phylogenetic tree inferred from 471 bp of endoglucanase (egl) gene sequences assigned Argentine strains as phylotype II sequevar 38 and sequevar 50. The tree was constructed using PhyML v3.0 under the GTR nucleotide substitution model with gamma-distributed rate heterogeneity ( = 0.33), as selected by the SMART model selection procedure implemented in PhyML (Lefort et al., 2017). The egl sequences from Argentine strains are highlighted in blue, and their corresponding GenBank accession numbers for both the egl nucleotide sequence and the whole-genome assembly are shown in parentheses. Reference egl sequences representing sequevars IIA-38 (CFBP6801 and CIP120) and IIA-50 (T1-UY and ACH1076) are also shown in bold and marked with yellow circles. A searchable PDF of this tree in rectangular format is available on Zenodo (doi.org/10.5281/zenodo.19502890). C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/721750v1_fig2.gif" ALT="Figure 2"> View larger version (53K): org.highwire.dtl.DTLVardef@39d776org.highwire.dtl.DTLVardef@170bd89org.highwire.dtl.DTLVardef@aba166org.highwire.dtl.DTLVardef@1f156dd_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 2.C_FLOATNO Maximum-likelihood phylogenetic tree inferred from 710 bp of endoglucanase (egl) gene sequences assigned Argentine strains as phylotype II sequevar 38 and sequevar 50. The phylogenetic tree was constructed using PhyML v3.0 under the GTR+R nucleotide substitution model, as selected by the SMART model selection procedure (Lefort et al., 2017). egl sequences from four Argentine strains (INTABV18, INTABV29, INTABV624, and INTABV2657) are shown in bold and highlighted in blue. Reference egl sequences representing sequevars IIA-38 (CFBP6801 and CIP120) and IIA-50 (T1-UY and ACH1076) are also shown in bold and marked with yellow circles. Two USA strains identified as IIA-38 (UCD576 and RS124) are shown in bold. A searchable PDF of this tree in rectangular format is available on Zenodo (doi.org/10.5281/zenodo.19502890). C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/721750v1_fig3.gif" ALT="Figure 3"> View larger version (37K): org.highwire.dtl.DTLVardef@17dd372org.highwire.dtl.DTLVardef@1c5156corg.highwire.dtl.DTLVardef@179d9org.highwire.dtl.DTLVardef@e6d529_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 3.C_FLOATNO Approximate maximum-likelihood phylogeny based on a concatenated alignment of 49 conserved genes places four Argentine genomes (INTABV18, INTABV29, INTABV624 and INTABV2657) within the phylotype IIA clade. The tree was constructed using the SpeciesTreeBuilder v0.1.4 application on the KBase platform, incorporating the four Argentine genomes into a reference dataset of 825 genomes representing the known global diversity of the RSSC. The tree was visualized and annotated using iTOL v7.4.2. Argentine genomes are shown in bold and highlighted in blue, and egl reference strains for the sequevar IIA-38 (CIP120 and CFBP6801) and IIA-50 (T1-UY) are shown in bold and marked with yellow circles. Branches with approximate likelihood-ratio support values higher than >70% are colored in blue. A searchable PDF of this tree in rectangular format is available on Zenodo (doi.org/10.5281/zenodo.19502890). C_FIG

Bactrocera zonata (Saunders) (Diptera: Tephritidae) poses a significant threat to global fruit production due to its high reproductive capacity and broad host range. This study aimed to evaluate the effects of gamma irradiation on key biological parameters of B. zonata. Six-day-old pupae were exposed to irradiation doses of 0, 30, 40, 50, 60, and 70 Gy, and subsequent developmental and reproductive traits were assessed to determine the impact of irradiation. Post-irradiation results revealed a dose-dependent trend. Higher doses ([≥]50 Gy) significantly reduced adult emergence, increased the incidence of partially emerged or deformed adults, and shortened adult longevity. Reproductive potential was significantly impaired in males irradiated at 60 and 70 Gy when mated with un-irradiated females, resulting in a marked decline in both fecundity and egg hatchability. Females irradiated at doses [≥]50 Gy failed to produce eggs when paired with either irradiated or non-irradiated males, indicating a high level of radio-sensitivity in female flies. Additionally, several traits in the F1 generation such as pupal recovery, pupal size, and adult development exhibited significant abnormalities and suggesting that the effects of irradiation may be transmitted to the next generation. Sterility was highest in males irradiated at 60 and 70 Gy, while females exhibited complete sterility at doses exceeding 40 Gy. The findings indicate that a dose of 70 Gy may be optimal for effective sterility induction in B. zonata. However, further detailed studies are required to standardize this dose, incorporating rigorous quality control measures to optimize its application in sterile insect technique (SIT) programs.

BackgroundThe plethora of Escherichia coli (E. coli) strains that show multidrug resistance (MDR) has risen. The production of extended-spectrum beta-lactamases (ESBL) enzymes has greatly aided in this. There have been speculations on the effectiveness of silver nanoparticles in treating drug-resistant infections. AimThis research aims to utilize Azadirachta indica (neem) leaf extract for the production of silver nanoparticles (AI-AgNPs), considering its medicinal and antimicrobial properties. Additionally, this research intends to evaluate the efficacy of these nanoparticles on resistant E. coli infections. MethodThe antimicrobial activities and cytotoxicity of silver nanoparticles synthesized using neem leaves extract were tested on MDR and ESBL producing E. coli strains, as well as on Human Embryonic Kidney-293 (HEK-239) cell line, respectively. The characterization of silver nanoparticles was done by UV-Vis Spectrophotometry, Fourier-transform infrared spectrometry (FTIR), Dynamic Light Scattering-Zeta Potential (DLS-Zeta), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Energy Dispersive X-Ray Spectroscopy (EDAX). ResultsThe synthesized nanoparticles were spherical, smooth, and stable with an average size of approximately 74 nm. The Minimum inhibitory concentration (MIC) of AI-AgNPs was 9.5 {micro}g/ml, and the Minimum bactericidal concentration (MBC) was 121 {micro}g/ml. The IC50 value for AgNPs was 369 {micro}g/mL for HEK-293 cell line exposure. ConclusionThis study showed that the biosynthesis of silver nanoparticles from A. indica extract is highly effective, exhibiting strong antibacterial activity against multidrug-resistant bacteria while exhibiting low toxicity to normal human kidney cells. Hence, biosynthesized silver nanoparticles may be useful as antimicrobial materials for infection control because of their remarkable antibacterial activity.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, can use host derived lipids as carbon and energy source for survival. Mammalian cell entry (Mce) associated membrane (Mam) proteins are important for the stability of lipid importing Mce complexes. Mtb has five homologs of Mam proteins referred as orphaned Mam (OmamA-E) proteins. A recent study suggested that OmamC (Rv1363c) is essential for the storage and utilization of lipids under starvation in Mtb. To understand the structure and interactions of OmamC, we generated a truncated soluble variant of OmamC (OmamC129-261). Here, we report on the challenges encountered during the crystallization and structure determination of OmamC129-261 and the strategies applied to overcome them. Despite the AlphaFold2 predicted model proving an initial molecular replacement solution, experimental phasing was necessary to determine the structure of OmamC129-261. Heat treatment of protein prior to crystallization setup removed partially unfolded protein present and played a critical role in enhancing the reproducibility and diffraction quality of OmamC129-261 crystals. Although reported earlier, it is not a widely used method. It is worth to try this method, especially, when faced with poor reproducibility and diffraction of crystals.

Purine moieties are essential for many functions within the eukaryotic cell, including energy, signaling and nucleic acid synthesis. While purine starvation is known to induce stress resistance in eukaryotic model organism budding yeast Saccharomyces cerevisiae, it remains unclear whether the physiological response is related to disruption of synthesis pathway in particular position or it is uniform across all genetic deficiencies within the de novo adenine biosynthesis pathway. It is also not known how purine starved cells perceive purine shortage - weather they share the same signaling elements with nitrogen starvation or not. MethodsWe characterised physiology of strains with deletions in adenine biosynthesis pathway when cultivated in full or purine deficient and compared to cell physiological parameters when cultivated in nitrogen deficient media. We tested stress tolerance, carbon flux, cell cycle arrest and did transcription profiling (RNA-seq). ResultsOur findings demonstrate that purine starvation-induced stress resistance is significantly modulated by the specific step at which the pathway is interrupted. Transcriptional analysis revealed that purine starvation in many aspects phenocopies nitrogen starvation, particularly - in both starvations strong downregulation of ribosome related genes occurs. In the same time several metabolic features which differ from N- and ade- starvations: pentose phosphate pathway is specifically upregulated within ade4{Delta}-ade2{Delta} and downregulated in N-cells. Notably, the expression of stress-responsive genes such as HSP12, HSP26, and GRE1 varied between mutants, suggesting that the accumulation of pathway intermediates (e.g., AIR in ade2{Delta}) or the absence of downstream precursors (AICAR) alters the perception of starvation especially in the case of ade16{Delta}ade17{Delta} strain. ConclusionsMetabolic and stress-tolerance phenotypes of purine auxotrophs are not merely a result of purine depletion but seems that the response is signalled via the same pathways, like TOR1. The results suggest that strains having mutations within various positions of the purine pathway "perceive" purine limitation a bit differently - especially when we compare the end of the pathway with the other mutants. Different phenotypic outcomes of the occasional purine depletion might give preferences for organisms which have mutations in the beginning rather at the end of the pathway. Besides, our findings might have implications in the design of synthetic pathways and the use of auxotrophic markers in yeast research.

Background The COVID-19 pandemic has caused significant global mortality. Despite declining infection rates, new variants of SARS-CoV-2 continue to emerge, necessitating new prevention strategies. Objective This study aimed to evaluate the effect of four over-the-counter (OTC) antiseptic mouthwash/gargling solutions in the U.S., compared with a distilled water control, on SARS-CoV-2 viral load across multiple oral and oropharyngeal sample types. Methods This pilot single-center randomized controlled clinical trial enrolled adults in the San Francisco Bay Area, California, who tested positive for COVID-19. Participants were randomized to distilled water, chlorine dioxide, hydrogen peroxide, cetylpyridinium chloride, and essential oils. Participants were instructed to rinse and gargle four times daily for four weeks using standardized instructions to ensure protocol adherence. Samples were collected on Days 1, 7, and 28 and analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The primary outcome was the change in SARS-CoV-2 viral load from baseline to Day 28, assessed using cycle threshold (Ct) values. Secondary outcomes included self-reported clinical symptoms and hospitalization. Results Forty-nine participants completed the study. No mouthwash demonstrated a statistically significant reduction in SARS-CoV-2 viral load over time. Cetylpyridinium chloride showed a transient increase in Ct values on Day 7 that was not sustained on Day 28. At baseline, throat swab samples had the lowest Ct values across all sample types. Due to limited subgroup sample sizes for secondary outcome measures, no statistical or moderator analyses were conducted. Conclusion Further large-scale randomized trials are needed before recommending antiseptic mouthwashes for SARS-CoV-2 prevention or management.

Species of Bacillus bacteria including Bacillus safensis and Bacillus subtilis are finding increasing uses in biotechnology and bioremediation, thanks in part to their metabolic robustness. Malate dehydrogenase (MDH) is at the heart of central metabolism and thus a better understanding of Bacillus MDH proteins could aid in the optimization of these applications. MDH of Bacillus spp. belong to the lactate dehydrogenase (LDH)-like class of MDHs, otherwise known as the MDH3 class. Despite wide prevalence in nature among prokaryotes and archaea, this typically homotetrameric class is understudied compared to the MDH1 and MDH2 classes found in eukaryotes. We therefore recombinantly expressed and purified MDH proteins from two societally relevant Bacillus spp.-B. safensis and B. subtilis-and characterized them biophysically (via Size Exclusion Chromatography-Small Angle X-ray Scattering (SEC-SAXS) and Differential Scanning Fluorimetry (DSF)) and enzymatically (via spectroscopic activity assays). As expected based on their high sequence identity, the two MDH orthologs had similar properties in most regards, including a tetrameric structure and high susceptibility to substrate inhibition. However, we uncovered differences in conditional thermal stability, in addition to subtle differences in enzymatic activity that offer insight into the workings of LDH-like MDH. Summary statementMalate dehydrogenase (MDH) is a fundamental metabolic enzyme, from microbes to mammals, yet comparably little is known about microbial MDH, especially MDH of the tetrameric MDH3 class. We compare the biophysical and enzymatic properties of two such enzymes from the societally relevant bacterial species Bacillus subtilis and Bacillus safensis, offering useful insight with potential biotechnological implications.

Staphylococcus aureus (S. aureus) is the most common pathogen associated with skin infections worldwide. Significant efforts have been made to identify and develop innovative therapeutic strategies against S. aureus as alternatives to conventional antibiotics. Physical plasma has a broad range of potential uses, with non-destructive disinfection being one of its earliest applications. Although the literature emphasizes the antibacterial properties of cold atmospheric plasma (CAP), the effect of plasma on S. aureus on damaged skin susceptible to S. aureus invasion through the itch-scratch cycle has not been studied to date. Thus, we examined the effectiveness of CAP treatment on S. aureus bacteria in atopic dermatitis lesions using floating electrode dielectric barrier discharge devices, as well as helium and argon plasma jets. Heat distribution on the skin target, ultraviolet C radiation, and ozone generation of plasma jets for the operator of plasma sources were evaluated. Microbial tests confirmed the presence of S. aureus on the lesions of the groups before treatment. The groups exposed to plasma treatment showed a notable reduction in bacterial population compared to the model group (p<0.05). Furthermore, our investigation indicated that plasma treatment reduced pruritus behavior. The findings suggest that cold atmospheric plasma treatment may potentially target skin infections caused by S. aureus in addition to conventional therapies.

Phage therapeutics are re-emerging as adjuncts or alternatives to antibiotics and their clinical translation will be enhanced with production methods that minimise downstream processing. We evaluated whether an endotoxin-reduced E. coli strain developed for production of recombinant proteins, ClearColi(R), can serve as a useful, safe phage production host without compromising yield and whether targeted receptor complementation can expand its utility. The parent strain BL21(DE3), and its lipid A modified derivative, ClearColi(R), were compared with respect to infection and generation of phage. Across a panel of 31 phage, a similar host range was observed between BL21(DE3) and ClearColi(R). To expand host range ompC was genetically engineered into the chromosome of ClearColi(R), thereby adding OmpC-dependent phage to its production capacity. Production metrics were broadly comparable between the hosts; efficiency of plating and final titres for representative phage were not significantly different; burst size varied by phage but without consistent host bias. Endotoxin activity in ClearColi(R)-propagated lysates was reduced by over 1000-fold relative to BL21(DE3), reaching the low hundreds of endotoxin units (EU) versus hundreds of thousands for BL21(DE3). Intravesical administration of ClearColi(R)-derived phage (LUC4) into pigs elicited no clinical abnormalities and no significant increases in circulating cytokines up to 48 hours after administration. ClearColi(R) allows efficient production of diverse phage with low endotoxin, reducing the requirement for downstream processing. Although its minimal LPS reduces its capacity for producing some LPS-dependent phage and its growth is slower than BL21(DE3), requiring optimisation for maximal phage titre, the safety and simplified manufacturing process support further development of endotoxin modified strains for phage production. Impact statementAntibiotic resistance is a current global problem and treatments based on phage and phage products already have a proven track record with particular bacterial infections, especially in the urinary tract. While progress is being made on in vitro phage synthesis, large scale bacteriophage preparations require a bacterial host for production, consequently toxic components in the initial lysate need to be removed or significantly diluted for safe clinical use. This is a study of the potential to utilise an endotoxin-reduced E. coli strain, ClearColi(R), to produce safer phage therapeutics. Such endotoxin modified strains should minimise the processing steps required and reduce overall production costs of a phage preparation. The research demonstrates that the endotoxin-reduced strain was able to produce a wide range of phage and for studied examples at phage titres equivalent to the more toxic parent strain. We also show that the strain can be modified to increase its host range and confirm the very low endotoxicity of basic phage lysates produced by the strain. Replicating this process to engineer additional low-toxicity bacterial production strains will accelerate the development of safer, more cost-effective phage therapeutics.

Industrial waste containing hydrophobic pollutants, like oils and hydrocarbons, is toxic and difficult to degrade, posing both ecological and human health risks. Biosurfactants are eco-friendly surface-active compounds produced by microorganisms, known for their ability to lower surface and interfacial tension, enhancing the solubility and bioavailability of hydrophobic compounds, facilitating their breakdown. The current study focuses on isolating biosurfactant-producing bacteria from industrial waste sources near Dhaka, Bangladesh, and characterizing their properties, determining potential usage. Using diesel-enriched nutrient agar, bacterial strains were isolated and screened for biosurfactant production by oil displacement, emulsification index (E24%), and drop collapse assay. The most promising isolates were characterized according to their biochemical activities and 16S rRNA amplicon-based sequencing. Isolation and characterization of the surfactants have been carried out using chromatographic techniques. The identified bacteria passed the drop collapse and oil displacement tests. CTAB agar assay, indicates their anionic nature, showing an emulsification index ranging 10-41%. The potential biosurfactant producers belong to Bacillus, Pseudomonas, Acinetobacter, and Enterobacterium genera. The surfactants showed antibacterial, antifungal, and plant growth promotion activity and have been characterized in terms of pH stability, salinity, adhesion, and temperature tolerance. The study successfully identified and characterized potential biosurfactant-producing bacteria from industrial waste, highlighting their efficiency in breaking down hydrophobic pollutants and hydrocarbons. These microorganisms provide a green and economical substitute for synthetic surfactants due to their biodegradability and lower toxicity. Upon further research and scaling, these bacteria can be a good source of biosurfactants for potential applications in industrial, agricultural, and biomedical fields. IMPORTANCEThe study carries high significance as it creates multi-disciplinary scopes for utilizing these environmentally adapted biosurfactant-producing bacteria in industry, agriculture, and medicine. Since the bacterial isolates have hydrocarbon degradation ability, upon optimization for higher production, industrial usage in oil refinery and other industries can be adopted. Due to their biodegradable nature, usage in wound healing bandages and as antimicrobial agents in medicine will be noteworthy. The isolates have plant growth promotion ability and utilizing them as biofertilizer will reduce the dependency on chemical fertilizers. This is the first detailed report on biosurfactant-producing bacteria from this industrial waste-polluted Turag River of Dhaka City. Moreover, it compiles detailed screening protocols and methods for analyzing such environmentally friendly microbes. Such characterization also opens the scope for optimizing the production of the surfactant compounds on a large scale and utilizing them commercially.

Pseudomonas aeruginosa is a clinically significant bacterial pathogen that poses a serious threat to aquaculture. However, there are limited information on Massilia isolates against pathogenic P. aeruginosa in aquaculture. In the present study, a facultative predator, M. varians isolate P2-4, was isolated from aquaculture sediment using Chinese mitten crab Eriocheir sinensis-pathogenic P. aeruginosa as the prey bacterium, and its genomic feature, bacteriolysis-related genes, safety, bacteriolytic spectrum, and in vitro and in vivo antibacterial effects against pathogenic P. aeruginosa in E. sinensis were further characterized. Isolate P2-4 consisted of one chromosome and one plasmid (with a total of 75 tRNAs, 7 5S rRNAs, 7 16S rRNAs, 7 23S rRNAs, 34 sRNAs, 5,238 coding genes, 20 genomic islands, 1 prophage, 23 insertion sequences, and 102 repeat sequences), and harbored 19 bacteriolysis-related genes (pilA, pilB, pilC, pilD, pilF, pilG, pilH, pilM, pilO, pilP, pilQ, pilS, pilR, pilT, mltA, mltB, mltC, mltD, and dacB) associated with cellular motility and cell wall lysis. In addition, the isolate carried no virulence genes, was unable to produce haemolysin, hydrogen sulfide, nitrite and ammonia, and avirulent in E. sinensis with a 7-day acute intraperitoneal LD50 value of above 5.0 x 108 CFU/mL. Furthermore, the isolate possessed a wide bacteriolytic spectrum against pathogenic Shewanella algae, Aeromonas caviae, A. hydrophila, and Photobacterium damselae besides P. aeruginosa, exhibited bacteriolysis rates of 99.35% to 99.99% towards the pathogenic P. aeruginosa at 1.0x103 to 1.0x10{square} CFU/mL, and displayed relative percentage survivals of 42.31% to 73.08% against P. aeruginosa infection in E. sinensis at doses of 6.0 x 103 to 6.0 x 105 CFU/g diet. To our knowledge, this study for the first time demonstrates a M. varians strain as a potential biocontrol agent against pathogenic P. aeruginosa in aquaculture.

A compact, in-house developed ultraviolet germicidal irradiation (UVGI) system adaptable to static, mobile, or robotic platforms was developed for the effective sterilization of bacteria and fungi using a wireless mode of operation. Under controlled laboratory conditions, its efficacy was evaluated against three representative biofilm-forming pathogens: Bacillus subtilis (Gram-positive, spore-forming, motile bacterium), Escherichia coli K12 (Gram-negative, non-spore-forming, non-motile bacterium), and Candida albicans M-207 (multi-drug-resistant, clinical yeast isolate). Microbial viability following UVGI exposure was assessed using colony-forming unit (CFU) and MTT assays, and morphological alterations were characterized by scanning electron microscopy (SEM). Cultures were exposed to UV-C radiation at distances of 1-5 m for 15-90 min. CFU assay demonstrated 100% kill of all tested organisms at 1 m and 15 min, corresponding to doses of 600.3, 576 & 697.5 mJ/cm{superscript 2}. Although MTT assays indicated residual metabolic activity under the same conditions, CFU results confirmed that surviving cells were unable to proliferate, highlighting the robustness of UV treatment for long-term inactivation. SEM confirmed distinct morphological alterations such as complete destruction of extracellular matrix & reduction in number of cells indicating cell death with increase in UV dose as compared to controls. A dose & time-dependent inactivation of biofilm-forming bacteria & fungi was observed on exposure to UVGI. Therefore, this pilot study validates the effectiveness of the newly developed UVGI surface sterilizer against biofilm-forming bacterial and fungal pathogens. Overall, the system demonstrates proof-of-concept efficacy under laboratory conditions and holds strong potential for future development and validation in hospitals and other contaminated public spaces. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/715580v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@150cefcorg.highwire.dtl.DTLVardef@450831org.highwire.dtl.DTLVardef@1cfd6borg.highwire.dtl.DTLVardef@1419ba8_HPS_FORMAT_FIGEXP M_FIG C_FIG IMPORTANCEMicroorganisms that form biofilms on surfaces are difficult to eliminate and contribute to the spread of infections in healthcare and indoor environments. There is a need for practical, easy-to-use disinfection technologies that can effectively reduce such contamination. In this study, we developed a compact, in-house, wireless UV-C disinfection system designed for flexible operation across different surface types. The system was evaluated under controlled laboratory conditions using representative biofilm-forming bacterial and fungal pathogens. Our findings show that the system can effectively reduce microbial contamination, demonstrating proof-of-concept efficacy. This work highlights the potential of accessible, non-chemical UV-based technologies and supports their further validation for applications in real-world disinfection settings.

BackgroundThere is currently no approved antiviral therapy against measles virus (MeV). Repurposing available compounds with broad antiviral activity may rapidly identify candidate drugs for clinical evaluation. Here we evaluated the antiviral activity of the clinically approved drugs azelastine hydrochloride and zafirlukast as well as the flavonoids quercetin and isoquercetin against MeV in preventative and therapeutic in vitro studies. MethodsCompounds were tested for antiviral activity against MeV in preventative (prophylactic and virucidal) and therapeutic (steady-state and persistent) assays in Vero/hSLAM cells. Viral loads and cell viability were measured 48h post-infection, and dose-response curves were used to calculate EC50 values. Flavonoids were also tested in the presence of 1 mM ascorbic acid. ResultsAzelastine hydrochloride did not show evidence of antiviral activity against MeV under these conditions, whereas zafirlukast, quercetin, and isoquercetin showed therapeutic activity against MeV. The addition of ascorbic acid enhanced the therapeutic potency of quercetin to 4.2-4.8 {micro}M and of isoquercetin to 10.7-10.9 {micro}M. Antiviral activity was dose-dependent when administered post-infection. ConclusionAmong the four compounds tested, quercetin showed the most potent therapeutic antiviral activity against MeV in vitro. Isoquercetin and zafirkulast also showed therapeutic activity. These findings support further evaluation of quercetin, isoquercetin, and zafirlukast as candidate antiviral drugs for MeV and highlight the utility of in vitro platforms for rapid antiviral drug screening.

This study assessed the prevalence of antibiotic resistance genes (ARGs) and virulence factor genes (VFs), DNA viruses, and medically-relevant pathogens in three major cities around the globe - Mysuru (India), Dubai (United Arab Emirates), and Tucson (Arizona, United States of America). Ten households were sampled in each city, at ten sites in the bathroom, kitchen, and living spaces. The alpha diversity of ARGs significantly differed between household locations in each country (ANOVA, p<0.05) and beta diversity (dissimilarity) analysis showed a significant association between the ARGs and the geographic locations (PERMANOVA, p<0.01). A set of ARGs were found in every location across the dataset (the core ARG profile) included 25 different genes. The alpha diversity of virulence factors differed across the household locations within the three cities (ANOVA, p<0.01). The beta diversity of VFs was not well explained by geographic location or location within the household (PERMANOVA, p=0.129 (geographic), p=0.127 (household)). There were 341 unique VFs found in the study, but only 5 core VFs across the dataset. Bacterial pathogens detected across the household included Escherichia coli, Acinetobacter baumanii, Klebsiella pneumoniae, and more. The DNA (and bacteriophage) virome varied between countries and was more diverse in Tucson and Dubai (top viral families included Poxviridae and Orthoherpesviridae - two families which contain human pathogens - and Steitzviridae, a family of bacteriophages) compared to Mysuru, where nearly all viruses were a part of the Muvirus genus (a bacteriophage which contributes to horizontal gene transfer by phage transduction). ImportanceThe diversity of the built environment microbiome is not well characterized globally. Household occupants interact with the built microbiome on a daily basis, and the built microbiome may have the potential to influence human health. The presence of pathogens in the built environment and the key genes contributing to microorganism pathogenicity were investigated in this study, as information on this is lacking on an international scale. The diversity of ARG and VFs across the globe, as well as the presence of medically relevant pathogens within the house that were found in this study highlights the need to explore further the factors which influence the household microbiome, virome, and resistome. This may aid in identify how the build microbiome may be shaped by humans and influence human health. Impact StatementThis research contributes to the understanding of the built microbiome, specifically how it varies within the house, within cities, and across the globe. This can aid in our understanding of microbial dynamics in environments with heavy human influence and help develop and improve hygiene habits and products which are mindful of the existing microbiome.